"""

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.

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

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, base is not used, link, p1, p2, delta ref

            if self.version == revlog.REVLOGV0:

                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.revdiff(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, 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)