# 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.

from __future__ import absolute_import

from .thirdparty.zope import (

    interface as zi,

)

from . import (

    repository,

    revlog,

)

@zi.implementer(repository.ifilestorage)

class filelog(revlog.revlog):

    def __init__(self, opener, path):

        super(filelog, self).__init__(opener,

        # full name of the user visible file, relative to the repository root

        self.filename = path

    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 = revlog.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 = revlog.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))

        if self.iscensored(rev):

            return 0

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

        return super(filelog, self).size(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 super(filelog, self).cmp(node, t)

        if samehashes:

            return False

        # censored files compare against the empty file

        if self.iscensored(self.rev(node)):

            return text != ''

        # 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