tools/json_schema_compiler/h_generator.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import os
   6
   7 from code import Code
   8 from model import PropertyType
   9 import cpp_util
  10 import schema_util
  11
  12 class HGenerator(object):
  13   def __init__(self, type_generator, cpp_namespace_pattern):
  14     self._type_generator = type_generator
  15     self._cpp_namespace_pattern = cpp_namespace_pattern
  16
  17   def Generate(self, namespace):
  18     return _Generator(namespace,
  19                       self._type_generator,
  20                       self._cpp_namespace_pattern).Generate()
  21
  22
  23 class _Generator(object):
  24   """A .h generator for a namespace.
  25   """
  26   def __init__(self, namespace, cpp_type_generator, cpp_namespace_pattern):
  27     self._namespace = namespace
  28     self._type_helper = cpp_type_generator
  29     self._cpp_namespace_pattern = cpp_namespace_pattern
  30     self._generate_error_messages = namespace.compiler_options.get(
  31         'generate_error_messages', False)
  32
  33   def Generate(self):
  34     """Generates a Code object with the .h for a single namespace.
  35     """
  36     c = Code()
  37     (c.Append(cpp_util.CHROMIUM_LICENSE)
  38       .Append()
  39       .Append(cpp_util.GENERATED_FILE_MESSAGE % self._namespace.source_file)
  40       .Append()
  41     )
  42
  43     # Hack: for the purpose of gyp the header file will always be the source
  44     # file with its file extension replaced by '.h'. Assume so.
  45     output_file = os.path.splitext(self._namespace.source_file)[0] + '.h'
  46     ifndef_name = cpp_util.GenerateIfndefName(output_file)
  47
  48     (c.Append('#ifndef %s' % ifndef_name)
  49       .Append('#define %s' % ifndef_name)
  50       .Append()
  51       .Append('#include <map>')
  52       .Append('#include <string>')
  53       .Append('#include <vector>')
  54       .Append()
  55       .Append('#include "base/basictypes.h"')
  56       .Append('#include "base/logging.h"')
  57       .Append('#include "base/memory/linked_ptr.h"')
  58       .Append('#include "base/memory/scoped_ptr.h"')
  59       .Append('#include "base/values.h"')
  60       .Cblock(self._type_helper.GenerateIncludes())
  61       .Append()
  62     )
  63
  64     # TODO(calamity): These forward declarations should be #includes to allow
  65     # $ref types from other files to be used as required params. This requires
  66     # some detangling of windows and tabs which will currently lead to circular
  67     # #includes.
  68     c.Cblock(self._type_helper.GenerateForwardDeclarations(
  69         self._cpp_namespace_pattern))
  70
  71     cpp_namespace = cpp_util.GetCppNamespace(self._cpp_namespace_pattern,
  72                                              self._namespace.unix_name)
  73     c.Concat(cpp_util.OpenNamespace(cpp_namespace))
  74     c.Append()
  75     if self._namespace.properties:
  76       (c.Append('//')
  77         .Append('// Properties')
  78         .Append('//')
  79         .Append()
  80       )
  81       for property in self._namespace.properties.values():
  82         property_code = self._type_helper.GeneratePropertyValues(
  83             property,
  84             'extern const %(type)s %(name)s;')
  85         if property_code:
  86           c.Cblock(property_code)
  87     if self._namespace.types:
  88       (c.Append('//')
  89         .Append('// Types')
  90         .Append('//')
  91         .Append()
  92         .Cblock(self._GenerateTypes(self._FieldDependencyOrder(),
  93                                     is_toplevel=True,
  94                                     generate_typedefs=True))
  95       )
  96     if self._namespace.functions:
  97       (c.Append('//')
  98         .Append('// Functions')
  99         .Append('//')
 100         .Append()
 101       )
 102       for function in self._namespace.functions.values():
 103         c.Cblock(self._GenerateFunction(function))
 104     if self._namespace.events:
 105       (c.Append('//')
 106         .Append('// Events')
 107         .Append('//')
 108         .Append()
 109       )
 110       for event in self._namespace.events.values():
 111         c.Cblock(self._GenerateEvent(event))
 112     (c.Concat(cpp_util.CloseNamespace(cpp_namespace))
 113       .Append('#endif  // %s' % ifndef_name)
 114       .Append()
 115     )
 116     return c
 117
 118   def _FieldDependencyOrder(self):
 119     """Generates the list of types in the current namespace in an order in which
 120     depended-upon types appear before types which depend on them.
 121     """
 122     dependency_order = []
 123
 124     def ExpandType(path, type_):
 125       if type_ in path:
 126         raise ValueError("Illegal circular dependency via cycle " +
 127                          ", ".join(map(lambda x: x.name, path + [type_])))
 128       for prop in type_.properties.values():
 129         if (prop.type_ == PropertyType.REF and
 130             schema_util.GetNamespace(prop.ref_type) == self._namespace.name):
 131           ExpandType(path + [type_], self._namespace.types[prop.ref_type])
 132       if not type_ in dependency_order:
 133         dependency_order.append(type_)
 134
 135     for type_ in self._namespace.types.values():
 136       ExpandType([], type_)
 137     return dependency_order
 138
 139   def _GenerateEnumDeclaration(self, enum_name, type_):
 140     """Generate a code object with the  declaration of a C++ enum.
 141     """
 142     c = Code()
 143     c.Sblock('enum %s {' % enum_name)
 144     c.Append(self._type_helper.GetEnumNoneValue(type_) + ',')
 145     for value in type_.enum_values:
 146       current_enum_string = self._type_helper.GetEnumValue(type_, value)
 147       c.Append(current_enum_string + ',')
 148     c.Append('%s = %s,' % (
 149         self._type_helper.GetEnumLastValue(type_), current_enum_string))
 150     c.Eblock('};')
 151     return c
 152
 153   def _GenerateFields(self, props):
 154     """Generates the field declarations when declaring a type.
 155     """
 156     c = Code()
 157     needs_blank_line = False
 158     for prop in props:
 159       if needs_blank_line:
 160         c.Append()
 161       needs_blank_line = True
 162       if prop.description:
 163         c.Comment(prop.description)
 164       # ANY is a base::Value which is abstract and cannot be a direct member, so
 165       # we always need to wrap it in a scoped_ptr.
 166       is_ptr = prop.optional or prop.type_.property_type == PropertyType.ANY
 167       (c.Append('%s %s;' % (
 168            self._type_helper.GetCppType(prop.type_, is_ptr=is_ptr),
 169            prop.unix_name))
 170       )
 171     return c
 172
 173   def _GenerateType(self, type_, is_toplevel=False, generate_typedefs=False):
 174     """Generates a struct for |type_|.
 175
 176     |is_toplevel|       implies that the type was declared in the "types" field
 177                         of an API schema. This determines the correct function
 178                         modifier(s).
 179     |generate_typedefs| controls whether primitive types should be generated as
 180                         a typedef. This may not always be desired. If false,
 181                         primitive types are ignored.
 182     """
 183     classname = cpp_util.Classname(schema_util.StripNamespace(type_.name))
 184     c = Code()
 185
 186     if type_.functions:
 187       # Wrap functions within types in the type's namespace.
 188       (c.Append('namespace %s {' % classname)
 189         .Append()
 190       )
 191       for function in type_.functions.values():
 192         c.Cblock(self._GenerateFunction(function))
 193       c.Append('}  // namespace %s' % classname)
 194     elif type_.property_type == PropertyType.ARRAY:
 195       if generate_typedefs and type_.description:
 196         c.Comment(type_.description)
 197       c.Cblock(self._GenerateType(type_.item_type))
 198       if generate_typedefs:
 199         (c.Append('typedef std::vector<%s > %s;' % (
 200                        self._type_helper.GetCppType(type_.item_type),
 201                        classname))
 202         )
 203     elif type_.property_type == PropertyType.STRING:
 204       if generate_typedefs:
 205         if type_.description:
 206           c.Comment(type_.description)
 207         c.Append('typedef std::string %(classname)s;')
 208     elif type_.property_type == PropertyType.ENUM:
 209       if type_.description:
 210         c.Comment(type_.description)
 211       c.Cblock(self._GenerateEnumDeclaration(classname, type_));
 212       # Top level enums are in a namespace scope so the methods shouldn't be
 213       # static. On the other hand, those declared inline (e.g. in an object) do.
 214       maybe_static = '' if is_toplevel else 'static '
 215       (c.Append()
 216         .Append('%sstd::string ToString(%s as_enum);' %
 217                 (maybe_static, classname))
 218         .Append('%s%s Parse%s(const std::string& as_string);' %
 219                 (maybe_static, classname, classname))
 220       )
 221     elif type_.property_type in (PropertyType.CHOICES,
 222                                  PropertyType.OBJECT):
 223       if type_.description:
 224         c.Comment(type_.description)
 225       (c.Sblock('struct %(classname)s {')
 226           .Append('%(classname)s();')
 227           .Append('~%(classname)s();')
 228       )
 229       if type_.origin.from_json:
 230         (c.Append()
 231           .Comment('Populates a %s object from a base::Value. Returns'
 232                    ' whether |out| was successfully populated.' % classname)
 233           .Append('static bool Populate(%s);' % self._GenerateParams(
 234               ('const base::Value& value', '%s* out' % classname)))
 235         )
 236         if is_toplevel:
 237           (c.Append()
 238             .Comment('Creates a %s object from a base::Value, or NULL on '
 239                      'failure.' % classname)
 240             .Append('static scoped_ptr<%s> FromValue(%s);' % (
 241                 classname, self._GenerateParams(('const base::Value& value',))))
 242           )
 243       if type_.origin.from_client:
 244         value_type = ('base::Value'
 245                       if type_.property_type is PropertyType.CHOICES else
 246                       'base::DictionaryValue')
 247         (c.Append()
 248           .Comment('Returns a new %s representing the serialized form of this '
 249                    '%s object.' % (value_type, classname))
 250           .Append('scoped_ptr<%s> ToValue() const;' % value_type)
 251         )
 252       if type_.property_type == PropertyType.CHOICES:
 253         # Choices are modelled with optional fields for each choice. Exactly one
 254         # field of the choice is guaranteed to be set by the compiler.
 255         c.Cblock(self._GenerateTypes(type_.choices))
 256         c.Append('// Choices:')
 257         for choice_type in type_.choices:
 258           c.Append('%s as_%s;' % (
 259               self._type_helper.GetCppType(choice_type, is_ptr=True),
 260               choice_type.unix_name))
 261       else:
 262         properties = type_.properties.values()
 263         (c.Append()
 264           .Cblock(self._GenerateTypes(p.type_ for p in properties))
 265           .Cblock(self._GenerateFields(properties)))
 266         if type_.additional_properties is not None:
 267           # Most additionalProperties actually have type "any", which is better
 268           # modelled as a DictionaryValue rather than a map of string -> Value.
 269           if type_.additional_properties.property_type == PropertyType.ANY:
 270             c.Append('base::DictionaryValue additional_properties;')
 271           else:
 272             (c.Cblock(self._GenerateType(type_.additional_properties))
 273               .Append('std::map<std::string, %s> additional_properties;' %
 274                   cpp_util.PadForGenerics(
 275                       self._type_helper.GetCppType(type_.additional_properties,
 276                                                    is_in_container=True)))
 277             )
 278       (c.Eblock()
 279         .Append()
 280         .Sblock(' private:')
 281           .Append('DISALLOW_COPY_AND_ASSIGN(%(classname)s);')
 282         .Eblock('};')
 283       )
 284     return c.Substitute({'classname': classname})
 285
 286   def _GenerateEvent(self, event):
 287     """Generates the namespaces for an event.
 288     """
 289     c = Code()
 290     # TODO(kalman): use event.unix_name not Classname.
 291     event_namespace = cpp_util.Classname(event.name)
 292     (c.Append('namespace %s {' % event_namespace)
 293       .Append()
 294       .Concat(self._GenerateEventNameConstant(event))
 295       .Concat(self._GenerateCreateCallbackArguments(event))
 296       .Eblock('}  // namespace %s' % event_namespace)
 297     )
 298     return c
 299
 300   def _GenerateFunction(self, function):
 301     """Generates the namespaces and structs for a function.
 302     """
 303     c = Code()
 304     # TODO(kalman): Use function.unix_name not Classname here.
 305     function_namespace = cpp_util.Classname(function.name)
 306     # Windows has a #define for SendMessage, so to avoid any issues, we need
 307     # to not use the name.
 308     if function_namespace == 'SendMessage':
 309       function_namespace = 'PassMessage'
 310     (c.Append('namespace %s {' % function_namespace)
 311       .Append()
 312       .Cblock(self._GenerateFunctionParams(function))
 313     )
 314     if function.callback:
 315       c.Cblock(self._GenerateFunctionResults(function.callback))
 316     c.Append('}  // namespace %s' % function_namespace)
 317     return c
 318
 319   def _GenerateFunctionParams(self, function):
 320     """Generates the struct for passing parameters from JSON to a function.
 321     """
 322     if not function.params:
 323       return Code()
 324
 325     c = Code()
 326     (c.Sblock('struct Params {')
 327       .Append('static scoped_ptr<Params> Create(%s);' % self._GenerateParams(
 328           ('const base::ListValue& args',)))
 329       .Append('~Params();')
 330       .Append()
 331       .Cblock(self._GenerateTypes(p.type_ for p in function.params))
 332       .Cblock(self._GenerateFields(function.params))
 333       .Eblock()
 334       .Append()
 335       .Sblock(' private:')
 336         .Append('Params();')
 337         .Append()
 338         .Append('DISALLOW_COPY_AND_ASSIGN(Params);')
 339       .Eblock('};')
 340     )
 341     return c
 342
 343   def _GenerateTypes(self, types, is_toplevel=False, generate_typedefs=False):
 344     """Generate the structures required by a property such as OBJECT classes
 345     and enums.
 346     """
 347     c = Code()
 348     for type_ in types:
 349       c.Cblock(self._GenerateType(type_,
 350                                   is_toplevel=is_toplevel,
 351                                   generate_typedefs=generate_typedefs))
 352     return c
 353
 354   def _GenerateCreateCallbackArguments(self, function):
 355     """Generates functions for passing parameters to a callback.
 356     """
 357     c = Code()
 358     params = function.params
 359     c.Cblock(self._GenerateTypes((p.type_ for p in params), is_toplevel=True))
 360
 361     declaration_list = []
 362     for param in params:
 363       if param.description:
 364         c.Comment(param.description)
 365       declaration_list.append(cpp_util.GetParameterDeclaration(
 366           param, self._type_helper.GetCppType(param.type_)))
 367     c.Append('scoped_ptr<base::ListValue> Create(%s);' %
 368              ', '.join(declaration_list))
 369     return c
 370
 371   def _GenerateEventNameConstant(self, event):
 372     """Generates a constant string array for the event name.
 373     """
 374     c = Code()
 375     c.Append('extern const char kEventName[];  // "%s.%s"' % (
 376                  self._namespace.name, event.name))
 377     c.Append()
 378     return c
 379
 380   def _GenerateFunctionResults(self, callback):
 381     """Generates namespace for passing a function's result back.
 382     """
 383     c = Code()
 384     (c.Append('namespace Results {')
 385       .Append()
 386       .Concat(self._GenerateCreateCallbackArguments(callback))
 387       .Append('}  // namespace Results')
 388     )
 389     return c
 390
 391   def _GenerateParams(self, params):
 392     """Builds the parameter list for a function, given an array of parameters.
 393     """
 394     # |error| is populated with warnings and/or errors found during parsing.
 395     # |error| being set does not necessarily imply failure and may be
 396     # recoverable.
 397     # For example, optional properties may have failed to parse, but the
 398     # parser was able to continue.
 399     if self._generate_error_messages:
 400       params += ('base::string16* error',)
 401     return ', '.join(str(p) for p in params)