view contrib/debugcmdserver.py @ 35998:dce43aaaf209

lfs: allow a pointer to be extracted from a context that removes the file

This is needed to let 'set:lfs()' and '{lfs_files}' work normally on removed
files.

Yuya suggested returning a null pointer for removed files, instead of the
pointer from the parent.  The first attempt at this was to return None for a non
LFS file, and a (pointer, ctx) tuple to hold the pointer and context (or parent
pointer and context for a removed file).  But this complicated the callers, even
the ones that didn't care about removed files.

Instead, let's use {} to represent a removed pointer.  This has the added
convenience of being a useful representation in the template language, and only
affects the callers that care about removed files (and only slightly).  Since
pointers are explicitly serialized with a call to a member function, there is no
danger of writing these to disk.

#!/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'

from __future__ import absolute_import, print_function
import struct
import sys

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()