#!/usr/bin/python

# Extract dumps from a git


# Copyright (c) 2010 Peter Palfrader
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import sys
import os
import optparse
import subprocess

parser = optparse.OptionParser()
parser.set_usage("%prog [<options>] list\n" +
          "Usage: %prog [<options>] get <revision>")
parser.add_option("-b", "--backing", dest="backing_git", metavar="GITDIR",
  default = 'backing-git',
  help="Location of backing git working copy.")
(options, args) = parser.parse_args()

if len(args) == 0:
    parser.print_help()
    sys.exit(1)

if not os.path.isdir(options.backing_git):
    print >> sys.stderr, "Error: %s does not exist or is not a directory."%(options.backing_git)
    sys.exit(1)

def list():
    p = subprocess.Popen(['git', 'log', '--reverse'], stdout=subprocess.PIPE)
    line = p.stdout.readline()
    while True:
        line = line.rstrip('\n')
        key, rev = line.split(' ', 1)
        if key != "commit":
            print >> sys.stderr, "Error: Cannot parse git log output.  Expected commit line but got"
            print >> sys.stderr, "| %s"%(line)
            sys.exit(1)
        if len(rev) != 40:
            print >> sys.stderr, "Error: Unexpected rev format in '%s'."%(rev)
            sys.exit(1)

        while True:
            line = p.stdout.readline().rstrip('\n')
            if line == "": break

        metadata = {}
        while True:
            line = p.stdout.readline().rstrip('\n')
            if line == "": break
            line = line.lstrip()
            s = line.split(':', 1)
            if len(s) == 2:
                key = s[0]
                value = s[1].lstrip()
                metadata[key] = value

        for k in ['UUID', 'Archive']:
            if not k in metadata:
                print >> sys.stderr, "Error: Did not find %s in commit msg of %s."%(k, rev)
                print >> sys.stderr, "Metadata is:", metadata
                sys.exit(1)

        print "%s %s:%s"%(metadata['UUID'], rev, metadata['Archive'])
        line = p.stdout.readline()
        if line == "": break # encountered eof

def get(object):
    subprocess.check_call(['git', 'show', object])

os.chdir(options.backing_git)
if args[0] == "list":
    if len(args) != 1:
        parser.print_help()
        sys.exit(1)
    list()
elif args[0] == "get":
    if len(args) != 2:
        parser.print_help()
        sys.exit(1)
    getarg = args[1]
    get(getarg)
else:
    print >> sys.stderr, "Error: Invalid mode %s."%(args[0])


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