"""

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, 2007 Benoit Boissinot <bboissin@gmail.com>

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 _

import changegroup, util, os, struct, bz2, tempfile, mdiff

import localrepo, changelog, manifest, filelog, revlog

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 = 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.LookupError(_("unknown parent %s") % short(p1))

            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 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, 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):

        localrepo.localrepository.__init__(self, ui, path)

        self._url = 'bundle:' + bundlename

        if path: self._url += '+' + 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.sopener, self.bundlefile)

        self.manifest = bundlemanifest(self.sopener, 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 url(self):

        return self._url

    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.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)

def instance(ui, path, create):

    if create:

        raise util.Abort(_('cannot create new bundle repository'))

    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 = "", s[0]

        else:

            repopath, bundlename = s

    else:

        repopath, bundlename = '', path

    return bundlerepository(ui, repopath, bundlename)