Improve CLI interface of C++ enums to Java generator

build/android/gyp/java_cpp_enum.py

Index: build/android/gyp/java_cpp_enum.py
diff --git a/build/android/gyp/java_cpp_enum.py b/build/android/gyp/java_cpp_enum.py
index 46417eca5e6735a1413256bad7c21588c0bca1af..8b9674c6ddac54d0294b0d0d29b4e650cc7fbd3a 100755
--- a/build/android/gyp/java_cpp_enum.py
+++ b/build/android/gyp/java_cpp_enum.py
@@ -228,14 +228,21 @@ def GetScriptName():
   return os.sep.join(script_components[build_index:])
 
 
-def DoGenerate(options, source_paths):
+def DoGenerate(options, output_dir_and_source_paths):

[cjhopman, 2015/02/17 21:38:25]

extracting out bits of the list like this is odd, can we do:
def DoGenerate(options, output_dir, source_paths):

[mnaganov (inactive), 2015/02/23 11:35:26]

Done.

+  output_dir = output_dir_and_source_paths[0]
+  source_paths = output_dir_and_source_paths[1:]
   output_paths = []
   for source_path in source_paths:
     enum_definitions = DoParseHeaderFile(source_path)
+    if not enum_definitions:
+      raise Exception('No enums found in %s\n'
+                      'Did you forget prefixing enums with '
+                      '"// GENERATED_JAVA_ENUM_PACKAGE: foo"?' %
+                      source_path)
     for enum_definition in enum_definitions:
       package_path = enum_definition.enum_package.replace('.', os.path.sep)
       file_name = enum_definition.class_name + '.java'
-      output_path = os.path.join(options.output_dir, package_path, file_name)
+      output_path = os.path.join(output_dir, package_path, file_name)
       output_paths.append(output_path)
       if not options.print_output_only:

[cjhopman, 2015/02/17 21:38:25]

We could totally get rid of the options argument here if we just passed this
flag explicitly as well.

[mnaganov (inactive), 2015/02/23 11:35:26]

Done.

         build_utils.MakeDirectory(os.path.dirname(output_path))
@@ -300,18 +307,19 @@ def AssertFilesList(output_paths, assert_files_list):
                     'add %s and remove %s.' % (need_to_add, need_to_remove))
 
 def DoMain(argv):
-  parser = optparse.OptionParser()
+  usage = 'usage: %prog [options] output_dir input_file(s)...'
+  parser = optparse.OptionParser(usage=usage)
 
   parser.add_option('--assert_file', action="append", default=[],
                     dest="assert_files_list", help='Assert that the given '
                     'file is an output. There can be multiple occurrences of '
                     'this flag.')
-  parser.add_option('--output_dir', help='Base path for generated files.')
   parser.add_option('--print_output_only', help='Only print output paths.',
                     action='store_true')
 
   options, args = parser.parse_args(argv)
-
+  if len(args) < 2:
+    parser.error('Need to specify output directory and at least one input file')
   output_paths = DoGenerate(options, args)
 
   if options.assert_files_list:
@@ -320,4 +328,4 @@ def DoMain(argv):
   return " ".join(output_paths)
 
 if __name__ == '__main__':
-  DoMain(sys.argv[1:])
+  print DoMain(sys.argv[1:])

[cjhopman, 2015/02/17 21:38:25]

We try to limit the output in a normal build, so I'd avoid printing this. If
this information is useful for debugging we could do something like a --verbose
flag (or a --quiet flag used in the build) and print more information.

[mnaganov (inactive), 2015/02/23 11:35:26]

I see. Added a flag then.