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 schema_loader import SchemaLoader
  30
  31 # Names of supported code generators, as specified on the command-line.
  32 # First is default.
  33 GENERATORS = ['cpp', 'cpp-bundle-registration', 'cpp-bundle-schema', 'dart']
  34
  35 def GenerateSchema(generator_name,
  36                    file_paths,
  37                    root,
  38                    destdir,
  39                    cpp_namespace_pattern,
  40                    dart_overrides_dir,
  41                    impl_dir):
  42   # Merge the source files into a single list of schemas.
  43   api_defs = []
  44   for file_path in file_paths:
  45     schema = os.path.normpath(file_path)
  46     schema_loader = SchemaLoader(
  47         os.path.dirname(os.path.relpath(schema, root)),
  48         os.path.dirname(file_path))
  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_name == '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   # If we have files from multiple source paths, we'll use the common parent
  63   # path as the source directory.
  64   src_path = None
  65
  66   # Load the actual namespaces into the model.
  67   for target_namespace, file_path in zip(api_defs, file_paths):
  68     relpath = os.path.relpath(os.path.normpath(file_path), root)
  69     namespace = api_model.AddNamespace(target_namespace,
  70                                        relpath,
  71                                        include_compiler_options=True)
  72
  73     if default_namespace is None:
  74       default_namespace = namespace
  75
  76     if src_path is None:
  77       src_path = namespace.source_file_dir
  78     else:
  79       src_path = os.path.commonprefix((src_path, namespace.source_file_dir))
  80
  81     path, filename = os.path.split(file_path)
  82     filename_base, _ = os.path.splitext(filename)
  83
  84   # Construct the type generator with all the namespaces in this model.
  85   type_generator = CppTypeGenerator(api_model,
  86                                     schema_loader,
  87                                     default_namespace)
  88   if generator_name in ('cpp-bundle-registration', 'cpp-bundle-schema'):
  89     cpp_bundle_generator = CppBundleGenerator(root,
  90                                               api_model,
  91                                               api_defs,
  92                                               type_generator,
  93                                               cpp_namespace_pattern,
  94                                               src_path,
  95                                               impl_dir)
  96     if generator_name == 'cpp-bundle-registration':
  97       generators = [
  98         ('generated_api_registration.cc',
  99          cpp_bundle_generator.api_cc_generator),
 100         ('generated_api_registration.h', cpp_bundle_generator.api_h_generator),
 101       ]
 102     elif generator_name == 'cpp-bundle-schema':
 103       generators = [
 104         ('generated_schemas.cc', cpp_bundle_generator.schemas_cc_generator),
 105         ('generated_schemas.h', cpp_bundle_generator.schemas_h_generator)
 106       ]
 107   elif generator_name == 'cpp':
 108     cpp_generator = CppGenerator(type_generator, cpp_namespace_pattern)
 109     generators = [
 110       ('%s.h' % filename_base, cpp_generator.h_generator),
 111       ('%s.cc' % filename_base, cpp_generator.cc_generator)
 112     ]
 113   elif generator_name == 'dart':
 114     generators = [
 115       ('%s.dart' % namespace.unix_name, DartGenerator(
 116           dart_overrides_dir))
 117     ]
 118   else:
 119     raise Exception('Unrecognised generator %s' % generator)
 120
 121   output_code = []
 122   for filename, generator in generators:
 123     code = generator.Generate(namespace).Render()
 124     if destdir:
 125       if generator_name == 'cpp-bundle-registration':
 126         # Function registrations must be output to impl_dir, since they link in
 127         # API implementations.
 128         output_dir = os.path.join(destdir, impl_dir)
 129       else:
 130         output_dir = os.path.join(destdir, src_path)
 131       if not os.path.exists(output_dir):
 132         os.makedirs(output_dir)
 133       with open(os.path.join(output_dir, filename), 'w') as f:
 134         f.write(code)
 135     output_code += [filename, '', code, '']
 136
 137   return '\n'.join(output_code)
 138
 139
 140 if __name__ == '__main__':
 141   parser = optparse.OptionParser(
 142       description='Generates a C++ model of an API from JSON schema',
 143       usage='usage: %prog [option]... schema')
 144   parser.add_option('-r', '--root', default='.',
 145       help='logical include root directory. Path to schema files from specified'
 146       ' dir will be the include path.')
 147   parser.add_option('-d', '--destdir',
 148       help='root directory to output generated files.')
 149   parser.add_option('-n', '--namespace', default='generated_api_schemas',
 150       help='C++ namespace for generated files. e.g extensions::api.')
 151   parser.add_option('-g', '--generator', default=GENERATORS[0],
 152       choices=GENERATORS,
 153       help='The generator to use to build the output code. Supported values are'
 154       ' %s' % GENERATORS)
 155   parser.add_option('-D', '--dart-overrides-dir', dest='dart_overrides_dir',
 156       help='Adds custom dart from files in the given directory (Dart only).')
 157   parser.add_option('-i', '--impl-dir', dest='impl_dir',
 158       help='The root path of all API implementations')
 159
 160   (opts, file_paths) = parser.parse_args()
 161
 162   if not file_paths:
 163     sys.exit(0) # This is OK as a no-op
 164
 165   # Unless in bundle mode, only one file should be specified.
 166   if (opts.generator not in ('cpp-bundle-registration', 'cpp-bundle-schema') and
 167       len(file_paths) > 1):
 168     # TODO(sashab): Could also just use file_paths[0] here and not complain.
 169     raise Exception(
 170         "Unless in bundle mode, only one file can be specified at a time.")
 171
 172   result = GenerateSchema(opts.generator, file_paths, opts.root, opts.destdir,
 173                           opts.namespace, opts.dart_overrides_dir,
 174                           opts.impl_dir)
 175   if not opts.destdir:
 176     print result