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 shlex
  22 import sys
  23
  24 from cpp_bundle_generator import CppBundleGenerator
  25 from cpp_generator import CppGenerator
  26 from cpp_type_generator import CppTypeGenerator
  27 import json_schema
  28 from cpp_namespace_environment import CppNamespaceEnvironment
  29 from model import Model
  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-registration', 'cpp-bundle-schema']
  35
  36 def GenerateSchema(generator_name,
  37                    file_paths,
  38                    root,
  39                    destdir,
  40                    cpp_namespace_pattern,
  41                    impl_dir,
  42                    include_rules):
  43   # Merge the source files into a single list of schemas.
  44   api_defs = []
  45   for file_path in file_paths:
  46     schema = os.path.relpath(file_path, root)
  47     schema_loader = SchemaLoader(
  48         root,
  49         os.path.dirname(schema),
  50         include_rules,
  51         cpp_namespace_pattern)
  52     api_def = schema_loader.LoadSchema(schema)
  53
  54     # If compiling the C++ model code, delete 'nocompile' nodes.
  55     if generator_name == 'cpp':
  56       api_def = json_schema.DeleteNodes(api_def, 'nocompile')
  57     api_defs.extend(api_def)
  58
  59   api_model = Model()
  60
  61   # For single-schema compilation make sure that the first (i.e. only) schema
  62   # is the default one.
  63   default_namespace = None
  64
  65   # If we have files from multiple source paths, we'll use the common parent
  66   # path as the source directory.
  67   src_path = None
  68
  69   # Load the actual namespaces into the model.
  70   for target_namespace, file_path in zip(api_defs, file_paths):
  71     relpath = os.path.relpath(os.path.normpath(file_path), root)
  72     namespace = api_model.AddNamespace(target_namespace,
  73                                        relpath,
  74                                        include_compiler_options=True,
  75                                        environment=CppNamespaceEnvironment(
  76                                            cpp_namespace_pattern))
  77
  78     if default_namespace is None:
  79       default_namespace = namespace
  80
  81     if src_path is None:
  82       src_path = namespace.source_file_dir
  83     else:
  84       src_path = os.path.commonprefix((src_path, namespace.source_file_dir))
  85
  86     _, filename = os.path.split(file_path)
  87     filename_base, _ = os.path.splitext(filename)
  88
  89   # Construct the type generator with all the namespaces in this model.
  90   type_generator = CppTypeGenerator(api_model,
  91                                     schema_loader,
  92                                     default_namespace)
  93   if generator_name in ('cpp-bundle-registration', 'cpp-bundle-schema'):
  94     cpp_bundle_generator = CppBundleGenerator(root,
  95                                               api_model,
  96                                               api_defs,
  97                                               type_generator,
  98                                               cpp_namespace_pattern,
  99                                               src_path,
 100                                               impl_dir)
 101     if generator_name == 'cpp-bundle-registration':
 102       generators = [
 103         ('generated_api_registration.cc',
 104          cpp_bundle_generator.api_cc_generator),
 105         ('generated_api_registration.h', cpp_bundle_generator.api_h_generator),
 106       ]
 107     elif generator_name == 'cpp-bundle-schema':
 108       generators = [
 109         ('generated_schemas.cc', cpp_bundle_generator.schemas_cc_generator),
 110         ('generated_schemas.h', cpp_bundle_generator.schemas_h_generator)
 111       ]
 112   elif generator_name == 'cpp':
 113     cpp_generator = CppGenerator(type_generator)
 114     generators = [
 115       ('%s.h' % filename_base, cpp_generator.h_generator),
 116       ('%s.cc' % filename_base, cpp_generator.cc_generator)
 117     ]
 118   else:
 119     raise Exception('Unrecognised generator %s' % generator_name)
 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('-i', '--impl-dir', dest='impl_dir',
 156       help='The root path of all API implementations')
 157   parser.add_option('-I', '--include-rules',
 158       help='A list of paths to include when searching for referenced objects,'
 159       ' with the namespace separated by a \':\'. Example: '
 160       '/foo/bar:Foo::Bar::%(namespace)s')
 161
 162   (opts, file_paths) = parser.parse_args()
 163
 164   if not file_paths:
 165     sys.exit(0) # This is OK as a no-op
 166
 167   # Unless in bundle mode, only one file should be specified.
 168   if (opts.generator not in ('cpp-bundle-registration', 'cpp-bundle-schema') and
 169       len(file_paths) > 1):
 170     # TODO(sashab): Could also just use file_paths[0] here and not complain.
 171     raise Exception(
 172         "Unless in bundle mode, only one file can be specified at a time.")
 173
 174   def split_path_and_namespace(path_and_namespace):
 175     if ':' not in path_and_namespace:
 176       raise ValueError('Invalid include rule "%s". Rules must be of '
 177                        'the form path:namespace' % path_and_namespace)
 178     return path_and_namespace.split(':', 1)
 179
 180   include_rules = []
 181   if opts.include_rules:
 182     include_rules = map(split_path_and_namespace,
 183                         shlex.split(opts.include_rules))
 184
 185   result = GenerateSchema(opts.generator, file_paths, opts.root, opts.destdir,
 186                           opts.namespace, opts.impl_dir, include_rules)
 187   if not opts.destdir:
 188     print result