Update PRESUBMIT.py to handle GN.

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 00bcc3e545910a89f381d575d74d94e877bff554..df59b27c3f188d9d433f7f31ffff4824766dc120 100755
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -256,6 +256,39 @@ def _CheckNoRtcBaseDeps(input_api, gyp_files, output_api):
         items=violating_files)]
   return []
 
+def _CheckNoRtcBaseDepsGn(input_api, gn_files, output_api):
+  pattern = input_api.re.compile(r'base:rtc_base\s*"')
+  violating_files = []
+  for f in gn_files:
+    gn_exceptions = (
+        os.path.join('base_tests', 'BUILD.gn'),
+        os.path.join('desktop_capture', 'BUILD.gn'),
+        os.path.join('p2p', 'BUILD.gn'),
+        os.path.join('sdk', 'BUILD.gn'),
+        os.path.join('webrtc_test_common', 'BUILD.gn'),
+        os.path.join('webrtc_tests', 'BUILD.gn'),
+
+        # This are not in GYP, but were in GN at the time of writing this

[ehmaldonado_webrtc, 2016/09/02 09:32:18]

What should we do with these files?

[kjellander_webrtc, 2016/09/02 12:13:22]

Leave them as is and add a reference to
https://bugs.chromium.org/p/webrtc/issues/detail?id=3806 here. It's a cleanup
that will have to be done at some point in the future. For now the important
thing is that we don't make things worse at least (which this PRESUBMIT check
somewhat prevents).

+        os.path.join('webrtc', 'BUILD.gn'),
+        os.path.join('xmllite', 'BUILD.gn'),
+        os.path.join('xmpp', 'BUILD.gn'),
+        os.path.join('modules', 'BUILD.gn'),
+        os.path.join('audio_device', 'BUILD.gn'),
+        os.path.join('pc', 'BUILD.gn'),
+    )
+    if f.LocalPath().endswith(gn_exceptions):
+      continue
+    contents = input_api.ReadFile(f)
+    if pattern.search(contents):
+      violating_files.append(f)
+  if violating_files:
+    return [output_api.PresubmitError(
+        'Depending on rtc_base is not allowed. Change your dependency to '
+        'rtc_base_approved and possibly sanitize and move the desired source '
+        'file(s) to rtc_base_approved.\nChanged GN files:',
+        items=violating_files)]
+  return []
+
 def _CheckNoSourcesAboveGyp(input_api, gyp_files, output_api):
   # Disallow referencing source files with paths above the GYP file location.
   source_pattern = input_api.re.compile(r'\'sources\'.*?\[(.*?)\]',
@@ -288,6 +321,34 @@ def _CheckNoSourcesAboveGyp(input_api, gyp_files, output_api):
         items=violating_gyp_files)]
   return []
 
+def _CheckNoSourcesAboveGn(input_api, gn_files, output_api):
+  # Disallow referencing source files with paths above the GN file location.
+  source_pattern = input_api.re.compile(r' +sources \+?= \[(.*?)\]',
+                                        re.MULTILINE | re.DOTALL)
+  file_pattern = input_api.re.compile(r'"((\.\./.*?)|(//.*?))"')
+  violating_gn_files = set()
+  violating_source_entries = []
+  for gn_file in gn_files:
+    contents = input_api.ReadFile(gn_file)
+    for source_block_match in source_pattern.finditer(contents):
+      # Find all source list entries starting with ../ in the source block
+      # (exclude overrides entries).
+      for file_list_match in file_pattern.finditer(source_block_match.group(1)):
+        source_file = file_list_match.group(1)
+        if 'overrides/' not in source_file:
+          violating_source_entries.append(source_file)
+          violating_gn_files.add(gn_file)
+  if violating_gn_files:
+    return [output_api.PresubmitError(
+        'Referencing source files above the directory of the GN file is not '
+        'allowed. Please introduce new GYP targets and/or GN files in the '
+        'proper location instead.\n'
+        'Invalid source entries:\n'
+        '%s\n'
+        'Violating GN files:' % '\n'.join(violating_source_entries),
+        items=violating_gn_files)]
+  return []
+
 def _CheckGypChanges(input_api, output_api):
   source_file_filter = lambda x: input_api.FilterSourceFile(
       x, white_list=(r'.+\.(gyp|gypi)$',))
@@ -307,6 +368,25 @@ def _CheckGypChanges(input_api, output_api):
     result.extend(_CheckNoSourcesAboveGyp(input_api, gyp_files, output_api))
   return result
 
+def _CheckGnChanges(input_api, output_api):
+  source_file_filter = lambda x: input_api.FilterSourceFile(
+      x, white_list=(r'.+\.(gn|gni)$',))
+
+  gn_files = []
+  for f in input_api.AffectedSourceFiles(source_file_filter):
+    if f.LocalPath().startswith('webrtc'):
+      gn_files.append(f)
+
+  result = []
+  if gn_files:
+    result.append(output_api.PresubmitNotifyResult(
+        'As you\'re changing GN files: please make sure corresponding GYP'
+        'files are also updated.\nChanged GN files:',
+        items=gn_files))
+    result.extend(_CheckNoRtcBaseDepsGn(input_api, gn_files, output_api))
+    result.extend(_CheckNoSourcesAboveGn(input_api, gn_files, output_api))
+  return result
+
 def _CheckUnwantedDependencies(input_api, output_api):
   """Runs checkdeps on #include statements added in this
   change. Breaking - rules is an error, breaking ! rules is a
@@ -489,6 +569,7 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckNoIOStreamInHeaders(input_api, output_api))
   results.extend(_CheckNoFRIEND_TEST(input_api, output_api))
   results.extend(_CheckGypChanges(input_api, output_api))
+  results.extend(_CheckGnChanges(input_api, output_api))
   results.extend(_CheckUnwantedDependencies(input_api, output_api))
   results.extend(_CheckJSONParseErrors(input_api, output_api))
   results.extend(_RunPythonTests(input_api, output_api))