stgit/gitmergeonefile.py

   1 """Performs a 3-way merge for GIT files
   2 """
   3
   4 __copyright__ = """
   5 Copyright (C) 2006, Catalin Marinas <catalin.marinas@gmail.com>
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License version 2 as
   9 published by the Free Software Foundation.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19 """
  20
  21 import sys, os
  22 from stgit.exception import *
  23 from stgit import basedir
  24 from stgit.config import config, file_extensions, ConfigOption
  25 from stgit.utils import append_string
  26 from stgit.out import *
  27 from stgit.run import *
  28
  29 class GitMergeException(StgException):
  30     pass
  31
  32
  33 #
  34 # Options
  35 #
  36 autoimerge = ConfigOption('stgit', 'autoimerge')
  37 keeporig = ConfigOption('stgit', 'keeporig')
  38
  39 #
  40 # Utility functions
  41 #
  42 def __str2none(x):
  43     if x == '':
  44         return None
  45     else:
  46         return x
  47
  48 class MRun(Run):
  49     exc = GitMergeException # use a custom exception class on errors
  50
  51 def __checkout_stages(filename):
  52     """Check-out the merge stages in the index for the give file
  53     """
  54     extensions = file_extensions()
  55     line = MRun('git', 'checkout-index', '--stage=all', '--', filename
  56                 ).output_one_line()
  57     stages, path = line.split('\t')
  58     stages = dict(zip(['ancestor', 'current', 'patched'],
  59                       stages.split(' ')))
  60
  61     for stage, fn in stages.iteritems():
  62         if stages[stage] == '.':
  63             stages[stage] = None
  64         else:
  65             newname = filename + extensions[stage]
  66             if os.path.exists(newname):
  67                 # remove the stage if it is already checked out
  68                 os.remove(newname)
  69             os.rename(stages[stage], newname)
  70             stages[stage] = newname
  71
  72     return stages
  73
  74 def __remove_stages(filename):
  75     """Remove the merge stages from the working directory
  76     """
  77     extensions = file_extensions()
  78     for ext in extensions.itervalues():
  79         fn = filename + ext
  80         if os.path.isfile(fn):
  81             os.remove(fn)
  82
  83 def interactive_merge(filename):
  84     """Run the interactive merger on the given file. Stages will be
  85     removed according to stgit.keeporig. If successful and stages
  86     kept, they will be removed via git.resolved().
  87     """
  88     stages = __checkout_stages(filename)
  89
  90     try:
  91         # Check whether we have all the files for the merge.
  92         if not (stages['current'] and stages['patched']):
  93             raise GitMergeException('Cannot run the interactive merge')
  94
  95         if stages['ancestor']:
  96             three_way = True
  97             files_dict = {'branch1': stages['current'],
  98                           'ancestor': stages['ancestor'],
  99                           'branch2': stages['patched'],
 100                           'output': filename}
 101             imerger = config.get('stgit.i3merge')
 102         else:
 103             three_way = False
 104             files_dict = {'branch1': stages['current'],
 105                           'branch2': stages['patched'],
 106                           'output': filename}
 107             imerger = config.get('stgit.i2merge')
 108
 109         if not imerger:
 110             raise GitMergeException, 'No interactive merge command configured'
 111
 112         mtime = os.path.getmtime(filename)
 113
 114         out.start('Trying the interactive %s merge'
 115                   % (three_way and 'three-way' or 'two-way'))
 116         err = os.system(imerger % files_dict)
 117         out.done()
 118         if err != 0:
 119             raise GitMergeException, 'The interactive merge failed'
 120         if not os.path.isfile(filename):
 121             raise GitMergeException, 'The "%s" file is missing' % filename
 122         if mtime == os.path.getmtime(filename):
 123             raise GitMergeException, 'The "%s" file was not modified' % filename
 124     finally:
 125         # keep the merge stages?
 126         if str(keeporig) != 'yes':
 127             __remove_stages(filename)
 128
 129 def clean_up(filename):
 130     """Remove merge conflict stages if they were generated.
 131     """
 132     if str(keeporig) == 'yes':
 133         __remove_stages(filename)
 134
 135 def merge(filename):
 136     """Merge one file if interactive is allowed or check out the stages
 137     if keeporig is set.
 138     """
 139     if str(autoimerge) == 'yes':
 140         try:
 141             interactive_merge(filename)
 142         except GitMergeException, ex:
 143             out.error(str(ex))
 144             return False
 145         return True
 146
 147     if str(keeporig) == 'yes':
 148         __checkout_stages(filename)
 149
 150     return False