tools/json_schema_compiler/compiler.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5 """Generator for C++ structs from api json files.
   6
   7 The purpose of this tool is to remove the need for hand-written code that
   8 converts to and from base::Value types when receiving javascript api calls.
   9 Originally written for generating code for extension apis. Reference schemas
  10 are in chrome/common/extensions/api.
  11
  12 Usage example:
  13   compiler.py --root /home/Work/src --namespace extensions windows.json
  14     tabs.json
  15   compiler.py --destdir gen --root /home/Work/src
  16     --namespace extensions windows.json tabs.json
  17 """
  18
  19 import optparse
  20 import os
  21 import sys
  22
  23 from cpp_bundle_generator import CppBundleGenerator
  24 from cpp_generator import CppGenerator
  25 from cpp_type_generator import CppTypeGenerator
  26 from dart_generator import DartGenerator
  27 import json_schema
  28 from model import Model
  29 from ppapi_generator import PpapiGenerator
  30 from schema_loader import SchemaLoader
  31
  32 # Names of supported code generators, as specified on the command-line.
  33 # First is default.
  34 GENERATORS = ['cpp', 'cpp-bundle', 'dart', 'ppapi']
  35
  36 def GenerateSchema(generator,
  37                    filenames,
  38                    root,
  39                    destdir,
  40                    root_namespace,
  41                    dart_overrides_dir):
  42   schema_loader = SchemaLoader(
  43       os.path.dirname(os.path.relpath(os.path.normpath(filenames[0]), root)),
  44       os.path.dirname(filenames[0]))
  45   # Merge the source files into a single list of schemas.
  46   api_defs = []
  47   for filename in filenames:
  48     schema = os.path.normpath(filename)
  49     api_def = schema_loader.LoadSchema(os.path.split(schema)[1])
  50
  51     # If compiling the C++ model code, delete 'nocompile' nodes.
  52     if generator == 'cpp':
  53       api_def = json_schema.DeleteNodes(api_def, 'nocompile')
  54     api_defs.extend(api_def)
  55
  56   api_model = Model()
  57
  58   # For single-schema compilation make sure that the first (i.e. only) schema
  59   # is the default one.
  60   default_namespace = None
  61
  62   # Load the actual namespaces into the model.
  63   for target_namespace, schema_filename in zip(api_defs, filenames):
  64     relpath = os.path.relpath(os.path.normpath(schema_filename), root)
  65     namespace = api_model.AddNamespace(target_namespace,
  66                                        relpath,
  67                                        include_compiler_options=True)
  68     if default_namespace is None:
  69       default_namespace = namespace
  70
  71     path, filename = os.path.split(schema_filename)
  72     short_filename, extension = os.path.splitext(filename)
  73
  74   # Construct the type generator with all the namespaces in this model.
  75   type_generator = CppTypeGenerator(api_model,
  76                                     schema_loader,
  77                                     default_namespace=default_namespace)
  78
  79   if generator == 'cpp-bundle':
  80     cpp_bundle_generator = CppBundleGenerator(root,
  81                                               api_model,
  82                                               api_defs,
  83                                               type_generator,
  84                                               root_namespace,
  85                                               namespace.source_file_dir)
  86     generators = [
  87       ('generated_api.cc', cpp_bundle_generator.api_cc_generator),
  88       ('generated_api.h', cpp_bundle_generator.api_h_generator),
  89       ('generated_schemas.cc', cpp_bundle_generator.schemas_cc_generator),
  90       ('generated_schemas.h', cpp_bundle_generator.schemas_h_generator)
  91     ]
  92   elif generator == 'cpp':
  93     cpp_generator = CppGenerator(type_generator, root_namespace)
  94     generators = [
  95       ('%s.h' % short_filename, cpp_generator.h_generator),
  96       ('%s.cc' % short_filename, cpp_generator.cc_generator)
  97     ]
  98   elif generator == 'dart':
  99     generators = [
 100       ('%s.dart' % namespace.unix_name, DartGenerator(
 101           dart_overrides_dir))
 102     ]
 103   elif generator == 'ppapi':
 104     generator = PpapiGenerator()
 105     generators = [
 106       (os.path.join('api', 'ppb_%s.idl' % namespace.unix_name),
 107        generator.idl_generator),
 108     ]
 109   else:
 110     raise Exception('Unrecognised generator %s' % generator)
 111
 112   output_code = []
 113   for filename, generator in generators:
 114     code = generator.Generate(namespace).Render()
 115     if destdir:
 116       with open(os.path.join(destdir, namespace.source_file_dir,
 117           filename), 'w') as f:
 118         f.write(code)
 119     output_code += [filename, '', code, '']
 120
 121   return '\n'.join(output_code)
 122
 123
 124 if __name__ == '__main__':
 125   parser = optparse.OptionParser(
 126       description='Generates a C++ model of an API from JSON schema',
 127       usage='usage: %prog [option]... schema')
 128   parser.add_option('-r', '--root', default='.',
 129       help='logical include root directory. Path to schema files from specified'
 130       ' dir will be the include path.')
 131   parser.add_option('-d', '--destdir',
 132       help='root directory to output generated files.')
 133   parser.add_option('-n', '--namespace', default='generated_api_schemas',
 134       help='C++ namespace for generated files. e.g extensions::api.')
 135   parser.add_option('-g', '--generator', default=GENERATORS[0],
 136       choices=GENERATORS,
 137       help='The generator to use to build the output code. Supported values are'
 138       ' %s' % GENERATORS)
 139   parser.add_option('-D', '--dart-overrides-dir', dest='dart_overrides_dir',
 140       help='Adds custom dart from files in the given directory (Dart only).')
 141
 142   (opts, filenames) = parser.parse_args()
 143
 144   if not filenames:
 145     sys.exit(0) # This is OK as a no-op
 146
 147   # Unless in bundle mode, only one file should be specified.
 148   if opts.generator != 'cpp-bundle' and len(filenames) > 1:
 149     # TODO(sashab): Could also just use filenames[0] here and not complain.
 150     raise Exception(
 151         "Unless in bundle mode, only one file can be specified at a time.")
 152
 153   result = GenerateSchema(opts.generator, filenames, opts.root, opts.destdir,
 154                           opts.namespace, opts.dart_overrides_dir)
 155   if not opts.destdir:
 156     print result