contrib/dumprevlog

commands: add more robust support for 'hg log -b' (issue2078)

Fixes issue2078 and adds tests to cover various 'hg log -b' uses.

This change adds a localrepo.lookupbranch(key, remote=None) function. This
will look up the branch of the revision with the given key. The algorithm
works like this:

    * If a remote repo is given and KEY is the name of a branch in that repo,
      return KEY.
    * If no remote repo is given and KEY is the name of a branch in the local
      repo object, return KEY.
    * Otherwise look up the revision with the identifier KEY in the local repo
      and return its branch.

This change also makes 'hg log -b' use this new functionality and adds a few
tests for it.

#!/usr/bin/env python
# Dump revlogs as raw data stream
# $ find .hg/store/ -name "*.i" | xargs dumprevlog > repo.dump

import sys
from mercurial import revlog, node, util

for fp in (sys.stdin, sys.stdout, sys.stderr):
    util.set_binary(fp)

for f in sys.argv[1:]:
    binopen = lambda fn: open(fn, 'rb')
    r = revlog.revlog(binopen, f)
    print "file:", f
    for i in r:
        n = r.node(i)
        p = r.parents(n)
        d = r.revision(n)
        print "node:", node.hex(n)
        print "linkrev:", r.linkrev(i)
        print "parents:", node.hex(p[0]), node.hex(p[1])
        print "length:", len(d)
        print "-start-"
        print d
        print "-end-"