Improve CLI interface of C++ enums to Java generator

1. Print error if input file doesn't have any annotated enums.

2. Convert "mandatory option" 'output_dir' into a positional argument.

3. Fix 'print_output_only' when running from command line.

BUG=458562

Review URL: https://codereview.chromium.org/934873002

Cr-Original-Commit-Position: refs/heads/master@{#317783}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 4e3301c82c48ac22439d1b9dc34ba05a0599e3e9

android/gyp/java_cpp_enum.py

@@ -228,16 +228,21 @@ def GetScriptName():
   return os.sep.join(script_components[build_index:])
 
 
-def DoGenerate(options, source_paths):
+def DoGenerate(output_dir, source_paths, print_output_only=False):
   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:
+      if not print_output_only:
         build_utils.MakeDirectory(os.path.dirname(output_path))
         DoWriteOutput(source_path, output_path, enum_definition)
   return output_paths
@@ -300,24 +305,32 @@ 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')
+  parser.add_option('--verbose', help='Print more information.',
+                    action='store_true')
 
   options, args = parser.parse_args(argv)
-
-  output_paths = DoGenerate(options, args)
+  if len(args) < 2:
+    parser.error('Need to specify output directory and at least one input file')
+  output_paths = DoGenerate(args[0], args[1:],
+                            print_output_only=options.print_output_only)
 
   if options.assert_files_list:
     AssertFilesList(output_paths, options.assert_files_list)
 
-  return " ".join(output_paths)
+  if options.verbose:
+    print 'Output paths:'
+    print '\n'.join(output_paths)
+
+  return ' '.join(output_paths)
 
 if __name__ == '__main__':
   DoMain(sys.argv[1:])

android/gyp/java_cpp_enum_tests.py

@@ -14,6 +14,7 @@ import os
 import sys
 import unittest
 
+import java_cpp_enum
 from java_cpp_enum import EnumDefinition, GenerateOutput, GetScriptName
 from java_cpp_enum import HeaderParser
 
@@ -151,6 +152,14 @@ public class ClassName {
     with self.assertRaises(Exception):
       HeaderParser(test_data).ParseDefinitions()
 
+  def testParseReturnsEmptyListWithoutDirectives(self):
+    test_data = """
+      enum EnumName {
+        VALUE_ONE,
+      };
+    """.split('\n')
+    self.assertEqual([], HeaderParser(test_data).ParseDefinitions())
+
   def testParseEnumClass(self):
     test_data = """
       // GENERATED_JAVA_ENUM_PACKAGE: test.namespace
@@ -403,6 +412,15 @@ public class ClassName {
     definition.Finalize()
     self.assertEqual(['A', 'B', 'NAME_LAST'], definition.entries.keys())
 
+  def testGenerateThrowsOnEmptyInput(self):
+    with self.assertRaises(Exception):
+      original_do_parse = java_cpp_enum.DoParseHeaderFile
+      try:
+        java_cpp_enum.DoParseHeaderFile = lambda _: []
+        java_cpp_enum.DoGenerate('dir', ['file'])
+      finally:
+        java_cpp_enum.DoParseHeaderFile = original_do_parse
+
 def main(argv):
   parser = optparse.OptionParser()
   parser.add_option("--stamp", help="File to touch on success.")

android/java_cpp_enum.gypi

@@ -24,7 +24,7 @@
     # Location where all generated Java sources will be placed.
     'output_dir': '<(SHARED_INTERMEDIATE_DIR)/enums/<(_target_name)',
     'generator_path': '<(DEPTH)/build/android/gyp/java_cpp_enum.py',
-    'generator_args': '--output_dir=<(output_dir) <(source_file)',
+    'generator_args': '<(output_dir) <(source_file)',
   },
   'direct_dependent_settings': {
     'variables': {

config/android/rules.gni

@@ -335,8 +335,8 @@ template("java_cpp_template") {
 #
 #   outputs: list of outputs, relative to the output_dir. These paths are
 #     verified at build time by the script. To get the list programatically run:
-#       python build/android/gyp/java_cpp_enum.py --output_dir=. \
-#         --print_output_only path/to/header/file.h
+#       python build/android/gyp/java_cpp_enum.py \
+#         --print_output_only . path/to/header/file.h
 #
 # Example
 #   java_cpp_enum("foo_generated_enum") {
@@ -366,16 +366,14 @@ template("java_cpp_enum") {
     outputs =
         get_path_info(rebase_path(invoker.outputs, ".", gen_dir), "abspath")
 
-    args = [
-      "--output_dir",
-      rebase_path(gen_dir, root_build_dir),
-    ]
+    args = []
     foreach(output, rebase_path(outputs, root_build_dir)) {
       args += [
         "--assert_file",
         output,
       ]
     }
+    args += [ rebase_path(gen_dir, root_build_dir) ]
     args += rebase_path(invoker.sources, root_build_dir)
   }