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                    impl_dir,
  43                    include_rules):
  44   # Merge the source files into a single list of schemas.
  45   api_defs = []
  46   for file_path in file_paths:
  47     schema = os.path.relpath(file_path, root)
  48     schema_loader = SchemaLoader(
  49         root,
  50         os.path.dirname(schema),
  51         include_rules,
  52         cpp_namespace_pattern)
  53     api_def = schema_loader.LoadSchema(schema)
  54
  55     # If compiling the C++ model code, delete 'nocompile' nodes.
  56     if generator_name == 'cpp':
  57       api_def = json_schema.DeleteNodes(api_def, 'nocompile')
  58     api_defs.extend(api_def)
  59
  60   api_model = Model(allow_inline_enums=False)
  61
  62   # For single-schema compilation make sure that the first (i.e. only) schema
  63   # is the default one.
  64   default_namespace = None
  65
  66   # If we have files from multiple source paths, we'll use the common parent
  67   # path as the source directory.
  68   src_path = None
  69
  70   # Load the actual namespaces into the model.
  71   for target_namespace, file_path in zip(api_defs, file_paths):
  72     relpath = os.path.relpath(os.path.normpath(file_path), root)
  73     namespace = api_model.AddNamespace(target_namespace,
  74                                        relpath,
  75                                        include_compiler_options=True,
  76                                        environment=CppNamespaceEnvironment(
  77                                            cpp_namespace_pattern))
  78
  79     if default_namespace is None:
  80       default_namespace = namespace
  81
  82     if src_path is None:
  83       src_path = namespace.source_file_dir
  84     else:
  85       src_path = os.path.commonprefix((src_path, namespace.source_file_dir))
  86
  87     _, filename = os.path.split(file_path)
  88     filename_base, _ = os.path.splitext(filename)
  89
  90   # Construct the type generator with all the namespaces in this model.
  91   type_generator = CppTypeGenerator(api_model,
  92                                     schema_loader,
  93                                     default_namespace)
  94   if generator_name in ('cpp-bundle-registration', 'cpp-bundle-schema'):
  95     cpp_bundle_generator = CppBundleGenerator(root,
  96                                               api_model,
  97                                               api_defs,
  98                                               type_generator,
  99                                               cpp_namespace_pattern,
 100                                               src_path,
 101                                               impl_dir)
 102     if generator_name == 'cpp-bundle-registration':
 103       generators = [
 104         ('generated_api_registration.cc',
 105          cpp_bundle_generator.api_cc_generator),
 106         ('generated_api_registration.h', cpp_bundle_generator.api_h_generator),
 107       ]
 108     elif generator_name == 'cpp-bundle-schema':
 109       generators = [
 110         ('generated_schemas.cc', cpp_bundle_generator.schemas_cc_generator),
 111         ('generated_schemas.h', cpp_bundle_generator.schemas_h_generator)
 112       ]
 113   elif generator_name == 'cpp':
 114     cpp_generator = CppGenerator(type_generator)
 115     generators = [
 116       ('%s.h' % filename_base, cpp_generator.h_generator),
 117       ('%s.cc' % filename_base, cpp_generator.cc_generator)
 118     ]
 119   elif generator_name == 'externs':
 120     generators = [
 121       ('%s_externs.js' % namespace.unix_name, JsExternsGenerator())
 122     ]
 123   else:
 124     raise Exception('Unrecognised generator %s' % generator_name)
 125
 126   output_code = []
 127   for filename, generator in generators:
 128     code = generator.Generate(namespace).Render()
 129     if destdir:
 130       if generator_name == 'cpp-bundle-registration':
 131         # Function registrations must be output to impl_dir, since they link in
 132         # API implementations.
 133         output_dir = os.path.join(destdir, impl_dir)
 134       else:
 135         output_dir = os.path.join(destdir, src_path)
 136       if not os.path.exists(output_dir):
 137         os.makedirs(output_dir)
 138       with open(os.path.join(output_dir, filename), 'w') as f:
 139         f.write(code)
 140     output_code += [filename, '', code, '']
 141
 142   return '\n'.join(output_code)
 143
 144
 145 if __name__ == '__main__':
 146   parser = optparse.OptionParser(
 147       description='Generates a C++ model of an API from JSON schema',
 148       usage='usage: %prog [option]... schema')
 149   parser.add_option('-r', '--root', default='.',
 150       help='logical include root directory. Path to schema files from specified'
 151       ' dir will be the include path.')
 152   parser.add_option('-d', '--destdir',
 153       help='root directory to output generated files.')
 154   parser.add_option('-n', '--namespace', default='generated_api_schemas',
 155       help='C++ namespace for generated files. e.g extensions::api.')
 156   parser.add_option('-g', '--generator', default=GENERATORS[0],
 157       choices=GENERATORS,
 158       help='The generator to use to build the output code. Supported values are'
 159       ' %s' % GENERATORS)
 160   parser.add_option('-i', '--impl-dir', dest='impl_dir',
 161       help='The root path of all API implementations')
 162   parser.add_option('-I', '--include-rules',
 163       help='A list of paths to include when searching for referenced objects,'
 164       ' with the namespace separated by a \':\'. Example: '
 165       '/foo/bar:Foo::Bar::%(namespace)s')
 166
 167   (opts, file_paths) = parser.parse_args()
 168
 169   if not file_paths:
 170     sys.exit(0) # This is OK as a no-op
 171
 172   # Unless in bundle mode, only one file should be specified.
 173   if (opts.generator not in ('cpp-bundle-registration', 'cpp-bundle-schema') and
 174       len(file_paths) > 1):
 175     # TODO(sashab): Could also just use file_paths[0] here and not complain.
 176     raise Exception(
 177         "Unless in bundle mode, only one file can be specified at a time.")
 178
 179   def split_path_and_namespace(path_and_namespace):
 180     if ':' not in path_and_namespace:
 181       raise ValueError('Invalid include rule "%s". Rules must be of '
 182                        'the form path:namespace' % path_and_namespace)
 183     return path_and_namespace.split(':', 1)
 184
 185   include_rules = []
 186   if opts.include_rules:
 187     include_rules = map(split_path_and_namespace,
 188                         shlex.split(opts.include_rules))
 189
 190   result = GenerateSchema(opts.generator, file_paths, opts.root, opts.destdir,
 191                           opts.namespace, opts.impl_dir, include_rules)
 192   if not opts.destdir:
 193     print result