contrib/dumprevlog

run-tests: cache hghave results

Spawning a process on Windows is expensive.  I've got a version of
test-lfs-test-server.t locally which prints the http request/responses that
totals 819 lines, with 149 conditional lines, 11 #if tests, and 2 test cases.
It takes just under 1 minute with this change to run both cases, vs just over
2 minutes without this change.  Worse, when I explored adding ui.debug to the
test, it takes 13 minutes due to all of the mismatches and retests, vs less than
1 minute with this change.  Overall, the difference when running all tests is
negligible- 103 minutes with this change, vs 105 without when using -j9.

It also looks like an exit value of 2 from `hghave` is treated specially, but
there's nothing preventing 2 missing features from also using this value.

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

from __future__ import absolute_import, print_function

import sys
from mercurial import (
    node,
    revlog,
    util,
)

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

def binopen(path, mode='rb'):
    if 'b' not in mode:
        mode = mode + 'b'
    return open(path, mode)

for f in sys.argv[1:]:
    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-")