mercurial/bundlerepo.py

make incoming work via ssh (issue139); move chunk code into separate module.

Incoming ssh needs to detect the end of the changegroup, otherwise it would
block trying to read from the ssh pipe. This is done by parsing the
changegroup chunks.

bundlerepo.getchunk() already is identical to
localrepo.addchangegroup.getchunk(), which is followed by getgroup which
looks much like what you can re-use in bundlerepository.__init__() and in
write_bundle(). bundlerevlog.__init__.genchunk() looks very similar, too,
as do some while loops in localrepo.py.

Applied patch from Benoit Boissinot to move duplicate/related code
to mercurial/changegroup.py and use this to fix incoming ssh.

"""
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")

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
        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 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
            e = (start, size, None, link, p1, p2, node, 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 len(self.index[rev]) > 7
    def bundlebase(self, rev): return self.index[rev][7]
    def chunk(self, rev):
        # 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)
        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 RevlogError(_("integrity check failed on %s:%d")
                          % (self.datafile, self.rev(node)))

        self.cache = (node, rev, 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)
        f = open(bundlename, "rb")
        s = os.fstat(f.fileno())
        self.bundlefile = f
        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":
            raise util.Abort(_("%s: compressed bundle not supported")
                             % bundlename)
        elif header == "HG10UN":
            # uncompressed bundle supported
            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()