contrib/dumprevlog

Make util.find_exe alway returns existing file, fixing issue1459

It seems like the old behaviour with different handling for commands with and
without path was intended, but I think this behaviour of util.find_exe is
better:
* Always returns existing file
* or None if command not found - no default
* Windows: Returned file thus always ends with extension from PATHEXT

This fixes http://www.selenic.com/mercurial/bts/issue1459. The change might
fix other unintended behaviour too.

#!/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-"