tests/printenv.py

changectx: increase perf of walk function

When running 'hg cat -r . <file>' it was doing an expensive ctx.walk(m) which
applied the regex to every file in the manifest.

This changes changectx.walk to iterate over just the files in the regex, if no
other patterns are specified. This cuts hg cat time by 50% in our repo and
probably benefits a few other commands as well.

# simple script to be used in hooks
#
# put something like this in the repo .hg/hgrc:
#
#     [hooks]
#     changegroup = python "$TESTDIR/printenv.py" <hookname> [exit] [output]
#
#   - <hookname> is a mandatory argument (e.g. "changegroup")
#   - [exit] is the exit code of the hook (default: 0)
#   - [output] is the name of the output file (default: use sys.stdout)
#              the file will be opened in append mode.
#
import os
import sys

try:
    import msvcrt
    msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

exitcode = 0
out = sys.stdout

name = sys.argv[1]
if len(sys.argv) > 2:
    exitcode = int(sys.argv[2])
    if len(sys.argv) > 3:
        out = open(sys.argv[3], "ab")

# variables with empty values may not exist on all platforms, filter
# them now for portability sake.
env = [(k, v) for k, v in os.environ.iteritems()
       if k.startswith("HG_") and v]
env.sort()

out.write("%s hook: " % name)
if os.name == 'nt':
    filter = lambda x: x.replace('\\', '/')
else:
    filter = lambda x: x
vars = ["%s=%s" % (k, filter(v)) for k, v in env]
out.write(" ".join(vars))
out.write("\n")
out.close()

sys.exit(exitcode)