# filelog.py - file history class for mercurial

#

# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

import revlog

import re

_mdre = re.compile('\1\n')

def _parsemeta(text):

    """return (metadatadict, keylist, metadatasize)"""

    # text can be buffer, so we can't use .startswith or .index

    if text[:2] != '\1\n':

        return None, None, None

    s = _mdre.search(text, 2).start()

    mtext = text[2:s]

    meta = {}

    keys = []

    for l in mtext.splitlines():

        k, v = l.split(": ", 1)

        meta[k] = v

        keys.append(k)

    return meta, keys, (s + 2)

def _packmeta(meta, keys=None):

    if not keys:

        keys = sorted(meta.iterkeys())

    return "".join("%s: %s\n" % (k, meta[k]) for k in keys)

class filelog(revlog.revlog):

    def __init__(self, opener, path):

        revlog.revlog.__init__(self, opener,

                        "/".join(("data", path + ".i")))

    def read(self, node):

        t = self.revision(node)

        if not t.startswith('\1\n'):

            return t

        s = t.index('\1\n', 2)

        return t[s + 2:]

    def add(self, text, meta, transaction, link, p1=None, p2=None):

        if meta or text.startswith('\1\n'):

            text = "\1\n%s\1\n%s" % (_packmeta(meta), text)

        return self.addrevision(text, transaction, link, p1, p2)

    def renamed(self, node):

        if self.parents(node)[0] != revlog.nullid:

            return False

        t = self.revision(node)

        m = _parsemeta(t)[0]

        if m and "copy" in m:

            return (m["copy"], revlog.bin(m["copyrev"]))

        return False

    def size(self, rev):

        """return the size of a given revision"""

        # for revisions with renames, we have to go the slow way

        node = self.node(rev)

        if self.renamed(node):

            return len(self.read(node))

        # XXX if self.read(node).startswith("\1\n"), this returns (size+4)

        return revlog.revlog.size(self, rev)

    def cmp(self, node, text):

        """compare text with a given file revision

        returns True if text is different than what is stored.

        """

        t = text

        if text.startswith('\1\n'):

            t = '\1\n\1\n' + text

        samehashes = not revlog.revlog.cmp(self, node, t)

        if samehashes:

            return False

        # renaming a file produces a different hash, even if the data

        # remains unchanged. Check if it's the case (slow):

        if self.renamed(node):

            t2 = self.read(node)

            return t2 != text

        return True

    def _file(self, f):

        return filelog(self.opener, f)