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 from js_externs_generator import JsExternsGenerator
  28 import json_schema
  29 from cpp_namespace_environment import CppNamespaceEnvironment
  30 from model import Model
  31 from schema_loader import SchemaLoader
  32
  33 # Names of supported code generators, as specified on the command-line.
  34 # First is default.
  35 GENERATORS = ['cpp', 'cpp-bundle-registration', 'cpp-bundle-schema', 'externs']
  36
  37 def GenerateSchema(generator_name,
  38                    file_paths,
  39                    root,
  40                    destdir,
  41                    cpp_namespace_pattern,
  42                    bundle_name,
  43                    impl_dir,
  44                    include_rules):
  45   # Merge the source files into a single list of schemas.
  46   api_defs = []
  47   for file_path in file_paths:
  48     schema = os.path.relpath(file_path, root)
  49     schema_loader = SchemaLoader(
  50         root,
  51         os.path.dirname(schema),
  52         include_rules,
  53         cpp_namespace_pattern)
  54     api_def = schema_loader.LoadSchema(schema)
  55
  56     # If compiling the C++ model code, delete 'nocompile' nodes.
  57     if generator_name == 'cpp':
  58       api_def = json_schema.DeleteNodes(api_def, 'nocompile')
  59     api_defs.extend(api_def)
  60
  61   api_model = Model(allow_inline_enums=False)
  62
  63   # For single-schema compilation make sure that the first (i.e. only) schema
  64   # is the default one.
  65   default_namespace = None
  66
  67   # If we have files from multiple source paths, we'll use the common parent
  68   # path as the source directory.
  69   src_path = None
  70
  71   # Load the actual namespaces into the model.
  72   for target_namespace, file_path in zip(api_defs, file_paths):
  73     relpath = os.path.relpath(os.path.normpath(file_path), root)
  74     namespace = api_model.AddNamespace(target_namespace,
  75                                        relpath,
  76                                        include_compiler_options=True,
  77                                        environment=CppNamespaceEnvironment(
  78                                            cpp_namespace_pattern))
  79
  80     if default_namespace is None:
  81       default_namespace = namespace
  82
  83     if src_path is None:
  84       src_path = namespace.source_file_dir
  85     else:
  86       src_path = os.path.commonprefix((src_path, namespace.source_file_dir))
  87
  88     _, filename = os.path.split(file_path)
  89     filename_base, _ = os.path.splitext(filename)
  90
  91   # Construct the type generator with all the namespaces in this model.
  92   type_generator = CppTypeGenerator(api_model,
  93                                     schema_loader,
  94                                     default_namespace)
  95   if generator_name in ('cpp-bundle-registration', 'cpp-bundle-schema'):
  96     cpp_bundle_generator = CppBundleGenerator(root,
  97                                               api_model,
  98                                               api_defs,
  99                                               type_generator,
 100                                               cpp_namespace_pattern,
 101                                               bundle_name,
 102                                               src_path,
 103                                               impl_dir)
 104     if generator_name == 'cpp-bundle-registration':
 105       generators = [
 106         ('generated_api_registration.cc',
 107          cpp_bundle_generator.api_cc_generator),
 108         ('generated_api_registration.h', cpp_bundle_generator.api_h_generator),
 109       ]
 110     elif generator_name == 'cpp-bundle-schema':
 111       generators = [
 112         ('generated_schemas.cc', cpp_bundle_generator.schemas_cc_generator),
 113         ('generated_schemas.h', cpp_bundle_generator.schemas_h_generator)
 114       ]
 115   elif generator_name == 'cpp':
 116     cpp_generator = CppGenerator(type_generator)
 117     generators = [
 118       ('%s.h' % filename_base, cpp_generator.h_generator),
 119       ('%s.cc' % filename_base, cpp_generator.cc_generator)
 120     ]
 121   elif generator_name == 'externs':
 122     generators = [
 123       ('%s_externs.js' % namespace.unix_name, JsExternsGenerator())
 124     ]
 125   else:
 126     raise Exception('Unrecognised generator %s' % generator_name)
 127
 128   output_code = []
 129   for filename, generator in generators:
 130     code = generator.Generate(namespace).Render()
 131     if destdir:
 132       if generator_name == 'cpp-bundle-registration':
 133         # Function registrations must be output to impl_dir, since they link in
 134         # API implementations.
 135         output_dir = os.path.join(destdir, impl_dir)
 136       else:
 137         output_dir = os.path.join(destdir, src_path)
 138       if not os.path.exists(output_dir):
 139         os.makedirs(output_dir)
 140       with open(os.path.join(output_dir, filename), 'w') as f:
 141         f.write(code)
 142     output_code += [filename, '', code, '']
 143
 144   return '\n'.join(output_code)
 145
 146
 147 if __name__ == '__main__':
 148   parser = optparse.OptionParser(
 149       description='Generates a C++ model of an API from JSON schema',
 150       usage='usage: %prog [option]... schema')
 151   parser.add_option('-r', '--root', default='.',
 152       help='logical include root directory. Path to schema files from specified'
 153       ' dir will be the include path.')
 154   parser.add_option('-d', '--destdir',
 155       help='root directory to output generated files.')
 156   parser.add_option('-n', '--namespace', default='generated_api_schemas',
 157       help='C++ namespace for generated files. e.g extensions::api.')
 158   parser.add_option('-b', '--bundle-name', default='',
 159       help='A string to prepend to generated bundle class names, so that '
 160            'multiple bundle rules can be used without conflicting. '
 161            'Only used with one of the cpp-bundle generators.')
 162   parser.add_option('-g', '--generator', default=GENERATORS[0],
 163       choices=GENERATORS,
 164       help='The generator to use to build the output code. Supported values are'
 165       ' %s' % GENERATORS)
 166   parser.add_option('-i', '--impl-dir', dest='impl_dir',
 167       help='The root path of all API implementations')
 168   parser.add_option('-I', '--include-rules',
 169       help='A list of paths to include when searching for referenced objects,'
 170       ' with the namespace separated by a \':\'. Example: '
 171       '/foo/bar:Foo::Bar::%(namespace)s')
 172
 173   (opts, file_paths) = parser.parse_args()
 174
 175   if not file_paths:
 176     sys.exit(0) # This is OK as a no-op
 177
 178   # Unless in bundle mode, only one file should be specified.
 179   if (opts.generator not in ('cpp-bundle-registration', 'cpp-bundle-schema') and
 180       len(file_paths) > 1):
 181     # TODO(sashab): Could also just use file_paths[0] here and not complain.
 182     raise Exception(
 183         "Unless in bundle mode, only one file can be specified at a time.")
 184
 185   def split_path_and_namespace(path_and_namespace):
 186     if ':' not in path_and_namespace:
 187       raise ValueError('Invalid include rule "%s". Rules must be of '
 188                        'the form path:namespace' % path_and_namespace)
 189     return path_and_namespace.split(':', 1)
 190
 191   include_rules = []
 192   if opts.include_rules:
 193     include_rules = map(split_path_and_namespace,
 194                         shlex.split(opts.include_rules))
 195
 196   result = GenerateSchema(opts.generator, file_paths, opts.root, opts.destdir,
 197                           opts.namespace, opts.bundle_name, opts.impl_dir,
 198                           include_rules)
 199   if not opts.destdir:
 200     print result