~bzr-pqm/bzr/bzr.dev

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
# Copyright (C) 2005-2011 Canonical Ltd
#   Authors: Robert Collins <robert.collins@canonical.com>
#            and others
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Configuration that affects the behaviour of Bazaar.

Currently this configuration resides in ~/.bazaar/bazaar.conf
and ~/.bazaar/locations.conf, which is written to by bzr.

In bazaar.conf the following options may be set:
[DEFAULT]
editor=name-of-program
email=Your Name <your@email.address>
check_signatures=require|ignore|check-available(default)
create_signatures=always|never|when-required(default)
gpg_signing_command=name-of-program
log_format=name-of-format
validate_signatures_in_log=true|false(default)
acceptable_keys=pattern1,pattern2
gpg_signing_key=amy@example.com

in locations.conf, you specify the url of a branch and options for it.
Wildcards may be used - * and ? as normal in shell completion. Options
set in both bazaar.conf and locations.conf are overridden by the locations.conf
setting.
[/home/robertc/source]
recurse=False|True(default)
email= as above
check_signatures= as above
create_signatures= as above.
validate_signatures_in_log=as above
acceptable_keys=as above

explanation of options
----------------------
editor - this option sets the pop up editor to use during commits.
email - this option sets the user id bzr will use when committing.
check_signatures - this option will control whether bzr will require good gpg
                   signatures, ignore them, or check them if they are
                   present.  Currently it is unused except that check_signatures
                   turns on create_signatures.
create_signatures - this option controls whether bzr will always create
                    gpg signatures or not on commits.  There is an unused
                    option which in future is expected to work if               
                    branch settings require signatures.
log_format - this option sets the default log format.  Possible values are
             long, short, line, or a plugin can register new formats.
validate_signatures_in_log - show GPG signature validity in log output
acceptable_keys - comma separated list of key patterns acceptable for
                  verify-signatures command

In bazaar.conf you can also define aliases in the ALIASES sections, example

[ALIASES]
lastlog=log --line -r-10..-1
ll=log --line -r-10..-1
h=help
up=pull
"""

import os
import string
import sys


from bzrlib.decorators import needs_write_lock
from bzrlib.lazy_import import lazy_import
lazy_import(globals(), """
import fnmatch
import re
from cStringIO import StringIO

from bzrlib import (
    atomicfile,
    bzrdir,
    debug,
    errors,
    lazy_regex,
    lockdir,
    mail_client,
    mergetools,
    osutils,
    symbol_versioning,
    trace,
    transport,
    ui,
    urlutils,
    win32utils,
    )
from bzrlib.util.configobj import configobj
""")
from bzrlib import (
    commands,
    hooks,
    lazy_regex,
    registry,
    )
from bzrlib.symbol_versioning import (
    deprecated_in,
    deprecated_method,
    )


CHECK_IF_POSSIBLE=0
CHECK_ALWAYS=1
CHECK_NEVER=2


SIGN_WHEN_REQUIRED=0
SIGN_ALWAYS=1
SIGN_NEVER=2


POLICY_NONE = 0
POLICY_NORECURSE = 1
POLICY_APPENDPATH = 2

_policy_name = {
    POLICY_NONE: None,
    POLICY_NORECURSE: 'norecurse',
    POLICY_APPENDPATH: 'appendpath',
    }
_policy_value = {
    None: POLICY_NONE,
    'none': POLICY_NONE,
    'norecurse': POLICY_NORECURSE,
    'appendpath': POLICY_APPENDPATH,
    }


STORE_LOCATION = POLICY_NONE
STORE_LOCATION_NORECURSE = POLICY_NORECURSE
STORE_LOCATION_APPENDPATH = POLICY_APPENDPATH
STORE_BRANCH = 3
STORE_GLOBAL = 4


class ConfigObj(configobj.ConfigObj):

    def __init__(self, infile=None, **kwargs):
        # We define our own interpolation mechanism calling it option expansion
        super(ConfigObj, self).__init__(infile=infile,
                                        interpolation=False,
                                        **kwargs)

    def get_bool(self, section, key):
        return self[section].as_bool(key)

    def get_value(self, section, name):
        # Try [] for the old DEFAULT section.
        if section == "DEFAULT":
            try:
                return self[name]
            except KeyError:
                pass
        return self[section][name]


# FIXME: Until we can guarantee that each config file is loaded once and
# only once for a given bzrlib session, we don't want to re-read the file every
# time we query for an option so we cache the value (bad ! watch out for tests
# needing to restore the proper value). -- vila 20110219
_expand_default_value = None
def _get_expand_default_value():
    global _expand_default_value
    if _expand_default_value is not None:
        return _expand_default_value
    conf = GlobalConfig()
    # Note that we must not use None for the expand value below or we'll run
    # into infinite recursion. Using False really would be quite silly ;)
    expand = conf.get_user_option_as_bool('bzr.config.expand', expand=True)
    if expand is None:
        # This is an opt-in feature, you *really* need to clearly say you want
        # to activate it !
        expand = False
    _expand_default_value = expand
    return expand


class Config(object):
    """A configuration policy - what username, editor, gpg needs etc."""

    def __init__(self):
        super(Config, self).__init__()

    def config_id(self):
        """Returns a unique ID for the config."""
        raise NotImplementedError(self.config_id)

    @deprecated_method(deprecated_in((2, 4, 0)))
    def get_editor(self):
        """Get the users pop up editor."""
        raise NotImplementedError

    def get_change_editor(self, old_tree, new_tree):
        from bzrlib import diff
        cmd = self._get_change_editor()
        if cmd is None:
            return None
        return diff.DiffFromTool.from_string(cmd, old_tree, new_tree,
                                             sys.stdout)

    def get_mail_client(self):
        """Get a mail client to use"""
        selected_client = self.get_user_option('mail_client')
        _registry = mail_client.mail_client_registry
        try:
            mail_client_class = _registry.get(selected_client)
        except KeyError:
            raise errors.UnknownMailClient(selected_client)
        return mail_client_class(self)

    def _get_signature_checking(self):
        """Template method to override signature checking policy."""

    def _get_signing_policy(self):
        """Template method to override signature creation policy."""

    option_ref_re = None

    def expand_options(self, string, env=None):
        """Expand option references in the string in the configuration context.

        :param string: The string containing option to expand.

        :param env: An option dict defining additional configuration options or
            overriding existing ones.

        :returns: The expanded string.
        """
        return self._expand_options_in_string(string, env)

    def _expand_options_in_list(self, slist, env=None, _ref_stack=None):
        """Expand options in  a list of strings in the configuration context.

        :param slist: A list of strings.

        :param env: An option dict defining additional configuration options or
            overriding existing ones.

        :param _ref_stack: Private list containing the options being
            expanded to detect loops.

        :returns: The flatten list of expanded strings.
        """
        # expand options in each value separately flattening lists
        result = []
        for s in slist:
            value = self._expand_options_in_string(s, env, _ref_stack)
            if isinstance(value, list):
                result.extend(value)
            else:
                result.append(value)
        return result

    def _expand_options_in_string(self, string, env=None, _ref_stack=None):
        """Expand options in the string in the configuration context.

        :param string: The string to be expanded.

        :param env: An option dict defining additional configuration options or
            overriding existing ones.

        :param _ref_stack: Private list containing the options being
            expanded to detect loops.

        :returns: The expanded string.
        """
        if string is None:
            # Not much to expand there
            return None
        if _ref_stack is None:
            # What references are currently resolved (to detect loops)
            _ref_stack = []
        if self.option_ref_re is None:
            # We want to match the most embedded reference first (i.e. for
            # '{{foo}}' we will get '{foo}',
            # for '{bar{baz}}' we will get '{baz}'
            self.option_ref_re = re.compile('({[^{}]+})')
        result = string
        # We need to iterate until no more refs appear ({{foo}} will need two
        # iterations for example).
        while True:
            raw_chunks = self.option_ref_re.split(result)
            if len(raw_chunks) == 1:
                # Shorcut the trivial case: no refs
                return result
            chunks = []
            list_value = False
            # Split will isolate refs so that every other chunk is a ref
            chunk_is_ref = False
            for chunk in raw_chunks:
                if not chunk_is_ref:
                    if chunk:
                        # Keep only non-empty strings (or we get bogus empty
                        # slots when a list value is involved).
                        chunks.append(chunk)
                    chunk_is_ref = True
                else:
                    name = chunk[1:-1]
                    if name in _ref_stack:
                        raise errors.OptionExpansionLoop(string, _ref_stack)
                    _ref_stack.append(name)
                    value = self._expand_option(name, env, _ref_stack)
                    if value is None:
                        raise errors.ExpandingUnknownOption(name, string)
                    if isinstance(value, list):
                        list_value = True
                        chunks.extend(value)
                    else:
                        chunks.append(value)
                    _ref_stack.pop()
                    chunk_is_ref = False
            if list_value:
                # Once a list appears as the result of an expansion, all
                # callers will get a list result. This allows a consistent
                # behavior even when some options in the expansion chain
                # defined as strings (no comma in their value) but their
                # expanded value is a list.
                return self._expand_options_in_list(chunks, env, _ref_stack)
            else:
                result = ''.join(chunks)
        return result

    def _expand_option(self, name, env, _ref_stack):
        if env is not None and name in env:
            # Special case, values provided in env takes precedence over
            # anything else
            value = env[name]
        else:
            # FIXME: This is a limited implementation, what we really need is a
            # way to query the bzr config for the value of an option,
            # respecting the scope rules (That is, once we implement fallback
            # configs, getting the option value should restart from the top
            # config, not the current one) -- vila 20101222
            value = self.get_user_option(name, expand=False)
            if isinstance(value, list):
                value = self._expand_options_in_list(value, env, _ref_stack)
            else:
                value = self._expand_options_in_string(value, env, _ref_stack)
        return value

    def _get_user_option(self, option_name):
        """Template method to provide a user option."""
        return None

    def get_user_option(self, option_name, expand=None):
        """Get a generic option - no special process, no default.

        :param option_name: The queried option.

        :param expand: Whether options references should be expanded.

        :returns: The value of the option.
        """
        if expand is None:
            expand = _get_expand_default_value()
        value = self._get_user_option(option_name)
        if expand:
            if isinstance(value, list):
                value = self._expand_options_in_list(value)
            elif isinstance(value, dict):
                trace.warning('Cannot expand "%s":'
                              ' Dicts do not support option expansion'
                              % (option_name,))
            else:
                value = self._expand_options_in_string(value)
        for hook in OldConfigHooks['get']:
            hook(self, option_name, value)
        return value

    def get_user_option_as_bool(self, option_name, expand=None, default=None):
        """Get a generic option as a boolean.

        :param expand: Allow expanding references to other config values.
        :param default: Default value if nothing is configured
        :return None if the option doesn't exist or its value can't be
            interpreted as a boolean. Returns True or False otherwise.
        """
        s = self.get_user_option(option_name, expand=expand)
        if s is None:
            # The option doesn't exist
            return default
        val = ui.bool_from_string(s)
        if val is None:
            # The value can't be interpreted as a boolean
            trace.warning('Value "%s" is not a boolean for "%s"',
                          s, option_name)
        return val

    def get_user_option_as_list(self, option_name, expand=None):
        """Get a generic option as a list - no special process, no default.

        :return None if the option doesn't exist. Returns the value as a list
            otherwise.
        """
        l = self.get_user_option(option_name, expand=expand)
        if isinstance(l, (str, unicode)):
            # A single value, most probably the user forgot (or didn't care to
            # add) the final ','
            l = [l]
        return l
        
    def get_user_option_as_int_from_SI(self,  option_name,  default=None):
        """Get a generic option from a human readable size in SI units, e.g 10MB
        
        Accepted suffixes are K,M,G. It is case-insensitive and may be followed
        by a trailing b (i.e. Kb, MB). This is intended to be practical and not
        pedantic.
        
        :return Integer, expanded to its base-10 value if a proper SI unit is 
            found. If the option doesn't exist, or isn't a value in 
            SI units, return default (which defaults to None)
        """
        val = self.get_user_option(option_name)
        if isinstance(val, list):
            val = val[0]
        if val is None:
            val = default
        else:
            p = re.compile("^(\d+)([kmg])*b*$", re.IGNORECASE)
            try:
                m = p.match(val)
                if m is not None:
                    val = int(m.group(1))
                    if m.group(2) is not None:
                        if m.group(2).lower() == 'k':
                            val *= 10**3
                        elif m.group(2).lower() == 'm':
                            val *= 10**6
                        elif m.group(2).lower() == 'g':
                            val *= 10**9
                else:
                    ui.ui_factory.show_warning(gettext('Invalid config value for "{0}" '
                                               ' value {1!r} is not an SI unit.').format(
                                                option_name, val))
                    val = default
            except TypeError:
                val = default
        return val
        

    def gpg_signing_command(self):
        """What program should be used to sign signatures?"""
        result = self._gpg_signing_command()
        if result is None:
            result = "gpg"
        return result

    def _gpg_signing_command(self):
        """See gpg_signing_command()."""
        return None

    def log_format(self):
        """What log format should be used"""
        result = self._log_format()
        if result is None:
            result = "long"
        return result

    def _log_format(self):
        """See log_format()."""
        return None

    def validate_signatures_in_log(self):
        """Show GPG signature validity in log"""
        result = self._validate_signatures_in_log()
        if result == "true":
            result = True
        else:
            result = False
        return result

    def _validate_signatures_in_log(self):
        """See validate_signatures_in_log()."""
        return None

    def acceptable_keys(self):
        """Comma separated list of key patterns acceptable to 
        verify-signatures command"""
        result = self._acceptable_keys()
        return result

    def _acceptable_keys(self):
        """See acceptable_keys()."""
        return None

    def post_commit(self):
        """An ordered list of python functions to call.

        Each function takes branch, rev_id as parameters.
        """
        return self._post_commit()

    def _post_commit(self):
        """See Config.post_commit."""
        return None

    def user_email(self):
        """Return just the email component of a username."""
        return extract_email_address(self.username())

    def username(self):
        """Return email-style username.

        Something similar to 'Martin Pool <mbp@sourcefrog.net>'

        $BZR_EMAIL can be set to override this, then
        the concrete policy type is checked, and finally
        $EMAIL is examined.
        If no username can be found, errors.NoWhoami exception is raised.
        """
        v = os.environ.get('BZR_EMAIL')
        if v:
            return v.decode(osutils.get_user_encoding())
        v = self._get_user_id()
        if v:
            return v
        v = os.environ.get('EMAIL')
        if v:
            return v.decode(osutils.get_user_encoding())
        name, email = _auto_user_id()
        if name and email:
            return '%s <%s>' % (name, email)
        elif email:
            return email
        raise errors.NoWhoami()

    def ensure_username(self):
        """Raise errors.NoWhoami if username is not set.

        This method relies on the username() function raising the error.
        """
        self.username()

    def signature_checking(self):
        """What is the current policy for signature checking?."""
        policy = self._get_signature_checking()
        if policy is not None:
            return policy
        return CHECK_IF_POSSIBLE

    def signing_policy(self):
        """What is the current policy for signature checking?."""
        policy = self._get_signing_policy()
        if policy is not None:
            return policy
        return SIGN_WHEN_REQUIRED

    def signature_needed(self):
        """Is a signature needed when committing ?."""
        policy = self._get_signing_policy()
        if policy is None:
            policy = self._get_signature_checking()
            if policy is not None:
                #this warning should go away once check_signatures is
                #implemented (if not before)
                trace.warning("Please use create_signatures,"
                              " not check_signatures to set signing policy.")
        elif policy == SIGN_ALWAYS:
            return True
        return False

    def gpg_signing_key(self):
        """GPG user-id to sign commits"""
        key = self.get_user_option('gpg_signing_key')
        if key == "default" or key == None:
            return self.user_email()
        else:
            return key

    def get_alias(self, value):
        return self._get_alias(value)

    def _get_alias(self, value):
        pass

    def get_nickname(self):
        return self._get_nickname()

    def _get_nickname(self):
        return None

    def get_bzr_remote_path(self):
        try:
            return os.environ['BZR_REMOTE_PATH']
        except KeyError:
            path = self.get_user_option("bzr_remote_path")
            if path is None:
                path = 'bzr'
            return path

    def suppress_warning(self, warning):
        """Should the warning be suppressed or emitted.

        :param warning: The name of the warning being tested.

        :returns: True if the warning should be suppressed, False otherwise.
        """
        warnings = self.get_user_option_as_list('suppress_warnings')
        if warnings is None or warning not in warnings:
            return False
        else:
            return True

    def get_merge_tools(self):
        tools = {}
        for (oname, value, section, conf_id, parser) in self._get_options():
            if oname.startswith('bzr.mergetool.'):
                tool_name = oname[len('bzr.mergetool.'):]
                tools[tool_name] = self.get_user_option(oname)
        trace.mutter('loaded merge tools: %r' % tools)
        return tools

    def find_merge_tool(self, name):
        # We fake a defaults mechanism here by checking if the given name can
        # be found in the known_merge_tools if it's not found in the config.
        # This should be done through the proposed config defaults mechanism
        # when it becomes available in the future.
        command_line = (self.get_user_option('bzr.mergetool.%s' % name,
                                             expand=False)
                        or mergetools.known_merge_tools.get(name, None))
        return command_line


class _ConfigHooks(hooks.Hooks):
    """A dict mapping hook names and a list of callables for configs.
    """

    def __init__(self):
        """Create the default hooks.

        These are all empty initially, because by default nothing should get
        notified.
        """
        super(_ConfigHooks, self).__init__('bzrlib.config', 'ConfigHooks')
        self.add_hook('load',
                      'Invoked when a config store is loaded.'
                      ' The signature is (store).',
                      (2, 4))
        self.add_hook('save',
                      'Invoked when a config store is saved.'
                      ' The signature is (store).',
                      (2, 4))
        # The hooks for config options
        self.add_hook('get',
                      'Invoked when a config option is read.'
                      ' The signature is (stack, name, value).',
                      (2, 4))
        self.add_hook('set',
                      'Invoked when a config option is set.'
                      ' The signature is (stack, name, value).',
                      (2, 4))
        self.add_hook('remove',
                      'Invoked when a config option is removed.'
                      ' The signature is (stack, name).',
                      (2, 4))
ConfigHooks = _ConfigHooks()


class _OldConfigHooks(hooks.Hooks):
    """A dict mapping hook names and a list of callables for configs.
    """

    def __init__(self):
        """Create the default hooks.

        These are all empty initially, because by default nothing should get
        notified.
        """
        super(_OldConfigHooks, self).__init__('bzrlib.config', 'OldConfigHooks')
        self.add_hook('load',
                      'Invoked when a config store is loaded.'
                      ' The signature is (config).',
                      (2, 4))
        self.add_hook('save',
                      'Invoked when a config store is saved.'
                      ' The signature is (config).',
                      (2, 4))
        # The hooks for config options
        self.add_hook('get',
                      'Invoked when a config option is read.'
                      ' The signature is (config, name, value).',
                      (2, 4))
        self.add_hook('set',
                      'Invoked when a config option is set.'
                      ' The signature is (config, name, value).',
                      (2, 4))
        self.add_hook('remove',
                      'Invoked when a config option is removed.'
                      ' The signature is (config, name).',
                      (2, 4))
OldConfigHooks = _OldConfigHooks()


class IniBasedConfig(Config):
    """A configuration policy that draws from ini files."""

    def __init__(self, get_filename=symbol_versioning.DEPRECATED_PARAMETER,
                 file_name=None):
        """Base class for configuration files using an ini-like syntax.

        :param file_name: The configuration file path.
        """
        super(IniBasedConfig, self).__init__()
        self.file_name = file_name
        if symbol_versioning.deprecated_passed(get_filename):
            symbol_versioning.warn(
                'IniBasedConfig.__init__(get_filename) was deprecated in 2.3.'
                ' Use file_name instead.',
                DeprecationWarning,
                stacklevel=2)
            if get_filename is not None:
                self.file_name = get_filename()
        else:
            self.file_name = file_name
        self._content = None
        self._parser = None

    @classmethod
    def from_string(cls, str_or_unicode, file_name=None, save=False):
        """Create a config object from a string.

        :param str_or_unicode: A string representing the file content. This will
            be utf-8 encoded.

        :param file_name: The configuration file path.

        :param _save: Whether the file should be saved upon creation.
        """
        conf = cls(file_name=file_name)
        conf._create_from_string(str_or_unicode, save)
        return conf

    def _create_from_string(self, str_or_unicode, save):
        self._content = StringIO(str_or_unicode.encode('utf-8'))
        # Some tests use in-memory configs, some other always need the config
        # file to exist on disk.
        if save:
            self._write_config_file()

    def _get_parser(self, file=symbol_versioning.DEPRECATED_PARAMETER):
        if self._parser is not None:
            return self._parser
        if symbol_versioning.deprecated_passed(file):
            symbol_versioning.warn(
                'IniBasedConfig._get_parser(file=xxx) was deprecated in 2.3.'
                ' Use IniBasedConfig(_content=xxx) instead.',
                DeprecationWarning,
                stacklevel=2)
        if self._content is not None:
            co_input = self._content
        elif self.file_name is None:
            raise AssertionError('We have no content to create the config')
        else:
            co_input = self.file_name
        try:
            self._parser = ConfigObj(co_input, encoding='utf-8')
        except configobj.ConfigObjError, e:
            raise errors.ParseConfigError(e.errors, e.config.filename)
        except UnicodeDecodeError:
            raise errors.ConfigContentError(self.file_name)
        # Make sure self.reload() will use the right file name
        self._parser.filename = self.file_name
        for hook in OldConfigHooks['load']:
            hook(self)
        return self._parser

    def reload(self):
        """Reload the config file from disk."""
        if self.file_name is None:
            raise AssertionError('We need a file name to reload the config')
        if self._parser is not None:
            self._parser.reload()
        for hook in ConfigHooks['load']:
            hook(self)

    def _get_matching_sections(self):
        """Return an ordered list of (section_name, extra_path) pairs.

        If the section contains inherited configuration, extra_path is
        a string containing the additional path components.
        """
        section = self._get_section()
        if section is not None:
            return [(section, '')]
        else:
            return []

    def _get_section(self):
        """Override this to define the section used by the config."""
        return "DEFAULT"

    def _get_sections(self, name=None):
        """Returns an iterator of the sections specified by ``name``.

        :param name: The section name. If None is supplied, the default
            configurations are yielded.

        :return: A tuple (name, section, config_id) for all sections that will
            be walked by user_get_option() in the 'right' order. The first one
            is where set_user_option() will update the value.
        """
        parser = self._get_parser()
        if name is not None:
            yield (name, parser[name], self.config_id())
        else:
            # No section name has been given so we fallback to the configobj
            # itself which holds the variables defined outside of any section.
            yield (None, parser, self.config_id())

    def _get_options(self, sections=None):
        """Return an ordered list of (name, value, section, config_id) tuples.

        All options are returned with their associated value and the section
        they appeared in. ``config_id`` is a unique identifier for the
        configuration file the option is defined in.

        :param sections: Default to ``_get_matching_sections`` if not
            specified. This gives a better control to daughter classes about
            which sections should be searched. This is a list of (name,
            configobj) tuples.
        """
        opts = []
        if sections is None:
            parser = self._get_parser()
            sections = []
            for (section_name, _) in self._get_matching_sections():
                try:
                    section = parser[section_name]
                except KeyError:
                    # This could happen for an empty file for which we define a
                    # DEFAULT section. FIXME: Force callers to provide sections
                    # instead ? -- vila 20100930
                    continue
                sections.append((section_name, section))
        config_id = self.config_id()
        for (section_name, section) in sections:
            for (name, value) in section.iteritems():
                yield (name, parser._quote(value), section_name,
                       config_id, parser)

    def _get_option_policy(self, section, option_name):
        """Return the policy for the given (section, option_name) pair."""
        return POLICY_NONE

    def _get_change_editor(self):
        return self.get_user_option('change_editor')

    def _get_signature_checking(self):
        """See Config._get_signature_checking."""
        policy = self._get_user_option('check_signatures')
        if policy:
            return self._string_to_signature_policy(policy)

    def _get_signing_policy(self):
        """See Config._get_signing_policy"""
        policy = self._get_user_option('create_signatures')
        if policy:
            return self._string_to_signing_policy(policy)

    def _get_user_id(self):
        """Get the user id from the 'email' key in the current section."""
        return self._get_user_option('email')

    def _get_user_option(self, option_name):
        """See Config._get_user_option."""
        for (section, extra_path) in self._get_matching_sections():
            try:
                value = self._get_parser().get_value(section, option_name)
            except KeyError:
                continue
            policy = self._get_option_policy(section, option_name)
            if policy == POLICY_NONE:
                return value
            elif policy == POLICY_NORECURSE:
                # norecurse items only apply to the exact path
                if extra_path:
                    continue
                else:
                    return value
            elif policy == POLICY_APPENDPATH:
                if extra_path:
                    value = urlutils.join(value, extra_path)
                return value
            else:
                raise AssertionError('Unexpected config policy %r' % policy)
        else:
            return None

    def _gpg_signing_command(self):
        """See Config.gpg_signing_command."""
        return self._get_user_option('gpg_signing_command')

    def _log_format(self):
        """See Config.log_format."""
        return self._get_user_option('log_format')

    def _validate_signatures_in_log(self):
        """See Config.validate_signatures_in_log."""
        return self._get_user_option('validate_signatures_in_log')

    def _acceptable_keys(self):
        """See Config.acceptable_keys."""
        return self._get_user_option('acceptable_keys')

    def _post_commit(self):
        """See Config.post_commit."""
        return self._get_user_option('post_commit')

    def _string_to_signature_policy(self, signature_string):
        """Convert a string to a signing policy."""
        if signature_string.lower() == 'check-available':
            return CHECK_IF_POSSIBLE
        if signature_string.lower() == 'ignore':
            return CHECK_NEVER
        if signature_string.lower() == 'require':
            return CHECK_ALWAYS
        raise errors.BzrError("Invalid signatures policy '%s'"
                              % signature_string)

    def _string_to_signing_policy(self, signature_string):
        """Convert a string to a signing policy."""
        if signature_string.lower() == 'when-required':
            return SIGN_WHEN_REQUIRED
        if signature_string.lower() == 'never':
            return SIGN_NEVER
        if signature_string.lower() == 'always':
            return SIGN_ALWAYS
        raise errors.BzrError("Invalid signing policy '%s'"
                              % signature_string)

    def _get_alias(self, value):
        try:
            return self._get_parser().get_value("ALIASES",
                                                value)
        except KeyError:
            pass

    def _get_nickname(self):
        return self.get_user_option('nickname')

    def remove_user_option(self, option_name, section_name=None):
        """Remove a user option and save the configuration file.

        :param option_name: The option to be removed.

        :param section_name: The section the option is defined in, default to
            the default section.
        """
        self.reload()
        parser = self._get_parser()
        if section_name is None:
            section = parser
        else:
            section = parser[section_name]
        try:
            del section[option_name]
        except KeyError:
            raise errors.NoSuchConfigOption(option_name)
        self._write_config_file()
        for hook in OldConfigHooks['remove']:
            hook(self, option_name)

    def _write_config_file(self):
        if self.file_name is None:
            raise AssertionError('We cannot save, self.file_name is None')
        conf_dir = os.path.dirname(self.file_name)
        ensure_config_dir_exists(conf_dir)
        atomic_file = atomicfile.AtomicFile(self.file_name)
        self._get_parser().write(atomic_file)
        atomic_file.commit()
        atomic_file.close()
        osutils.copy_ownership_from_path(self.file_name)
        for hook in OldConfigHooks['save']:
            hook(self)


class LockableConfig(IniBasedConfig):
    """A configuration needing explicit locking for access.

    If several processes try to write the config file, the accesses need to be
    serialized.

    Daughter classes should decorate all methods that update a config with the
    ``@needs_write_lock`` decorator (they call, directly or indirectly, the
    ``_write_config_file()`` method. These methods (typically ``set_option()``
    and variants must reload the config file from disk before calling
    ``_write_config_file()``), this can be achieved by calling the
    ``self.reload()`` method. Note that the lock scope should cover both the
    reading and the writing of the config file which is why the decorator can't
    be applied to ``_write_config_file()`` only.

    This should be enough to implement the following logic:
    - lock for exclusive write access,
    - reload the config file from disk,
    - set the new value
    - unlock

    This logic guarantees that a writer can update a value without erasing an
    update made by another writer.
    """

    lock_name = 'lock'

    def __init__(self, file_name):
        super(LockableConfig, self).__init__(file_name=file_name)
        self.dir = osutils.dirname(osutils.safe_unicode(self.file_name))
        # FIXME: It doesn't matter that we don't provide possible_transports
        # below since this is currently used only for local config files ;
        # local transports are not shared. But if/when we start using
        # LockableConfig for other kind of transports, we will need to reuse
        # whatever connection is already established -- vila 20100929
        self.transport = transport.get_transport_from_path(self.dir)
        self._lock = lockdir.LockDir(self.transport, self.lock_name)

    def _create_from_string(self, unicode_bytes, save):
        super(LockableConfig, self)._create_from_string(unicode_bytes, False)
        if save:
            # We need to handle the saving here (as opposed to IniBasedConfig)
            # to be able to lock
            self.lock_write()
            self._write_config_file()
            self.unlock()

    def lock_write(self, token=None):
        """Takes a write lock in the directory containing the config file.

        If the directory doesn't exist it is created.
        """
        ensure_config_dir_exists(self.dir)
        return self._lock.lock_write(token)

    def unlock(self):
        self._lock.unlock()

    def break_lock(self):
        self._lock.break_lock()

    @needs_write_lock
    def remove_user_option(self, option_name, section_name=None):
        super(LockableConfig, self).remove_user_option(option_name,
                                                       section_name)

    def _write_config_file(self):
        if self._lock is None or not self._lock.is_held:
            # NB: if the following exception is raised it probably means a
            # missing @needs_write_lock decorator on one of the callers.
            raise errors.ObjectNotLocked(self)
        super(LockableConfig, self)._write_config_file()


class GlobalConfig(LockableConfig):
    """The configuration that should be used for a specific location."""

    def __init__(self):
        super(GlobalConfig, self).__init__(file_name=config_filename())

    def config_id(self):
        return 'bazaar'

    @classmethod
    def from_string(cls, str_or_unicode, save=False):
        """Create a config object from a string.

        :param str_or_unicode: A string representing the file content. This
            will be utf-8 encoded.

        :param save: Whether the file should be saved upon creation.
        """
        conf = cls()
        conf._create_from_string(str_or_unicode, save)
        return conf

    @deprecated_method(deprecated_in((2, 4, 0)))
    def get_editor(self):
        return self._get_user_option('editor')

    @needs_write_lock
    def set_user_option(self, option, value):
        """Save option and its value in the configuration."""
        self._set_option(option, value, 'DEFAULT')

    def get_aliases(self):
        """Return the aliases section."""
        if 'ALIASES' in self._get_parser():
            return self._get_parser()['ALIASES']
        else:
            return {}

    @needs_write_lock
    def set_alias(self, alias_name, alias_command):
        """Save the alias in the configuration."""
        self._set_option(alias_name, alias_command, 'ALIASES')

    @needs_write_lock
    def unset_alias(self, alias_name):
        """Unset an existing alias."""
        self.reload()
        aliases = self._get_parser().get('ALIASES')
        if not aliases or alias_name not in aliases:
            raise errors.NoSuchAlias(alias_name)
        del aliases[alias_name]
        self._write_config_file()

    def _set_option(self, option, value, section):
        self.reload()
        self._get_parser().setdefault(section, {})[option] = value
        self._write_config_file()
        for hook in OldConfigHooks['set']:
            hook(self, option, value)

    def _get_sections(self, name=None):
        """See IniBasedConfig._get_sections()."""
        parser = self._get_parser()
        # We don't give access to options defined outside of any section, we
        # used the DEFAULT section by... default.
        if name in (None, 'DEFAULT'):
            # This could happen for an empty file where the DEFAULT section
            # doesn't exist yet. So we force DEFAULT when yielding
            name = 'DEFAULT'
            if 'DEFAULT' not in parser:
               parser['DEFAULT']= {}
        yield (name, parser[name], self.config_id())

    @needs_write_lock
    def remove_user_option(self, option_name, section_name=None):
        if section_name is None:
            # We need to force the default section.
            section_name = 'DEFAULT'
        # We need to avoid the LockableConfig implementation or we'll lock
        # twice
        super(LockableConfig, self).remove_user_option(option_name,
                                                       section_name)

def _iter_for_location_by_parts(sections, location):
    """Keep only the sessions matching the specified location.

    :param sections: An iterable of section names.

    :param location: An url or a local path to match against.

    :returns: An iterator of (section, extra_path, nb_parts) where nb is the
        number of path components in the section name, section is the section
        name and extra_path is the difference between location and the section
        name.

    ``location`` will always be a local path and never a 'file://' url but the
    section names themselves can be in either form.
    """
    location_parts = location.rstrip('/').split('/')

    for section in sections:
        # location is a local path if possible, so we need to convert 'file://'
        # urls in section names to local paths if necessary.

        # This also avoids having file:///path be a more exact
        # match than '/path'.

        # FIXME: This still raises an issue if a user defines both file:///path
        # *and* /path. Should we raise an error in this case -- vila 20110505

        if section.startswith('file://'):
            section_path = urlutils.local_path_from_url(section)
        else:
            section_path = section
        section_parts = section_path.rstrip('/').split('/')

        matched = True
        if len(section_parts) > len(location_parts):
            # More path components in the section, they can't match
            matched = False
        else:
            # Rely on zip truncating in length to the length of the shortest
            # argument sequence.
            names = zip(location_parts, section_parts)
            for name in names:
                if not fnmatch.fnmatch(name[0], name[1]):
                    matched = False
                    break
        if not matched:
            continue
        # build the path difference between the section and the location
        extra_path = '/'.join(location_parts[len(section_parts):])
        yield section, extra_path, len(section_parts)


class LocationConfig(LockableConfig):
    """A configuration object that gives the policy for a location."""

    def __init__(self, location):
        super(LocationConfig, self).__init__(
            file_name=locations_config_filename())
        # local file locations are looked up by local path, rather than
        # by file url. This is because the config file is a user
        # file, and we would rather not expose the user to file urls.
        if location.startswith('file://'):
            location = urlutils.local_path_from_url(location)
        self.location = location

    def config_id(self):
        return 'locations'

    @classmethod
    def from_string(cls, str_or_unicode, location, save=False):
        """Create a config object from a string.

        :param str_or_unicode: A string representing the file content. This will
            be utf-8 encoded.

        :param location: The location url to filter the configuration.

        :param save: Whether the file should be saved upon creation.
        """
        conf = cls(location)
        conf._create_from_string(str_or_unicode, save)
        return conf

    def _get_matching_sections(self):
        """Return an ordered list of section names matching this location."""
        matches = list(_iter_for_location_by_parts(self._get_parser(),
                                                   self.location))
        # put the longest (aka more specific) locations first
        matches.sort(
            key=lambda (section, extra_path, length): (length, section),
            reverse=True)
        for (section, extra_path, length) in matches:
            yield section, extra_path
            # should we stop looking for parent configs here?
            try:
                if self._get_parser()[section].as_bool('ignore_parents'):
                    break
            except KeyError:
                pass

    def _get_sections(self, name=None):
        """See IniBasedConfig._get_sections()."""
        # We ignore the name here as the only sections handled are named with
        # the location path and we don't expose embedded sections either.
        parser = self._get_parser()
        for name, extra_path in self._get_matching_sections():
            yield (name, parser[name], self.config_id())

    def _get_option_policy(self, section, option_name):
        """Return the policy for the given (section, option_name) pair."""
        # check for the old 'recurse=False' flag
        try:
            recurse = self._get_parser()[section].as_bool('recurse')
        except KeyError:
            recurse = True
        if not recurse:
            return POLICY_NORECURSE

        policy_key = option_name + ':policy'
        try:
            policy_name = self._get_parser()[section][policy_key]
        except KeyError:
            policy_name = None

        return _policy_value[policy_name]

    def _set_option_policy(self, section, option_name, option_policy):
        """Set the policy for the given option name in the given section."""
        # The old recurse=False option affects all options in the
        # section.  To handle multiple policies in the section, we
        # need to convert it to a policy_norecurse key.
        try:
            recurse = self._get_parser()[section].as_bool('recurse')
        except KeyError:
            pass
        else:
            symbol_versioning.warn(
                'The recurse option is deprecated as of 0.14.  '
                'The section "%s" has been converted to use policies.'
                % section,
                DeprecationWarning)
            del self._get_parser()[section]['recurse']
            if not recurse:
                for key in self._get_parser()[section].keys():
                    if not key.endswith(':policy'):
                        self._get_parser()[section][key +
                                                    ':policy'] = 'norecurse'

        policy_key = option_name + ':policy'
        policy_name = _policy_name[option_policy]
        if policy_name is not None:
            self._get_parser()[section][policy_key] = policy_name
        else:
            if policy_key in self._get_parser()[section]:
                del self._get_parser()[section][policy_key]

    @needs_write_lock
    def set_user_option(self, option, value, store=STORE_LOCATION):
        """Save option and its value in the configuration."""
        if store not in [STORE_LOCATION,
                         STORE_LOCATION_NORECURSE,
                         STORE_LOCATION_APPENDPATH]:
            raise ValueError('bad storage policy %r for %r' %
                (store, option))
        self.reload()
        location = self.location
        if location.endswith('/'):
            location = location[:-1]
        parser = self._get_parser()
        if not location in parser and not location + '/' in parser:
            parser[location] = {}
        elif location + '/' in parser:
            location = location + '/'
        parser[location][option]=value
        # the allowed values of store match the config policies
        self._set_option_policy(location, option, store)
        self._write_config_file()
        for hook in OldConfigHooks['set']:
            hook(self, option, value)


class BranchConfig(Config):
    """A configuration object giving the policy for a branch."""

    def __init__(self, branch):
        super(BranchConfig, self).__init__()
        self._location_config = None
        self._branch_data_config = None
        self._global_config = None
        self.branch = branch
        self.option_sources = (self._get_location_config,
                               self._get_branch_data_config,
                               self._get_global_config)

    def config_id(self):
        return 'branch'

    def _get_branch_data_config(self):
        if self._branch_data_config is None:
            self._branch_data_config = TreeConfig(self.branch)
            self._branch_data_config.config_id = self.config_id
        return self._branch_data_config

    def _get_location_config(self):
        if self._location_config is None:
            self._location_config = LocationConfig(self.branch.base)
        return self._location_config

    def _get_global_config(self):
        if self._global_config is None:
            self._global_config = GlobalConfig()
        return self._global_config

    def _get_best_value(self, option_name):
        """This returns a user option from local, tree or global config.

        They are tried in that order.  Use get_safe_value if trusted values
        are necessary.
        """
        for source in self.option_sources:
            value = getattr(source(), option_name)()
            if value is not None:
                return value
        return None

    def _get_safe_value(self, option_name):
        """This variant of get_best_value never returns untrusted values.

        It does not return values from the branch data, because the branch may
        not be controlled by the user.

        We may wish to allow locations.conf to control whether branches are
        trusted in the future.
        """
        for source in (self._get_location_config, self._get_global_config):
            value = getattr(source(), option_name)()
            if value is not None:
                return value
        return None

    def _get_user_id(self):
        """Return the full user id for the branch.

        e.g. "John Hacker <jhacker@example.com>"
        This is looked up in the email controlfile for the branch.
        """
        try:
            return (self.branch._transport.get_bytes("email")
                    .decode(osutils.get_user_encoding())
                    .rstrip("\r\n"))
        except (errors.NoSuchFile, errors.PermissionDenied), e:
            pass

        return self._get_best_value('_get_user_id')

    def _get_change_editor(self):
        return self._get_best_value('_get_change_editor')

    def _get_signature_checking(self):
        """See Config._get_signature_checking."""
        return self._get_best_value('_get_signature_checking')

    def _get_signing_policy(self):
        """See Config._get_signing_policy."""
        return self._get_best_value('_get_signing_policy')

    def _get_user_option(self, option_name):
        """See Config._get_user_option."""
        for source in self.option_sources:
            value = source()._get_user_option(option_name)
            if value is not None:
                return value
        return None

    def _get_sections(self, name=None):
        """See IniBasedConfig.get_sections()."""
        for source in self.option_sources:
            for section in source()._get_sections(name):
                yield section

    def _get_options(self, sections=None):
        opts = []
        # First the locations options
        for option in self._get_location_config()._get_options():
            yield option
        # Then the branch options
        branch_config = self._get_branch_data_config()
        if sections is None:
            sections = [('DEFAULT', branch_config._get_parser())]
        # FIXME: We shouldn't have to duplicate the code in IniBasedConfig but
        # Config itself has no notion of sections :( -- vila 20101001
        config_id = self.config_id()
        for (section_name, section) in sections:
            for (name, value) in section.iteritems():
                yield (name, value, section_name,
                       config_id, branch_config._get_parser())
        # Then the global options
        for option in self._get_global_config()._get_options():
            yield option

    def set_user_option(self, name, value, store=STORE_BRANCH,
        warn_masked=False):
        if store == STORE_BRANCH:
            self._get_branch_data_config().set_option(value, name)
        elif store == STORE_GLOBAL:
            self._get_global_config().set_user_option(name, value)
        else:
            self._get_location_config().set_user_option(name, value, store)
        if not warn_masked:
            return
        if store in (STORE_GLOBAL, STORE_BRANCH):
            mask_value = self._get_location_config().get_user_option(name)
            if mask_value is not None:
                trace.warning('Value "%s" is masked by "%s" from'
                              ' locations.conf', value, mask_value)
            else:
                if store == STORE_GLOBAL:
                    branch_config = self._get_branch_data_config()
                    mask_value = branch_config.get_user_option(name)
                    if mask_value is not None:
                        trace.warning('Value "%s" is masked by "%s" from'
                                      ' branch.conf', value, mask_value)

    def remove_user_option(self, option_name, section_name=None):
        self._get_branch_data_config().remove_option(option_name, section_name)

    def _gpg_signing_command(self):
        """See Config.gpg_signing_command."""
        return self._get_safe_value('_gpg_signing_command')

    def _post_commit(self):
        """See Config.post_commit."""
        return self._get_safe_value('_post_commit')

    def _get_nickname(self):
        value = self._get_explicit_nickname()
        if value is not None:
            return value
        return urlutils.unescape(self.branch.base.split('/')[-2])

    def has_explicit_nickname(self):
        """Return true if a nickname has been explicitly assigned."""
        return self._get_explicit_nickname() is not None

    def _get_explicit_nickname(self):
        return self._get_best_value('_get_nickname')

    def _log_format(self):
        """See Config.log_format."""
        return self._get_best_value('_log_format')

    def _validate_signatures_in_log(self):
        """See Config.validate_signatures_in_log."""
        return self._get_best_value('_validate_signatures_in_log')

    def _acceptable_keys(self):
        """See Config.acceptable_keys."""
        return self._get_best_value('_acceptable_keys')


def ensure_config_dir_exists(path=None):
    """Make sure a configuration directory exists.
    This makes sure that the directory exists.
    On windows, since configuration directories are 2 levels deep,
    it makes sure both the directory and the parent directory exists.
    """
    if path is None:
        path = config_dir()
    if not os.path.isdir(path):
        if sys.platform == 'win32':
            parent_dir = os.path.dirname(path)
            if not os.path.isdir(parent_dir):
                trace.mutter('creating config parent directory: %r', parent_dir)
                os.mkdir(parent_dir)
        trace.mutter('creating config directory: %r', path)
        os.mkdir(path)
        osutils.copy_ownership_from_path(path)


def config_dir():
    """Return per-user configuration directory.

    By default this is %APPDATA%/bazaar/2.0 on Windows, ~/.bazaar on Mac OS X
    and Linux.  On Linux, if there is a $XDG_CONFIG_HOME/bazaar directory,
    that will be used instead.

    TODO: Global option --config-dir to override this.
    """
    base = os.environ.get('BZR_HOME', None)
    if sys.platform == 'win32':
        # environ variables on Windows are in user encoding/mbcs. So decode
        # before using one
        if base is not None:
            base = base.decode('mbcs')
        if base is None:
            base = win32utils.get_appdata_location_unicode()
        if base is None:
            base = os.environ.get('HOME', None)
            if base is not None:
                base = base.decode('mbcs')
        if base is None:
            raise errors.BzrError('You must have one of BZR_HOME, APPDATA,'
                                  ' or HOME set')
        return osutils.pathjoin(base, 'bazaar', '2.0')
    else:
        if base is not None:
            base = base.decode(osutils._fs_enc)
    if sys.platform == 'darwin':
        if base is None:
            # this takes into account $HOME
            base = os.path.expanduser("~")
        return osutils.pathjoin(base, '.bazaar')
    else:
        if base is None:
            xdg_dir = os.environ.get('XDG_CONFIG_HOME', None)
            if xdg_dir is None:
                xdg_dir = osutils.pathjoin(os.path.expanduser("~"), ".config")
            xdg_dir = osutils.pathjoin(xdg_dir, 'bazaar')
            if osutils.isdir(xdg_dir):
                trace.mutter(
                    "Using configuration in XDG directory %s." % xdg_dir)
                return xdg_dir
            base = os.path.expanduser("~")
        return osutils.pathjoin(base, ".bazaar")


def config_filename():
    """Return per-user configuration ini file filename."""
    return osutils.pathjoin(config_dir(), 'bazaar.conf')


def locations_config_filename():
    """Return per-user configuration ini file filename."""
    return osutils.pathjoin(config_dir(), 'locations.conf')


def authentication_config_filename():
    """Return per-user authentication ini file filename."""
    return osutils.pathjoin(config_dir(), 'authentication.conf')


def user_ignore_config_filename():
    """Return the user default ignore filename"""
    return osutils.pathjoin(config_dir(), 'ignore')


def crash_dir():
    """Return the directory name to store crash files.

    This doesn't implicitly create it.

    On Windows it's in the config directory; elsewhere it's /var/crash
    which may be monitored by apport.  It can be overridden by
    $APPORT_CRASH_DIR.
    """
    if sys.platform == 'win32':
        return osutils.pathjoin(config_dir(), 'Crash')
    else:
        # XXX: hardcoded in apport_python_hook.py; therefore here too -- mbp
        # 2010-01-31
        return os.environ.get('APPORT_CRASH_DIR', '/var/crash')


def xdg_cache_dir():
    # See http://standards.freedesktop.org/basedir-spec/latest/ar01s03.html
    # Possibly this should be different on Windows?
    e = os.environ.get('XDG_CACHE_DIR', None)
    if e:
        return e
    else:
        return os.path.expanduser('~/.cache')


def _get_default_mail_domain():
    """If possible, return the assumed default email domain.

    :returns: string mail domain, or None.
    """
    if sys.platform == 'win32':
        # No implementation yet; patches welcome
        return None
    try:
        f = open('/etc/mailname')
    except (IOError, OSError), e:
        return None
    try:
        domain = f.read().strip()
        return domain
    finally:
        f.close()


def _auto_user_id():
    """Calculate automatic user identification.

    :returns: (realname, email), either of which may be None if they can't be
    determined.

    Only used when none is set in the environment or the id file.

    This only returns an email address if we can be fairly sure the 
    address is reasonable, ie if /etc/mailname is set on unix.

    This doesn't use the FQDN as the default domain because that may be 
    slow, and it doesn't use the hostname alone because that's not normally 
    a reasonable address.
    """
    if sys.platform == 'win32':
        # No implementation to reliably determine Windows default mail
        # address; please add one.
        return None, None

    default_mail_domain = _get_default_mail_domain()
    if not default_mail_domain:
        return None, None

    import pwd
    uid = os.getuid()
    try:
        w = pwd.getpwuid(uid)
    except KeyError:
        trace.mutter('no passwd entry for uid %d?' % uid)
        return None, None

    # we try utf-8 first, because on many variants (like Linux),
    # /etc/passwd "should" be in utf-8, and because it's unlikely to give
    # false positives.  (many users will have their user encoding set to
    # latin-1, which cannot raise UnicodeError.)
    try:
        gecos = w.pw_gecos.decode('utf-8')
        encoding = 'utf-8'
    except UnicodeError:
        try:
            encoding = osutils.get_user_encoding()
            gecos = w.pw_gecos.decode(encoding)
        except UnicodeError, e:
            trace.mutter("cannot decode passwd entry %s" % w)
            return None, None
    try:
        username = w.pw_name.decode(encoding)
    except UnicodeError, e:
        trace.mutter("cannot decode passwd entry %s" % w)
        return None, None

    comma = gecos.find(',')
    if comma == -1:
        realname = gecos
    else:
        realname = gecos[:comma]

    return realname, (username + '@' + default_mail_domain)


def parse_username(username):
    """Parse e-mail username and return a (name, address) tuple."""
    match = re.match(r'(.*?)\s*<?([\w+.-]+@[\w+.-]+)>?', username)
    if match is None:
        return (username, '')
    else:
        return (match.group(1), match.group(2))


def extract_email_address(e):
    """Return just the address part of an email string.

    That is just the user@domain part, nothing else.
    This part is required to contain only ascii characters.
    If it can't be extracted, raises an error.

    >>> extract_email_address('Jane Tester <jane@test.com>')
    "jane@test.com"
    """
    name, email = parse_username(e)
    if not email:
        raise errors.NoEmailInUsername(e)
    return email


class TreeConfig(IniBasedConfig):
    """Branch configuration data associated with its contents, not location"""

    # XXX: Really needs a better name, as this is not part of the tree! -- mbp 20080507

    def __init__(self, branch):
        self._config = branch._get_config()
        self.branch = branch

    def _get_parser(self, file=None):
        if file is not None:
            return IniBasedConfig._get_parser(file)
        return self._config._get_configobj()

    def get_option(self, name, section=None, default=None):
        self.branch.lock_read()
        try:
            return self._config.get_option(name, section, default)
        finally:
            self.branch.unlock()

    def set_option(self, value, name, section=None):
        """Set a per-branch configuration option"""
        # FIXME: We shouldn't need to lock explicitly here but rather rely on
        # higher levels providing the right lock -- vila 20101004
        self.branch.lock_write()
        try:
            self._config.set_option(value, name, section)
        finally:
            self.branch.unlock()

    def remove_option(self, option_name, section_name=None):
        # FIXME: We shouldn't need to lock explicitly here but rather rely on
        # higher levels providing the right lock -- vila 20101004
        self.branch.lock_write()
        try:
            self._config.remove_option(option_name, section_name)
        finally:
            self.branch.unlock()


class AuthenticationConfig(object):
    """The authentication configuration file based on a ini file.

    Implements the authentication.conf file described in
    doc/developers/authentication-ring.txt.
    """

    def __init__(self, _file=None):
        self._config = None # The ConfigObj
        if _file is None:
            self._filename = authentication_config_filename()
            self._input = self._filename = authentication_config_filename()
        else:
            # Tests can provide a string as _file
            self._filename = None
            self._input = _file

    def _get_config(self):
        if self._config is not None:
            return self._config
        try:
            # FIXME: Should we validate something here ? Includes: empty
            # sections are useless, at least one of
            # user/password/password_encoding should be defined, etc.

            # Note: the encoding below declares that the file itself is utf-8
            # encoded, but the values in the ConfigObj are always Unicode.
            self._config = ConfigObj(self._input, encoding='utf-8')
        except configobj.ConfigObjError, e:
            raise errors.ParseConfigError(e.errors, e.config.filename)
        except UnicodeError:
            raise errors.ConfigContentError(self._filename)
        return self._config

    def _save(self):
        """Save the config file, only tests should use it for now."""
        conf_dir = os.path.dirname(self._filename)
        ensure_config_dir_exists(conf_dir)
        f = file(self._filename, 'wb')
        try:
            self._get_config().write(f)
        finally:
            f.close()

    def _set_option(self, section_name, option_name, value):
        """Set an authentication configuration option"""
        conf = self._get_config()
        section = conf.get(section_name)
        if section is None:
            conf[section] = {}
            section = conf[section]
        section[option_name] = value
        self._save()

    def get_credentials(self, scheme, host, port=None, user=None, path=None,
                        realm=None):
        """Returns the matching credentials from authentication.conf file.

        :param scheme: protocol

        :param host: the server address

        :param port: the associated port (optional)

        :param user: login (optional)

        :param path: the absolute path on the server (optional)
        
        :param realm: the http authentication realm (optional)

        :return: A dict containing the matching credentials or None.
           This includes:
           - name: the section name of the credentials in the
             authentication.conf file,
           - user: can't be different from the provided user if any,
           - scheme: the server protocol,
           - host: the server address,
           - port: the server port (can be None),
           - path: the absolute server path (can be None),
           - realm: the http specific authentication realm (can be None),
           - password: the decoded password, could be None if the credential
             defines only the user
           - verify_certificates: https specific, True if the server
             certificate should be verified, False otherwise.
        """
        credentials = None
        for auth_def_name, auth_def in self._get_config().items():
            if type(auth_def) is not configobj.Section:
                raise ValueError("%s defined outside a section" % auth_def_name)

            a_scheme, a_host, a_user, a_path = map(
                auth_def.get, ['scheme', 'host', 'user', 'path'])

            try:
                a_port = auth_def.as_int('port')
            except KeyError:
                a_port = None
            except ValueError:
                raise ValueError("'port' not numeric in %s" % auth_def_name)
            try:
                a_verify_certificates = auth_def.as_bool('verify_certificates')
            except KeyError:
                a_verify_certificates = True
            except ValueError:
                raise ValueError(
                    "'verify_certificates' not boolean in %s" % auth_def_name)

            # Attempt matching
            if a_scheme is not None and scheme != a_scheme:
                continue
            if a_host is not None:
                if not (host == a_host
                        or (a_host.startswith('.') and host.endswith(a_host))):
                    continue
            if a_port is not None and port != a_port:
                continue
            if (a_path is not None and path is not None
                and not path.startswith(a_path)):
                continue
            if (a_user is not None and user is not None
                and a_user != user):
                # Never contradict the caller about the user to be used
                continue
            if a_user is None:
                # Can't find a user
                continue
            # Prepare a credentials dictionary with additional keys
            # for the credential providers
            credentials = dict(name=auth_def_name,
                               user=a_user,
                               scheme=a_scheme,
                               host=host,
                               port=port,
                               path=path,
                               realm=realm,
                               password=auth_def.get('password', None),
                               verify_certificates=a_verify_certificates)
            # Decode the password in the credentials (or get one)
            self.decode_password(credentials,
                                 auth_def.get('password_encoding', None))
            if 'auth' in debug.debug_flags:
                trace.mutter("Using authentication section: %r", auth_def_name)
            break

        if credentials is None:
            # No credentials were found in authentication.conf, try the fallback
            # credentials stores.
            credentials = credential_store_registry.get_fallback_credentials(
                scheme, host, port, user, path, realm)

        return credentials

    def set_credentials(self, name, host, user, scheme=None, password=None,
                        port=None, path=None, verify_certificates=None,
                        realm=None):
        """Set authentication credentials for a host.

        Any existing credentials with matching scheme, host, port and path
        will be deleted, regardless of name.

        :param name: An arbitrary name to describe this set of credentials.
        :param host: Name of the host that accepts these credentials.
        :param user: The username portion of these credentials.
        :param scheme: The URL scheme (e.g. ssh, http) the credentials apply
            to.
        :param password: Password portion of these credentials.
        :param port: The IP port on the host that these credentials apply to.
        :param path: A filesystem path on the host that these credentials
            apply to.
        :param verify_certificates: On https, verify server certificates if
            True.
        :param realm: The http authentication realm (optional).
        """
        values = {'host': host, 'user': user}
        if password is not None:
            values['password'] = password
        if scheme is not None:
            values['scheme'] = scheme
        if port is not None:
            values['port'] = '%d' % port
        if path is not None:
            values['path'] = path
        if verify_certificates is not None:
            values['verify_certificates'] = str(verify_certificates)
        if realm is not None:
            values['realm'] = realm
        config = self._get_config()
        for_deletion = []
        for section, existing_values in config.items():
            for key in ('scheme', 'host', 'port', 'path', 'realm'):
                if existing_values.get(key) != values.get(key):
                    break
            else:
                del config[section]
        config.update({name: values})
        self._save()

    def get_user(self, scheme, host, port=None, realm=None, path=None,
                 prompt=None, ask=False, default=None):
        """Get a user from authentication file.

        :param scheme: protocol

        :param host: the server address

        :param port: the associated port (optional)

        :param realm: the realm sent by the server (optional)

        :param path: the absolute path on the server (optional)

        :param ask: Ask the user if there is no explicitly configured username 
                    (optional)

        :param default: The username returned if none is defined (optional).

        :return: The found user.
        """
        credentials = self.get_credentials(scheme, host, port, user=None,
                                           path=path, realm=realm)
        if credentials is not None:
            user = credentials['user']
        else:
            user = None
        if user is None:
            if ask:
                if prompt is None:
                    # Create a default prompt suitable for most cases
                    prompt = u'%s' % (scheme.upper(),) + u' %(host)s username'
                # Special handling for optional fields in the prompt
                if port is not None:
                    prompt_host = '%s:%d' % (host, port)
                else:
                    prompt_host = host
                user = ui.ui_factory.get_username(prompt, host=prompt_host)
            else:
                user = default
        return user

    def get_password(self, scheme, host, user, port=None,
                     realm=None, path=None, prompt=None):
        """Get a password from authentication file or prompt the user for one.

        :param scheme: protocol

        :param host: the server address

        :param port: the associated port (optional)

        :param user: login

        :param realm: the realm sent by the server (optional)

        :param path: the absolute path on the server (optional)

        :return: The found password or the one entered by the user.
        """
        credentials = self.get_credentials(scheme, host, port, user, path,
                                           realm)
        if credentials is not None:
            password = credentials['password']
            if password is not None and scheme is 'ssh':
                trace.warning('password ignored in section [%s],'
                              ' use an ssh agent instead'
                              % credentials['name'])
                password = None
        else:
            password = None
        # Prompt user only if we could't find a password
        if password is None:
            if prompt is None:
                # Create a default prompt suitable for most cases
                prompt = u'%s' % scheme.upper() + u' %(user)s@%(host)s password'
            # Special handling for optional fields in the prompt
            if port is not None:
                prompt_host = '%s:%d' % (host, port)
            else:
                prompt_host = host
            password = ui.ui_factory.get_password(prompt,
                                                  host=prompt_host, user=user)
        return password

    def decode_password(self, credentials, encoding):
        try:
            cs = credential_store_registry.get_credential_store(encoding)
        except KeyError:
            raise ValueError('%r is not a known password_encoding' % encoding)
        credentials['password'] = cs.decode_password(credentials)
        return credentials


class CredentialStoreRegistry(registry.Registry):
    """A class that registers credential stores.

    A credential store provides access to credentials via the password_encoding
    field in authentication.conf sections.

    Except for stores provided by bzr itself, most stores are expected to be
    provided by plugins that will therefore use
    register_lazy(password_encoding, module_name, member_name, help=help,
    fallback=fallback) to install themselves.

    A fallback credential store is one that is queried if no credentials can be
    found via authentication.conf.
    """

    def get_credential_store(self, encoding=None):
        cs = self.get(encoding)
        if callable(cs):
            cs = cs()
        return cs

    def is_fallback(self, name):
        """Check if the named credentials store should be used as fallback."""
        return self.get_info(name)

    def get_fallback_credentials(self, scheme, host, port=None, user=None,
                                 path=None, realm=None):
        """Request credentials from all fallback credentials stores.

        The first credentials store that can provide credentials wins.
        """
        credentials = None
        for name in self.keys():
            if not self.is_fallback(name):
                continue
            cs = self.get_credential_store(name)
            credentials = cs.get_credentials(scheme, host, port, user,
                                             path, realm)
            if credentials is not None:
                # We found some credentials
                break
        return credentials

    def register(self, key, obj, help=None, override_existing=False,
                 fallback=False):
        """Register a new object to a name.

        :param key: This is the key to use to request the object later.
        :param obj: The object to register.
        :param help: Help text for this entry. This may be a string or
                a callable. If it is a callable, it should take two
                parameters (registry, key): this registry and the key that
                the help was registered under.
        :param override_existing: Raise KeyErorr if False and something has
                already been registered for that key. If True, ignore if there
                is an existing key (always register the new value).
        :param fallback: Whether this credential store should be 
                used as fallback.
        """
        return super(CredentialStoreRegistry,
                     self).register(key, obj, help, info=fallback,
                                    override_existing=override_existing)

    def register_lazy(self, key, module_name, member_name,
                      help=None, override_existing=False,
                      fallback=False):
        """Register a new credential store to be loaded on request.

        :param module_name: The python path to the module. Such as 'os.path'.
        :param member_name: The member of the module to return.  If empty or
                None, get() will return the module itself.
        :param help: Help text for this entry. This may be a string or
                a callable.
        :param override_existing: If True, replace the existing object
                with the new one. If False, if there is already something
                registered with the same key, raise a KeyError
        :param fallback: Whether this credential store should be 
                used as fallback.
        """
        return super(CredentialStoreRegistry, self).register_lazy(
            key, module_name, member_name, help,
            info=fallback, override_existing=override_existing)


credential_store_registry = CredentialStoreRegistry()


class CredentialStore(object):
    """An abstract class to implement storage for credentials"""

    def decode_password(self, credentials):
        """Returns a clear text password for the provided credentials."""
        raise NotImplementedError(self.decode_password)

    def get_credentials(self, scheme, host, port=None, user=None, path=None,
                        realm=None):
        """Return the matching credentials from this credential store.

        This method is only called on fallback credential stores.
        """
        raise NotImplementedError(self.get_credentials)



class PlainTextCredentialStore(CredentialStore):
    __doc__ = """Plain text credential store for the authentication.conf file"""

    def decode_password(self, credentials):
        """See CredentialStore.decode_password."""
        return credentials['password']


credential_store_registry.register('plain', PlainTextCredentialStore,
                                   help=PlainTextCredentialStore.__doc__)
credential_store_registry.default_key = 'plain'


class BzrDirConfig(object):

    def __init__(self, bzrdir):
        self._bzrdir = bzrdir
        self._config = bzrdir._get_config()

    def set_default_stack_on(self, value):
        """Set the default stacking location.

        It may be set to a location, or None.

        This policy affects all branches contained by this bzrdir, except for
        those under repositories.
        """
        if self._config is None:
            raise errors.BzrError("Cannot set configuration in %s" % self._bzrdir)
        if value is None:
            self._config.set_option('', 'default_stack_on')
        else:
            self._config.set_option(value, 'default_stack_on')

    def get_default_stack_on(self):
        """Return the default stacking location.

        This will either be a location, or None.

        This policy affects all branches contained by this bzrdir, except for
        those under repositories.
        """
        if self._config is None:
            return None
        value = self._config.get_option('default_stack_on')
        if value == '':
            value = None
        return value


class TransportConfig(object):
    """A Config that reads/writes a config file on a Transport.

    It is a low-level object that considers config data to be name/value pairs
    that may be associated with a section.  Assigning meaning to these values
    is done at higher levels like TreeConfig.
    """

    def __init__(self, transport, filename):
        self._transport = transport
        self._filename = filename

    def get_option(self, name, section=None, default=None):
        """Return the value associated with a named option.

        :param name: The name of the value
        :param section: The section the option is in (if any)
        :param default: The value to return if the value is not set
        :return: The value or default value
        """
        configobj = self._get_configobj()
        if section is None:
            section_obj = configobj
        else:
            try:
                section_obj = configobj[section]
            except KeyError:
                return default
        value = section_obj.get(name, default)
        for hook in OldConfigHooks['get']:
            hook(self, name, value)
        return value

    def set_option(self, value, name, section=None):
        """Set the value associated with a named option.

        :param value: The value to set
        :param name: The name of the value to set
        :param section: The section the option is in (if any)
        """
        configobj = self._get_configobj()
        if section is None:
            configobj[name] = value
        else:
            configobj.setdefault(section, {})[name] = value
        for hook in OldConfigHooks['set']:
            hook(self, name, value)
        self._set_configobj(configobj)

    def remove_option(self, option_name, section_name=None):
        configobj = self._get_configobj()
        if section_name is None:
            del configobj[option_name]
        else:
            del configobj[section_name][option_name]
        for hook in OldConfigHooks['remove']:
            hook(self, option_name)
        self._set_configobj(configobj)

    def _get_config_file(self):
        try:
            f = StringIO(self._transport.get_bytes(self._filename))
            for hook in OldConfigHooks['load']:
                hook(self)
            return f
        except errors.NoSuchFile:
            return StringIO()
        except errors.PermissionDenied, e:
            trace.warning("Permission denied while trying to open "
                "configuration file %s.", urlutils.unescape_for_display(
                urlutils.join(self._transport.base, self._filename), "utf-8"))
            return StringIO()

    def _external_url(self):
        return urlutils.join(self._transport.external_url(), self._filename)

    def _get_configobj(self):
        f = self._get_config_file()
        try:
            try:
                conf = ConfigObj(f, encoding='utf-8')
            except configobj.ConfigObjError, e:
                raise errors.ParseConfigError(e.errors, self._external_url())
            except UnicodeDecodeError:
                raise errors.ConfigContentError(self._external_url())
        finally:
            f.close()
        return conf

    def _set_configobj(self, configobj):
        out_file = StringIO()
        configobj.write(out_file)
        out_file.seek(0)
        self._transport.put_file(self._filename, out_file)
        for hook in OldConfigHooks['save']:
            hook(self)


class Option(object):
    """An option definition.

    The option *values* are stored in config files and found in sections.

    Here we define various properties about the option itself, its default
    value, how to convert it from stores, what to do when invalid values are
    encoutered, in which config files it can be stored.
    """

    def __init__(self, name, default=None, default_from_env=None,
                 help=None,
                 from_unicode=None, invalid=None):
        """Build an option definition.

        :param name: the name used to refer to the option.

        :param default: the default value to use when none exist in the config
            stores. This is either a string that ``from_unicode`` will convert
            into the proper type or a python object that can be stringified (so
            only the empty list is supported for example).

        :param default_from_env: A list of environment variables which can
           provide a default value. 'default' will be used only if none of the
           variables specified here are set in the environment.

        :param help: a doc string to explain the option to the user.

        :param from_unicode: a callable to convert the unicode string
            representing the option value in a store. This is not called for
            the default value.

        :param invalid: the action to be taken when an invalid value is
            encountered in a store. This is called only when from_unicode is
            invoked to convert a string and returns None or raise ValueError or
            TypeError. Accepted values are: None (ignore invalid values),
            'warning' (emit a warning), 'error' (emit an error message and
            terminates).
        """
        if default_from_env is None:
            default_from_env = []
        self.name = name
        # Convert the default value to a unicode string so all values are
        # strings internally before conversion (via from_unicode) is attempted.
        if default is None:
            self.default = None
        elif isinstance(default, list):
            # Only the empty list is supported
            if default:
                raise AssertionError(
                    'Only empty lists are supported as default values')
            self.default = u','
        elif isinstance(default, (str, unicode, bool, int)):
            # Rely on python to convert strings, booleans and integers
            self.default = u'%s' % (default,)
        else:
            # other python objects are not expected
            raise AssertionError('%r is not supported as a default value'
                                 % (default,))
        self.default_from_env = default_from_env
        self.help = help
        self.from_unicode = from_unicode
        if invalid and invalid not in ('warning', 'error'):
            raise AssertionError("%s not supported for 'invalid'" % (invalid,))
        self.invalid = invalid

    def convert_from_unicode(self, unicode_value):
        if self.from_unicode is None or unicode_value is None:
            # Don't convert or nothing to convert
            return unicode_value
        try:
            converted = self.from_unicode(unicode_value)
        except (ValueError, TypeError):
            # Invalid values are ignored
            converted = None
        if converted is None and self.invalid is not None:
            # The conversion failed
            if self.invalid == 'warning':
                trace.warning('Value "%s" is not valid for "%s"',
                              unicode_value, self.name)
            elif self.invalid == 'error':
                raise errors.ConfigOptionValueError(self.name, unicode_value)
        return converted

    def get_default(self):
        value = None
        for var in self.default_from_env:
            try:
                # If the env variable is defined, its value is the default one
                value = os.environ[var]
                break
            except KeyError:
                continue
        if value is None:
            # Otherwise, fallback to the value defined at registration
            value = self.default
        return value

    def get_help_text(self, additional_see_also=None, plain=True):
        result = self.help
        from bzrlib import help_topics
        result += help_topics._format_see_also(additional_see_also)
        if plain:
            result = help_topics.help_as_plain_text(result)
        return result


# Predefined converters to get proper values from store

def bool_from_store(unicode_str):
    return ui.bool_from_string(unicode_str)


def int_from_store(unicode_str):
    return int(unicode_str)


# Use a an empty dict to initialize an empty configobj avoiding all
# parsing and encoding checks
_list_converter_config = configobj.ConfigObj(
    {}, encoding='utf-8', list_values=True, interpolation=False)


def list_from_store(unicode_str):
    if not isinstance(unicode_str, basestring):
        raise TypeError
    # Now inject our string directly as unicode. All callers got their value
    # from configobj, so values that need to be quoted are already properly
    # quoted.
    _list_converter_config.reset()
    _list_converter_config._parse([u"list=%s" % (unicode_str,)])
    maybe_list = _list_converter_config['list']
    # ConfigObj return '' instead of u''. Use 'str' below to catch all cases.
    if isinstance(maybe_list, basestring):
        if maybe_list:
            # A single value, most probably the user forgot (or didn't care to
            # add) the final ','
            l = [maybe_list]
        else:
            # The empty string, convert to empty list
            l = []
    else:
        # We rely on ConfigObj providing us with a list already
        l = maybe_list
    return l


class OptionRegistry(registry.Registry):
    """Register config options by their name.

    This overrides ``registry.Registry`` to simplify registration by acquiring
    some information from the option object itself.
    """

    def register(self, option):
        """Register a new option to its name.

        :param option: The option to register. Its name is used as the key.
        """
        super(OptionRegistry, self).register(option.name, option,
                                             help=option.help)

    def register_lazy(self, key, module_name, member_name):
        """Register a new option to be loaded on request.

        :param key: the key to request the option later. Since the registration
            is lazy, it should be provided and match the option name.

        :param module_name: the python path to the module. Such as 'os.path'.

        :param member_name: the member of the module to return.  If empty or 
                None, get() will return the module itself.
        """
        super(OptionRegistry, self).register_lazy(key,
                                                  module_name, member_name)

    def get_help(self, key=None):
        """Get the help text associated with the given key"""
        option = self.get(key)
        the_help = option.help
        if callable(the_help):
            return the_help(self, key)
        return the_help


option_registry = OptionRegistry()


# Registered options in lexicographical order

option_registry.register(
    Option('bzr.workingtree.worth_saving_limit', default=10,
           from_unicode=int_from_store,  invalid='warning',
           help='''\
How many changes before saving the dirstate.

-1 means that we will never rewrite the dirstate file for only
stat-cache changes. Regardless of this setting, we will always rewrite
the dirstate file if a file is added/removed/renamed/etc. This flag only
affects the behavior of updating the dirstate file after we notice that
a file has been touched.
'''))
option_registry.register(
    Option('dirstate.fdatasync', default=True,
           from_unicode=bool_from_store,
           help='''\
Flush dirstate changes onto physical disk?

If true (default), working tree metadata changes are flushed through the
OS buffers to physical disk.  This is somewhat slower, but means data
should not be lost if the machine crashes.  See also repository.fdatasync.
'''))
option_registry.register(
    Option('debug_flags', default=[], from_unicode=list_from_store,
           help='Debug flags to activate.'))
option_registry.register(
    Option('default_format', default='2a',
           help='Format used when creating branches.'))
option_registry.register(
    Option('dpush_strict', default=None,
           from_unicode=bool_from_store,
           help='''\
The default value for ``dpush --strict``.

If present, defines the ``--strict`` option default value for checking
uncommitted changes before pushing into a different VCS without any
custom bzr metadata.
'''))
option_registry.register(
    Option('editor',
           help='The command called to launch an editor to enter a message.'))
option_registry.register(
    Option('ignore_missing_extensions', default=False,
           from_unicode=bool_from_store,
           help='''\
Control the missing extensions warning display.

The warning will not be emitted if set to True.
'''))
option_registry.register(
    Option('language',
           help='Language to translate messages into.'))
option_registry.register(
    Option('locks.steal_dead', default=False, from_unicode=bool_from_store,
           help='''\
Steal locks that appears to be dead.

If set to True, bzr will check if a lock is supposed to be held by an
active process from the same user on the same machine. If the user and
machine match, but no process with the given PID is active, then bzr
will automatically break the stale lock, and create a new lock for
this process.
Otherwise, bzr will prompt as normal to break the lock.
'''))
option_registry.register(
    Option('output_encoding',
           help= 'Unicode encoding for output'
           ' (terminal encoding if not specified).'))
option_registry.register(
    Option('push_strict', default=None,
           from_unicode=bool_from_store,
           help='''\
The default value for ``push --strict``.

If present, defines the ``--strict`` option default value for checking
uncommitted changes before sending a merge directive.
'''))
option_registry.register(
    Option('repository.fdatasync', default=True,
           from_unicode=bool_from_store,
           help='''\
Flush repository changes onto physical disk?

If true (default), repository changes are flushed through the OS buffers
to physical disk.  This is somewhat slower, but means data should not be
lost if the machine crashes.  See also dirstate.fdatasync.
'''))
option_registry.register(
    Option('send_strict', default=None,
           from_unicode=bool_from_store,
           help='''\
The default value for ``send --strict``.

If present, defines the ``--strict`` option default value for checking
uncommitted changes before pushing.
'''))


class Section(object):
    """A section defines a dict of option name => value.

    This is merely a read-only dict which can add some knowledge about the
    options. It is *not* a python dict object though and doesn't try to mimic
    its API.
    """

    def __init__(self, section_id, options):
        self.id = section_id
        # We re-use the dict-like object received
        self.options = options

    def get(self, name, default=None):
        return self.options.get(name, default)

    def __repr__(self):
        # Mostly for debugging use
        return "<config.%s id=%s>" % (self.__class__.__name__, self.id)


_NewlyCreatedOption = object()
"""Was the option created during the MutableSection lifetime"""


class MutableSection(Section):
    """A section allowing changes and keeping track of the original values."""

    def __init__(self, section_id, options):
        super(MutableSection, self).__init__(section_id, options)
        self.orig = {}

    def set(self, name, value):
        if name not in self.options:
            # This is a new option
            self.orig[name] = _NewlyCreatedOption
        elif name not in self.orig:
            self.orig[name] = self.get(name, None)
        self.options[name] = value

    def remove(self, name):
        if name not in self.orig:
            self.orig[name] = self.get(name, None)
        del self.options[name]


class Store(object):
    """Abstract interface to persistent storage for configuration options."""

    readonly_section_class = Section
    mutable_section_class = MutableSection

    def is_loaded(self):
        """Returns True if the Store has been loaded.

        This is used to implement lazy loading and ensure the persistent
        storage is queried only when needed.
        """
        raise NotImplementedError(self.is_loaded)

    def load(self):
        """Loads the Store from persistent storage."""
        raise NotImplementedError(self.load)

    def _load_from_string(self, bytes):
        """Create a store from a string in configobj syntax.

        :param bytes: A string representing the file content.
        """
        raise NotImplementedError(self._load_from_string)

    def unload(self):
        """Unloads the Store.

        This should make is_loaded() return False. This is used when the caller
        knows that the persistent storage has changed or may have change since
        the last load.
        """
        raise NotImplementedError(self.unload)

    def save(self):
        """Saves the Store to persistent storage."""
        raise NotImplementedError(self.save)

    def external_url(self):
        raise NotImplementedError(self.external_url)

    def get_sections(self):
        """Returns an ordered iterable of existing sections.

        :returns: An iterable of (name, dict).
        """
        raise NotImplementedError(self.get_sections)

    def get_mutable_section(self, section_name=None):
        """Returns the specified mutable section.

        :param section_name: The section identifier
        """
        raise NotImplementedError(self.get_mutable_section)

    def __repr__(self):
        # Mostly for debugging use
        return "<config.%s(%s)>" % (self.__class__.__name__,
                                    self.external_url())


class IniFileStore(Store):
    """A config Store using ConfigObj for storage.

    :ivar transport: The transport object where the config file is located.

    :ivar file_name: The config file basename in the transport directory.

    :ivar _config_obj: Private member to hold the ConfigObj instance used to
        serialize/deserialize the config file.
    """

    def __init__(self, transport, file_name):
        """A config Store using ConfigObj for storage.

        :param transport: The transport object where the config file is located.

        :param file_name: The config file basename in the transport directory.
        """
        super(IniFileStore, self).__init__()
        self.transport = transport
        self.file_name = file_name
        self._config_obj = None

    def is_loaded(self):
        return self._config_obj != None

    def unload(self):
        self._config_obj = None

    def load(self):
        """Load the store from the associated file."""
        if self.is_loaded():
            return
        try:
            content = self.transport.get_bytes(self.file_name)
        except errors.PermissionDenied:
            trace.warning("Permission denied while trying to load "
                          "configuration store %s.", self.external_url())
            raise
        self._load_from_string(content)
        for hook in ConfigHooks['load']:
            hook(self)

    def _load_from_string(self, bytes):
        """Create a config store from a string.

        :param bytes: A string representing the file content.
        """
        if self.is_loaded():
            raise AssertionError('Already loaded: %r' % (self._config_obj,))
        co_input = StringIO(bytes)
        try:
            # The config files are always stored utf8-encoded
            self._config_obj = ConfigObj(co_input, encoding='utf-8',
                                         list_values=False)
        except configobj.ConfigObjError, e:
            self._config_obj = None
            raise errors.ParseConfigError(e.errors, self.external_url())
        except UnicodeDecodeError:
            raise errors.ConfigContentError(self.external_url())

    def save(self):
        if not self.is_loaded():
            # Nothing to save
            return
        out = StringIO()
        self._config_obj.write(out)
        self.transport.put_bytes(self.file_name, out.getvalue())
        for hook in ConfigHooks['save']:
            hook(self)

    def external_url(self):
        # FIXME: external_url should really accepts an optional relpath
        # parameter (bug #750169) :-/ -- vila 2011-04-04
        # The following will do in the interim but maybe we don't want to
        # expose a path here but rather a config ID and its associated
        # object </hand wawe>.
        return urlutils.join(self.transport.external_url(), self.file_name)

    def get_sections(self):
        """Get the configobj section in the file order.

        :returns: An iterable of (name, dict).
        """
        # We need a loaded store
        try:
            self.load()
        except (errors.NoSuchFile, errors.PermissionDenied):
            # If the file can't be read, there is no sections
            return
        cobj = self._config_obj
        if cobj.scalars:
            yield self.readonly_section_class(None, cobj)
        for section_name in cobj.sections:
            yield self.readonly_section_class(section_name, cobj[section_name])

    def get_mutable_section(self, section_name=None):
        # We need a loaded store
        try:
            self.load()
        except errors.NoSuchFile:
            # The file doesn't exist, let's pretend it was empty
            self._load_from_string('')
        if section_name is None:
            section = self._config_obj
        else:
            section = self._config_obj.setdefault(section_name, {})
        return self.mutable_section_class(section_name, section)


# Note that LockableConfigObjStore inherits from ConfigObjStore because we need
# unlockable stores for use with objects that can already ensure the locking
# (think branches). If different stores (not based on ConfigObj) are created,
# they may face the same issue.


class LockableIniFileStore(IniFileStore):
    """A ConfigObjStore using locks on save to ensure store integrity."""

    def __init__(self, transport, file_name, lock_dir_name=None):
        """A config Store using ConfigObj for storage.

        :param transport: The transport object where the config file is located.

        :param file_name: The config file basename in the transport directory.
        """
        if lock_dir_name is None:
            lock_dir_name = 'lock'
        self.lock_dir_name = lock_dir_name
        super(LockableIniFileStore, self).__init__(transport, file_name)
        self._lock = lockdir.LockDir(self.transport, self.lock_dir_name)

    def lock_write(self, token=None):
        """Takes a write lock in the directory containing the config file.

        If the directory doesn't exist it is created.
        """
        # FIXME: This doesn't check the ownership of the created directories as
        # ensure_config_dir_exists does. It should if the transport is local
        # -- vila 2011-04-06
        self.transport.create_prefix()
        return self._lock.lock_write(token)

    def unlock(self):
        self._lock.unlock()

    def break_lock(self):
        self._lock.break_lock()

    @needs_write_lock
    def save(self):
        # We need to be able to override the undecorated implementation
        self.save_without_locking()

    def save_without_locking(self):
        super(LockableIniFileStore, self).save()


# FIXME: global, bazaar, shouldn't that be 'user' instead or even
# 'user_defaults' as opposed to 'user_overrides', 'system_defaults'
# (/etc/bzr/bazaar.conf) and 'system_overrides' ? -- vila 2011-04-05

# FIXME: Moreover, we shouldn't need classes for these stores either, factory
# functions or a registry will make it easier and clearer for tests, focusing
# on the relevant parts of the API that needs testing -- vila 20110503 (based
# on a poolie's remark)
class GlobalStore(LockableIniFileStore):

    def __init__(self, possible_transports=None):
        t = transport.get_transport_from_path(
            config_dir(), possible_transports=possible_transports)
        super(GlobalStore, self).__init__(t, 'bazaar.conf')


class LocationStore(LockableIniFileStore):

    def __init__(self, possible_transports=None):
        t = transport.get_transport_from_path(
            config_dir(), possible_transports=possible_transports)
        super(LocationStore, self).__init__(t, 'locations.conf')


class BranchStore(IniFileStore):

    def __init__(self, branch):
        super(BranchStore, self).__init__(branch.control_transport,
                                          'branch.conf')
        self.branch = branch

    def lock_write(self, token=None):
        return self.branch.lock_write(token)

    def unlock(self):
        return self.branch.unlock()

    @needs_write_lock
    def save(self):
        # We need to be able to override the undecorated implementation
        self.save_without_locking()

    def save_without_locking(self):
        super(BranchStore, self).save()


class ControlStore(LockableIniFileStore):

    def __init__(self, bzrdir):
        super(ControlStore, self).__init__(bzrdir.transport,
                                          'control.conf',
                                           lock_dir_name='branch_lock')


class SectionMatcher(object):
    """Select sections into a given Store.

    This is intended to be used to postpone getting an iterable of sections
    from a store.
    """

    def __init__(self, store):
        self.store = store

    def get_sections(self):
        # This is where we require loading the store so we can see all defined
        # sections.
        sections = self.store.get_sections()
        # Walk the revisions in the order provided
        for s in sections:
            if self.match(s):
                yield s

    def match(self, section):
        """Does the proposed section match.

        :param section: A Section object.

        :returns: True if the section matches, False otherwise.
        """
        raise NotImplementedError(self.match)


class NameMatcher(SectionMatcher):

    def __init__(self, store, section_id):
        super(NameMatcher, self).__init__(store)
        self.section_id = section_id

    def match(self, section):
        return section.id == self.section_id


class LocationSection(Section):

    def __init__(self, section, length, extra_path):
        super(LocationSection, self).__init__(section.id, section.options)
        self.length = length
        self.extra_path = extra_path

    def get(self, name, default=None):
        value = super(LocationSection, self).get(name, default)
        if value is not None:
            policy_name = self.get(name + ':policy', None)
            policy = _policy_value.get(policy_name, POLICY_NONE)
            if policy == POLICY_APPENDPATH:
                value = urlutils.join(value, self.extra_path)
        return value


class LocationMatcher(SectionMatcher):

    def __init__(self, store, location):
        super(LocationMatcher, self).__init__(store)
        if location.startswith('file://'):
            location = urlutils.local_path_from_url(location)
        self.location = location

    def _get_matching_sections(self):
        """Get all sections matching ``location``."""
        # We slightly diverge from LocalConfig here by allowing the no-name
        # section as the most generic one and the lower priority.
        no_name_section = None
        all_sections = []
        # Filter out the no_name_section so _iter_for_location_by_parts can be
        # used (it assumes all sections have a name).
        for section in self.store.get_sections():
            if section.id is None:
                no_name_section = section
            else:
                all_sections.append(section)
        # Unfortunately _iter_for_location_by_parts deals with section names so
        # we have to resync.
        filtered_sections = _iter_for_location_by_parts(
            [s.id for s in all_sections], self.location)
        iter_all_sections = iter(all_sections)
        matching_sections = []
        if no_name_section is not None:
            matching_sections.append(
                LocationSection(no_name_section, 0, self.location))
        for section_id, extra_path, length in filtered_sections:
            # a section id is unique for a given store so it's safe to take the
            # first matching section while iterating. Also, all filtered
            # sections are part of 'all_sections' and will always be found
            # there.
            while True:
                section = iter_all_sections.next()
                if section_id == section.id:
                    matching_sections.append(
                        LocationSection(section, length, extra_path))
                    break
        return matching_sections

    def get_sections(self):
        # Override the default implementation as we want to change the order
        matching_sections = self._get_matching_sections()
        # We want the longest (aka more specific) locations first
        sections = sorted(matching_sections,
                          key=lambda section: (section.length, section.id),
                          reverse=True)
        # Sections mentioning 'ignore_parents' restrict the selection
        for section in sections:
            # FIXME: We really want to use as_bool below -- vila 2011-04-07
            ignore = section.get('ignore_parents', None)
            if ignore is not None:
                ignore = ui.bool_from_string(ignore)
            if ignore:
                break
            # Finally, we have a valid section
            yield section


class Stack(object):
    """A stack of configurations where an option can be defined"""

    _option_ref_re = lazy_regex.lazy_compile('({[^{}]+})')
    """Describes an exandable option reference.

    We want to match the most embedded reference first.

    I.e. for '{{foo}}' we will get '{foo}',
    for '{bar{baz}}' we will get '{baz}'
    """

    def __init__(self, sections_def, store=None, mutable_section_name=None):
        """Creates a stack of sections with an optional store for changes.

        :param sections_def: A list of Section or callables that returns an
            iterable of Section. This defines the Sections for the Stack and
            can be called repeatedly if needed.

        :param store: The optional Store where modifications will be
            recorded. If none is specified, no modifications can be done.

        :param mutable_section_name: The name of the MutableSection where
            changes are recorded. This requires the ``store`` parameter to be
            specified.
        """
        self.sections_def = sections_def
        self.store = store
        self.mutable_section_name = mutable_section_name

    def get(self, name, expand=None):
        """Return the *first* option value found in the sections.

        This is where we guarantee that sections coming from Store are loaded
        lazily: the loading is delayed until we need to either check that an
        option exists or get its value, which in turn may require to discover
        in which sections it can be defined. Both of these (section and option
        existence) require loading the store (even partially).

        :param name: The queried option.

        :param expand: Whether options references should be expanded.

        :returns: The value of the option.
        """
        # FIXME: No caching of options nor sections yet -- vila 20110503
        if expand is None:
            expand = _get_expand_default_value()
        value = None
        # Ensuring lazy loading is achieved by delaying section matching (which
        # implies querying the persistent storage) until it can't be avoided
        # anymore by using callables to describe (possibly empty) section
        # lists.
        for section_or_callable in self.sections_def:
            # Each section can expand to multiple ones when a callable is used
            if callable(section_or_callable):
                sections = section_or_callable()
            else:
                sections = [section_or_callable]
            for section in sections:
                value = section.get(name)
                if value is not None:
                    break
            if value is not None:
                break
        # If the option is registered, it may provide additional info about
        # value handling
        try:
            opt = option_registry.get(name)
        except KeyError:
            # Not registered
            opt = None
        def expand_and_convert(val):
            # This may need to be called twice if the value is None or ends up
            # being None during expansion or conversion.
            if val is not None:
                if expand:
                    if isinstance(val, basestring):
                        val = self._expand_options_in_string(val)
                    else:
                        trace.warning('Cannot expand "%s":'
                                      ' %s does not support option expansion'
                                      % (name, type(val)))
                if opt is not None:
                    val = opt.convert_from_unicode(val)
            return val
        value = expand_and_convert(value)
        if opt is not None and value is None:
            # If the option is registered, it may provide a default value
            value = opt.get_default()
            value = expand_and_convert(value)
        for hook in ConfigHooks['get']:
            hook(self, name, value)
        return value

    def expand_options(self, string, env=None):
        """Expand option references in the string in the configuration context.

        :param string: The string containing option(s) to expand.

        :param env: An option dict defining additional configuration options or
            overriding existing ones.

        :returns: The expanded string.
        """
        return self._expand_options_in_string(string, env)

    def _expand_options_in_string(self, string, env=None, _refs=None):
        """Expand options in the string in the configuration context.

        :param string: The string to be expanded.

        :param env: An option dict defining additional configuration options or
            overriding existing ones.

        :param _refs: Private list (FIFO) containing the options being expanded
            to detect loops.

        :returns: The expanded string.
        """
        if string is None:
            # Not much to expand there
            return None
        if _refs is None:
            # What references are currently resolved (to detect loops)
            _refs = []
        result = string
        # We need to iterate until no more refs appear ({{foo}} will need two
        # iterations for example).
        while True:
            raw_chunks = Stack._option_ref_re.split(result)
            if len(raw_chunks) == 1:
                # Shorcut the trivial case: no refs
                return result
            chunks = []
            # Split will isolate refs so that every other chunk is a ref
            chunk_is_ref = False
            for chunk in raw_chunks:
                if not chunk_is_ref:
                    chunks.append(chunk)
                    chunk_is_ref = True
                else:
                    name = chunk[1:-1]
                    if name in _refs:
                        raise errors.OptionExpansionLoop(string, _refs)
                    _refs.append(name)
                    value = self._expand_option(name, env, _refs)
                    if value is None:
                        raise errors.ExpandingUnknownOption(name, string)
                    chunks.append(value)
                    _refs.pop()
                    chunk_is_ref = False
            result = ''.join(chunks)
        return result

    def _expand_option(self, name, env, _refs):
        if env is not None and name in env:
            # Special case, values provided in env takes precedence over
            # anything else
            value = env[name]
        else:
            # FIXME: This is a limited implementation, what we really need is a
            # way to query the bzr config for the value of an option,
            # respecting the scope rules (That is, once we implement fallback
            # configs, getting the option value should restart from the top
            # config, not the current one) -- vila 20101222
            value = self.get(name, expand=False)
            value = self._expand_options_in_string(value, env, _refs)
        return value

    def _get_mutable_section(self):
        """Get the MutableSection for the Stack.

        This is where we guarantee that the mutable section is lazily loaded:
        this means we won't load the corresponding store before setting a value
        or deleting an option. In practice the store will often be loaded but
        this allows helps catching some programming errors.
        """
        section = self.store.get_mutable_section(self.mutable_section_name)
        return section

    def set(self, name, value):
        """Set a new value for the option."""
        section = self._get_mutable_section()
        section.set(name, value)
        for hook in ConfigHooks['set']:
            hook(self, name, value)

    def remove(self, name):
        """Remove an existing option."""
        section = self._get_mutable_section()
        section.remove(name)
        for hook in ConfigHooks['remove']:
            hook(self, name)

    def __repr__(self):
        # Mostly for debugging use
        return "<config.%s(%s)>" % (self.__class__.__name__, id(self))


class _CompatibleStack(Stack):
    """Place holder for compatibility with previous design.

    This is intended to ease the transition from the Config-based design to the
    Stack-based design and should not be used nor relied upon by plugins.

    One assumption made here is that the daughter classes will all use Stores
    derived from LockableIniFileStore).

    It implements set() by re-loading the store before applying the
    modification and saving it.

    The long term plan being to implement a single write by store to save
    all modifications, this class should not be used in the interim.
    """

    def set(self, name, value):
        # Force a reload
        self.store.unload()
        super(_CompatibleStack, self).set(name, value)
        # Force a write to persistent storage
        self.store.save()


class GlobalStack(_CompatibleStack):
    """Global options only stack."""

    def __init__(self):
        # Get a GlobalStore
        gstore = GlobalStore()
        super(GlobalStack, self).__init__([gstore.get_sections], gstore)


class LocationStack(_CompatibleStack):
    """Per-location options falling back to global options stack."""

    def __init__(self, location):
        """Make a new stack for a location and global configuration.
        
        :param location: A URL prefix to """
        lstore = LocationStore()
        matcher = LocationMatcher(lstore, location)
        gstore = GlobalStore()
        super(LocationStack, self).__init__(
            [matcher.get_sections, gstore.get_sections], lstore)


class BranchStack(_CompatibleStack):
    """Per-location options falling back to branch then global options stack."""

    def __init__(self, branch):
        bstore = BranchStore(branch)
        lstore = LocationStore()
        matcher = LocationMatcher(lstore, branch.base)
        gstore = GlobalStore()
        super(BranchStack, self).__init__(
            [matcher.get_sections, bstore.get_sections, gstore.get_sections],
            bstore)
        self.branch = branch


class RemoteControlStack(_CompatibleStack):
    """Remote control-only options stack."""

    def __init__(self, bzrdir):
        cstore = ControlStore(bzrdir)
        super(RemoteControlStack, self).__init__(
            [cstore.get_sections],
            cstore)
        self.bzrdir = bzrdir


class RemoteBranchStack(_CompatibleStack):
    """Remote branch-only options stack."""

    def __init__(self, branch):
        bstore = BranchStore(branch)
        super(RemoteBranchStack, self).__init__(
            [bstore.get_sections],
            bstore)
        self.branch = branch


class cmd_config(commands.Command):
    __doc__ = """Display, set or remove a configuration option.

    Display the active value for a given option.

    If --all is specified, NAME is interpreted as a regular expression and all
    matching options are displayed mentioning their scope. The active value
    that bzr will take into account is the first one displayed for each option.

    If no NAME is given, --all .* is implied.

    Setting a value is achieved by using name=value without spaces. The value
    is set in the most relevant scope and can be checked by displaying the
    option again.
    """

    takes_args = ['name?']

    takes_options = [
        'directory',
        # FIXME: This should be a registry option so that plugins can register
        # their own config files (or not) -- vila 20101002
        commands.Option('scope', help='Reduce the scope to the specified'
                        ' configuration file',
                        type=unicode),
        commands.Option('all',
            help='Display all the defined values for the matching options.',
            ),
        commands.Option('remove', help='Remove the option from'
                        ' the configuration file'),
        ]

    _see_also = ['configuration']

    @commands.display_command
    def run(self, name=None, all=False, directory=None, scope=None,
            remove=False):
        if directory is None:
            directory = '.'
        directory = urlutils.normalize_url(directory)
        if remove and all:
            raise errors.BzrError(
                '--all and --remove are mutually exclusive.')
        elif remove:
            # Delete the option in the given scope
            self._remove_config_option(name, directory, scope)
        elif name is None:
            # Defaults to all options
            self._show_matching_options('.*', directory, scope)
        else:
            try:
                name, value = name.split('=', 1)
            except ValueError:
                # Display the option(s) value(s)
                if all:
                    self._show_matching_options(name, directory, scope)
                else:
                    self._show_value(name, directory, scope)
            else:
                if all:
                    raise errors.BzrError(
                        'Only one option can be set.')
                # Set the option value
                self._set_config_option(name, value, directory, scope)

    def _get_configs(self, directory, scope=None):
        """Iterate the configurations specified by ``directory`` and ``scope``.

        :param directory: Where the configurations are derived from.

        :param scope: A specific config to start from.
        """
        if scope is not None:
            if scope == 'bazaar':
                yield GlobalConfig()
            elif scope == 'locations':
                yield LocationConfig(directory)
            elif scope == 'branch':
                (_, br, _) = bzrdir.BzrDir.open_containing_tree_or_branch(
                    directory)
                yield br.get_config()
        else:
            try:
                (_, br, _) = bzrdir.BzrDir.open_containing_tree_or_branch(
                    directory)
                yield br.get_config()
            except errors.NotBranchError:
                yield LocationConfig(directory)
                yield GlobalConfig()

    def _show_value(self, name, directory, scope):
        displayed = False
        for c in self._get_configs(directory, scope):
            if displayed:
                break
            for (oname, value, section, conf_id, parser) in c._get_options():
                if name == oname:
                    # Display only the first value and exit

                    # FIXME: We need to use get_user_option to take policies
                    # into account and we need to make sure the option exists
                    # too (hence the two for loops), this needs a better API
                    # -- vila 20101117
                    value = c.get_user_option(name)
                    # Quote the value appropriately
                    value = parser._quote(value)
                    self.outf.write('%s\n' % (value,))
                    displayed = True
                    break
        if not displayed:
            raise errors.NoSuchConfigOption(name)

    def _show_matching_options(self, name, directory, scope):
        name = lazy_regex.lazy_compile(name)
        # We want any error in the regexp to be raised *now* so we need to
        # avoid the delay introduced by the lazy regexp.  But, we still do
        # want the nicer errors raised by lazy_regex.
        name._compile_and_collapse()
        cur_conf_id = None
        cur_section = None
        for c in self._get_configs(directory, scope):
            for (oname, value, section, conf_id, parser) in c._get_options():
                if name.search(oname):
                    if cur_conf_id != conf_id:
                        # Explain where the options are defined
                        self.outf.write('%s:\n' % (conf_id,))
                        cur_conf_id = conf_id
                        cur_section = None
                    if (section not in (None, 'DEFAULT')
                        and cur_section != section):
                        # Display the section if it's not the default (or only)
                        # one.
                        self.outf.write('  [%s]\n' % (section,))
                        cur_section = section
                    self.outf.write('  %s = %s\n' % (oname, value))

    def _set_config_option(self, name, value, directory, scope):
        for conf in self._get_configs(directory, scope):
            conf.set_user_option(name, value)
            break
        else:
            raise errors.NoSuchConfig(scope)

    def _remove_config_option(self, name, directory, scope):
        if name is None:
            raise errors.BzrCommandError(
                '--remove expects an option to remove.')
        removed = False
        for conf in self._get_configs(directory, scope):
            for (section_name, section, conf_id) in conf._get_sections():
                if scope is not None and conf_id != scope:
                    # Not the right configuration file
                    continue
                if name in section:
                    if conf_id != conf.config_id():
                        conf = self._get_configs(directory, conf_id).next()
                    # We use the first section in the first config where the
                    # option is defined to remove it
                    conf.remove_user_option(name, section_name)
                    removed = True
                    break
            break
        else:
            raise errors.NoSuchConfig(scope)
        if not removed:
            raise errors.NoSuchConfigOption(name)

# Test registries
#
# We need adapters that can build a Store or a Stack in a test context. Test
# classes, based on TestCaseWithTransport, can use the registry to parametrize
# themselves. The builder will receive a test instance and should return a
# ready-to-use store or stack.  Plugins that define new store/stacks can also
# register themselves here to be tested against the tests defined in
# bzrlib.tests.test_config. Note that the builder can be called multiple times
# for the same tests.

# The registered object should be a callable receiving a test instance
# parameter (inheriting from tests.TestCaseWithTransport) and returning a Store
# object.
test_store_builder_registry = registry.Registry()

# The registered object should be a callable receiving a test instance
# parameter (inheriting from tests.TestCaseWithTransport) and returning a Stack
# object.
test_stack_builder_registry = registry.Registry()