view contrib/debugcmdserver.py @ 24572:b83679eb5f86

manifestv2: add support for reading new manifest format

The new manifest format is designed to be smaller, in particular to
produce smaller deltas. It stores hashes in binary and puts the hash
on a new line (for smaller deltas). It also uses stem compression to
save space for long paths. The format has room for metadata, but
that's there only for future-proofing. The parser thus accepts any
metadata and throws it away. For more information, see
http://mercurial.selenic.com/wiki/ManifestV2Plan.

The current manifest format doesn't allow an empty filename, so we use
an empty filename on the first line to tell a manifest of the new
format from the old. Since we still never write manifests in the new
format, the added code is unused, but it is tested by
test-manifest.py.

#!/usr/bin/env python
#
# Dumps output generated by Mercurial's command server in a formatted style to a
# given file or stderr if '-' is specified. Output is also written in its raw
# format to stdout.
#
# $ ./hg serve --cmds pipe | ./contrib/debugcmdserver.py -
# o, 52   -> 'capabilities: getencoding runcommand\nencoding: UTF-8'

import sys, struct

if len(sys.argv) != 2:
    print 'usage: debugcmdserver.py FILE'
    sys.exit(1)

outputfmt = '>cI'
outputfmtsize = struct.calcsize(outputfmt)

if sys.argv[1] == '-':
    log = sys.stderr
else:
    log = open(sys.argv[1], 'a')

def read(size):
    data = sys.stdin.read(size)
    if not data:
        raise EOFError
    sys.stdout.write(data)
    sys.stdout.flush()
    return data

try:
    while True:
        header = read(outputfmtsize)
        channel, length = struct.unpack(outputfmt, header)
        log.write('%s, %-4d' % (channel, length))
        if channel in 'IL':
            log.write(' -> waiting for input\n')
        else:
            data = read(length)
            log.write(' -> %r\n' % data)
        log.flush()
except EOFError:
    pass
finally:
    if log != sys.stderr:
        log.close()