We are currently indexing your data, so search results may be incomplete until we finish.
/ dulwich |
|
# object_store.py -- Object store for git objects
# Copyright (C) 2008-2009 Jelmer Vernooij <jelmer@samba.org>
#
# 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
# or (at your option) a 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.
"""Git object store interfaces and implementation."""
import itertools
import os
import stat
import tempfile
import urllib2
from dulwich.errors import (
NotTreeError,
)
from dulwich.objects import (
Commit,
ShaFile,
Tag,
Tree,
hex_to_sha,
sha_to_hex,
S_ISGITLINK,
)
from dulwich.pack import (
Pack,
PackData,
iter_sha1,
load_pack_index,
write_pack,
write_pack_data,
write_pack_index_v2,
)
PACKDIR = 'pack'
class BaseObjectStore(object):
"""Object store interface."""
def determine_wants_all(self, refs):
return [sha for (ref, sha) in refs.iteritems() if not sha in self and not ref.endswith("^{}")]
def iter_shas(self, shas):
"""Iterate over the objects for the specified shas.
:param shas: Iterable object with SHAs
:return: Object iterator
"""
return ObjectStoreIterator(self, shas)
def __contains__(self, sha):
"""Check if a particular object is present by SHA1."""
raise NotImplementedError(self.__contains__)
def get_raw(self, name):
"""Obtain the raw text for an object.
:param name: sha for the object.
:return: tuple with object type and object contents.
"""
raise NotImplementedError(self.get_raw)
def __getitem__(self, sha):
"""Obtain an object by SHA1."""
type, uncomp = self.get_raw(sha)
return ShaFile.from_raw_string(type, uncomp)
def __iter__(self):
"""Iterate over the SHAs that are present in this store."""
raise NotImplementedError(self.__iter__)
def add_object(self, obj):
"""Add a single object to this object store.
"""
raise NotImplementedError(self.add_object)
def add_objects(self, objects):
"""Add a set of objects to this object store.
:param objects: Iterable over a list of objects.
"""
raise NotImplementedError(self.add_objects)
def tree_changes(self, source, target, want_unchanged=False):
"""Find the differences between the contents of two trees
:param object_store: Object store to use for retrieving tree contents
:param tree: SHA1 of the root tree
:param want_unchanged: Whether unchanged files should be reported
:return: Iterator over tuples with (oldpath, newpath), (oldmode, newmode), (oldsha, newsha)
"""
todo = set([(source, target, "")])
while todo:
(sid, tid, path) = todo.pop()
if sid is not None:
stree = self[sid]
else:
stree = {}
if tid is not None:
ttree = self[tid]
else:
ttree = {}
for name, oldmode, oldhexsha in stree.iteritems():
if path == "":
oldchildpath = name
else:
oldchildpath = "%s/%s" % (path, name)
try:
(newmode, newhexsha) = ttree[name]
newchildpath = oldchildpath
except KeyError:
newmode = None
newhexsha = None
newchildpath = None
if (want_unchanged or oldmode != newmode or
oldhexsha != newhexsha):
if stat.S_ISDIR(oldmode):
if newmode is None or stat.S_ISDIR(newmode):
todo.add((oldhexsha, newhexsha, oldchildpath))
else:
# entry became a file
todo.add((oldhexsha, None, oldchildpath))
yield ((None, newchildpath), (None, newmode), (None, newhexsha))
else:
if newmode is not None and stat.S_ISDIR(newmode):
# entry became a dir
yield ((oldchildpath, None), (oldmode, None), (oldhexsha, None))
todo.add((None, newhexsha, newchildpath))
else:
yield ((oldchildpath, newchildpath), (oldmode, newmode), (oldhexsha, newhexsha))
for name, newmode, newhexsha in ttree.iteritems():
if path == "":
childpath = name
else:
childpath = "%s/%s" % (path, name)
if not name in stree:
if not stat.S_ISDIR(newmode):
yield ((None, childpath), (None, newmode), (None, newhexsha))
else:
todo.add((None, newhexsha, childpath))
def iter_tree_contents(self, tree):
"""Yield (path, mode, hexsha) tuples for all non-Tree objects in a tree.
:param tree: SHA1 of the root of the tree
"""
todo = set([(tree, "")])
while todo:
(tid, tpath) = todo.pop()
tree = self[tid]
for name, mode, hexsha in tree.iteritems():
if tpath == "":
path = name
else:
path = "%s/%s" % (tpath, name)
if stat.S_ISDIR(mode):
todo.add((hexsha, path))
else:
yield path, mode, hexsha
def find_missing_objects(self, haves, wants, progress=None):
"""Find the missing objects required for a set of revisions.
:param haves: Iterable over SHAs already in common.
:param wants: Iterable over SHAs of objects to fetch.
:param progress: Simple progress function that will be called with
updated progress strings.
:return: Iterator over (sha, path) pairs.
"""
return iter(MissingObjectFinder(self, haves, wants, progress).next, None)
def find_common_revisions(self, graphwalker):
"""Find which revisions this store has in common using graphwalker.
:param graphwalker: A graphwalker object.
:return: List of SHAs that are in common
"""
haves = []
sha = graphwalker.next()
while sha:
if sha in self:
haves.append(sha)
graphwalker.ack(sha)
sha = graphwalker.next()
return haves
def get_graph_walker(self, heads):
"""Obtain a graph walker for this object store.
:param heads: Local heads to start search with
:return: GraphWalker object
"""
return ObjectStoreGraphWalker(heads, lambda sha: self[sha].parents)
def generate_pack_contents(self, have, want):
"""Iterate over the contents of a pack file.
:param have: List of SHA1s of objects that should not be sent
:param want: List of SHA1s of objects that should be sent
"""
return self.iter_shas(self.find_missing_objects(have, want))
class DiskObjectStore(BaseObjectStore):
"""Git-style object store that exists on disk."""
def __init__(self, path):
"""Open an object store.
:param path: Path of the object store.
"""
self.path = path
self._pack_cache = None
self.pack_dir = os.path.join(self.path, PACKDIR)
def __contains__(self, sha):
"""Check if a particular object is present by SHA1."""
for pack in self.packs:
if sha in pack:
return True
ret = self._get_shafile(sha)
if ret is not None:
return True
return False
def __iter__(self):
"""Iterate over the SHAs that are present in this store."""
iterables = self.packs + [self._iter_shafile_shas()]
return itertools.chain(*iterables)
@property
def packs(self):
"""List with pack objects."""
if self._pack_cache is None:
self._pack_cache = list(self._load_packs())
return self._pack_cache
def _load_packs(self):
if not os.path.exists(self.pack_dir):
return
for name in os.listdir(self.pack_dir):
if name.startswith("pack-") and name.endswith(".pack"):
yield Pack(os.path.join(self.pack_dir, name[:-len(".pack")]))
def _add_known_pack(self, path):
"""Add a newly appeared pack to the cache by path.
"""
if self._pack_cache is not None:
self._pack_cache.append(Pack(path))
def _get_shafile_path(self, sha):
dir = sha[:2]
file = sha[2:]
# Check from object dir
return os.path.join(self.path, dir, file)
def _iter_shafile_shas(self):
for base in os.listdir(self.path):
if len(base) != 2:
continue
for rest in os.listdir(os.path.join(self.path, base)):
yield base+rest
def _get_shafile(self, sha):
path = self._get_shafile_path(sha)
if os.path.exists(path):
return ShaFile.from_file(path)
return None
def _add_shafile(self, sha, o):
dir = os.path.join(self.path, sha[:2])
if not os.path.isdir(dir):
os.mkdir(dir)
path = os.path.join(dir, sha[2:])
if os.path.exists(path):
return # Already there, no need to write again
f = open(path, 'w+')
try:
f.write(o.as_legacy_object())
finally:
f.close()
def get_raw(self, name):
"""Obtain the raw text for an object.
:param name: sha for the object.
:return: tuple with object type and object contents.
"""
if len(name) == 40:
sha = hex_to_sha(name)
hexsha = name
elif len(name) == 20:
sha = name
hexsha = None
else:
raise AssertionError
for pack in self.packs:
try:
return pack.get_raw(sha)
except KeyError:
pass
if hexsha is None:
hexsha = sha_to_hex(name)
ret = self._get_shafile(hexsha)
if ret is not None:
return ret.type, ret.as_raw_string()
raise KeyError(hexsha)
def move_in_thin_pack(self, path):
"""Move a specific file containing a pack into the pack directory.
:note: The file should be on the same file system as the
packs directory.
:param path: Path to the pack file.
"""
data = PackData(path)
# Write index for the thin pack (do we really need this?)
temppath = os.path.join(self.pack_dir,
sha_to_hex(urllib2.randombytes(20))+".tempidx")
data.create_index_v2(temppath, self.get_raw)
p = Pack.from_objects(data, load_pack_index(temppath))
# Write a full pack version
temppath = os.path.join(self.pack_dir,
sha_to_hex(urllib2.randombytes(20))+".temppack")
write_pack(temppath, ((o, None) for o in p.iterobjects(self.get_raw)),
len(p))
pack_sha = load_pack_index(temppath+".idx").objects_sha1()
newbasename = os.path.join(self.pack_dir, "pack-%s" % pack_sha)
os.rename(temppath+".pack", newbasename+".pack")
os.rename(temppath+".idx", newbasename+".idx")
self._add_known_pack(newbasename)
def move_in_pack(self, path):
"""Move a specific file containing a pack into the pack directory.
:note: The file should be on the same file system as the
packs directory.
:param path: Path to the pack file.
"""
p = PackData(path)
entries = p.sorted_entries()
basename = os.path.join(self.pack_dir,
"pack-%s" % iter_sha1(entry[0] for entry in entries))
write_pack_index_v2(basename+".idx", entries, p.get_stored_checksum())
p.close()
os.rename(path, basename + ".pack")
self._add_known_pack(basename)
def add_thin_pack(self):
"""Add a new thin pack to this object store.
Thin packs are packs that contain deltas with parents that exist
in a different pack.
"""
fd, path = tempfile.mkstemp(dir=self.pack_dir, suffix=".pack")
f = os.fdopen(fd, 'wb')
def commit():
os.fsync(fd)
f.close()
if os.path.getsize(path) > 0:
self.move_in_thin_pack(path)
return f, commit
def add_pack(self):
"""Add a new pack to this object store.
:return: Fileobject to write to and a commit function to
call when the pack is finished.
"""
fd, path = tempfile.mkstemp(dir=self.pack_dir, suffix=".pack")
f = os.fdopen(fd, 'wb')
def commit():
os.fsync(fd)
f.close()
if os.path.getsize(path) > 0:
self.move_in_pack(path)
return f, commit
def add_object(self, obj):
"""Add a single object to this object store.
:param obj: Object to add
"""
self._add_shafile(obj.id, obj)
def add_objects(self, objects):
"""Add a set of objects to this object store.
:param objects: Iterable over objects, should support __len__.
"""
if len(objects) == 0:
# Don't bother writing an empty pack file
return
f, commit = self.add_pack()
write_pack_data(f, objects, len(objects))
commit()
class MemoryObjectStore(BaseObjectStore):
"""Object store that keeps all objects in memory."""
def __init__(self):
super(MemoryObjectStore, self).__init__()
self._data = {}
def __contains__(self, sha):
"""Check if the object with a particular SHA is present."""
return sha in self._data
def __iter__(self):
"""Iterate over the SHAs that are present in this store."""
return self._data.iterkeys()
def get_raw(self, name):
"""Obtain the raw text for an object.
:param name: sha for the object.
:return: tuple with object type and object contents.
"""
return self[name].as_raw_string()
def __getitem__(self, name):
return self._data[name]
def add_object(self, obj):
"""Add a single object to this object store.
"""
self._data[obj.id] = obj
def add_objects(self, objects):
"""Add a set of objects to this object store.
:param objects: Iterable over a list of objects.
"""
for obj, path in objects:
self._data[obj.id] = obj
class ObjectImporter(object):
"""Interface for importing objects."""
def __init__(self, count):
"""Create a new ObjectImporter.
:param count: Number of objects that's going to be imported.
"""
self.count = count
def add_object(self, object):
"""Add an object."""
raise NotImplementedError(self.add_object)
def finish(self, object):
"""Finish the imoprt and write objects to disk."""
raise NotImplementedError(self.finish)
class ObjectIterator(object):
"""Interface for iterating over objects."""
def iterobjects(self):
raise NotImplementedError(self.iterobjects)
class ObjectStoreIterator(ObjectIterator):
"""ObjectIterator that works on top of an ObjectStore."""
def __init__(self, store, sha_iter):
"""Create a new ObjectIterator.
:param store: Object store to retrieve from
:param sha_iter: Iterator over (sha, path) tuples
"""
self.store = store
self.sha_iter = sha_iter
self._shas = []
def __iter__(self):
"""Yield tuple with next object and path."""
for sha, path in self.itershas():
yield self.store[sha], path
def iterobjects(self):
"""Iterate over just the objects."""
for o, path in self:
yield o
def itershas(self):
"""Iterate over the SHAs."""
for sha in self._shas:
yield sha
for sha in self.sha_iter:
self._shas.append(sha)
yield sha
def __contains__(self, needle):
"""Check if an object is present.
:note: This checks if the object is present in
the underlying object store, not if it would
be yielded by the iterator.
:param needle: SHA1 of the object to check for
"""
return needle in self.store
def __getitem__(self, key):
"""Find an object by SHA1.
:note: This retrieves the object from the underlying
object store. It will also succeed if the object would
not be returned by the iterator.
"""
return self.store[key]
def __len__(self):
"""Return the number of objects."""
return len(list(self.itershas()))
def tree_lookup_path(lookup_obj, root_sha, path):
"""Lookup an object in a Git tree.
:param lookup_obj: Callback for retrieving object by SHA1
:param root_sha: SHA1 of the root tree
:param path: Path to lookup
"""
parts = path.split("/")
sha = root_sha
for p in parts:
obj = lookup_obj(sha)
if type(obj) is not Tree:
raise NotTreeError(sha)
if p == '':
continue
mode, sha = obj[p]
return mode, sha
class MissingObjectFinder(object):
"""Find the objects missing from another object store.
:param object_store: Object store containing at least all objects to be
sent
:param haves: SHA1s of commits not to send (already present in target)
:param wants: SHA1s of commits to send
:param progress: Optional function to report progress to.
"""
def __init__(self, object_store, haves, wants, progress=None):
self.sha_done = set(haves)
self.objects_to_send = set([(w, None, False) for w in wants if w not in haves])
self.object_store = object_store
if progress is None:
self.progress = lambda x: None
else:
self.progress = progress
def add_todo(self, entries):
self.objects_to_send.update([e for e in entries if not e[0] in self.sha_done])
def parse_tree(self, tree):
self.add_todo([(sha, name, not stat.S_ISDIR(mode)) for (mode, name, sha) in tree.entries() if not S_ISGITLINK(mode)])
def parse_commit(self, commit):
self.add_todo([(commit.tree, "", False)])
self.add_todo([(p, None, False) for p in commit.parents])
def parse_tag(self, tag):
self.add_todo([(tag.object[1], None, False)])
def next(self):
if not self.objects_to_send:
return None
(sha, name, leaf) = self.objects_to_send.pop()
if not leaf:
o = self.object_store[sha]
if isinstance(o, Commit):
self.parse_commit(o)
elif isinstance(o, Tree):
self.parse_tree(o)
elif isinstance(o, Tag):
self.parse_tag(o)
self.sha_done.add(sha)
self.progress("counting objects: %d\r" % len(self.sha_done))
return (sha, name)
class ObjectStoreGraphWalker(object):
"""Graph walker that finds out what commits are missing from an object store."""
def __init__(self, local_heads, get_parents):
"""Create a new instance.
:param local_heads: Heads to start search with
:param get_parents: Function for finding the parents of a SHA1.
"""
self.heads = set(local_heads)
self.get_parents = get_parents
self.parents = {}
def ack(self, sha):
"""Ack that a particular revision and its ancestors are present in the source."""
if sha in self.heads:
self.heads.remove(sha)
if sha in self.parents:
for p in self.parents[sha]:
self.ack(p)
def next(self):
"""Iterate over ancestors of heads in the target."""
if self.heads:
ret = self.heads.pop()
ps = self.get_parents(ret)
self.parents[ret] = ps
self.heads.update(ps)
return ret
return None
|
Loading...