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                    impl_dir):
  43   # Merge the source files into a single list of schemas.
  44   api_defs = []
  45   for filename in filenames:
  46     schema = os.path.normpath(filename)
  47     schema_loader = SchemaLoader(
  48         os.path.dirname(os.path.relpath(os.path.normpath(filename), root)),
  49         os.path.dirname(filename))
  50     api_def = schema_loader.LoadSchema(os.path.split(schema)[1])
  51
  52     # If compiling the C++ model code, delete 'nocompile' nodes.
  53     if generator == 'cpp':
  54       api_def = json_schema.DeleteNodes(api_def, 'nocompile')
  55     api_defs.extend(api_def)
  56
  57   api_model = Model()
  58
  59   # For single-schema compilation make sure that the first (i.e. only) schema
  60   # is the default one.
  61   default_namespace = None
  62
  63   # If we have files from multiple source paths, we'll use the common parent
  64   # path as the source directory.
  65   src_path = None
  66
  67   # Load the actual namespaces into the model.
  68   for target_namespace, schema_filename in zip(api_defs, filenames):
  69     relpath = os.path.relpath(os.path.normpath(schema_filename), root)
  70     namespace = api_model.AddNamespace(target_namespace,
  71                                        relpath,
  72                                        include_compiler_options=True)
  73
  74     if default_namespace is None:
  75       default_namespace = namespace
  76
  77     if src_path is None:
  78       src_path = namespace.source_file_dir
  79     else:
  80       src_path = os.path.commonprefix((src_path, namespace.source_file_dir))
  81
  82     path, filename = os.path.split(schema_filename)
  83     short_filename, extension = os.path.splitext(filename)
  84
  85   # Construct the type generator with all the namespaces in this model.
  86   type_generator = CppTypeGenerator(api_model,
  87                                     schema_loader,
  88                                     default_namespace=default_namespace)
  89   if generator == 'cpp-bundle':
  90     cpp_bundle_generator = CppBundleGenerator(root,
  91                                               api_model,
  92                                               api_defs,
  93                                               type_generator,
  94                                               root_namespace,
  95                                               src_path,
  96                                               impl_dir)
  97     generators = [
  98       ('generated_api.cc', cpp_bundle_generator.api_cc_generator),
  99       ('generated_api.h', cpp_bundle_generator.api_h_generator),
 100       ('generated_schemas.cc', cpp_bundle_generator.schemas_cc_generator),
 101       ('generated_schemas.h', cpp_bundle_generator.schemas_h_generator)
 102     ]
 103   elif generator == 'cpp':
 104     cpp_generator = CppGenerator(type_generator, root_namespace)
 105     generators = [
 106       ('%s.h' % short_filename, cpp_generator.h_generator),
 107       ('%s.cc' % short_filename, cpp_generator.cc_generator)
 108     ]
 109   elif generator == 'dart':
 110     generators = [
 111       ('%s.dart' % namespace.unix_name, DartGenerator(
 112           dart_overrides_dir))
 113     ]
 114   elif generator == 'ppapi':
 115     generator = PpapiGenerator()
 116     generators = [
 117       (os.path.join('api', 'ppb_%s.idl' % namespace.unix_name),
 118        generator.idl_generator),
 119     ]
 120   else:
 121     raise Exception('Unrecognised generator %s' % generator)
 122
 123   output_code = []
 124   for filename, generator in generators:
 125     code = generator.Generate(namespace).Render()
 126     if destdir:
 127       output_dir = os.path.join(destdir, src_path)
 128       if not os.path.exists(output_dir):
 129         os.makedirs(output_dir)
 130       with open(os.path.join(output_dir, filename), 'w') as f:
 131         f.write(code)
 132     output_code += [filename, '', code, '']
 133
 134   return '\n'.join(output_code)
 135
 136
 137 if __name__ == '__main__':
 138   parser = optparse.OptionParser(
 139       description='Generates a C++ model of an API from JSON schema',
 140       usage='usage: %prog [option]... schema')
 141   parser.add_option('-r', '--root', default='.',
 142       help='logical include root directory. Path to schema files from specified'
 143       ' dir will be the include path.')
 144   parser.add_option('-d', '--destdir',
 145       help='root directory to output generated files.')
 146   parser.add_option('-n', '--namespace', default='generated_api_schemas',
 147       help='C++ namespace for generated files. e.g extensions::api.')
 148   parser.add_option('-g', '--generator', default=GENERATORS[0],
 149       choices=GENERATORS,
 150       help='The generator to use to build the output code. Supported values are'
 151       ' %s' % GENERATORS)
 152   parser.add_option('-D', '--dart-overrides-dir', dest='dart_overrides_dir',
 153       help='Adds custom dart from files in the given directory (Dart only).')
 154   parser.add_option('-i', '--impl-dir', dest='impl_dir',
 155       help='The root path of all API implementations')
 156
 157   (opts, filenames) = parser.parse_args()
 158
 159   if not filenames:
 160     sys.exit(0) # This is OK as a no-op
 161
 162   # Unless in bundle mode, only one file should be specified.
 163   if opts.generator != 'cpp-bundle' and len(filenames) > 1:
 164     # TODO(sashab): Could also just use filenames[0] here and not complain.
 165     raise Exception(
 166         "Unless in bundle mode, only one file can be specified at a time.")
 167
 168   result = GenerateSchema(opts.generator, filenames, opts.root, opts.destdir,
 169                           opts.namespace, opts.dart_overrides_dir,
 170                           opts.impl_dir)
 171   if not opts.destdir:
 172     print result