145
141
Names in this stack will get emitted into the output as they are popped
148
self._node_name_stack.append(node_name)
149
self._pending_parents_stack.append(list(parents))
152
"""Pop the top node off the stack
154
The node is appended to the sorted output.
156
# we are returning from the flattened call frame:
157
# pop off the local variables
158
node_name = self._node_name_stack.pop()
159
self._pending_parents_stack.pop()
161
self._completed_node_names.add(node_name)
165
def merge_sort(graph, branch_tip, mainline_revisions=None, generate_revno=False):
166
"""Topological sort a graph which groups merges.
168
:param graph: sequence of pairs of node->parents_list.
169
:param branch_tip: the tip of the branch to graph. Revisions not
170
reachable from branch_tip are not included in the
172
:param mainline_revisions: If not None this forces a mainline to be
173
used rather than synthesised from the graph.
174
This must be a valid path through some part
175
of the graph. If the mainline does not cover all
176
the revisions, output stops at the start of the
177
old revision listed in the mainline revisions
179
The order for this parameter is oldest-first.
180
:param generate_revno: Optional parameter controlling the generation of
181
revision number sequences in the output. See the output description of
182
the MergeSorter docstring for details.
183
:result: See the MergeSorter docstring for details.
184
node identifiers can be any hashable object, and are typically strings.
186
return MergeSorter(graph, branch_tip, mainline_revisions,
187
generate_revno).sorted()
190
class MergeSorter(object):
192
__slots__ = ['_node_name_stack',
193
'_node_merge_depth_stack',
194
'_pending_parents_stack',
195
'_assigned_sequence_stack',
196
'_left_subtree_pushed_stack',
199
'_mainline_revisions',
204
'_completed_node_names',
208
def __init__(self, graph, branch_tip, mainline_revisions=None,
209
generate_revno=False):
210
"""Merge-aware topological sorting of a graph.
212
:param graph: sequence of pairs of node_name->parent_names_list.
213
i.e. [('C', ['B']), ('B', ['A']), ('A', [])]
214
For this input the output from the sort or
215
iter_topo_order routines will be:
217
:param branch_tip: the tip of the branch to graph. Revisions not
218
reachable from branch_tip are not included in the
220
:param mainline_revisions: If not None this forces a mainline to be
221
used rather than synthesised from the graph.
222
This must be a valid path through some part
223
of the graph. If the mainline does not cover all
224
the revisions, output stops at the start of the
225
old revision listed in the mainline revisions
227
The order for this parameter is oldest-first.
228
:param generate_revno: Optional parameter controlling the generation of
229
revision number sequences in the output. See the output description
232
The result is a list sorted so that all parents come before
233
their children. Each element of the list is a tuple containing:
234
(sequence_number, node_name, merge_depth, end_of_merge)
235
* sequence_number: The sequence of this row in the output. Useful for
237
* node_name: The node name: opaque text to the merge routine.
238
* merge_depth: How many levels of merging deep this node has been
240
* revno_sequence: When requested this field provides a sequence of
241
revision numbers for all revisions. The format is:
242
REVNO[[.BRANCHREVNO.REVNO] ...]. BRANCHREVNO is the number of the
243
branch that the revno is on. From left to right the REVNO numbers
244
are the sequence numbers within that branch of the revision.
245
For instance, the graph {A:[], B:['A'], C:['A', 'B']} will get
246
the following revno_sequences assigned: A:(1,), B:(1,1,1), C:(2,).
247
This should be read as 'A is the first commit in the trunk',
248
'B is the first commit on the first branch made from A', 'C is the
249
second commit in the trunk'.
250
* end_of_merge: When True the next node is part of a different merge.
253
node identifiers can be any hashable object, and are typically strings.
255
If you have a graph like [('a', ['b']), ('a', ['c'])] this will only use
256
one of the two values for 'a'.
258
The graph is sorted lazily: until you iterate or sort the input is
259
not processed other than to create an internal representation.
261
iteration or sorting may raise GraphCycleError if a cycle is present
264
Background information on the design:
265
-------------------------------------
266
definition: the end of any cluster or 'merge' occurs when:
267
1 - the next revision has a lower merge depth than we do.
274
C, D are the ends of clusters, E might be but we need more data.
275
2 - or the next revision at our merge depth is not our left most
277
This is required to handle multiple-merges in one commit.
285
C is the end of a cluster due to rule 1.
286
D is not the end of a cluster from rule 1, but is from rule 2: E
287
is not its left most ancestor
288
E is the end of a cluster due to rule 1
289
F might be but we need more data.
291
we show connecting lines to a parent when:
292
- The parent is the start of a merge within this cluster.
293
That is, the merge was not done to the mainline before this cluster
294
was merged to the mainline.
295
This can be detected thus:
296
* The parent has a higher merge depth and is the next revision in
299
The next revision in the list constraint is needed for this case:
301
B 1 [C, F] # we do not want to show a line to F which is depth 2
303
C 1 [H] # note that this is a long line to show back to the
304
ancestor - see the end of merge rules.
310
- Part of this merges 'branch':
311
The parent has the same merge depth and is our left most parent and we
312
are not the end of the cluster.
313
A 0 [C, B] lines: [B, C]
314
B 1 [E, C] lines: [C]
316
D 0 [F, E] lines: [E, F]
319
- The end of this merge/cluster:
320
we can ONLY have multiple parents at the end of a cluster if this
321
branch was previously merged into the 'mainline'.
322
- if we have one and only one parent, show it
323
Note that this may be to a greater merge depth - for instance if
324
this branch continued from a deeply nested branch to add something
326
- if we have more than one parent - show the second oldest (older ==
327
further down the list) parent with
328
an equal or lower merge depth
329
XXXX revisit when awake. ddaa asks about the relevance of each one
330
- maybe more than one parent is relevant
332
self._generate_revno = generate_revno
333
# a dict of the graph.
334
self._graph = dict(graph)
335
# if there is an explicit mainline, alter the graph to match. This is
336
# easier than checking at every merge whether we are on the mainline and
337
# if so which path to take.
338
if mainline_revisions is None:
339
self._mainline_revisions = []
340
self._stop_revision = None
342
self._mainline_revisions = list(mainline_revisions)
343
self._stop_revision = self._mainline_revisions[0]
344
# skip the first revision, its what we reach and its parents are
345
# therefore irrelevant
346
for index, revision in enumerate(self._mainline_revisions[1:]):
347
# NB: index 0 means self._mainline_revisions[1]
348
# if the mainline matches the graph, nothing to do.
349
parent = self._mainline_revisions[index]
351
# end of mainline_revisions history
353
if self._graph[revision][0] == parent:
355
# remove it from its prior spot
356
self._graph[revision].remove(parent)
357
# insert it into the start of the mainline
358
self._graph[revision].insert(0, parent)
359
# we need to do a check late in the process to detect end-of-merges
360
# which requires the parents to be accessible: its easier for now
361
# to just keep the original graph around.
362
self._original_graph = dict(self._graph.items())
363
# we need to know the revision numbers of revisions to determine
364
# the revision numbers of their descendants
365
# this is a graph from node to [revno_tuple, sequence_number]
366
# where sequence is the number of branches made from the node,
367
# and revno_tuple is the tuple that was assigned to the node.
368
# we dont know revnos to start with, so we start it seeded with
370
self._revnos = dict((revision, [None, 0]) for revision in self._graph)
371
# the global implicit root node has revno 0, but we need to know
372
# the sequence number for it too:
373
self._root_sequence = 0
375
# this is a stack storing the depth first search into the graph.
376
self._node_name_stack = []
377
# at each level of recursion we need the merge depth this node is at:
378
self._node_merge_depth_stack = []
379
# at each level of 'recursion' we have to check each parent. This
380
# stack stores the parents we have not yet checked for the node at the
381
# matching depth in _node_name_stack
382
self._pending_parents_stack = []
383
# When we first look at a node we assign it a seqence number from its
385
self._assigned_sequence_stack = []
386
# this is a set of the nodes who have been completely analysed for fast
387
# membership checking
388
self._completed_node_names = set()
389
# this is the scheduling of nodes list.
390
# Nodes are scheduled
391
# from the bottom left of the tree: in the tree
398
# the scheduling order is: F, E, D, C, B, A
399
# that is - 'left subtree, right subtree, node'
400
# which would mean that when we schedule A we can emit the entire tree.
401
self._scheduled_nodes = []
402
# This records for each node when we have processed its left most
403
# unmerged subtree. After this subtree is scheduled, all other subtrees
404
# have their merge depth increased by one from this nodes merge depth.
405
# it contains tuples - name, merge_depth
406
self._left_subtree_pushed_stack = []
408
# seed the search with the tip of the branch
409
if branch_tip is not None:
410
parents = self._graph.pop(branch_tip)
411
self._push_node(branch_tip, 0, parents)
414
"""Sort the graph and return as a list.
416
After calling this the sorter is empty and you must create a new one.
418
return list(self.iter_topo_order())
420
def iter_topo_order(self):
421
"""Yield the nodes of the graph in a topological order.
423
After finishing iteration the sorter is empty and you cannot continue
426
# These are safe to offload to local variables, because they are used
427
# as a stack and modified in place, never assigned to.
428
node_name_stack = self._node_name_stack
429
node_merge_depth_stack = self._node_merge_depth_stack
430
pending_parents_stack = self._pending_parents_stack
431
left_subtree_pushed_stack = self._left_subtree_pushed_stack
432
completed_node_names = self._completed_node_names
433
scheduled_nodes = self._scheduled_nodes
435
graph_pop = self._graph.pop
437
def push_node(node_name, merge_depth, parents,
438
node_name_stack_append=node_name_stack.append,
439
node_merge_depth_stack_append=node_merge_depth_stack.append,
440
left_subtree_pushed_stack_append=left_subtree_pushed_stack.append,
441
pending_parents_stack_append=pending_parents_stack.append,
442
assigned_sequence_stack_append=self._assigned_sequence_stack.append,
443
original_graph=self._original_graph,
446
"""Add node_name to the pending node stack.
448
Names in this stack will get emitted into the output as they are popped
451
This inlines a lot of self._variable.append functions as local
454
node_name_stack_append(node_name)
455
node_merge_depth_stack_append(merge_depth)
456
left_subtree_pushed_stack_append(False)
457
pending_parents_stack_append(list(parents))
458
# as we push it, assign it a sequence number against its parent:
459
parents = original_graph[node_name]
461
# node has parents, assign from the left most parent.
462
parent_revno = revnos[parents[0]]
463
sequence = parent_revno[1]
466
# no parents, use the root sequence
467
sequence = self._root_sequence
468
self._root_sequence +=1
469
assigned_sequence_stack_append(sequence)
471
def pop_node(node_name_stack_pop=node_name_stack.pop,
472
node_merge_depth_stack_pop=node_merge_depth_stack.pop,
473
assigned_sequence_stack_pop=self._assigned_sequence_stack.pop,
474
left_subtree_pushed_stack_pop=left_subtree_pushed_stack.pop,
475
pending_parents_stack_pop=pending_parents_stack.pop,
476
original_graph=self._original_graph,
478
completed_node_names_add=self._completed_node_names.add,
479
scheduled_nodes_append=scheduled_nodes.append,
481
"""Pop the top node off the stack
483
The node is appended to the sorted output.
485
# we are returning from the flattened call frame:
486
# pop off the local variables
487
node_name = node_name_stack_pop()
488
merge_depth = node_merge_depth_stack_pop()
489
sequence = assigned_sequence_stack_pop()
490
# remove this node from the pending lists:
491
left_subtree_pushed_stack_pop()
492
pending_parents_stack_pop()
494
parents = original_graph[node_name]
496
# node has parents, assign from the left most parent.
497
parent_revno = revnos[parents[0]]
499
# not the first child, make a new branch
500
revno = parent_revno[0] + (sequence, 1)
502
# increment the sequence number within the branch
503
revno = parent_revno[0][:-1] + (parent_revno[0][-1] + 1,)
505
# no parents, use the root sequence
507
# make a parallel import revision number
508
revno = (0, sequence, 1)
512
# store the revno for this node for future reference
513
revnos[node_name][0] = revno
514
completed_node_names_add(node_name)
515
scheduled_nodes_append((node_name, merge_depth, revno))
519
while node_name_stack:
520
# loop until this call completes.
521
parents_to_visit = pending_parents_stack[-1]
522
# if all parents are done, the revision is done
523
if not parents_to_visit:
524
# append the revision to the topo sorted scheduled list:
525
# all the nodes parents have been scheduled added, now
526
# we can add it to the output.
529
while pending_parents_stack[-1]:
530
if not left_subtree_pushed_stack[-1]:
531
# recurse depth first into the primary parent
532
next_node_name = pending_parents_stack[-1].pop(0)
534
# place any merges in right-to-left order for scheduling
535
# which gives us left-to-right order after we reverse
536
# the scheduled queue. XXX: This has the effect of
537
# allocating common-new revisions to the right-most
538
# subtree rather than the left most, which will
539
# display nicely (you get smaller trees at the top
540
# of the combined merge).
541
next_node_name = pending_parents_stack[-1].pop()
542
if next_node_name in completed_node_names:
543
# this parent was completed by a child on the
544
# call stack. skip it.
546
# otherwise transfer it from the source graph into the
547
# top of the current depth first search stack.
549
parents = graph_pop(next_node_name)
551
# if the next node is not in the source graph it has
552
# already been popped from it and placed into the
553
# current search stack (but not completed or we would
554
# have hit the continue 4 lines up.
555
# this indicates a cycle.
556
raise errors.GraphCycleError(node_name_stack)
558
if left_subtree_pushed_stack[-1]:
559
# a new child branch from name_stack[-1]
563
left_subtree_pushed_stack[-1] = True
565
node_merge_depth_stack[-1] + next_merge_depth)
570
# and do not continue processing parents until this 'call'
574
# We have scheduled the graph. Now deliver the ordered output:
576
stop_revision = self._stop_revision
577
generate_revno = self._generate_revno
578
original_graph = self._original_graph
580
while scheduled_nodes:
581
node_name, merge_depth, revno = scheduled_nodes.pop()
582
if node_name == stop_revision:
584
if not len(scheduled_nodes):
585
# last revision is the end of a merge
587
elif scheduled_nodes[-1][1] < merge_depth:
588
# the next node is to our left
590
elif (scheduled_nodes[-1][1] == merge_depth and
591
(scheduled_nodes[-1][0] not in
592
original_graph[node_name])):
593
# the next node was part of a multiple-merge.
598
yield (sequence_number, node_name, merge_depth, revno, end_of_merge)
600
yield (sequence_number, node_name, merge_depth, end_of_merge)
603
def _push_node(self, node_name, merge_depth, parents):
604
"""Add node_name to the pending node stack.
606
Names in this stack will get emitted into the output as they are popped
609
self._node_name_stack.append(node_name)
610
self._node_merge_depth_stack.append(merge_depth)
611
self._left_subtree_pushed_stack.append(False)
612
self._pending_parents_stack.append(list(parents))
613
# as we push it, assign it a sequence number against its parent:
614
parents = self._original_graph[node_name]
616
# node has parents, assign from the left most parent.
617
parent_revno = self._revnos[parents[0]]
618
sequence = parent_revno[1]
621
# no parents, use the root sequence
622
sequence = self._root_sequence
623
self._root_sequence +=1
624
self._assigned_sequence_stack.append(sequence)
627
"""Pop the top node off the stack
629
The node is appended to the sorted output.
631
# we are returning from the flattened call frame:
632
# pop off the local variables
633
node_name = self._node_name_stack.pop()
634
merge_depth = self._node_merge_depth_stack.pop()
635
sequence = self._assigned_sequence_stack.pop()
636
# remove this node from the pending lists:
637
self._left_subtree_pushed_stack.pop()
638
self._pending_parents_stack.pop()
640
parents = self._original_graph[node_name]
642
# node has parents, assign from the left most parent.
643
parent_revno = self._revnos[parents[0]]
645
# not the first child, make a new branch
646
revno = parent_revno[0] + (sequence, 1)
648
# increment the sequence number within the branch
649
revno = parent_revno[0][:-1] + (parent_revno[0][-1] + 1,)
651
# no parents, use the root sequence
653
# make a parallel import revision number
654
revno = (0, sequence, 1)
658
# store the revno for this node for future reference
659
self._revnos[node_name][0] = revno
660
self._completed_node_names.add(node_name)
661
self._scheduled_nodes.append((node_name, merge_depth, self._revnos[node_name][0]))
145
self._node_name_stack.append(node_name)
146
self._pending_parents_stack.append(list(parents))
149
"""Pop the top node off the stack
151
The node is appended to the sorted output.
153
# we are returning from the flattened call frame:
154
# pop off the local variables
155
node_name = self._node_name_stack.pop()
156
self._pending_parents_stack.pop()
158
self._completed_node_names.add(node_name)
added
removed
bzrlib/tsort.py
