Have run_tool.py automatically invoke clang-format-diff.py if available.

This makes for nicer code and removes the extra post-processing step.
It also provides more granular warnings; simply returning the formatter
across the entire diff will provide cryptic errors like missing { at
line 540.

BUG=

Review URL: https://codereview.chromium.org/13605003

git-svn-id: http://src.chromium.org/svn/trunk/src/tools/clang@192359 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

empty_string/tests/test-expected.cc

@@ -12,17 +12,17 @@ void TestDeclarations() { std::string a, b("abc"), c; }
 // Tests for std::string allocated with new.
 void TestNew() {
   std::string* a = new std::string,
-              *b = new std::string("abc"),
-              *c = new std::string,
-              *d = new std::string();
+               *b = new std::string("abc"),
+                *c = new std::string,
+                 *d = new std::string();
 }
 
 // Tests for std::string construction in initializer lists.
 class TestInitializers {
  public:
-  TestInitializers()  {}
-  TestInitializers(bool)  {}
-  TestInitializers(double) :  b("cat"), c() {}
+  TestInitializers() {}
+  TestInitializers(bool) {}
+  TestInitializers(double) : b("cat"), c() {}
 
  private:
   std::string a;
@@ -43,4 +43,3 @@ void TestWideTemporaries(const std::wstring& reference_argument,
   TestWideTemporaries(std::wstring(), std::wstring());
   TestWideTemporaries(std::wstring(), std::wstring());
 }
-

scripts/run_tool.py

@@ -183,11 +183,14 @@ def __ProcessResult(self, result):
     sys.stdout.flush()
 
 
-def _ApplyEdits(edits):
+def _ApplyEdits(edits, clang_format_diff_path):
   """Apply the generated edits.
 
   Args:
     edits: A dict mapping filenames to Edit instances that apply to that file.
+    clang_format_diff_path: Path to the clang-format-diff.py helper to help
+      automatically reformat diffs to avoid style violations. Pass None if the
+      clang-format step should be skipped.
   """
   edit_count = 0
   for k, v in edits.iteritems():
@@ -210,6 +213,10 @@ def _ApplyEdits(edits):
       f.seek(0)
       f.truncate()
       f.write(contents)
+    if clang_format_diff_path:
+      if subprocess.call('git diff -U0 %s | python %s -style=Chromium' % (
+          k, clang_format_diff_path), shell=True) != 0:
+        print 'clang-format failed for %s' % k
   print 'Applied %d edits to %d files' % (edit_count, len(edits))
 
 
@@ -266,6 +273,14 @@ def main(argv):
     print '  <path 1> <path2> ... can be used to filter what files are edited'
     return 1
 
+  clang_format_diff_path = os.path.join(
+      os.path.dirname(os.path.realpath(__file__)),
+      '../../../third_party/llvm/tools/clang/tools/clang-format',
+      'clang-format-diff.py')
+  # TODO(dcheng): Allow this to be controlled with a flag as well.
+  if not os.path.isfile(clang_format_diff_path):
+    clang_format_diff_path = None
+
   filenames = frozenset(_GetFilesFromGit(argv[2:]))
   # Filter out files that aren't C/C++/Obj-C/Obj-C++.
   extensions = frozenset(('.c', '.cc', '.m', '.mm'))
@@ -277,9 +292,8 @@ def main(argv):
   # useful to modify files that aren't under source control--typically, these
   # are generated files or files in a git submodule that's not part of Chromium.
   _ApplyEdits({k : v for k, v in dispatcher.edits.iteritems()
-                    if k in filenames})
-  # TODO(dcheng): Consider clang-formatting the result to avoid egregious style
-  # violations.
+                    if k in filenames},
+              clang_format_diff_path)
   if dispatcher.failed_count != 0:
     return 2
   return 0