annotate mercurial/bundlerepo.py @ 2439:e8c4f3d3df8c

extend network protocol to stop clients from locking servers

now all repositories have capabilities slot, tuple with list of names.

if 'unbundle' capability present, repo supports push where client does
not need to lock server.  repository classes that have unbundle capability
also have unbundle method.

implemented for ssh now, will be base for push over http.

unbundle protocol acts this way.  server tells client what heads it
has during normal negotiate step.  client starts unbundle by repeat
server's heads back to it.  if server has new heads, abort immediately.
otherwise, transfer changes to server.  once data transferred, server
locks and checks heads again.  if heads same, changes can be added.
else someone else added heads, and server aborts.

if client wants to force server to add heads, sends special heads list of
'force'.

"""
bundlerepo.py - repository class for viewing uncompressed bundles

This provides a read-only repository interface to bundles as if
they were part of the actual repository.

Copyright 2006 Benoit Boissinot <[e-mail]>

This software may be used and distributed according to the terms
of the GNU General Public License, incorporated herein by reference.
"""

from node import *
from i18n import gettext as _
from demandload import demandload
demandload(globals(), "changegroup util os struct bz2 tempfile")

import localrepo, changelog, manifest, filelog, revlog

class bundlerevlog(revlog.revlog):
    def __init__(self, opener, indexfile, datafile, 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, datafile)
        self.bundlefile = bundlefile
        self.basemap = {}
        def chunkpositer():
            for chunk in changegroup.chunkiter(bundlefile):
                pos = bundlefile.tell()
                yield chunk, pos - len(chunk)
        n = self.count()
        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 revlog.RevlogError(_("unknown parent %s") % short(p1))
            if linkmapper is None:
                link = n
            else:
                link = linkmapper(cs)

            if not prev:
                prev = p1
            # start, size, base is not used, link, p1, p2, delta ref
            if self.version == 0:
                e = (start, size, None, link, p1, p2, node)
            else:
                e = (self.offset_type(start, 0), size, -1, None, link,
                     self.rev(p1), self.rev(p2), node)
            self.basemap[n] = prev
            self.index.append(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, cachelen)
        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.chunk(self, rev1, rev2)

        return self.diff(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 = self.patches(text, [delta])

        p1, p2 = self.parents(node)
        if node != revlog.hash(text, p1, p2):
            raise revlog.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, unique=0):
        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, "00changelog.i", "00changelog.d",
                              bundlefile)

class bundlemanifest(bundlerevlog, manifest.manifest):
    def __init__(self, opener, bundlefile, linkmapper):
        manifest.manifest.__init__(self, opener)
        bundlerevlog.__init__(self, opener, self.indexfile, self.datafile,
                              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, self.datafile,
                              bundlefile, linkmapper)

class bundlerepository(localrepo.localrepository):
    def __init__(self, ui, path, bundlename):
        localrepo.localrepository.__init__(self, ui, path)
        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":
            fdtemp, temp = tempfile.mkstemp(prefix="hg-bundle-",
                                            suffix=".hg10un", dir=self.path)
            self.tempfile = temp
            fptemp = os.fdopen(fdtemp, 'wb')
            def generator(f):
                zd = bz2.BZ2Decompressor()
                zd.decompress("BZ")
                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)
        self.changelog = bundlechangelog(self.opener, self.bundlefile)
        self.manifest = bundlemanifest(self.opener, self.bundlefile,
                                       self.changelog.rev)
        # dict with the mapping 'filename' -> position in the bundle
        self.bundlefilespos = {}
        while 1:
            f = changegroup.getchunk(self.bundlefile)
            if not f:
                break
            self.bundlefilespos[f] = self.bundlefile.tell()
            for c in changegroup.chunkiter(self.bundlefile):
                pass

    def dev(self):
        return -1

    def file(self, f):
        if f[0] == '/':
            f = f[1:]
        if f in self.bundlefilespos:
            self.bundlefile.seek(self.bundlefilespos[f])
            return bundlefilelog(self.opener, f, self.bundlefile,
                                 self.changelog.rev)
        else:
            return filelog.filelog(self.opener, f)

    def close(self):
        """Close assigned bundle file immediately."""
        self.bundlefile.close()

    def __del__(self):
        if not self.bundlefile.closed:
            self.bundlefile.close()
        if self.tempfile is not None:
            os.unlink(self.tempfile)