Add a Presubmit to check if a file must be included or imported.

PRESUBMIT.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
@@ skipping 40 matching lines @@
 )
 
 
 _TEST_ONLY_WARNING = (
     'You might be calling functions intended only for testing from\n'
     'production code.  It is OK to ignore this warning if you know what\n'
     'you are doing, as the heuristics used to detect the situation are\n'
     'not perfect.  The commit queue will not block on this warning.')
 
 
+_INCLUDE_IMPORT_WARNING = (
+    'You are including ObjC headers or importing C++ headers. Remember to use '
+    'the right #include/#import directive.')
+
+
 _INCLUDE_ORDER_WARNING = (
     'Your #include order seems to be broken. Remember to use the right '
     'collation (LC_COLLATE=C) and check\nhttps://google.github.io/styleguide/'
     'cppguide.html#Names_and_Order_of_Includes')
 
 
 _BANNED_OBJC_FUNCTIONS = (
     (
       'addTrackingRect:',
       (
@@ skipping 712 matching lines @@
       if pattern.match(line):
         errors.append('    %s:%d' % (f.LocalPath(), line_num))
 
   results = []
   if errors:
     results.append(output_api.PresubmitError(
       'Header files should not include ui/aura/window_property.h', errors))
   return results
 
 
+def _CheckHeaderIsObjectiveC(input_api, included_file, included_file_content):
+  """Checks if f is a C++ or an Objective-C header.
+
+  An Objective-C header is a header with a line starting with
+  - #import
+  - @class
+  - @interface
+  - @implementation
+  - @protocol
+  - @end
+
+  or with the two lines
+  #if !defined(__OBJC__)
+  #error ...
+
+  Returns a pair of booleans.
+  - First is true if the determination of Objective-C could be done without
+    error
+  - Second is true if the file has been determined as Objective-C header.
+  """
+  file_path_ios_mac_pattern = input_api.re.compile(
+      r'(?:.*[_./])?(?:ios|mac)[_./].*')
+  if not file_path_ios_mac_pattern.match(included_file):
+    return (False, False)
+  guard_noobjc_pattern = input_api.re.compile(
+      r'\s*#if !defined\(__OBJC__\).*')
+  guard_objc_pattern = input_api.re.compile(
+      r'\s*#if defined\(__OBJC__\).*')
+  error_pattern = input_api.re.compile(
+      r'\s*#error .*')
+  block_pattern = input_api.re.compile(
+      r'\s*typedef.*\(\^.*')
+  objc_pattern = input_api.re.compile(
+      r'\s*(@class|@interface|@end|@implementation|@protocol|#import).*')
+  lines = included_file_content.NewContents()
+  previous_was_noobjc_define = False
+  for included_line in lines:
+    if guard_noobjc_pattern.match(included_line):
+      previous_was_noobjc_define = True
+      continue
+    if previous_was_noobjc_define:
+      # Found No Objc Guard. The next line must be check to see if it is
+      # throwing an error.
+      if error_pattern.match(included_line):
+        # There is an error thrown if the file is compiled without ObjC.
+        # Header is Objective-C.
+        return (True, True)
+      else:
+        # There are ifdefs about Objective-C, file can likely be imported or
+        # included.
+        return (False, False)
+    previous_was_noobjc_define = False
+    if guard_objc_pattern.match(included_line):
+      # Found ObjcGuard. This file can be included or imported.
+      return (False, False)
+    if objc_pattern.match(included_line) or block_pattern.match(included_line):
+      # Found an Objective-C keyword. File is an Objective-C header.
+      return (True, True)
+  # No Objective-C clue, file must be C++.
+  return (True, False)
+
+
+def _CheckIncludeImportInFile(input_api, f):
+  """Checks the include/import coherence in file f."""
+  custom_include_pattern = input_api.re.compile(r'\s*#include "(?P<FILE>.*)"')
+  custom_import_pattern = input_api.re.compile(r'\s*#import "(?P<FILE>.*)"')
+  contents = f.NewContents()
+  warnings = []
+  for (line_num, line) in enumerate(contents):
+    is_imported = False
+    included_file = ""
+    match_cpp = custom_include_pattern.match(line)
+    if match_cpp:
+      match_dict = match_cpp.groupdict()
+      included_file = match_dict['FILE']
+    match_objc = custom_import_pattern.match(line)
+    if match_objc:
+      match_dict = match_objc.groupdict()
+      included_file = match_dict['FILE']
+      is_imported = True
+    if included_file == "":
+      continue
+    included_absolute_path = input_api.os_path.join(
+        input_api.change.RepositoryRoot(), included_file)
+    if not input_api.os_path.isfile(included_absolute_path):
+      # Included file may need a custom -I flag.
+      # Ignore it.
+      continue
+    included_file_content = input_api.ReadFile(included_absolute_path)
+    (detection_ok, has_objc) = \
+        _CheckHeaderIsObjectiveC(input_api,
+                                 included_file,
+                                 included_file_content)
+    if not detection_ok:
+      # There is an Objective-C guard, the file is internded to be included or
+      # imported.
+      continue
+    if is_imported and f.LocalPath().endswith('.cc'):
+      warnings.append('%s:%d %s' % (f.LocalPath(), line_num, line))
+      warnings.append('Header is imported in a C++ file.')
+    if has_objc and not is_imported:
+      warnings.append('%s:%d %s' % (f.LocalPath(), line_num, line))
+      warnings.append('Header is included but has Objective-C instructions.')
+    if not has_objc and is_imported:
+      warnings.append('%s:%d %s' % (f.LocalPath(), line_num, line))
+      warnings.append('Header is imported but has no Objective-C instructions.')
+  return warnings
+
+
+def _CheckIncludeImport(input_api, output_api):
+  """Checks that C++ headers are included, Objective-C headers imported.
+  """
+  def FileFilterIncludeImport(affected_file):
+    black_list = (_EXCLUDED_PATHS + input_api.DEFAULT_BLACK_LIST)
+    return input_api.FilterSourceFile(affected_file, black_list=black_list)
+
+  warnings = []
+  for f in input_api.AffectedFiles(file_filter=FileFilterIncludeImport):
+    warnings.extend(_CheckIncludeImportInFile(input_api, f))
+
+  results = []
+  if warnings:
+    results.append(output_api.PresubmitPromptOrNotify(_INCLUDE_IMPORT_WARNING,
+                                                      warnings))
+  return results
+
+
 def _CheckIncludeOrderForScope(scope, input_api, file_path, changed_linenums):
   """Checks that the lines in scope occur in the right order.
 
   1. C system files in alphabetical order
   2. C++ system files in alphabetical order
   3. Project's .h files
   """
 
   c_system_include_pattern = input_api.re.compile(r'\s*#include <.*\.h>')
   cpp_system_include_pattern = input_api.re.compile(r'\s*#include <.*>')
@@ skipping 1278 matching lines @@
   results.extend(_CheckDCHECK_IS_ONHasBraces(input_api, output_api))
   results.extend(_CheckNoNewWStrings(input_api, output_api))
   results.extend(_CheckNoDEPSGIT(input_api, output_api))
   results.extend(_CheckNoBannedFunctions(input_api, output_api))
   results.extend(_CheckNoPragmaOnce(input_api, output_api))
   results.extend(_CheckNoTrinaryTrueFalse(input_api, output_api))
   results.extend(_CheckUnwantedDependencies(input_api, output_api))
   results.extend(_CheckFilePermissions(input_api, output_api))
   results.extend(_CheckTeamTags(input_api, output_api))
   results.extend(_CheckNoAuraWindowPropertyHInHeaders(input_api, output_api))
+  results.extend(_CheckIncludeImport(input_api, output_api))
   results.extend(_CheckIncludeOrder(input_api, output_api))
   results.extend(_CheckForVersionControlConflicts(input_api, output_api))
   results.extend(_CheckPatchFiles(input_api, output_api))
   results.extend(_CheckHardcodedGoogleHostsInLowerLayers(input_api, output_api))
   results.extend(_CheckNoAbbreviationInPngFileName(input_api, output_api))
   results.extend(_CheckForInvalidOSMacros(input_api, output_api))
   results.extend(_CheckForInvalidIfDefinedMacros(input_api, output_api))
   results.extend(_CheckFlakyTestUsage(input_api, output_api))
   results.extend(_CheckAddedDepsHaveTargetApprovals(input_api, output_api))
   results.extend(
@@ skipping 266 matching lines @@
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
       input_api,
       output_api,
       json_url='http://chromium-status.appspot.com/current?format=json'))
 
   results.extend(input_api.canned_checks.CheckChangeHasBugField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   return results