Search for the source root rather than checkout root in clang_format.py.

clang_format.py

Index: clang_format.py
diff --git a/clang_format.py b/clang_format.py
index 27539f86da08e0a37a2cde8e6638340797b6b608..1c5b76be82ff98a67c6afbd24ca2d97d88947405 100755
--- a/clang_format.py
+++ b/clang_format.py
@@ -23,19 +23,22 @@ class NotFoundError(Exception):
         '  %s' % e)
 
 
-def _FindChromiumTree():
-  """Return the root of the current chromium checkout, or die trying."""
-  source_root = gclient_utils.FindFileUpwards('.gclient')
+def _FindChromiumSourceRoot():
+  """Return the source root of the current chromium checkout, or die trying."""
+  # The use of .gn is somewhat incongruous here, but we need a file uniquely
+  # existing at src/. GN does the same thing at least.
+  source_root = gclient_utils.FindFileUpwards('.gn')

[ajm, 2014/01/28 01:54:31]

I at first wanted to use .clang-format here, but noticed that v8 has one as
well. This would break if run from under third_party/v8.

Open to alternatives.

[ncarter (slow), 2014/01/30 00:35:06]

I think .gn is the best of our currently available alternatives.

   if not source_root:
     raise NotFoundError(
-        '.gclient file not found in any parent of the current path.')
+        '.gn file not found in any parent of the current path.')
   return source_root
 
 
 def FindClangFormatToolInChromiumTree():
   """Return a path to the clang-format executable, or die trying."""
-  # The binaries in platform-specific subdirectories in src/tools/gn/bin.
-  tool_path = os.path.join(_FindChromiumTree(), 'src', 'third_party',
+  # The binaries in platform-specific subdirectories in
+  # third_party/clang_format/bin.
+  tool_path = os.path.join(_FindChromiumSourceRoot(), 'third_party',
                            'clang_format', 'bin',
                            gclient_utils.GetMacWinOrLinux(),
                            'clang-format' + gclient_utils.GetExeSuffix())
@@ -62,8 +65,9 @@ def FindClangFormatToolInChromiumTree():
 
 def FindClangFormatScriptInChromiumTree(script_name):
   """Return a path to a clang-format helper script, or die trying."""
-  # The binaries in platform-specific subdirectories in src/tools/gn/bin.
-  script_path = os.path.join(_FindChromiumTree(), 'src', 'third_party',
+  # The binaries in platform-specific subdirectories in
+  # third_party/clang_format/bin.

[ncarter (slow), 2014/01/30 00:35:06]

oof, thanks for fixing these comments.

+  script_path = os.path.join(_FindChromiumSourceRoot(), 'third_party',
                              'clang_format', 'scripts', script_name)
   if not os.path.exists(script_path):
     raise NotFoundError('File does not exist: %s' % script_path)