/usr/share/pyshared/dulwich/walk.py is in python-dulwich 0.8.5-2.
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# Copyright (C) 2010 Google, Inc.
#
# 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; version 2
# or (at your option) any later version of the License.
#
# 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.
"""General implementation of walking commits and their contents."""
try:
from collections import defaultdict
except ImportError:
from _compat import defaultdict
import collections
import heapq
import itertools
from dulwich._compat import (
all,
)
from dulwich.diff_tree import (
RENAME_CHANGE_TYPES,
tree_changes,
tree_changes_for_merge,
RenameDetector,
)
from dulwich.errors import (
MissingCommitError,
)
ORDER_DATE = 'date'
ORDER_TOPO = 'topo'
ALL_ORDERS = (ORDER_DATE, ORDER_TOPO)
# Maximum number of commits to walk past a commit time boundary.
_MAX_EXTRA_COMMITS = 5
class WalkEntry(object):
"""Object encapsulating a single result from a walk."""
def __init__(self, walker, commit):
self.commit = commit
self._store = walker.store
self._changes = None
self._rename_detector = walker.rename_detector
def changes(self):
"""Get the tree changes for this entry.
:return: For commits with up to one parent, a list of TreeChange
objects; if the commit has no parents, these will be relative to the
empty tree. For merge commits, a list of lists of TreeChange
objects; see dulwich.diff.tree_changes_for_merge.
"""
if self._changes is None:
commit = self.commit
if not commit.parents:
changes_func = tree_changes
parent = None
elif len(commit.parents) == 1:
changes_func = tree_changes
parent = self._store[commit.parents[0]].tree
else:
changes_func = tree_changes_for_merge
parent = [self._store[p].tree for p in commit.parents]
self._changes = list(changes_func(
self._store, parent, commit.tree,
rename_detector=self._rename_detector))
return self._changes
def __repr__(self):
return '<WalkEntry commit=%s, changes=%r>' % (
self.commit.id, self.changes())
class _CommitTimeQueue(object):
"""Priority queue of WalkEntry objects by commit time."""
def __init__(self, walker):
self._walker = walker
self._store = walker.store
self._excluded = walker.excluded
self._pq = []
self._pq_set = set()
self._seen = set()
self._done = set()
self._min_time = walker.since
self._last = None
self._extra_commits_left = _MAX_EXTRA_COMMITS
self._is_finished = False
for commit_id in itertools.chain(walker.include, walker.excluded):
self._push(commit_id)
def _push(self, commit_id):
try:
commit = self._store[commit_id]
except KeyError:
raise MissingCommitError(commit_id)
if commit_id not in self._pq_set and commit_id not in self._done:
heapq.heappush(self._pq, (-commit.commit_time, commit))
self._pq_set.add(commit_id)
self._seen.add(commit_id)
def _exclude_parents(self, commit):
excluded = self._excluded
seen = self._seen
todo = [commit]
while todo:
commit = todo.pop()
for parent in commit.parents:
if parent not in excluded and parent in seen:
# TODO: This is inefficient unless the object store does
# some caching (which DiskObjectStore currently does not).
# We could either add caching in this class or pass around
# parsed queue entry objects instead of commits.
todo.append(self._store[parent])
excluded.add(parent)
def next(self):
if self._is_finished:
return None
while self._pq:
_, commit = heapq.heappop(self._pq)
sha = commit.id
self._pq_set.remove(sha)
if sha in self._done:
continue
self._done.add(commit.id)
for parent_id in commit.parents:
self._push(parent_id)
reset_extra_commits = True
is_excluded = sha in self._excluded
if is_excluded:
self._exclude_parents(commit)
if self._pq and all(c.id in self._excluded
for _, c in self._pq):
_, n = self._pq[0]
if n.commit_time >= self._last.commit_time:
# If the next commit is newer than the last one, we need
# to keep walking in case its parents (which we may not
# have seen yet) are excluded. This gives the excluded
# set a chance to "catch up" while the commit is still
# in the Walker's output queue.
reset_extra_commits = True
else:
reset_extra_commits = False
if (self._min_time is not None and
commit.commit_time < self._min_time):
# We want to stop walking at min_time, but commits at the
# boundary may be out of order with respect to their parents. So
# we walk _MAX_EXTRA_COMMITS more commits once we hit this
# boundary.
reset_extra_commits = False
if reset_extra_commits:
# We're not at a boundary, so reset the counter.
self._extra_commits_left = _MAX_EXTRA_COMMITS
else:
self._extra_commits_left -= 1
if not self._extra_commits_left:
break
if not is_excluded:
self._last = commit
return WalkEntry(self._walker, commit)
self._is_finished = True
return None
class Walker(object):
"""Object for performing a walk of commits in a store.
Walker objects are initialized with a store and other options and can then
be treated as iterators of Commit objects.
"""
def __init__(self, store, include, exclude=None, order=ORDER_DATE,
reverse=False, max_entries=None, paths=None,
rename_detector=None, follow=False, since=None, until=None,
queue_cls=_CommitTimeQueue):
"""Constructor.
:param store: ObjectStore instance for looking up objects.
:param include: Iterable of SHAs of commits to include along with their
ancestors.
:param exclude: Iterable of SHAs of commits to exclude along with their
ancestors, overriding includes.
:param order: ORDER_* constant specifying the order of results. Anything
other than ORDER_DATE may result in O(n) memory usage.
:param reverse: If True, reverse the order of output, requiring O(n)
memory.
:param max_entries: The maximum number of entries to yield, or None for
no limit.
:param paths: Iterable of file or subtree paths to show entries for.
:param rename_detector: diff.RenameDetector object for detecting
renames.
:param follow: If True, follow path across renames/copies. Forces a
default rename_detector.
:param since: Timestamp to list commits after.
:param until: Timestamp to list commits before.
:param queue_cls: A class to use for a queue of commits, supporting the
iterator protocol. The constructor takes a single argument, the
Walker.
"""
# Note: when adding arguments to this method, please also update
# dulwich.repo.BaseRepo.get_walker
if order not in ALL_ORDERS:
raise ValueError('Unknown walk order %s' % order)
self.store = store
self.include = include
self.excluded = set(exclude or [])
self.order = order
self.reverse = reverse
self.max_entries = max_entries
self.paths = paths and set(paths) or None
if follow and not rename_detector:
rename_detector = RenameDetector(store)
self.rename_detector = rename_detector
self.follow = follow
self.since = since
self.until = until
self._num_entries = 0
self._queue = queue_cls(self)
self._out_queue = collections.deque()
def _path_matches(self, changed_path):
if changed_path is None:
return False
for followed_path in self.paths:
if changed_path == followed_path:
return True
if (changed_path.startswith(followed_path) and
changed_path[len(followed_path)] == '/'):
return True
return False
def _change_matches(self, change):
old_path = change.old.path
new_path = change.new.path
if self._path_matches(new_path):
if self.follow and change.type in RENAME_CHANGE_TYPES:
self.paths.add(old_path)
self.paths.remove(new_path)
return True
elif self._path_matches(old_path):
return True
return False
def _should_return(self, entry):
"""Determine if a walk entry should be returned..
:param entry: The WalkEntry to consider.
:return: True if the WalkEntry should be returned by this walk, or False
otherwise (e.g. if it doesn't match any requested paths).
"""
commit = entry.commit
if self.since is not None and commit.commit_time < self.since:
return False
if self.until is not None and commit.commit_time > self.until:
return False
if commit.id in self.excluded:
return False
if self.paths is None:
return True
if len(commit.parents) > 1:
for path_changes in entry.changes():
# For merge commits, only include changes with conflicts for
# this path. Since a rename conflict may include different
# old.paths, we have to check all of them.
for change in path_changes:
if self._change_matches(change):
return True
else:
for change in entry.changes():
if self._change_matches(change):
return True
return None
def _next(self):
max_entries = self.max_entries
while max_entries is None or self._num_entries < max_entries:
entry = self._queue.next()
if entry is not None:
self._out_queue.append(entry)
if entry is None or len(self._out_queue) > _MAX_EXTRA_COMMITS:
if not self._out_queue:
return None
entry = self._out_queue.popleft()
if self._should_return(entry):
self._num_entries += 1
return entry
return None
def _reorder(self, results):
"""Possibly reorder a results iterator.
:param results: An iterator of WalkEntry objects, in the order returned
from the queue_cls.
:return: An iterator or list of WalkEntry objects, in the order required
by the Walker.
"""
if self.order == ORDER_TOPO:
results = _topo_reorder(results)
if self.reverse:
results = reversed(list(results))
return results
def __iter__(self):
return iter(self._reorder(iter(self._next, None)))
def _topo_reorder(entries):
"""Reorder an iterable of entries topologically.
This works best assuming the entries are already in almost-topological
order, e.g. in commit time order.
:param entries: An iterable of WalkEntry objects.
:yield: WalkEntry objects from entries in FIFO order, except where a parent
would be yielded before any of its children.
"""
todo = collections.deque()
pending = {}
num_children = defaultdict(int)
for entry in entries:
todo.append(entry)
for p in entry.commit.parents:
num_children[p] += 1
while todo:
entry = todo.popleft()
commit = entry.commit
commit_id = commit.id
if num_children[commit_id]:
pending[commit_id] = entry
continue
for parent_id in commit.parents:
num_children[parent_id] -= 1
if not num_children[parent_id]:
parent_entry = pending.pop(parent_id, None)
if parent_entry:
todo.appendleft(parent_entry)
yield entry
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