tools/json_schema_compiler/cc_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 from code import Code
   6 from model import PropertyType
   7 import cpp_util
   8 import schema_util
   9 import util_cc_helper
  10 from cpp_namespace_environment import CppNamespaceEnvironment
  11
  12 class CCGenerator(object):
  13   def __init__(self, type_generator):
  14     self._type_generator = type_generator
  15
  16   def Generate(self, namespace):
  17     return _Generator(namespace, self._type_generator).Generate()
  18
  19
  20 class _Generator(object):
  21   """A .cc generator for a namespace.
  22   """
  23   def __init__(self, namespace, cpp_type_generator):
  24     assert type(namespace.environment) is CppNamespaceEnvironment
  25     self._namespace = namespace
  26     self._type_helper = cpp_type_generator
  27     self._util_cc_helper = (
  28         util_cc_helper.UtilCCHelper(self._type_helper))
  29     self._generate_error_messages = namespace.compiler_options.get(
  30         'generate_error_messages', False)
  31
  32   def Generate(self):
  33     """Generates a Code object with the .cc for a single namespace.
  34     """
  35     cpp_namespace = cpp_util.GetCppNamespace(
  36         self._namespace.environment.namespace_pattern,
  37         self._namespace.unix_name)
  38
  39     c = Code()
  40     (c.Append(cpp_util.CHROMIUM_LICENSE)
  41       .Append()
  42       .Append(cpp_util.GENERATED_FILE_MESSAGE % self._namespace.source_file)
  43       .Append()
  44       .Append(self._util_cc_helper.GetIncludePath())
  45       .Append('#include "base/logging.h"')
  46       .Append('#include "base/stl_util.h"')
  47       .Append('#include "base/strings/string_number_conversions.h"')
  48       .Append('#include "base/strings/utf_string_conversions.h"')
  49       .Append('#include "%s/%s.h"' %
  50               (self._namespace.source_file_dir, self._namespace.short_filename))
  51       .Append('#include <set>')
  52       .Cblock(self._type_helper.GenerateIncludes(include_soft=True))
  53       .Append()
  54       .Append('using base::UTF8ToUTF16;')
  55       .Append()
  56       .Concat(cpp_util.OpenNamespace(cpp_namespace))
  57     )
  58     if self._namespace.properties:
  59       (c.Append('//')
  60         .Append('// Properties')
  61         .Append('//')
  62         .Append()
  63       )
  64       for prop in self._namespace.properties.values():
  65         property_code = self._type_helper.GeneratePropertyValues(
  66             prop,
  67             'const %(type)s %(name)s = %(value)s;',
  68             nodoc=True)
  69         if property_code:
  70           c.Cblock(property_code)
  71     if self._namespace.types:
  72       (c.Append('//')
  73         .Append('// Types')
  74         .Append('//')
  75         .Append()
  76         .Cblock(self._GenerateTypes(None, self._namespace.types.values()))
  77       )
  78     if self._namespace.functions:
  79       (c.Append('//')
  80         .Append('// Functions')
  81         .Append('//')
  82         .Append()
  83       )
  84     for function in self._namespace.functions.values():
  85       c.Cblock(self._GenerateFunction(function))
  86     if self._namespace.events:
  87       (c.Append('//')
  88         .Append('// Events')
  89         .Append('//')
  90         .Append()
  91       )
  92       for event in self._namespace.events.values():
  93         c.Cblock(self._GenerateEvent(event))
  94     c.Cblock(cpp_util.CloseNamespace(cpp_namespace))
  95     c.Append()
  96     return c
  97
  98   def _GenerateType(self, cpp_namespace, type_):
  99     """Generates the function definitions for a type.
 100     """
 101     classname = cpp_util.Classname(schema_util.StripNamespace(type_.name))
 102     c = Code()
 103
 104     if type_.functions:
 105       # Wrap functions within types in the type's namespace.
 106       (c.Append('namespace %s {' % classname)
 107         .Append())
 108       for function in type_.functions.values():
 109         c.Cblock(self._GenerateFunction(function))
 110       c.Append('}  // namespace %s' % classname)
 111     elif type_.property_type == PropertyType.ARRAY:
 112       c.Cblock(self._GenerateType(cpp_namespace, type_.item_type))
 113     elif type_.property_type in (PropertyType.CHOICES,
 114                                  PropertyType.OBJECT):
 115       if cpp_namespace is None:
 116         classname_in_namespace = classname
 117       else:
 118         classname_in_namespace = '%s::%s' % (cpp_namespace, classname)
 119
 120       if type_.property_type == PropertyType.OBJECT:
 121         c.Cblock(self._GeneratePropertyFunctions(classname_in_namespace,
 122                                                  type_.properties.values()))
 123       else:
 124         c.Cblock(self._GenerateTypes(classname_in_namespace, type_.choices))
 125
 126       (c.Append('%s::%s()' % (classname_in_namespace, classname))
 127         .Cblock(self._GenerateInitializersAndBody(type_))
 128         .Append('%s::~%s() {}' % (classname_in_namespace, classname))
 129         .Append()
 130       )
 131       if type_.origin.from_json:
 132         c.Cblock(self._GenerateTypePopulate(classname_in_namespace, type_))
 133         if cpp_namespace is None:  # only generate for top-level types
 134           c.Cblock(self._GenerateTypeFromValue(classname_in_namespace, type_))
 135       if type_.origin.from_client:
 136         c.Cblock(self._GenerateTypeToValue(classname_in_namespace, type_))
 137     elif type_.property_type == PropertyType.ENUM:
 138       (c.Cblock(self._GenerateEnumToString(cpp_namespace, type_))
 139         .Cblock(self._GenerateEnumFromString(cpp_namespace, type_))
 140       )
 141
 142     return c
 143
 144   def _GenerateInitializersAndBody(self, type_):
 145     items = []
 146     for prop in type_.properties.values():
 147       t = prop.type_
 148
 149       real_t = self._type_helper.FollowRef(t)
 150       if real_t.property_type == PropertyType.ENUM:
 151         items.append('%s(%s)' % (
 152             prop.unix_name,
 153             self._type_helper.GetEnumNoneValue(t)))
 154       elif prop.optional:
 155         continue
 156       elif t.property_type == PropertyType.INTEGER:
 157         items.append('%s(0)' % prop.unix_name)
 158       elif t.property_type == PropertyType.DOUBLE:
 159         items.append('%s(0.0)' % prop.unix_name)
 160       elif t.property_type == PropertyType.BOOLEAN:
 161         items.append('%s(false)' % prop.unix_name)
 162       elif (t.property_type == PropertyType.ANY or
 163             t.property_type == PropertyType.ARRAY or
 164             t.property_type == PropertyType.BINARY or
 165             t.property_type == PropertyType.CHOICES or
 166             t.property_type == PropertyType.OBJECT or
 167             t.property_type == PropertyType.FUNCTION or
 168             t.property_type == PropertyType.REF or
 169             t.property_type == PropertyType.STRING):
 170         # TODO(miket): It would be nice to initialize CHOICES, but we
 171         # don't presently have the semantics to indicate which one of a set
 172         # should be the default.
 173         continue
 174       else:
 175         raise TypeError(t)
 176
 177     if items:
 178       s = ': %s' % (', '.join(items))
 179     else:
 180       s = ''
 181     s = s + ' {}'
 182     return Code().Append(s)
 183
 184   def _GenerateTypePopulate(self, cpp_namespace, type_):
 185     """Generates the function for populating a type given a pointer to it.
 186
 187     E.g for type "Foo", generates Foo::Populate()
 188     """
 189     classname = cpp_util.Classname(schema_util.StripNamespace(type_.name))
 190     c = Code()
 191     (c.Append('// static')
 192       .Append('bool %(namespace)s::Populate(')
 193       .Sblock('    %s) {' % self._GenerateParams(
 194           ('const base::Value& value', '%(name)s* out'))))
 195
 196     if self._generate_error_messages:
 197       c.Append('DCHECK(error);')
 198
 199     if type_.property_type == PropertyType.CHOICES:
 200       for choice in type_.choices:
 201         (c.Sblock('if (%s) {' % self._GenerateValueIsTypeExpression('value',
 202                                                                     choice))
 203             .Concat(self._GeneratePopulateVariableFromValue(
 204                 choice,
 205                 '(&value)',
 206                 'out->as_%s' % choice.unix_name,
 207                 'false',
 208                 is_ptr=True))
 209             .Append('return true;')
 210           .Eblock('}')
 211         )
 212       (c.Concat(self._GenerateError(
 213           '"expected %s, got " +  %s' %
 214               (" or ".join(choice.name for choice in type_.choices),
 215               self._util_cc_helper.GetValueTypeString('value'))))
 216         .Append('return false;'))
 217     elif type_.property_type == PropertyType.OBJECT:
 218       (c.Sblock('if (!value.IsType(base::Value::TYPE_DICTIONARY)) {')
 219         .Concat(self._GenerateError(
 220           '"expected dictionary, got " + ' +
 221           self._util_cc_helper.GetValueTypeString('value')))
 222         .Append('return false;')
 223         .Eblock('}'))
 224
 225       if type_.properties or type_.additional_properties is not None:
 226         c.Append('const base::DictionaryValue* dict = '
 227                      'static_cast<const base::DictionaryValue*>(&value);')
 228         if self._generate_error_messages:
 229             c.Append('std::set<std::string> keys;')
 230       for prop in type_.properties.itervalues():
 231         c.Concat(self._InitializePropertyToDefault(prop, 'out'))
 232       for prop in type_.properties.itervalues():
 233         if self._generate_error_messages:
 234           c.Append('keys.insert("%s");' % (prop.name))
 235         c.Concat(self._GenerateTypePopulateProperty(prop, 'dict', 'out'))
 236       # Check for extra values.
 237       if self._generate_error_messages:
 238         (c.Sblock('for (base::DictionaryValue::Iterator it(*dict); '
 239                        '!it.IsAtEnd(); it.Advance()) {')
 240           .Sblock('if (!keys.count(it.key())) {')
 241           .Concat(self._GenerateError('"found unexpected key \'" + '
 242                                           'it.key() + "\'"'))
 243           .Eblock('}')
 244           .Eblock('}')
 245         )
 246       if type_.additional_properties is not None:
 247         if type_.additional_properties.property_type == PropertyType.ANY:
 248           c.Append('out->additional_properties.MergeDictionary(dict);')
 249         else:
 250           cpp_type = self._type_helper.GetCppType(type_.additional_properties,
 251                                                   is_in_container=True)
 252           (c.Append('for (base::DictionaryValue::Iterator it(*dict);')
 253             .Sblock('     !it.IsAtEnd(); it.Advance()) {')
 254               .Append('%s tmp;' % cpp_type)
 255               .Concat(self._GeneratePopulateVariableFromValue(
 256                   type_.additional_properties,
 257                   '(&it.value())',
 258                   'tmp',
 259                   'false'))
 260               .Append('out->additional_properties[it.key()] = tmp;')
 261             .Eblock('}')
 262           )
 263       c.Append('return true;')
 264     (c.Eblock('}')
 265       .Substitute({'namespace': cpp_namespace, 'name': classname}))
 266     return c
 267
 268   def _GenerateValueIsTypeExpression(self, var, type_):
 269     real_type = self._type_helper.FollowRef(type_)
 270     if real_type.property_type is PropertyType.CHOICES:
 271       return '(%s)' % ' || '.join(self._GenerateValueIsTypeExpression(var,
 272                                                                       choice)
 273                                   for choice in real_type.choices)
 274     return '%s.IsType(%s)' % (var, cpp_util.GetValueType(real_type))
 275
 276   def _GenerateTypePopulateProperty(self, prop, src, dst):
 277     """Generate the code to populate a single property in a type.
 278
 279     src: base::DictionaryValue*
 280     dst: Type*
 281     """
 282     c = Code()
 283     value_var = prop.unix_name + '_value'
 284     c.Append('const base::Value* %(value_var)s = NULL;')
 285     if prop.optional:
 286       (c.Sblock(
 287           'if (%(src)s->GetWithoutPathExpansion("%(key)s", &%(value_var)s)) {')
 288         .Concat(self._GeneratePopulatePropertyFromValue(
 289             prop, value_var, dst, 'false')))
 290       underlying_type = self._type_helper.FollowRef(prop.type_)
 291       if underlying_type.property_type == PropertyType.ENUM:
 292         (c.Append('} else {')
 293           .Append('%%(dst)s->%%(name)s = %s;' %
 294               self._type_helper.GetEnumNoneValue(prop.type_)))
 295       c.Eblock('}')
 296     else:
 297       (c.Sblock(
 298           'if (!%(src)s->GetWithoutPathExpansion("%(key)s", &%(value_var)s)) {')
 299         .Concat(self._GenerateError('"\'%%(key)s\' is required"'))
 300         .Append('return false;')
 301         .Eblock('}')
 302         .Concat(self._GeneratePopulatePropertyFromValue(
 303             prop, value_var, dst, 'false'))
 304       )
 305     c.Append()
 306     c.Substitute({
 307       'value_var': value_var,
 308       'key': prop.name,
 309       'src': src,
 310       'dst': dst,
 311       'name': prop.unix_name
 312     })
 313     return c
 314
 315   def _GenerateTypeFromValue(self, cpp_namespace, type_):
 316     classname = cpp_util.Classname(schema_util.StripNamespace(type_.name))
 317     c = Code()
 318     (c.Append('// static')
 319       .Append('scoped_ptr<%s> %s::FromValue(%s) {' % (classname,
 320         cpp_namespace, self._GenerateParams(('const base::Value& value',))))
 321     )
 322     if self._generate_error_messages:
 323       c.Append('DCHECK(error);')
 324     (c.Append('  scoped_ptr<%s> out(new %s());' % (classname, classname))
 325       .Append('  if (!Populate(%s))' % self._GenerateArgs(
 326           ('value', 'out.get()')))
 327       .Append('    return scoped_ptr<%s>();' % classname)
 328       .Append('  return out.Pass();')
 329       .Append('}')
 330     )
 331     return c
 332
 333   def _GenerateTypeToValue(self, cpp_namespace, type_):
 334     """Generates a function that serializes the type into a base::Value.
 335     E.g. for type "Foo" generates Foo::ToValue()
 336     """
 337     if type_.property_type == PropertyType.OBJECT:
 338       return self._GenerateObjectTypeToValue(cpp_namespace, type_)
 339     elif type_.property_type == PropertyType.CHOICES:
 340       return self._GenerateChoiceTypeToValue(cpp_namespace, type_)
 341     else:
 342       raise ValueError("Unsupported property type %s" % type_.type_)
 343
 344   def _GenerateObjectTypeToValue(self, cpp_namespace, type_):
 345     """Generates a function that serializes an object-representing type
 346     into a base::DictionaryValue.
 347     """
 348     c = Code()
 349     (c.Sblock('scoped_ptr<base::DictionaryValue> %s::ToValue() const {' %
 350           cpp_namespace)
 351         .Append('scoped_ptr<base::DictionaryValue> value('
 352                     'new base::DictionaryValue());')
 353         .Append()
 354     )
 355
 356     for prop in type_.properties.values():
 357       prop_var = 'this->%s' % prop.unix_name
 358       if prop.optional:
 359         # Optional enum values are generated with a NONE enum value.
 360         underlying_type = self._type_helper.FollowRef(prop.type_)
 361         if underlying_type.property_type == PropertyType.ENUM:
 362           c.Sblock('if (%s != %s) {' %
 363               (prop_var,
 364                self._type_helper.GetEnumNoneValue(prop.type_)))
 365         else:
 366           c.Sblock('if (%s.get()) {' % prop_var)
 367
 368       # ANY is a base::Value which is abstract and cannot be a direct member, so
 369       # it will always be a pointer.
 370       is_ptr = prop.optional or prop.type_.property_type == PropertyType.ANY
 371       c.Cblock(self._CreateValueFromType(
 372           'value->SetWithoutPathExpansion("%s", %%s);' % prop.name,
 373           prop.name,
 374           prop.type_,
 375           prop_var,
 376           is_ptr=is_ptr))
 377
 378       if prop.optional:
 379         c.Eblock('}')
 380
 381     if type_.additional_properties is not None:
 382       if type_.additional_properties.property_type == PropertyType.ANY:
 383         c.Append('value->MergeDictionary(&additional_properties);')
 384       else:
 385         # Non-copyable types will be wrapped in a linked_ptr for inclusion in
 386         # maps, so we need to unwrap them.
 387         needs_unwrap = (
 388             not self._type_helper.IsCopyable(type_.additional_properties))
 389         (c.Sblock('for (const auto& it : additional_properties) {')
 390           .Cblock(self._CreateValueFromType(
 391               'value->SetWithoutPathExpansion(it.first, %s);',
 392               type_.additional_properties.name,
 393               type_.additional_properties,
 394               '%sit.second' % ('*' if needs_unwrap else '')))
 395           .Eblock('}')
 396         )
 397
 398     return (c.Append()
 399              .Append('return value.Pass();')
 400            .Eblock('}'))
 401
 402   def _GenerateChoiceTypeToValue(self, cpp_namespace, type_):
 403     """Generates a function that serializes a choice-representing type
 404     into a base::Value.
 405     """
 406     c = Code()
 407     c.Sblock('scoped_ptr<base::Value> %s::ToValue() const {' % cpp_namespace)
 408     c.Append('scoped_ptr<base::Value> result;')
 409     for choice in type_.choices:
 410       choice_var = 'as_%s' % choice.unix_name
 411       (c.Sblock('if (%s) {' % choice_var)
 412           .Append('DCHECK(!result) << "Cannot set multiple choices for %s";' %
 413                       type_.unix_name)
 414           .Cblock(self._CreateValueFromType('result.reset(%s);',
 415                                             choice.name,
 416                                             choice,
 417                                             '*%s' % choice_var))
 418         .Eblock('}')
 419       )
 420     (c.Append('DCHECK(result) << "Must set at least one choice for %s";' %
 421                   type_.unix_name)
 422       .Append('return result.Pass();')
 423       .Eblock('}')
 424     )
 425     return c
 426
 427   def _GenerateFunction(self, function):
 428     """Generates the definitions for function structs.
 429     """
 430     c = Code()
 431
 432     # TODO(kalman): use function.unix_name not Classname.
 433     function_namespace = cpp_util.Classname(function.name)
 434     # Windows has a #define for SendMessage, so to avoid any issues, we need
 435     # to not use the name.
 436     if function_namespace == 'SendMessage':
 437       function_namespace = 'PassMessage'
 438     (c.Append('namespace %s {' % function_namespace)
 439       .Append()
 440     )
 441
 442     # Params::Populate function
 443     if function.params:
 444       c.Concat(self._GeneratePropertyFunctions('Params', function.params))
 445       (c.Append('Params::Params() {}')
 446         .Append('Params::~Params() {}')
 447         .Append()
 448         .Cblock(self._GenerateFunctionParamsCreate(function))
 449       )
 450
 451     # Results::Create function
 452     if function.callback:
 453       c.Concat(self._GenerateCreateCallbackArguments('Results',
 454                                                      function.callback))
 455
 456     c.Append('}  // namespace %s' % function_namespace)
 457     return c
 458
 459   def _GenerateEvent(self, event):
 460     # TODO(kalman): use event.unix_name not Classname.
 461     c = Code()
 462     event_namespace = cpp_util.Classname(event.name)
 463     (c.Append('namespace %s {' % event_namespace)
 464       .Append()
 465       .Cblock(self._GenerateEventNameConstant(event))
 466       .Cblock(self._GenerateCreateCallbackArguments(None, event))
 467       .Append('}  // namespace %s' % event_namespace)
 468     )
 469     return c
 470
 471   def _CreateValueFromType(self, code, prop_name, type_, var, is_ptr=False):
 472     """Creates a base::Value given a type. Generated code passes ownership
 473     to caller.
 474
 475     var: variable or variable*
 476
 477     E.g for std::string, generate new base::StringValue(var)
 478     """
 479     c = Code()
 480     underlying_type = self._type_helper.FollowRef(type_)
 481     if underlying_type.property_type == PropertyType.ARRAY:
 482       # Enums are treated specially because C++ templating thinks that they're
 483       # ints, but really they're strings. So we create a vector of strings and
 484       # populate it with the names of the enum in the array. The |ToString|
 485       # function of the enum can be in another namespace when the enum is
 486       # referenced. Templates can not be used here because C++ templating does
 487       # not support passing a namespace as an argument.
 488       item_type = self._type_helper.FollowRef(underlying_type.item_type)
 489       if item_type.property_type == PropertyType.ENUM:
 490         varname = ('*' if is_ptr else '') + '(%s)' % var
 491
 492         maybe_namespace = ''
 493         if type_.item_type.property_type == PropertyType.REF:
 494           maybe_namespace = '%s::' % item_type.namespace.unix_name
 495
 496         enum_list_var = '%s_list' % prop_name
 497         # Scope the std::vector variable declaration inside braces.
 498         (c.Sblock('{')
 499           .Append('std::vector<std::string> %s;' % enum_list_var)
 500           .Append('for (const auto& it : %s) {' % varname)
 501           .Append('%s.push_back(%sToString(it));' % (enum_list_var,
 502                                                      maybe_namespace))
 503           .Eblock('}'))
 504
 505         # Because the std::vector above is always created for both required and
 506         # optional enum arrays, |is_ptr| is set to false and uses the
 507         # std::vector to create the values.
 508         (c.Append(code %
 509             self._GenerateCreateValueFromType(type_, enum_list_var, False))
 510           .Eblock('}'))
 511         return c
 512
 513     c.Append(code % self._GenerateCreateValueFromType(type_, var, is_ptr))
 514     return c
 515
 516   def _GenerateCreateValueFromType(self, type_, var, is_ptr):
 517     """Generates the statement to create a base::Value given a type.
 518
 519     type_:  The type of the values being converted.
 520     var:    The name of the variable.
 521     is_ptr: Whether |type_| is optional.
 522     """
 523     underlying_type = self._type_helper.FollowRef(type_)
 524     if (underlying_type.property_type == PropertyType.CHOICES or
 525         underlying_type.property_type == PropertyType.OBJECT):
 526       if is_ptr:
 527         return '(%s)->ToValue().release()' % var
 528       else:
 529         return '(%s).ToValue().release()' % var
 530     elif (underlying_type.property_type == PropertyType.ANY or
 531           underlying_type.property_type == PropertyType.FUNCTION):
 532       if is_ptr:
 533         vardot = '(%s)->' % var
 534       else:
 535         vardot = '(%s).' % var
 536       return '%sDeepCopy()' % vardot
 537     elif underlying_type.property_type == PropertyType.ENUM:
 538       maybe_namespace = ''
 539       if type_.property_type == PropertyType.REF:
 540         maybe_namespace = '%s::' % underlying_type.namespace.unix_name
 541       return 'new base::StringValue(%sToString(%s))' % (maybe_namespace, var)
 542     elif underlying_type.property_type == PropertyType.BINARY:
 543       if is_ptr:
 544         vardot = var + '->'
 545         ref = var + '.get()'
 546       else:
 547         vardot = var + '.'
 548         ref = '&' + var
 549       return ('base::BinaryValue::CreateWithCopiedBuffer(vector_as_array(%s),'
 550               ' %ssize())' % (ref, vardot))
 551     elif underlying_type.property_type == PropertyType.ARRAY:
 552       return '%s.release()' % self._util_cc_helper.CreateValueFromArray(
 553           var,
 554           is_ptr)
 555     elif underlying_type.property_type.is_fundamental:
 556       if is_ptr:
 557         var = '*%s' % var
 558       if underlying_type.property_type == PropertyType.STRING:
 559         return 'new base::StringValue(%s)' % var
 560       else:
 561         return 'new base::FundamentalValue(%s)' % var
 562     else:
 563       raise NotImplementedError('Conversion of %s to base::Value not '
 564                                 'implemented' % repr(type_.type_))
 565
 566   def _GenerateParamsCheck(self, function, var):
 567     """Generates a check for the correct number of arguments when creating
 568     Params.
 569     """
 570     c = Code()
 571     num_required = 0
 572     for param in function.params:
 573       if not param.optional:
 574         num_required += 1
 575     if num_required == len(function.params):
 576       c.Sblock('if (%(var)s.GetSize() != %(total)d) {')
 577     elif not num_required:
 578       c.Sblock('if (%(var)s.GetSize() > %(total)d) {')
 579     else:
 580       c.Sblock('if (%(var)s.GetSize() < %(required)d'
 581           ' || %(var)s.GetSize() > %(total)d) {')
 582     (c.Concat(self._GenerateError(
 583         '"expected %%(total)d arguments, got " '
 584         '+ base::IntToString(%%(var)s.GetSize())'))
 585       .Append('return scoped_ptr<Params>();')
 586       .Eblock('}')
 587       .Substitute({
 588         'var': var,
 589         'required': num_required,
 590         'total': len(function.params),
 591     }))
 592     return c
 593
 594   def _GenerateFunctionParamsCreate(self, function):
 595     """Generate function to create an instance of Params. The generated
 596     function takes a base::ListValue of arguments.
 597
 598     E.g for function "Bar", generate Bar::Params::Create()
 599     """
 600     c = Code()
 601     (c.Append('// static')
 602       .Sblock('scoped_ptr<Params> Params::Create(%s) {' % self._GenerateParams(
 603         ['const base::ListValue& args']))
 604     )
 605     if self._generate_error_messages:
 606       c.Append('DCHECK(error);')
 607     (c.Concat(self._GenerateParamsCheck(function, 'args'))
 608       .Append('scoped_ptr<Params> params(new Params());')
 609     )
 610
 611     for param in function.params:
 612       c.Concat(self._InitializePropertyToDefault(param, 'params'))
 613
 614     for i, param in enumerate(function.params):
 615       # Any failure will cause this function to return. If any argument is
 616       # incorrect or missing, those following it are not processed. Note that
 617       # for optional arguments, we allow missing arguments and proceed because
 618       # there may be other arguments following it.
 619       failure_value = 'scoped_ptr<Params>()'
 620       c.Append()
 621       value_var = param.unix_name + '_value'
 622       (c.Append('const base::Value* %(value_var)s = NULL;')
 623         .Append('if (args.Get(%(i)s, &%(value_var)s) &&')
 624         .Sblock('    !%(value_var)s->IsType(base::Value::TYPE_NULL)) {')
 625         .Concat(self._GeneratePopulatePropertyFromValue(
 626             param, value_var, 'params', failure_value))
 627         .Eblock('}')
 628       )
 629       if not param.optional:
 630         (c.Sblock('else {')
 631           .Concat(self._GenerateError('"\'%%(key)s\' is required"'))
 632           .Append('return %s;' % failure_value)
 633           .Eblock('}'))
 634       c.Substitute({'value_var': value_var, 'i': i, 'key': param.name})
 635     (c.Append()
 636       .Append('return params.Pass();')
 637       .Eblock('}')
 638       .Append()
 639     )
 640
 641     return c
 642
 643   def _GeneratePopulatePropertyFromValue(self,
 644                                          prop,
 645                                          src_var,
 646                                          dst_class_var,
 647                                          failure_value):
 648     """Generates code to populate property |prop| of |dst_class_var| (a
 649     pointer) from a Value*. See |_GeneratePopulateVariableFromValue| for
 650     semantics.
 651     """
 652     return self._GeneratePopulateVariableFromValue(prop.type_,
 653                                                    src_var,
 654                                                    '%s->%s' % (dst_class_var,
 655                                                                prop.unix_name),
 656                                                    failure_value,
 657                                                    is_ptr=prop.optional)
 658
 659   def _GeneratePopulateVariableFromValue(self,
 660                                          type_,
 661                                          src_var,
 662                                          dst_var,
 663                                          failure_value,
 664                                          is_ptr=False):
 665     """Generates code to populate a variable |dst_var| of type |type_| from a
 666     Value* at |src_var|. The Value* is assumed to be non-NULL. In the generated
 667     code, if |dst_var| fails to be populated then Populate will return
 668     |failure_value|.
 669     """
 670     c = Code()
 671
 672     underlying_type = self._type_helper.FollowRef(type_)
 673
 674     if underlying_type.property_type.is_fundamental:
 675       if is_ptr:
 676         (c.Append('%(cpp_type)s temp;')
 677           .Sblock('if (!%s) {' % cpp_util.GetAsFundamentalValue(
 678                       self._type_helper.FollowRef(type_), src_var, '&temp'))
 679           .Concat(self._GenerateError(
 680             '"\'%%(key)s\': expected ' + '%s, got " + %s' % (
 681                 type_.name,
 682                 self._util_cc_helper.GetValueTypeString(
 683                     '%%(src_var)s', True)))))
 684         c.Append('%(dst_var)s.reset();')
 685         if not self._generate_error_messages:
 686           c.Append('return %(failure_value)s;')
 687         (c.Eblock('}')
 688           .Append('else')
 689           .Append('  %(dst_var)s.reset(new %(cpp_type)s(temp));')
 690         )
 691       else:
 692         (c.Sblock('if (!%s) {' % cpp_util.GetAsFundamentalValue(
 693                       self._type_helper.FollowRef(type_),
 694                       src_var,
 695                       '&%s' % dst_var))
 696           .Concat(self._GenerateError(
 697             '"\'%%(key)s\': expected ' + '%s, got " + %s' % (
 698                 type_.name,
 699                 self._util_cc_helper.GetValueTypeString(
 700                     '%%(src_var)s', True))))
 701           .Append('return %(failure_value)s;')
 702           .Eblock('}')
 703         )
 704     elif underlying_type.property_type == PropertyType.OBJECT:
 705       if is_ptr:
 706         (c.Append('const base::DictionaryValue* dictionary = NULL;')
 707           .Sblock('if (!%(src_var)s->GetAsDictionary(&dictionary)) {')
 708           .Concat(self._GenerateError(
 709             '"\'%%(key)s\': expected dictionary, got " + ' +
 710             self._util_cc_helper.GetValueTypeString('%%(src_var)s', True))))
 711         # If an optional property fails to populate, the population can still
 712         # succeed with a warning. If no error messages are generated, this
 713         # warning is not set and we fail out instead.
 714         if not self._generate_error_messages:
 715           c.Append('return %(failure_value)s;')
 716         (c.Eblock('}')
 717           .Sblock('else {')
 718           .Append('scoped_ptr<%(cpp_type)s> temp(new %(cpp_type)s());')
 719           .Append('if (!%%(cpp_type)s::Populate(%s)) {' % self._GenerateArgs(
 720             ('*dictionary', 'temp.get()')))
 721           .Append('  return %(failure_value)s;')
 722         )
 723         (c.Append('}')
 724           .Append('else')
 725           .Append('  %(dst_var)s = temp.Pass();')
 726           .Eblock('}')
 727         )
 728       else:
 729         (c.Append('const base::DictionaryValue* dictionary = NULL;')
 730           .Sblock('if (!%(src_var)s->GetAsDictionary(&dictionary)) {')
 731           .Concat(self._GenerateError(
 732             '"\'%%(key)s\': expected dictionary, got " + ' +
 733             self._util_cc_helper.GetValueTypeString('%%(src_var)s', True)))
 734           .Append('return %(failure_value)s;')
 735           .Eblock('}')
 736           .Append('if (!%%(cpp_type)s::Populate(%s)) {' % self._GenerateArgs(
 737             ('*dictionary', '&%(dst_var)s')))
 738           .Append('  return %(failure_value)s;')
 739           .Append('}')
 740         )
 741     elif underlying_type.property_type == PropertyType.FUNCTION:
 742       if is_ptr:
 743         c.Append('%(dst_var)s.reset(new base::DictionaryValue());')
 744     elif underlying_type.property_type == PropertyType.ANY:
 745       c.Append('%(dst_var)s.reset(%(src_var)s->DeepCopy());')
 746     elif underlying_type.property_type == PropertyType.ARRAY:
 747       # util_cc_helper deals with optional and required arrays
 748       (c.Append('const base::ListValue* list = NULL;')
 749         .Sblock('if (!%(src_var)s->GetAsList(&list)) {')
 750           .Concat(self._GenerateError(
 751             '"\'%%(key)s\': expected list, got " + ' +
 752             self._util_cc_helper.GetValueTypeString('%%(src_var)s', True)))
 753       )
 754       if is_ptr and self._generate_error_messages:
 755         c.Append('%(dst_var)s.reset();')
 756       else:
 757         c.Append('return %(failure_value)s;')
 758       c.Eblock('}')
 759       c.Sblock('else {')
 760       item_type = self._type_helper.FollowRef(underlying_type.item_type)
 761       if item_type.property_type == PropertyType.ENUM:
 762         c.Concat(self._GenerateListValueToEnumArrayConversion(
 763                      item_type,
 764                      'list',
 765                      dst_var,
 766                      failure_value,
 767                      is_ptr=is_ptr))
 768       else:
 769         c.Sblock('if (!%s) {' % self._util_cc_helper.PopulateArrayFromList(
 770             'list',
 771             dst_var,
 772             is_ptr))
 773         c.Concat(self._GenerateError(
 774             '"unable to populate array \'%%(parent_key)s\'"'))
 775         if is_ptr and self._generate_error_messages:
 776           c.Append('%(dst_var)s.reset();')
 777         else:
 778           c.Append('return %(failure_value)s;')
 779         c.Eblock('}')
 780       c.Eblock('}')
 781     elif underlying_type.property_type == PropertyType.CHOICES:
 782       if is_ptr:
 783         (c.Append('scoped_ptr<%(cpp_type)s> temp(new %(cpp_type)s());')
 784           .Append('if (!%%(cpp_type)s::Populate(%s))' % self._GenerateArgs(
 785             ('*%(src_var)s', 'temp.get()')))
 786           .Append('  return %(failure_value)s;')
 787           .Append('%(dst_var)s = temp.Pass();')
 788         )
 789       else:
 790         (c.Append('if (!%%(cpp_type)s::Populate(%s))' % self._GenerateArgs(
 791             ('*%(src_var)s', '&%(dst_var)s')))
 792           .Append('  return %(failure_value)s;'))
 793     elif underlying_type.property_type == PropertyType.ENUM:
 794       c.Concat(self._GenerateStringToEnumConversion(underlying_type,
 795                                                     src_var,
 796                                                     dst_var,
 797                                                     failure_value))
 798     elif underlying_type.property_type == PropertyType.BINARY:
 799       (c.Append('const base::BinaryValue* binary_value = NULL;')
 800         .Sblock('if (!%(src_var)s->IsType(base::Value::TYPE_BINARY)) {')
 801         .Concat(self._GenerateError(
 802           '"\'%%(key)s\': expected binary, got " + ' +
 803           self._util_cc_helper.GetValueTypeString('%%(src_var)s', True)))
 804       )
 805       if not self._generate_error_messages:
 806         c.Append('return %(failure_value)s;')
 807       (c.Eblock('}')
 808         .Sblock('else {')
 809         .Append(' binary_value =')
 810         .Append('   static_cast<const base::BinaryValue*>(%(src_var)s);')
 811       )
 812       if is_ptr:
 813         (c.Append('%(dst_var)s.reset(new std::vector<char>(')
 814           .Append('    binary_value->GetBuffer(),')
 815           .Append('    binary_value->GetBuffer() + binary_value->GetSize()));')
 816         )
 817       else:
 818         (c.Append('%(dst_var)s.assign(')
 819           .Append('    binary_value->GetBuffer(),')
 820           .Append('    binary_value->GetBuffer() + binary_value->GetSize());')
 821         )
 822       c.Eblock('}')
 823     else:
 824       raise NotImplementedError(type_)
 825     if c.IsEmpty():
 826       return c
 827     return Code().Sblock('{').Concat(c.Substitute({
 828       'cpp_type': self._type_helper.GetCppType(type_),
 829       'src_var': src_var,
 830       'dst_var': dst_var,
 831       'failure_value': failure_value,
 832       'key': type_.name,
 833       'parent_key': type_.parent.name,
 834     })).Eblock('}')
 835
 836   def _GenerateListValueToEnumArrayConversion(self,
 837                                               item_type,
 838                                               src_var,
 839                                               dst_var,
 840                                               failure_value,
 841                                               is_ptr=False):
 842     """Returns Code that converts a ListValue of string constants from
 843     |src_var| into an array of enums of |type_| in |dst_var|. On failure,
 844     returns |failure_value|.
 845     """
 846     c = Code()
 847     accessor = '.'
 848     if is_ptr:
 849       accessor = '->'
 850       cpp_type = self._type_helper.GetCppType(item_type, is_in_container=True)
 851       c.Append('%s.reset(new std::vector<%s>);' %
 852                    (dst_var, cpp_util.PadForGenerics(cpp_type)))
 853     (c.Sblock('for (const auto& it : *(%s)) {' % src_var)
 854       .Append('%s tmp;' % self._type_helper.GetCppType(item_type))
 855       .Concat(self._GenerateStringToEnumConversion(item_type,
 856                                                    '(it)',
 857                                                    'tmp',
 858                                                    failure_value))
 859       .Append('%s%spush_back(tmp);' % (dst_var, accessor))
 860       .Eblock('}')
 861     )
 862     return c
 863
 864   def _GenerateStringToEnumConversion(self,
 865                                       type_,
 866                                       src_var,
 867                                       dst_var,
 868                                       failure_value):
 869     """Returns Code that converts a string type in |src_var| to an enum with
 870     type |type_| in |dst_var|. In the generated code, if |src_var| is not
 871     a valid enum name then the function will return |failure_value|.
 872     """
 873     if type_.property_type != PropertyType.ENUM:
 874       raise TypeError(type_)
 875     c = Code()
 876     enum_as_string = '%s_as_string' % type_.unix_name
 877     cpp_type_namespace = ''
 878     if type_.namespace != self._namespace:
 879       cpp_type_namespace = '%s::' % type_.namespace.unix_name
 880     (c.Append('std::string %s;' % enum_as_string)
 881       .Sblock('if (!%s->GetAsString(&%s)) {' % (src_var, enum_as_string))
 882       .Concat(self._GenerateError(
 883         '"\'%%(key)s\': expected string, got " + ' +
 884         self._util_cc_helper.GetValueTypeString('%%(src_var)s', True)))
 885       .Append('return %s;' % failure_value)
 886       .Eblock('}')
 887       .Append('%s = %sParse%s(%s);' % (dst_var,
 888                                        cpp_type_namespace,
 889                                        cpp_util.Classname(type_.name),
 890                                        enum_as_string))
 891       .Sblock('if (%s == %s%s) {' % (dst_var,
 892                                      cpp_type_namespace,
 893                                      self._type_helper.GetEnumNoneValue(type_)))
 894       .Concat(self._GenerateError(
 895         '\"\'%%(key)s\': expected \\"' +
 896         '\\" or \\"'.join(
 897             enum_value.name
 898             for enum_value in self._type_helper.FollowRef(type_).enum_values) +
 899         '\\", got \\"" + %s + "\\""' % enum_as_string))
 900       .Append('return %s;' % failure_value)
 901       .Eblock('}')
 902       .Substitute({'src_var': src_var, 'key': type_.name})
 903     )
 904     return c
 905
 906   def _GeneratePropertyFunctions(self, namespace, params):
 907     """Generates the member functions for a list of parameters.
 908     """
 909     return self._GenerateTypes(namespace, (param.type_ for param in params))
 910
 911   def _GenerateTypes(self, namespace, types):
 912     """Generates the member functions for a list of types.
 913     """
 914     c = Code()
 915     for type_ in types:
 916       c.Cblock(self._GenerateType(namespace, type_))
 917     return c
 918
 919   def _GenerateEnumToString(self, cpp_namespace, type_):
 920     """Generates ToString() which gets the string representation of an enum.
 921     """
 922     c = Code()
 923     classname = cpp_util.Classname(schema_util.StripNamespace(type_.name))
 924
 925     if cpp_namespace is not None:
 926       c.Append('// static')
 927     maybe_namespace = '' if cpp_namespace is None else '%s::' % cpp_namespace
 928
 929     c.Sblock('std::string %sToString(%s enum_param) {' %
 930                  (maybe_namespace, classname))
 931     c.Sblock('switch (enum_param) {')
 932     for enum_value in self._type_helper.FollowRef(type_).enum_values:
 933       name = enum_value.name
 934       if 'camel_case_enum_to_string' in self._namespace.compiler_options:
 935         name = enum_value.CamelName()
 936       (c.Append('case %s: ' % self._type_helper.GetEnumValue(type_, enum_value))
 937         .Append('  return "%s";' % name))
 938     (c.Append('case %s:' % self._type_helper.GetEnumNoneValue(type_))
 939       .Append('  return "";')
 940       .Eblock('}')
 941       .Append('NOTREACHED();')
 942       .Append('return "";')
 943       .Eblock('}')
 944     )
 945     return c
 946
 947   def _GenerateEnumFromString(self, cpp_namespace, type_):
 948     """Generates FromClassNameString() which gets an enum from its string
 949     representation.
 950     """
 951     c = Code()
 952     classname = cpp_util.Classname(schema_util.StripNamespace(type_.name))
 953
 954     if cpp_namespace is not None:
 955       c.Append('// static')
 956     maybe_namespace = '' if cpp_namespace is None else '%s::' % cpp_namespace
 957
 958     c.Sblock('%s%s %sParse%s(const std::string& enum_string) {' %
 959                  (maybe_namespace, classname, maybe_namespace, classname))
 960     for _, enum_value in enumerate(
 961           self._type_helper.FollowRef(type_).enum_values):
 962       # This is broken up into all ifs with no else ifs because we get
 963       # "fatal error C1061: compiler limit : blocks nested too deeply"
 964       # on Windows.
 965       (c.Append('if (enum_string == "%s")' % enum_value.name)
 966         .Append('  return %s;' %
 967             self._type_helper.GetEnumValue(type_, enum_value)))
 968     (c.Append('return %s;' % self._type_helper.GetEnumNoneValue(type_))
 969       .Eblock('}')
 970     )
 971     return c
 972
 973   def _GenerateCreateCallbackArguments(self,
 974                                        function_scope,
 975                                        callback):
 976     """Generate all functions to create Value parameters for a callback.
 977
 978     E.g for function "Bar", generate Bar::Results::Create
 979     E.g for event "Baz", generate Baz::Create
 980
 981     function_scope: the function scope path, e.g. Foo::Bar for the function
 982                     Foo::Bar::Baz(). May be None if there is no function scope.
 983     callback: the Function object we are creating callback arguments for.
 984     """
 985     c = Code()
 986     params = callback.params
 987     c.Concat(self._GeneratePropertyFunctions(function_scope, params))
 988
 989     (c.Sblock('scoped_ptr<base::ListValue> %(function_scope)s'
 990                   'Create(%(declaration_list)s) {')
 991       .Append('scoped_ptr<base::ListValue> create_results('
 992               'new base::ListValue());')
 993     )
 994     declaration_list = []
 995     for param in params:
 996       declaration_list.append(cpp_util.GetParameterDeclaration(
 997           param, self._type_helper.GetCppType(param.type_)))
 998       c.Cblock(self._CreateValueFromType('create_results->Append(%s);',
 999                                          param.name,
1000                                          param.type_,
1001                                          param.unix_name))
1002     c.Append('return create_results.Pass();')
1003     c.Eblock('}')
1004     c.Substitute({
1005         'function_scope': ('%s::' % function_scope) if function_scope else '',
1006         'declaration_list': ', '.join(declaration_list),
1007         'param_names': ', '.join(param.unix_name for param in params)
1008     })
1009     return c
1010
1011   def _GenerateEventNameConstant(self, event):
1012     """Generates a constant string array for the event name.
1013     """
1014     c = Code()
1015     c.Append('const char kEventName[] = "%s.%s";' % (
1016                  self._namespace.name, event.name))
1017     return c
1018
1019   def _InitializePropertyToDefault(self, prop, dst):
1020     """Initialize a model.Property to its default value inside an object.
1021
1022     E.g for optional enum "state", generate dst->state = STATE_NONE;
1023
1024     dst: Type*
1025     """
1026     c = Code()
1027     underlying_type = self._type_helper.FollowRef(prop.type_)
1028     if (underlying_type.property_type == PropertyType.ENUM and
1029         prop.optional):
1030       c.Append('%s->%s = %s;' % (
1031         dst,
1032         prop.unix_name,
1033         self._type_helper.GetEnumNoneValue(prop.type_)))
1034     return c
1035
1036   def _GenerateError(self, body):
1037     """Generates an error message pertaining to population failure.
1038
1039     E.g 'expected bool, got int'
1040     """
1041     c = Code()
1042     if not self._generate_error_messages:
1043       return c
1044     (c.Append('if (error->length())')
1045       .Append('  error->append(UTF8ToUTF16("; "));')
1046       .Append('error->append(UTF8ToUTF16(%s));' % body))
1047     return c
1048
1049   def _GenerateParams(self, params):
1050     """Builds the parameter list for a function, given an array of parameters.
1051     """
1052     if self._generate_error_messages:
1053       params = list(params) + ['base::string16* error']
1054     return ', '.join(str(p) for p in params)
1055
1056   def _GenerateArgs(self, args):
1057     """Builds the argument list for a function, given an array of arguments.
1058     """
1059     if self._generate_error_messages:
1060       args = list(args) + ['error']
1061     return ', '.join(str(a) for a in args)