Add a wrapper around beyondcompare/kdiff3 so that it can be plugged into

svn merge's diff3-cmd. Eventually, others can use this for other
diff3 tools as well, they'll just need to add the right tweaks
to support other tools.
Review URL: http://codereview.chromium.org/11520

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6192 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 127 insertions, 9 deletions

diff --git a/webkit/tools/merge/diff3-wrapper.py b/webkit/tools/merge/diff3-wrapper.py
new file mode 100755
index 0000000..50dc310
--- /dev/null
+++ b/webkit/tools/merge/diff3-wrapper.py
@@ -0,0 +1,104 @@
+#!/bin/env python

+# Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.

+# Use of this source code is governed by a BSD-style license that can be

+# found in the LICENSE file.

+

+"""Wrapper around BeyondCompare so it can be used as svn's diff3-cmd tool.

+

+The basic idea here is based heavily off of diffwrap.py at:

+http://svnbook.red-bean.com/en/1.5/svn.advanced.externaldifftools.html#svn.advanced.externaldifftools.diff3.ex-1

+"""

+

+import optparse

+import os

+import subprocess

+import sys

+

+CYGDRIVE = '/cygdrive/'

+CYGLEN = len(CYGDRIVE)

+

+# TODO(ojan): Eventually make this a cross-platform script that makes it easy

+# to use different diffing tools (an enum of tools maybe?).

+# The difficulty is that each tool has its own supported arguments.

+def EnsureWindowsPath(path):

+  """ Returns a Windows-style path given a Windows path or a cygwin path.

+  """

+  if path.startswith(CYGDRIVE):

+    path = path[CYGLEN:CYGLEN + 1] + ':' + path[CYGLEN + 1:]

+    path = path.replace('/', '\\')

+  return path

+  

+def GetPathToBinary(exe):

+  """ Try to find a copy of the binary that exists. Search for the full path

+  and then the basename.

+  """

+  if not os.path.exists(exe):

+    exe = os.path.basename(exe)

+  return exe

+

+def main(args):

+  """ Provides a wrapper around 3rd-party diffing tools so they can be used as

+  the diff3-cmd in svn merge.

+

+  args: The arguments passed by svn merge to its diff3 tool.

+  """

+  # Grab the arguments from the end of the list since svn will add any other 

+  # arguments provided before these.

+  

+  # The titles of the files being diffed.

+  title_mine = EnsureWindowsPath(args[-8])

+  title_older = EnsureWindowsPath(args[-6])

+  title_yours = EnsureWindowsPath(args[-4])

+

+  # The paths to the files being diffed. These will be temp files.

+  mine = EnsureWindowsPath(args[-3])

+  older = EnsureWindowsPath(args[-2])

+  yours = EnsureWindowsPath(args[-1])

+  

+  # The command for which diff3 tool to use.

+  diff_tool = args[1]

+  

+  if diff_tool == "--use-beyondcompare":

+    exe = GetPathToBinary("/cygdrive/c/Progra~1/Beyond~1/BComp.exe")

+    cmd = [exe, 

+           mine,

+           yours,

+           older,

+           mine,

+           '/reviewconflicts',

+           '/automerge',

+           '/leftreadonly',

+           '/rightreadonly',

+           '/ignoreunimportant',

+           '/lefttitle', title_mine, 

+           '/righttitle', title_yours, 

+           '/centertitle', title_older, 

+           '/outputtitle', 'merged']

+  elif diff_tool == "--use-kdiff3":

+    exe = GetPathToBinary("/cygdrive/c/Progra~1/KDiff3/kdiff3.exe")

+    cmd = [exe,

+           older,

+           mine,

+           yours,

+           "--merge",

+           "--auto",

+           "--output", mine]

+  else:

+    # TODO(ojan): Maybe fall back to diff3?

+    raise Exception, "Must specify a diff tool to use."

+           

+  value = subprocess.call(cmd, stdout=subprocess.PIPE)

+

+  # After performing the merge, this script needs to print the contents

+  # of the merged file to stdout. 

+  # Return an errorcode of 0 on successful merge, 1 if unresolved conflicts

+  # remain in the result.  Any other errorcode will be treated as fatal.

+  merged_file_contents = open(mine).read()

+  # For reasons I don't understand, an extra line break gets added at the end

+  # of the file. Strip it.

+  merged_file_contents = merged_file_contents[:len(merged_file_contents)-1]

+  print merged_file_contents

+  sys.exit(value)

+

+if '__main__' == __name__:

+  main(sys.argv)
\ No newline at end of file
diff --git a/webkit/tools/merge/merge.py b/webkit/tools/merge/merge.py
index e6cfd6b..afcd8bd 100755
--- a/webkit/tools/merge/merge.py
+++ b/webkit/tools/merge/merge.py
@@ -10,11 +10,12 @@ to find the repository and revision to merge from.
 Example usage:
   merge.py
   merge.py --new_revision 12345
-  merge.py --diff3_cmd myfancydiffcommand.exe
+  merge.py --diff3-tool kdiff3
 
 """
 
 import optparse
+import os
 import subprocess
 import xml.dom.minidom
 
@@ -23,8 +24,11 @@ import google.path_utils
 class Merger(object):
   """ Does svn merges. """
   
+  DIFF3_WRAPPER_PATH = os.path.join('..', '..', 'webkit', 'tools', 'merge', 
+      'diff3-wrapper.py')
+  
   def __init__(self, repository, webkit_root, old_revision, 
-      new_revision, is_dry_run, diff3_cmd=None):
+      new_revision, is_dry_run, diff3_tool=None):
     """
     Args:
       repository: the repository that we are merging to/from.
@@ -34,14 +38,14 @@ class Merger(object):
       new_revision: the revision we are merging to.
       is_dry_run: whether to actually make changes or just print intended
           changes.
-      diff3_cmd: the tool for doing 3-way diffs.
+      diff3_tool: the tool for doing 3-way diffs.
     """
     self._repository = repository
     self._webkit_root = webkit_root
     self._old_revision = old_revision
     self._new_revision = new_revision
     self._is_dry_run = is_dry_run
-    self._diff3_cmd = diff3_cmd
+    self._diff3_tool = diff3_tool
 
   def MergeDirectory(self, directory):
     """ Merges the given directory in the repository into the same directory
@@ -50,9 +54,11 @@ class Merger(object):
     command = ["svn", "merge", "--accept", "edit", "-r", 
         "%s:%s" % (self._old_revision, self._new_revision), 
         "%s/%s" % (self._repository, directory), directory]
-    if self._diff3_cmd is not None:
+    if self._diff3_tool is not None:
       command.append("--diff3-cmd")
-      command.append(self._diff3_cmd)
+      command.append(self.DIFF3_WRAPPER_PATH)
+      command.append("-x")
+      command.append("--use-%s" % self._diff3_tool)
     print ' '.join(command)
     if not self._is_dry_run:
       #TODO(ojan): Check return code here.
@@ -98,6 +104,10 @@ def UpdateWebKitMergeRevision(webkit_merge_revision_path, repository,
     #TODO(ojan): Check that the write suceeded.
     file.write(new_merge_revision)
 
+def UpdateDeps(deps_path, new_revision, is_dry_run):
+  #TODO(ojan): Get this to update the revision of the appropriate bits in DEPS.
+  pass
+  
 def main(options, args):
   """ Does the merge and updates WEBKIT_MERGE_REVISION.
   
@@ -114,6 +124,9 @@ def main(options, args):
 
   webkit_merge_revision_path = google.path_utils.FindUpward(
       google.path_utils.ScriptDir(), 'WEBKIT_MERGE_REVISION')
+      
+  deps_path = google.path_utils.FindUpward(
+      google.path_utils.ScriptDir(), 'DEPS')
 
   repository_and_revision = GetCurrentRepositoryAndRevision(
       webkit_merge_revision_path)
@@ -129,17 +142,18 @@ def main(options, args):
       'third_party', 'WebKit')
 
   merger = Merger(repository, webkit_root, old_revision, new_revision, 
-      options.dry_run, options.diff3_cmd)
+      options.dry_run, options.diff3_tool)
   merger.MergeDirectory("JavaScriptCore")
   merger.MergeDirectory("WebCore")
   
   UpdateWebKitMergeRevision(webkit_merge_revision_path, repository,
       new_revision, options.dry_run)
+  UpdateDeps(deps_path, new_revision, options.dry_run)
 
 if '__main__' == __name__:
   option_parser = optparse.OptionParser()
-  option_parser.add_option("", "--diff3-cmd", default=None,
-                           help="Optional. Path to 3-way diff tool.")
+  option_parser.add_option("", "--diff3-tool", default=None,
+      help="Optional. diff3 tool to use. Can be 'kdiff3' or 'beyondcompare'")
   option_parser.add_option("", "--new-revision", default=None,
                            help="Optional. Revision to merge to. Tip of tree "
                                 "revision will be used if omitted.")