205
class _MPDiffGenerator(object):
206
"""Pull out the functionality for generating mp_diffs."""
208
def __init__(self, vf, keys):
210
# This is the order the keys were requested in
211
self.ordered_keys = tuple(keys)
212
# keys + their parents, what we need to compute the diffs
213
self.needed_keys = ()
214
# Map from key: mp_diff
216
# Map from key: parents_needed (may have ghosts)
218
# Parents that aren't present
219
self.ghost_parents = ()
220
# Map from parent_key => number of children for this text
222
# Content chunks that are cached while we still need them
225
def _find_needed_keys(self):
226
"""Find the set of keys we need to request.
228
This includes all the original keys passed in, and the non-ghost
229
parents of those keys.
231
:return: (needed_keys, refcounts)
232
needed_keys is the set of all texts we need to extract
233
refcounts is a dict of {key: num_children} letting us know when we
234
no longer need to cache a given parent text
236
# All the keys and their parents
237
needed_keys = set(self.ordered_keys)
238
parent_map = self.vf.get_parent_map(needed_keys)
239
self.parent_map = parent_map
240
# TODO: Should we be using a different construct here? I think this
241
# uses difference_update internally, and we expect the result to
243
missing_keys = needed_keys.difference(parent_map)
245
raise errors.RevisionNotPresent(list(missing_keys)[0], self.vf)
246
# Parents that might be missing. They are allowed to be ghosts, but we
247
# should check for them
249
setdefault = refcounts.setdefault
251
for child_key, parent_keys in parent_map.iteritems():
253
# parent_keys may be None if a given VersionedFile claims to
254
# not support graph operations.
256
just_parents.update(parent_keys)
257
needed_keys.update(parent_keys)
258
for p in parent_keys:
259
refcounts[p] = setdefault(p, 0) + 1
260
just_parents.difference_update(parent_map)
261
# Remove any parents that are actually ghosts from the needed set
262
self.present_parents = set(self.vf.get_parent_map(just_parents))
263
self.ghost_parents = just_parents.difference(self.present_parents)
264
needed_keys.difference_update(self.ghost_parents)
265
self.needed_keys = needed_keys
266
self.refcounts = refcounts
267
return needed_keys, refcounts
269
def _compute_diff(self, key, parent_lines, lines):
270
"""Compute a single mp_diff, and store it in self._diffs"""
271
if len(parent_lines) > 0:
272
# XXX: _extract_blocks is not usefully defined anywhere...
273
# It was meant to extract the left-parent diff without
274
# having to recompute it for Knit content (pack-0.92,
275
# etc). That seems to have regressed somewhere
276
left_parent_blocks = self.vf._extract_blocks(key,
277
parent_lines[0], lines)
279
left_parent_blocks = None
280
diff = multiparent.MultiParent.from_lines(lines,
281
parent_lines, left_parent_blocks)
282
self.diffs[key] = diff
284
def _process_one_record(self, key, this_chunks):
286
if key in self.parent_map:
287
# This record should be ready to diff, since we requested
288
# content in 'topological' order
289
parent_keys = self.parent_map.pop(key)
290
# If a VersionedFile claims 'no-graph' support, then it may return
291
# None for any parent request, so we replace it with an empty tuple
292
if parent_keys is None:
295
for p in parent_keys:
296
# Alternatively we could check p not in self.needed_keys, but
297
# ghost_parents should be tiny versus huge
298
if p in self.ghost_parents:
300
refcount = self.refcounts[p]
301
if refcount == 1: # Last child reference
302
self.refcounts.pop(p)
303
parent_chunks = self.chunks.pop(p)
305
self.refcounts[p] = refcount - 1
306
parent_chunks = self.chunks[p]
307
p_lines = osutils.chunks_to_lines(parent_chunks)
308
# TODO: Should we cache the line form? We did the
309
# computation to get it, but storing it this way will
310
# be less memory efficient...
311
parent_lines.append(p_lines)
313
lines = osutils.chunks_to_lines(this_chunks)
314
# Since we needed the lines, we'll go ahead and cache them this way
316
self._compute_diff(key, parent_lines, lines)
318
# Is this content required for any more children?
319
if key in self.refcounts:
320
self.chunks[key] = this_chunks
322
def _extract_diffs(self):
323
needed_keys, refcounts = self._find_needed_keys()
324
for record in self.vf.get_record_stream(needed_keys,
325
'topological', True):
326
if record.storage_kind == 'absent':
327
raise errors.RevisionNotPresent(record.key, self.vf)
328
self._process_one_record(record.key,
329
record.get_bytes_as('chunked'))
331
def compute_diffs(self):
332
self._extract_diffs()
333
dpop = self.diffs.pop
334
return [dpop(k) for k in self.ordered_keys]
337
209
class VersionedFile(object):
338
210
"""Versioned text file storage.
1184
1048
def make_mpdiffs(self, keys):
1185
1049
"""Create multiparent diffs for specified keys."""
1186
generator = _MPDiffGenerator(self, keys)
1187
return generator.compute_diffs()
1189
def get_annotator(self):
1190
return annotate.Annotator(self)
1050
keys_order = tuple(keys)
1051
keys = frozenset(keys)
1052
knit_keys = set(keys)
1053
parent_map = self.get_parent_map(keys)
1054
for parent_keys in parent_map.itervalues():
1056
knit_keys.update(parent_keys)
1057
missing_keys = keys - set(parent_map)
1059
raise errors.RevisionNotPresent(list(missing_keys)[0], self)
1060
# We need to filter out ghosts, because we can't diff against them.
1061
maybe_ghosts = knit_keys - keys
1062
ghosts = maybe_ghosts - set(self.get_parent_map(maybe_ghosts))
1063
knit_keys.difference_update(ghosts)
1065
chunks_to_lines = osutils.chunks_to_lines
1066
for record in self.get_record_stream(knit_keys, 'topological', True):
1067
lines[record.key] = chunks_to_lines(record.get_bytes_as('chunked'))
1068
# line_block_dict = {}
1069
# for parent, blocks in record.extract_line_blocks():
1070
# line_blocks[parent] = blocks
1071
# line_blocks[record.key] = line_block_dict
1073
for key in keys_order:
1075
parents = parent_map[key] or []
1076
# Note that filtering knit_keys can lead to a parent difference
1077
# between the creation and the application of the mpdiff.
1078
parent_lines = [lines[p] for p in parents if p in knit_keys]
1079
if len(parent_lines) > 0:
1080
left_parent_blocks = self._extract_blocks(key, parent_lines[0],
1083
left_parent_blocks = None
1084
diffs.append(multiparent.MultiParent.from_lines(target,
1085
parent_lines, left_parent_blocks))
1192
1088
missing_keys = index._missing_keys_from_parent_map
1194
1090
def _extract_blocks(self, version_id, source, target):
1197
def _transitive_fallbacks(self):
1198
"""Return the whole stack of fallback versionedfiles.
1200
This VersionedFiles may have a list of fallbacks, but it doesn't
1201
necessarily know about the whole stack going down, and it can't know
1202
at open time because they may change after the objects are opened.
1205
for a_vfs in self._immediate_fallback_vfs:
1206
all_fallbacks.append(a_vfs)
1207
all_fallbacks.extend(a_vfs._transitive_fallbacks())
1208
return all_fallbacks
1211
1094
class ThunkedVersionedFiles(VersionedFiles):
1212
1095
"""Storage for many versioned files thunked onto a 'VersionedFile' class.
1741
class NoDupeAddLinesDecorator(object):
1742
"""Decorator for a VersionedFiles that skips doing an add_lines if the key
1746
def __init__(self, store):
1749
def add_lines(self, key, parents, lines, parent_texts=None,
1750
left_matching_blocks=None, nostore_sha=None, random_id=False,
1751
check_content=True):
1752
"""See VersionedFiles.add_lines.
1754
This implementation may return None as the third element of the return
1755
value when the original store wouldn't.
1758
raise NotImplementedError(
1759
"NoDupeAddLinesDecorator.add_lines does not implement the "
1760
"nostore_sha behaviour.")
1762
sha1 = osutils.sha_strings(lines)
1763
key = ("sha1:" + sha1,)
1766
if key in self._store.get_parent_map([key]):
1767
# This key has already been inserted, so don't do it again.
1769
sha1 = osutils.sha_strings(lines)
1770
return sha1, sum(map(len, lines)), None
1771
return self._store.add_lines(key, parents, lines,
1772
parent_texts=parent_texts,
1773
left_matching_blocks=left_matching_blocks,
1774
nostore_sha=nostore_sha, random_id=random_id,
1775
check_content=check_content)
1777
def __getattr__(self, name):
1778
return getattr(self._store, name)
1781
1627
def network_bytes_to_kind_and_offset(network_bytes):
1782
1628
"""Strip of a record kind from the front of network_bytes.
added
removed
bzrlib/versionedfile.py
