Adding Java style presubmit check.

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 2a96a9b3b986766ab658ea7453bc5b01ace60100..466533fb79fdaa90b46d3efbdf9bf49829202de2 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -976,6 +976,61 @@ def _CheckCygwinShell(input_api, output_api):
   return []
 
 
+def _CheckJavaStyle(input_api, output_api):
+  """Runs checkstyle on changed java files and returns errors if any exist."""
+  style_file = './tools/android/checkstyle/chromium-style-5.0.xml'
+  import os

[newt (away), 2013/12/10 00:04:28]

move "import" to beginning of function

+  if not os.path.exists(style_file):
+    file_error = ('  Java checkstyle configuration file is missing')

[newt (away), 2013/12/10 00:04:28]

I'd include the path to the missing file to help people debug this error

[aurimas (slooooooooow), 2013/12/10 02:31:47]

Done.

+    return [output_api.PresubmitError(file_error)]
+
+  # Filter out non-Java files and files that were deleted.
+  java_files = [x.LocalPath() for x in input_api.AffectedFiles(False, False)
+                if os.path.splitext(x.LocalPath())[1].lower() == '.java']
+  if not java_files:
+    return []
+
+  # Run checkstyle
+  checkstyle_env = os.environ.copy()
+  checkstyle_env['JAVA_CMD'] = 'java'
+  try:
+    check = subprocess.Popen(['checkstyle', '-c', style_file] + java_files,
+                             stdout=subprocess.PIPE, env=checkstyle_env)
+    stdout, _ = check.communicate()
+    if check.returncode == 0:
+      return []
+  except OSError as e:
+    import errno
+    if e.errno == errno.ENOENT:
+      install_error = ('  checkstyle is not installed. Please run '
+                       'build/install-build-deps-android.sh')
+      return [output_api.PresubmitPromptWarning(install_error)]
+
+  # Remove non-error values from stdout
+  errors = stdout.splitlines()
+  output_header = 'Starting audit...'
+  output_footer = 'Audit done.'
+
+  if errors and errors[0] == output_header:
+    del errors[0]
+  if errors and errors[-1] == output_footer:
+    del errors[-1]
+
+  # Filter out warnings
+  errors = [x for x in errors if 'warning: ' not in x]
+  if not errors:
+    return []
+  else:
+    local_path = input_api.PresubmitLocalPath()
+    output = []
+    for error in errors:
+      # Change the full file path to relative path in the output lines
+      full_path, end = error.split(':', 1)
+      rel_path = os.path.relpath(full_path, local_path)
+      output.append('  %s:%s' % (rel_path, end))
+    return [output_api.PresubmitPromptWarning('\n'.join(output))]
+
+
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
@@ -983,7 +1038,7 @@ def _CommonChecks(input_api, output_api):
       input_api, output_api, excluded_paths=_EXCLUDED_PATHS))
   results.extend(_CheckAuthorizedAuthor(input_api, output_api))
   results.extend(
-    _CheckNoProductionCodeUsingTestOnlyFunctions(input_api, output_api))
+      _CheckNoProductionCodeUsingTestOnlyFunctions(input_api, output_api))
   results.extend(_CheckNoIOStreamInHeaders(input_api, output_api))
   results.extend(_CheckNoUNIT_TESTInSourceFiles(input_api, output_api))
   results.extend(_CheckNoNewWStrings(input_api, output_api))
@@ -1009,6 +1064,7 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckSpamLogging(input_api, output_api))
   results.extend(_CheckForAnonymousVariables(input_api, output_api))
   results.extend(_CheckCygwinShell(input_api, output_api))
+  results.extend(_CheckJavaStyle(input_api, output_api))
 
   if any('PRESUBMIT.py' == f.LocalPath() for f in input_api.AffectedFiles()):
     results.extend(input_api.canned_checks.RunUnitTestsInDirectory(