contrib/dumprevlog

hgweb: side-by-side comparison functionality

Adds new web command to the core, ``comparison``, which enables colorful
side-by-side change display, which for some might be much easier to work with
than the standard line diff output. The idea how to implement comes from the
SonicHq extension.
The web interface gets a new link to call the comparison functionality. It lets
users configure the amount of context lines around change blocks, or to show
full files - check help (also in this changeset) for details and defaults. The
setting in hgrc can be overridden by adding ``context=<value>`` to the request
query string. The comparison creates addressable lines, so as to enable sharing
links to specific lines, just as standard diff does.
Incorporates updates to all web related styles.

Known limitations:
* the column diff is done against the first parent, just as the standard diff
* this change allows examining diffs for single files only (as I am not sure if
  examining the whole changeset in this way would be helpful)
* syntax highlighting of the output changes is not performed (enabling the
  highlight extension has no influence on 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.setbinary(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-"