Update PRESUBMIT.py to handle GN.

PRESUBMIT.py

 # Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import json
 import os
@@ skipping 238 matching lines @@
     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 GYP files:',
         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\'.*?\[(.*?)\]',
                                         re.MULTILINE | re.DOTALL)
   file_pattern = input_api.re.compile(r"'((\.\./.*?)|(<\(webrtc_root\).*?))'")
   violating_gyp_files = set()
   violating_source_entries = []
   for gyp_file in gyp_files:
     if 'supplement.gypi' in gyp_file.LocalPath():
       # Exclude supplement.gypi from this check, as the LSan and TSan
@@ skipping 12 matching lines @@
     return [output_api.PresubmitError(
         'Referencing source files above the directory of the GYP file is not '
         'allowed. Please introduce new GYP targets and/or GYP files in the '
         'proper location instead.\n'
         'Invalid source entries:\n'
         '%s\n'
         'Violating GYP files:' % '\n'.join(violating_source_entries),
         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)$',))
 
   gyp_files = []
   for f in input_api.AffectedSourceFiles(source_file_filter):
     if f.LocalPath().startswith('webrtc'):
       gyp_files.append(f)
 
   result = []
   if gyp_files:
     result.append(output_api.PresubmitNotifyResult(
         'As you\'re changing GYP files: please make sure corresponding '
         'BUILD.gn files are also updated.\nChanged GYP files:',
         items=gyp_files))
     result.extend(_CheckNoRtcBaseDeps(input_api, gyp_files, 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
   warning.
   """
   # Copied from Chromium's src/PRESUBMIT.py.
 
   # We need to wait until we have an input_api object and use this
   # roundabout construct to import checkdeps because this file is
   # eval-ed and thus doesn't have __file__.
@@ skipping 162 matching lines @@
   results.extend(input_api.canned_checks.CheckChangeHasNoTabs(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeTodoHasOwner(
       input_api, output_api))
   results.extend(_CheckNativeApiHeaderChanges(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))
   return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   results.extend(
@@ skipping 36 matching lines @@
     for builder in masters[master]:
       if 'presubmit' in builder:
         # Do not trigger presubmit builders, since they're likely to fail
         # (e.g. OWNERS checks before finished code review), and we're running
         # local presubmit anyway.
         pass
       else:
         try_config[master][builder] = ['defaulttests']
 
   return try_config