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