Add "make format-diff" and "make format" commands that use clang-format to reformat source.

CMakeLists.txt

@@ -9,6 +9,7 @@ include(cmake/Deb.cmake)
 include(cmake/Rpm.cmake)
 include(cmake/SpotifyVersion.cmake)
 include(cmake/OptionalSource.cmake)
+include(cmake/Format.cmake)
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
 
 if (CMAKE_CXX_COMPILER MATCHES ".*clang")

cmake/Format.cmake

@@ -0,0 +1,4 @@
+add_custom_target(format-diff
+  COMMAND python ${CMAKE_SOURCE_DIR}/dist/format.py)
+add_custom_target(format
+  COMMAND python ${CMAKE_SOURCE_DIR}/dist/format.py -i)

dist/format.py

@@ -0,0 +1,71 @@
+import argparse
+import difflib
+import os
+import subprocess
+import sys
+import urllib2
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description='Reformats C++ source files that have changed from a given '
+                  'git ref.')
+  parser.add_argument('--url',
+      default='http://clang.clementine-player.org/format',
+      help='a URL of a Clang-in-the-cloud service')
+  parser.add_argument('--ref', default='origin/master',
+      help='the git-ref to compare against')
+  parser.add_argument('--extension', action='append', metavar='EXT',
+      default=['cc', 'cpp', 'h', 'c', 'cxx', 'm', 'mm'],
+      help='file extensions to reformat')
+  parser.add_argument('-i', dest='inplace', action='store_true',
+      help='edit files inplace instead of showing a diff')
+  args = parser.parse_args()
+
+  try:
+    root_dir = subprocess.check_output([
+        'git', 'rev-parse', '--show-toplevel']).strip()
+  except subprocess.CalledProcessError:
+    # Probably we were not called from a git working directory, just ignore this
+    # error.
+    return
+
+  changed_files = subprocess.check_output([
+      'git', 'diff-index', args.ref, '--name-only']).splitlines()
+
+  if not changed_files:
+    print >> sys.stderr, 'No changes from %s' % args.ref
+    return
+
+  for filename in changed_files:
+    if not os.path.splitext(filename)[1][1:] in args.extension:
+      continue
+
+    path = os.path.join(root_dir, filename)
+    original = open(path).read()
+    response = urllib2.urlopen(args.url, original)
+    formatted = response.read()
+
+    if original == formatted:
+      print >> sys.stderr, '%s: formatting is correct!' % filename
+      continue
+
+    diff = difflib.unified_diff(
+        original.split('\n'), formatted.split('\n'),
+        os.path.join('a', filename), os.path.join('b', filename),
+        lineterm='')
+
+    if args.inplace:
+      with open(path, 'w') as fh:
+        fh.write(formatted)
+
+      print >> sys.stderr, '%s: %d insertion(s), %d deletion(s)' % (
+          filename,
+          sum(1 for x in diff if x.startswith('+')),
+          sum(1 for x in diff if x.startswith('-')))
+    else:
+      print '\n'.join(diff)
+
+
+if __name__ == '__main__':
+  main()