New C++ -> Java enum build rule + parser/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
new file mode 100755
index 0000000000000000000000000000000000000000..ad0974232a07da5cd3d3aad28ef546853d095fae
--- /dev/null
+++ b/build/android/gyp/java_cpp_enum.py
@@ -0,0 +1,237 @@
+#!/usr/bin/env python
+#
+# Copyright 2014 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 collections
+import re
+import optparse
+import os
+from string import Template
+import sys
+
+from util import build_utils
+
+class EnumDefinition(object):
+  def __init__(self, class_name=None, class_package=None, entries=None):
+    self.class_name = class_name
+    self.class_package = class_package
+    self.entries = collections.OrderedDict(entries or [])
+    self.prefix_to_strip = ''
+
+  def AppendEntry(self, key, value):
+    if key in self.entries:
+      raise Exception('Multiple definitions of key %s found.' % key)
+    self.entries[key] = value
+
+  def Finalize(self):
+    self._Validate()
+    self._AssignEntryIndices()
+    self._StripPrefix()
+
+  def _Validate(self):
+    assert self.class_name
+    assert self.class_package
+    assert self.entries
+
+  def _AssignEntryIndices(self):
+    # Supporting the same set enum value assignments the compiler does is rather
+    # complicated, so we limit ourselves to these cases:
+    # - all the enum constants have values assigned,
+    # - enum constants reference other enum constants or have no value assigned.
+
+    if not all(self.entries.values()):
+      index = 0
+      for key, value in self.entries.iteritems():
+        if not value:
+          self.entries[key] = index
+          index = index + 1
+        elif value in self.entries:
+          self.entries[key] = self.entries[value]
+        else:
+          raise Exception('You can only reference other enum constants unless '
+                          'you assign values to all of the constants.')
+
+  def _StripPrefix(self):
+    if not self.prefix_to_strip:
+      prefix_to_strip = re.sub('(?!^)([A-Z]+)', r'_\1', self.class_name).upper()
+      prefix_to_strip += '_'
+      if not all([w.startswith(prefix_to_strip) for w in self.entries.keys()]):
+        prefix_to_strip = ''
+    else:
+      prefix_to_strip = self.prefix_to_strip
+    entries = ((k.replace(prefix_to_strip, '', 1), v) for (k, v) in
+               self.entries.iteritems())
+    self.entries = collections.OrderedDict(entries)
+
+class HeaderParser(object):
+  single_line_comment_re = re.compile(r'\s*//')
+  multi_line_comment_start_re = re.compile(r'\s*/\*')
+  enum_start_re = re.compile(r'^\s*enum\s+(\w+)\s+{\s*$')
+  enum_line_re = re.compile(r'^\s*(\w+)(\s*\=\s*([^,\n]+))?,?\s*$')
+  enum_end_re = re.compile(r'^\s*}\s*;\s*$')
+  generator_directive_re = re.compile(
+      r'^\s*//\s+GENERATED_JAVA_(\w+)\s*:\s*([\.\w]+)$')
+
+  def __init__(self, lines):
+    self._lines = lines
+    self._enum_definitions = []
+    self._in_enum = False
+    self._current_definition = None
+    self._generator_directives = {}
+
+  def ParseDefinitions(self):
+    for line in self._lines:
+      self._ParseLine(line)
+    return self._enum_definitions
+
+  def _ParseLine(self, line):
+    if not self._in_enum:
+      self._ParseRegularLine(line)
+    else:
+      self._ParseEnumLine(line)
+
+  def _ParseEnumLine(self, line):
+    if HeaderParser.single_line_comment_re.match(line):
+      return
+    if HeaderParser.multi_line_comment_start_re.match(line):
+      raise Exception('Multi-line comments in enums are not supported.')
+    enum_end = HeaderParser.enum_end_re.match(line)
+    enum_entry = HeaderParser.enum_line_re.match(line)
+    if enum_end:
+      self._ApplyGeneratorDirectives()
+      self._current_definition.Finalize()
+      self._enum_definitions.append(self._current_definition)
+      self._in_enum = False
+    elif enum_entry:
+      enum_key = enum_entry.groups()[0]
+      enum_value = enum_entry.groups()[2]
+      self._current_definition.AppendEntry(enum_key, enum_value)
+
+  def _GetCurrentEnumPackageName(self):
+    return self._generator_directives.get('ENUM_PACKAGE')
+
+  def _GetCurrentEnumPrefixToStrip(self):
+    return self._generator_directives.get('PREFIX_TO_STRIP', '')
+
+  def _ApplyGeneratorDirectives(self):
+    current_definition = self._current_definition
+    current_definition.class_package = self._GetCurrentEnumPackageName()
+    current_definition.prefix_to_strip = self._GetCurrentEnumPrefixToStrip()
+    self._generator_directives = {}
+
+  def _ParseRegularLine(self, line):
+    enum_start = HeaderParser.enum_start_re.match(line)
+    generator_directive = HeaderParser.generator_directive_re.match(line)
+    if enum_start:
+      if not self._GetCurrentEnumPackageName():
+        return
+      self._current_definition = EnumDefinition()
+      self._current_definition.class_name = enum_start.groups()[0]
+      self._in_enum = True
+    elif generator_directive:
+      directive_name = generator_directive.groups()[0]
+      directive_value = generator_directive.groups()[1]
+      self._generator_directives[directive_name] = directive_value
+
+
+def GetScriptName():
+  script_components = os.path.abspath(sys.argv[0]).split(os.path.sep)
+  build_index = script_components.index('build')
+  return os.sep.join(script_components[build_index:])
+
+
+def DoGenerate(options, source_paths):
+  output_paths = []
+  for source_path in source_paths:
+    enum_definitions = DoParseHeaderFile(source_path)
+    for enum_definition in enum_definitions:
+      package_path = enum_definition.class_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_paths.append(output_path)
+      if not options.print_output_only:
+        build_utils.MakeDirectory(os.path.dirname(output_path))
+        DoWriteOutput(source_path, output_path, enum_definition)
+  return output_paths
+
+
+def DoParseHeaderFile(path):
+  with open(path) as f:
+    return HeaderParser(f.readlines()).ParseDefinitions()
+
+
+def GenerateOutput(source_path, enum_definition):
+  template = Template("""
+// Copyright 2014 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.
+
+// This file is autogenerated by
+//     ${SCRIPT_NAME}
+// From
+//     ${SOURCE_PATH}
+
+package ${PACKAGE};
+
+public class ${CLASS_NAME} {
+${ENUM_ENTRIES}
+}
+""")
+
+  enum_template = Template('  public static final int ${NAME} = ${VALUE};')
+  enum_entries_string = []
+  for enum_name, enum_value in enum_definition.entries.iteritems():
+    values = {
+        'NAME': enum_name,
+        'VALUE': enum_value,
+    }
+    enum_entries_string.append(enum_template.substitute(values))
+  enum_entries_string = '\n'.join(enum_entries_string)
+
+  values = {
+      'CLASS_NAME': enum_definition.class_name,
+      'ENUM_ENTRIES': enum_entries_string,
+      'PACKAGE': enum_definition.class_package,
+      'SCRIPT_NAME': GetScriptName(),
+      'SOURCE_PATH': source_path,
+  }
+  return template.substitute(values)
+
+
+def DoWriteOutput(source_path, output_path, enum_definition):
+  with open(output_path, 'w') as out_file:
+    out_file.write(GenerateOutput(source_path, enum_definition))
+
+def AssertFilesList(output_paths, assert_files_list):
+  actual = set(output_paths)
+  expected = set(assert_files_list)
+  if not actual == expected:
+    need_to_add = list(actual - expected)
+    need_to_remove = list(expected - actual)
+    raise Exception('Output files list does not match expectations. Please '
+                    'add %s and remove %s.' % (need_to_add, need_to_remove))
+
+def DoMain(argv):
+  parser = optparse.OptionParser()
+
+  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)
+
+  output_paths = DoGenerate(options, args)
+
+  if options.assert_files_list:
+    AssertFilesList(output_paths, options.assert_files_list)
+
+  return " ".join(output_paths)
+
+if __name__ == '__main__':
+  DoMain(sys.argv[1:])