GN: Use interface jars in the classpath to speed up compiling (a little)

build/android/gyp/javac.py

 #!/usr/bin/env python
 #
 # Copyright 2013 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.
 
 import optparse
 import os
 import shutil
 import re
@@ skipping 115 matching lines @@
       action='append',
       default=[],
       help='Boot classpath for javac. If this is specified multiple times, '
       'they will all be appended to construct the classpath.')
   parser.add_option(
       '--classpath',
       action='append',
       help='Classpath for javac. If this is specified multiple times, they '
       'will all be appended to construct the classpath.')
   parser.add_option(
+      '--use-ijars',
+      action='store_true',
+      help='Whether to use interface jars (.interface.jar) when compiling')
+  parser.add_option(
       '--javac-includes',
       default='',
       help='A list of file patterns. If provided, only java files that match'
       'one of the patterns will be compiled.')
   parser.add_option(
       '--jar-excluded-classes',
       default='',
       help='List of .class file patterns to exclude from the jar.')
 
   parser.add_option(
@@ skipping 48 matching lines @@
   colorama.init()
 
   argv = build_utils.ExpandFileArgs(argv)
   options, java_files = _ParseOptions(argv)
 
   if options.src_gendirs:
     java_files += build_utils.FindInDirectories(options.src_gendirs, '*.java')
 
   java_files = _FilterJavaFiles(java_files, options.javac_includes)
 
+  runtime_classpath = options.classpath
+  compile_classpath = runtime_classpath
+  if options.use_ijars:
+    ijar_re = re.compile(r'\.jar$')
+    compile_classpath = (
+        [ijar_re.sub('.interface.jar', p) for p in runtime_classpath])
+
   javac_args = [
       '-g',
       # Chromium only allows UTF8 source files.  Being explicit avoids
       # javac pulling a default encoding from the user's environment.
       '-encoding', 'UTF-8',
-      '-classpath', ':'.join(options.classpath),
+      '-classpath', ':'.join(compile_classpath),
       ]
 
   if options.bootclasspath:
     javac_args.extend([
         '-bootclasspath', ':'.join(options.bootclasspath),
         '-source', '1.7',
         '-target', '1.7',
         ])
 
   if options.chromium_code:
     # TODO(aurimas): re-enable '-Xlint:deprecation' checks once they are fixed.
     javac_args.extend(['-Xlint:unchecked'])
   else:
     # XDignore.symbol.file makes javac compile against rt.jar instead of
     # ct.sym. This means that using a java internal package/class will not
     # trigger a compile warning or error.
     javac_args.extend(['-XDignore.symbol.file'])
 
   javac_cmd = ['javac']
   if options.use_errorprone_path:
     javac_cmd = [options.use_errorprone_path] + ERRORPRONE_OPTIONS
 
   # Compute the list of paths that when changed, we need to rebuild.
   input_paths = options.bootclasspath + options.java_srcjars + java_files
-  for path in options.classpath:
-    if os.path.exists(path + '.TOC'):
-      input_paths.append(path + '.TOC')
-    else:
-      input_paths.append(path)
+  # TODO(agrieve): Remove this .TOC heuristic once GYP is no more.
+  if not options.use_ijars:
+    for path in compile_classpath:
+      if os.path.exists(path + '.TOC'):
+        input_paths.append(path + '.TOC')
+      else:
+        input_paths.append(path)
   python_deps = build_utils.GetPythonDependencies()
 
   def OnStaleMd5():
     with build_utils.TempDir() as temp_dir:
       if options.java_srcjars:
         java_dir = os.path.join(temp_dir, 'java')
         os.makedirs(java_dir)
         for srcjar in options.java_srcjars:
           build_utils.ExtractAll(srcjar, path=java_dir, pattern='*.java')
         jar_srcs = build_utils.FindInDirectory(java_dir, '*.java')
@@ skipping 10 matching lines @@
         build_utils.CheckOutput(
             cmd,
             print_stdout=options.chromium_code,
             stderr_filter=ColorJavacOutput)
 
       if options.main_class or options.manifest_entry:
         entries = []
         if options.manifest_entry:
           entries = [e.split(':') for e in options.manifest_entry]
         manifest_file = os.path.join(temp_dir, 'manifest')
-        _CreateManifest(manifest_file, options.classpath, options.main_class,
+        _CreateManifest(manifest_file, runtime_classpath, options.main_class,
                         entries)
       else:
         manifest_file = None
       jar.JarDirectory(classes_dir,
                        options.jar_excluded_classes,
                        options.jar_path,
                        manifest_file=manifest_file)
 
     if options.stamp:
       build_utils.Touch(options.stamp)
@@ skipping 10 matching lines @@
       input_paths=input_paths,
       input_strings=javac_cmd + javac_args + python_deps,
       force=not os.path.exists(options.jar_path))
 
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))