inotify: server: new data structure to keep track of changes.
== Rationale for the new structure ==
Current structure was a dictionary tree. One directory was tracked
as a dictionary:
- keys: file/subdir name
- values:
- for a file, the status (a/r/m/...)
- for a subdir, the directory representing the subdir
It allowed efficient lookups, no matter of the type of the terminal leaf:
for part in path.split('/'): tree = tree[part]
However, there is no way to represent a directory and a file with the same name
because keys are conflicting in the dictionary. Concrete example:
Initial state:
root dir
|- foo (file)
|- bar (file)
# data state is: {'foo': 'n', 'bar': 'n'}
Remove foo:
root dir
|- bar (file)
# Data becomes {'foo': 'r'} until next commit.
Add foo, as a directory, and foo/barbar file:
root dir
|- bar (file)
|-> foo (dir)
|- barbar (file)
# New state should be represented as:
{'foo': {'barbar': 'a'}, 'bar': 'n'}
however, the key "foo" is already used and represents the old file.
The dirstate:
D foo
A foo/barbar
cannot be represented, hence the need for a new structure.
== The new structure ==
'directory' class. Represents one directory level.
* Notable attributes:
Two dictionaries:
- 'files' Maps filename -> status for the current dir.
- 'dirs' Maps subdir's name -> directory object representing the subdir
* methods
- walk(), formerly server.walk
- lookup(), old server.lookup
- dir(), old server.dir
This new class allows embedding all the tree walks/lookups in its own class,
instead of having everything mixed together in server.
Incidently, since files and directories are not stored in the same
dictionaries, we are solving the previous key conflict problem.
The small drawback is that lookup operation is a bit more complex:
for a path a/b/c/d/e we have to check twice the leaf, if e is a directory or a
file.
# bundlerepo.py - repository class for viewing uncompressed bundles
#
# Copyright 2006, 2007 Benoit Boissinot <bboissin@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2, incorporated herein by reference.
"""Repository class for viewing uncompressed bundles.
This provides a read-only repository interface to bundles as if they
were part of the actual repository.
"""
from node import nullid
from i18n import _
import os, struct, bz2, zlib, tempfile, shutil
import changegroup, util, mdiff
import localrepo, changelog, manifest, filelog, revlog, error
class bundlerevlog(revlog.revlog):
def __init__(self, opener, indexfile, bundlefile,
linkmapper=None):
# How it works:
# to retrieve a revision, we need to know the offset of
# the revision in the bundlefile (an opened file).
#
# We store this offset in the index (start), to differentiate a
# rev in the bundle and from a rev in the revlog, we check
# len(index[r]). If the tuple is bigger than 7, it is a bundle
# (it is bigger since we store the node to which the delta is)
#
revlog.revlog.__init__(self, opener, indexfile)
self.bundlefile = bundlefile
self.basemap = {}
def chunkpositer():
for chunk in changegroup.chunkiter(bundlefile):
pos = bundlefile.tell()
yield chunk, pos - len(chunk)
n = len(self)
prev = None
for chunk, start in chunkpositer():
size = len(chunk)
if size < 80:
raise util.Abort(_("invalid changegroup"))
start += 80
size -= 80
node, p1, p2, cs = struct.unpack("20s20s20s20s", chunk[:80])
if node in self.nodemap:
prev = node
continue
for p in (p1, p2):
if not p in self.nodemap:
raise error.LookupError(p1, self.indexfile,
_("unknown parent"))
if linkmapper is None:
link = n
else:
link = linkmapper(cs)
if not prev:
prev = p1
# start, size, full unc. size, base (unused), link, p1, p2, node
e = (revlog.offset_type(start, 0), size, -1, -1, link,
self.rev(p1), self.rev(p2), node)
self.basemap[n] = prev
self.index.insert(-1, e)
self.nodemap[node] = n
prev = node
n += 1
def bundle(self, rev):
"""is rev from the bundle"""
if rev < 0:
return False
return rev in self.basemap
def bundlebase(self, rev): return self.basemap[rev]
def chunk(self, rev, df=None, cachelen=4096):
# Warning: in case of bundle, the diff is against bundlebase,
# not against rev - 1
# XXX: could use some caching
if not self.bundle(rev):
return revlog.revlog.chunk(self, rev, df)
self.bundlefile.seek(self.start(rev))
return self.bundlefile.read(self.length(rev))
def revdiff(self, rev1, rev2):
"""return or calculate a delta between two revisions"""
if self.bundle(rev1) and self.bundle(rev2):
# hot path for bundle
revb = self.rev(self.bundlebase(rev2))
if revb == rev1:
return self.chunk(rev2)
elif not self.bundle(rev1) and not self.bundle(rev2):
return revlog.revlog.revdiff(self, rev1, rev2)
return mdiff.textdiff(self.revision(self.node(rev1)),
self.revision(self.node(rev2)))
def revision(self, node):
"""return an uncompressed revision of a given"""
if node == nullid: return ""
text = None
chain = []
iter_node = node
rev = self.rev(iter_node)
# reconstruct the revision if it is from a changegroup
while self.bundle(rev):
if self._cache and self._cache[0] == iter_node:
text = self._cache[2]
break
chain.append(rev)
iter_node = self.bundlebase(rev)
rev = self.rev(iter_node)
if text is None:
text = revlog.revlog.revision(self, iter_node)
while chain:
delta = self.chunk(chain.pop())
text = mdiff.patches(text, [delta])
p1, p2 = self.parents(node)
if node != revlog.hash(text, p1, p2):
raise error.RevlogError(_("integrity check failed on %s:%d")
% (self.datafile, self.rev(node)))
self._cache = (node, self.rev(node), text)
return text
def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):
raise NotImplementedError
def addgroup(self, revs, linkmapper, transaction):
raise NotImplementedError
def strip(self, rev, minlink):
raise NotImplementedError
def checksize(self):
raise NotImplementedError
class bundlechangelog(bundlerevlog, changelog.changelog):
def __init__(self, opener, bundlefile):
changelog.changelog.__init__(self, opener)
bundlerevlog.__init__(self, opener, self.indexfile, bundlefile)
class bundlemanifest(bundlerevlog, manifest.manifest):
def __init__(self, opener, bundlefile, linkmapper):
manifest.manifest.__init__(self, opener)
bundlerevlog.__init__(self, opener, self.indexfile, bundlefile,
linkmapper)
class bundlefilelog(bundlerevlog, filelog.filelog):
def __init__(self, opener, path, bundlefile, linkmapper):
filelog.filelog.__init__(self, opener, path)
bundlerevlog.__init__(self, opener, self.indexfile, bundlefile,
linkmapper)
class bundlerepository(localrepo.localrepository):
def __init__(self, ui, path, bundlename):
self._tempparent = None
try:
localrepo.localrepository.__init__(self, ui, path)
except error.RepoError:
self._tempparent = tempfile.mkdtemp()
localrepo.instance(ui,self._tempparent,1)
localrepo.localrepository.__init__(self, ui, self._tempparent)
if path:
self._url = 'bundle:' + path + '+' + bundlename
else:
self._url = 'bundle:' + bundlename
self.tempfile = None
self.bundlefile = open(bundlename, "rb")
header = self.bundlefile.read(6)
if not header.startswith("HG"):
raise util.Abort(_("%s: not a Mercurial bundle file") % bundlename)
elif not header.startswith("HG10"):
raise util.Abort(_("%s: unknown bundle version") % bundlename)
elif (header == "HG10BZ") or (header == "HG10GZ"):
fdtemp, temp = tempfile.mkstemp(prefix="hg-bundle-",
suffix=".hg10un", dir=self.path)
self.tempfile = temp
fptemp = os.fdopen(fdtemp, 'wb')
def generator(f):
if header == "HG10BZ":
zd = bz2.BZ2Decompressor()
zd.decompress("BZ")
elif header == "HG10GZ":
zd = zlib.decompressobj()
for chunk in f:
yield zd.decompress(chunk)
gen = generator(util.filechunkiter(self.bundlefile, 4096))
try:
fptemp.write("HG10UN")
for chunk in gen:
fptemp.write(chunk)
finally:
fptemp.close()
self.bundlefile.close()
self.bundlefile = open(self.tempfile, "rb")
# seek right after the header
self.bundlefile.seek(6)
elif header == "HG10UN":
# nothing to do
pass
else:
raise util.Abort(_("%s: unknown bundle compression type")
% bundlename)
# dict with the mapping 'filename' -> position in the bundle
self.bundlefilespos = {}
@util.propertycache
def changelog(self):
c = bundlechangelog(self.sopener, self.bundlefile)
self.manstart = self.bundlefile.tell()
return c
@util.propertycache
def manifest(self):
self.bundlefile.seek(self.manstart)
m = bundlemanifest(self.sopener, self.bundlefile, self.changelog.rev)
self.filestart = self.bundlefile.tell()
return m
@util.propertycache
def manstart(self):
self.changelog
return self.manstart
@util.propertycache
def filestart(self):
self.manifest
return self.filestart
def url(self):
return self._url
def file(self, f):
if not self.bundlefilespos:
self.bundlefile.seek(self.filestart)
while 1:
chunk = changegroup.getchunk(self.bundlefile)
if not chunk:
break
self.bundlefilespos[chunk] = self.bundlefile.tell()
for c in changegroup.chunkiter(self.bundlefile):
pass
if f[0] == '/':
f = f[1:]
if f in self.bundlefilespos:
self.bundlefile.seek(self.bundlefilespos[f])
return bundlefilelog(self.sopener, f, self.bundlefile,
self.changelog.rev)
else:
return filelog.filelog(self.sopener, f)
def close(self):
"""Close assigned bundle file immediately."""
self.bundlefile.close()
def __del__(self):
bundlefile = getattr(self, 'bundlefile', None)
if bundlefile and not bundlefile.closed:
bundlefile.close()
tempfile = getattr(self, 'tempfile', None)
if tempfile is not None:
os.unlink(tempfile)
if self._tempparent:
shutil.rmtree(self._tempparent, True)
def cancopy(self):
return False
def getcwd(self):
return os.getcwd() # always outside the repo
def instance(ui, path, create):
if create:
raise util.Abort(_('cannot create new bundle repository'))
parentpath = ui.config("bundle", "mainreporoot", "")
if parentpath:
# Try to make the full path relative so we get a nice, short URL.
# In particular, we don't want temp dir names in test outputs.
cwd = os.getcwd()
if parentpath == cwd:
parentpath = ''
else:
cwd = os.path.join(cwd,'')
if parentpath.startswith(cwd):
parentpath = parentpath[len(cwd):]
path = util.drop_scheme('file', path)
if path.startswith('bundle:'):
path = util.drop_scheme('bundle', path)
s = path.split("+", 1)
if len(s) == 1:
repopath, bundlename = parentpath, s[0]
else:
repopath, bundlename = s
else:
repopath, bundlename = parentpath, path
return bundlerepository(ui, repopath, bundlename)