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