# filelog.py - file history class for mercurial
#
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from revlog import *
from demandload import *
demandload(globals(), "bdiff os")

class filelog(revlog):
    def __init__(self, opener, path, defversion=REVLOG_DEFAULT_VERSION):
        revlog.__init__(self, opener,
                        os.path.join("data", self.encodedir(path + ".i")),
                        os.path.join("data", self.encodedir(path + ".d")),
                        defversion)

    # This avoids a collision between a file named foo and a dir named
    # foo.i or foo.d
    def encodedir(self, path):
        return (path
                .replace(".hg/", ".hg.hg/")
                .replace(".i/", ".i.hg/")
                .replace(".d/", ".d.hg/"))

    def decodedir(self, path):
        return (path
                .replace(".d.hg/", ".d/")
                .replace(".i.hg/", ".i/")
                .replace(".hg.hg/", ".hg/"))

    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 readmeta(self, node):
        t = self.revision(node)
        if not t.startswith('\1\n'):
            return {}
        s = t.index('\1\n', 2)
        mt = t[2:s]
        m = {}
        for l in mt.splitlines():
            k, v = l.split(": ", 1)
            m[k] = v
        return m

    def add(self, text, meta, transaction, link, p1=None, p2=None):
        if meta or text.startswith('\1\n'):
            mt = ""
            if meta:
                mt = [ "%s: %s\n" % (k, v) for k,v in meta.items() ]
            text = "\1\n%s\1\n%s" % ("".join(mt), text)
        return self.addrevision(text, transaction, link, p1, p2)

    def renamed(self, node):
        if self.parents(node)[0] != nullid:
            return False
        m = self.readmeta(node)
        if m and m.has_key("copy"):
            return (m["copy"], 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))

        return revlog.size(self, rev)

    def cmp(self, node, text):
        """compare text with a given file revision"""

        # for renames, we have to go the slow way
        if self.renamed(node):
            t2 = self.read(node)
            return t2 != text

        return revlog.cmp(self, node, text)

    def annotate(self, node):

        def decorate(text, rev):
            return ([rev] * len(text.splitlines()), text)

        def pair(parent, child):
            for a1, a2, b1, b2 in bdiff.blocks(parent[1], child[1]):
                child[0][b1:b2] = parent[0][a1:a2]
            return child

        # find all ancestors
        needed = {(self, node):1}
        files = [self]
        visit = [(self, node)]
        while visit:
            f, n = visit.pop(0)
            rn = f.renamed(n)
            if rn:
                f, n = rn
                f = filelog(self.opener, f, self.defversion)
                files.insert(0, f)
                if (f, n) not in needed:
                    needed[(f, n)] = 1
                else:
                    needed[(f, n)] += 1
            for p in f.parents(n):
                if p == nullid:
                    continue
                if (f, p) not in needed:
                    needed[(f, p)] = 1
                    visit.append((f, p))
                else:
                    # count how many times we'll use this
                    needed[(f, p)] += 1

        # sort by revision (per file) which is a topological order
        visit = []
        for f in files:
            fn = [(f.rev(n[1]), f, n[1]) for n in needed.keys() if n[0] == f]
            fn.sort()
            visit.extend(fn)
        hist = {}

        for i in range(len(visit)):
            r, f, n = visit[i]
            curr = decorate(f.read(n), f.linkrev(n))
            if r == -1:
                continue
            parents = f.parents(n)
            # follow parents across renames
            if r < 1 and i > 0:
                j = i
                while j > 0 and visit[j][1] == f:
                    j -= 1
                parents = (visit[j][2],)
                f = visit[j][1]
            else:
                parents = f.parents(n)
            for p in parents:
                if p != nullid:
                    curr = pair(hist[p], curr)
                    # trim the history of unneeded revs
                    needed[(f, p)] -= 1
                    if not needed[(f, p)]:
                        del hist[p]
            hist[n] = curr

        return zip(hist[n][0], hist[n][1].splitlines(1))