+"""Performs a 3-way merge for GIT files
+"""
+
+__copyright__ = """
+Copyright (C) 2006, Catalin Marinas <catalin.marinas@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License version 2 as
+published by the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+"""
+
+import sys, os
+from stgit.config import config
+from stgit.utils import append_string
+
+
+class GitMergeException(Exception):
+ pass
+
+
+#
+# Options
+#
+try:
+ merger = config.get('gitmergeonefile', 'merger')
+except Exception, err:
+ raise GitMergeException, 'Configuration error: %s' % err
+
+if config.has_option('gitmergeonefile', 'keeporig'):
+ keeporig = config.get('gitmergeonefile', 'keeporig')
+else:
+ keeporig = 'yes'
+
+
+#
+# Utility functions
+#
+def __str2none(x):
+ if x == '':
+ return None
+ else:
+ return x
+
+def __output(cmd):
+ f = os.popen(cmd, 'r')
+ string = f.readline().rstrip()
+ if f.close():
+ raise GitMergeException, 'Error: failed to execute "%s"' % cmd
+ return string
+
+def __checkout_files(orig_hash, file1_hash, file2_hash,
+ path,
+ orig_mode, file1_mode, file2_mode):
+ """Check out the files passed as arguments
+ """
+ global orig, src1, src2
+
+ if orig_hash:
+ orig = '%s.older' % path
+ tmp = __output('git-unpack-file %s' % orig_hash)
+ os.chmod(tmp, int(orig_mode, 8))
+ os.renames(tmp, orig)
+ if file1_hash:
+ src1 = '%s.local' % path
+ tmp = __output('git-unpack-file %s' % file1_hash)
+ os.chmod(tmp, int(file1_mode, 8))
+ os.renames(tmp, src1)
+ if file2_hash:
+ src2 = '%s.remote' % path
+ tmp = __output('git-unpack-file %s' % file2_hash)
+ os.chmod(tmp, int(file2_mode, 8))
+ os.renames(tmp, src2)
+
+def __remove_files(orig_hash, file1_hash, file2_hash):
+ """Remove any temporary files
+ """
+ if orig_hash:
+ os.remove(orig)
+ if file1_hash:
+ os.remove(src1)
+ if file2_hash:
+ os.remove(src2)
+ pass
+
+# GIT_DIR value cached
+__base_dir = None
+
+def __conflict(path):
+ """Write the conflict file for the 'path' variable and exit
+ """
+ global __base_dir
+
+ if not __base_dir:
+ if 'GIT_DIR' in os.environ:
+ __base_dir = os.environ['GIT_DIR']
+ else:
+ __base_dir = __output('git-rev-parse --git-dir')
+
+ append_string(os.path.join(__base_dir, 'conflicts'), path)
+
+
+#
+# Main algorithm
+#
+def merge(orig_hash, file1_hash, file2_hash,
+ path,
+ orig_mode, file1_mode, file2_mode):
+ """Three-way merge for one file algorithm
+ """
+ __checkout_files(orig_hash, file1_hash, file2_hash,
+ path,
+ orig_mode, file1_mode, file2_mode)
+
+ # file exists in origin
+ if orig_hash:
+ # modified in both
+ if file1_hash and file2_hash:
+ # if modes are the same (git-read-tree probably dealt with it)
+ if file1_hash == file2_hash:
+ if os.system('git-update-index --cacheinfo %s %s %s'
+ % (file1_mode, file1_hash, path)) != 0:
+ print >> sys.stderr, 'Error: git-update-index failed'
+ __conflict(path)
+ return 1
+ if os.system('git-checkout-index -u -f -- %s' % path):
+ print >> sys.stderr, 'Error: git-checkout-index failed'
+ __conflict(path)
+ return 1
+ if file1_mode != file2_mode:
+ print >> sys.stderr, \
+ 'Error: File added in both, permissions conflict'
+ __conflict(path)
+ return 1
+ # 3-way merge
+ else:
+ merge_ok = os.system(merger % {'branch1': src1,
+ 'ancestor': orig,
+ 'branch2': src2,
+ 'output': path }) == 0
+
+ if merge_ok:
+ os.system('git-update-index -- %s' % path)
+ __remove_files(orig_hash, file1_hash, file2_hash)
+ return 0
+ else:
+ print >> sys.stderr, \
+ 'Error: three-way merge tool failed for file "%s"' \
+ % path
+ # reset the cache to the first branch
+ os.system('git-update-index --cacheinfo %s %s %s'
+ % (file1_mode, file1_hash, path))
+ if keeporig != 'yes':
+ __remove_files(orig_hash, file1_hash, file2_hash)
+ __conflict(path)
+ return 1
+ # file deleted in both or deleted in one and unchanged in the other
+ elif not (file1_hash or file2_hash) \
+ or file1_hash == orig_hash or file2_hash == orig_hash:
+ if os.path.exists(path):
+ os.remove(path)
+ __remove_files(orig_hash, file1_hash, file2_hash)
+ return os.system('git-update-index --remove -- %s' % path)
+ # file deleted in one and changed in the other
+ else:
+ # Do something here - we must at least merge the entry in
+ # the cache, instead of leaving it in U(nmerged) state. In
+ # fact, stg resolved does not handle that.
+
+ # Do the same thing cogito does - remove the file in any case.
+ os.system('git-update-index --remove -- %s' % path)
+
+ #if file1_hash:
+ ## file deleted upstream and changed in the patch. The
+ ## patch is probably going to move the changes
+ ## elsewhere.
+
+ #os.system('git-update-index --remove -- %s' % path)
+ #else:
+ ## file deleted in the patch and changed upstream. We
+ ## could re-delete it, but for now leave it there -
+ ## and let the user check if he still wants to remove
+ ## the file.
+
+ ## reset the cache to the first branch
+ #os.system('git-update-index --cacheinfo %s %s %s'
+ # % (file1_mode, file1_hash, path))
+ __conflict(path)
+ return 1
+
+ # file does not exist in origin
+ else:
+ # file added in both
+ if file1_hash and file2_hash:
+ # files are the same
+ if file1_hash == file2_hash:
+ if os.system('git-update-index --add --cacheinfo %s %s %s'
+ % (file1_mode, file1_hash, path)) != 0:
+ print >> sys.stderr, 'Error: git-update-index failed'
+ __conflict(path)
+ return 1
+ if os.system('git-checkout-index -u -f -- %s' % path):
+ print >> sys.stderr, 'Error: git-checkout-index failed'
+ __conflict(path)
+ return 1
+ if file1_mode != file2_mode:
+ print >> sys.stderr, \
+ 'Error: File "s" added in both, ' \
+ 'permissions conflict' % path
+ __conflict(path)
+ return 1
+ # files are different
+ else:
+ print >> sys.stderr, \
+ 'Error: File "%s" added in branches but different' % path
+ __conflict(path)
+ return 1
+ # file added in one
+ elif file1_hash or file2_hash:
+ if file1_hash:
+ mode = file1_mode
+ obj = file1_hash
+ else:
+ mode = file2_mode
+ obj = file2_hash
+ if os.system('git-update-index --add --cacheinfo %s %s %s'
+ % (mode, obj, path)) != 0:
+ print >> sys.stderr, 'Error: git-update-index failed'
+ __conflict(path)
+ return 1
+ __remove_files(orig_hash, file1_hash, file2_hash)
+ return os.system('git-checkout-index -u -f -- %s' % path)
+
+ # Unhandled case
+ print >> sys.stderr, 'Error: Unhandled merge conflict: ' \
+ '"%s" "%s" "%s" "%s" "%s" "%s" "%s"' \
+ % (orig_hash, file1_hash, file2_hash,
+ path,
+ orig_mode, file1_mode, file2_mode)
+ __conflict(path)
+ return 1