tools/json_schema_compiler/cpp_type_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 from json_parse import OrderedDict
   9 import schema_util
  10
  11 class _TypeDependency(object):
  12   """Contains information about a dependency a namespace has on a type: the
  13   type's model, and whether that dependency is "hard" meaning that it cannot be
  14   forward declared.
  15   """
  16   def __init__(self, type_, hard=False):
  17     self.type_ = type_
  18     self.hard = hard
  19
  20   def GetSortKey(self):
  21     return '%s.%s' % (self.type_.namespace.name, self.type_.name)
  22
  23
  24 class CppTypeGenerator(object):
  25   """Manages the types of properties and provides utilities for getting the
  26   C++ type out of a model.Property
  27   """
  28   def __init__(self, model, schema_loader, default_namespace=None):
  29     """Creates a cpp_type_generator. The given root_namespace should be of the
  30     format extensions::api::sub. The generator will generate code suitable for
  31     use in the given model's namespace.
  32     """
  33     self._default_namespace = default_namespace
  34     if self._default_namespace is None:
  35       self._default_namespace = model.namespaces.values()[0]
  36     self._schema_loader = schema_loader
  37
  38   def GetCppNamespaceName(self, namespace):
  39     """Gets the mapped C++ namespace name for the given namespace relative to
  40     the root namespace.
  41     """
  42     return namespace.unix_name
  43
  44   def GetNamespaceStart(self):
  45     """Get opening self._default_namespace namespace declaration.
  46     """
  47     return Code().Append('namespace %s {' %
  48         self.GetCppNamespaceName(self._default_namespace))
  49
  50   def GetNamespaceEnd(self):
  51     """Get closing self._default_namespace namespace declaration.
  52     """
  53     return Code().Append('}  // %s' %
  54         self.GetCppNamespaceName(self._default_namespace))
  55
  56   def GetEnumNoneValue(self, type_):
  57     """Gets the enum value in the given model.Property indicating no value has
  58     been set.
  59     """
  60     return '%s_NONE' % self.FollowRef(type_).unix_name.upper()
  61
  62   def GetEnumValue(self, type_, enum_value):
  63     """Gets the enum value of the given model.Property of the given type.
  64
  65     e.g VAR_STRING
  66     """
  67     value = cpp_util.Classname(enum_value.name.upper())
  68     if not type_.cpp_omit_enum_type:
  69       value = '%s_%s' % (self.FollowRef(type_).unix_name.upper(), value)
  70     # To avoid collisions with built-in OS_* preprocessor definitions, we add a
  71     # trailing slash to enum names that start with OS_.
  72     if value.startswith("OS_"):
  73       value += "_"
  74     return value
  75
  76   def GetCppType(self, type_, is_ptr=False, is_in_container=False):
  77     """Translates a model.Property or model.Type into its C++ type.
  78
  79     If REF types from different namespaces are referenced, will resolve
  80     using self._schema_loader.
  81
  82     Use |is_ptr| if the type is optional. This will wrap the type in a
  83     scoped_ptr if possible (it is not possible to wrap an enum).
  84
  85     Use |is_in_container| if the type is appearing in a collection, e.g. a
  86     std::vector or std::map. This will wrap it in the correct type with spacing.
  87     """
  88     cpp_type = None
  89     if type_.property_type == PropertyType.REF:
  90       ref_type = self._FindType(type_.ref_type)
  91       if ref_type is None:
  92         raise KeyError('Cannot find referenced type: %s' % type_.ref_type)
  93       if self._default_namespace is ref_type.namespace:
  94         cpp_type = ref_type.name
  95       else:
  96         cpp_type = '%s::%s' % (ref_type.namespace.unix_name, ref_type.name)
  97     elif type_.property_type == PropertyType.BOOLEAN:
  98       cpp_type = 'bool'
  99     elif type_.property_type == PropertyType.INTEGER:
 100       cpp_type = 'int'
 101     elif type_.property_type == PropertyType.INT64:
 102       cpp_type = 'int64'
 103     elif type_.property_type == PropertyType.DOUBLE:
 104       cpp_type = 'double'
 105     elif type_.property_type == PropertyType.STRING:
 106       cpp_type = 'std::string'
 107     elif type_.property_type == PropertyType.ENUM:
 108       cpp_type = cpp_util.Classname(type_.name)
 109     elif type_.property_type == PropertyType.ANY:
 110       cpp_type = 'base::Value'
 111     elif (type_.property_type == PropertyType.OBJECT or
 112           type_.property_type == PropertyType.CHOICES):
 113       cpp_type = cpp_util.Classname(type_.name)
 114     elif type_.property_type == PropertyType.FUNCTION:
 115       # Functions come into the json schema compiler as empty objects. We can
 116       # record these as empty DictionaryValues so that we know if the function
 117       # was passed in or not.
 118       cpp_type = 'base::DictionaryValue'
 119     elif type_.property_type == PropertyType.ARRAY:
 120       item_cpp_type = self.GetCppType(type_.item_type, is_in_container=True)
 121       cpp_type = 'std::vector<%s>' % cpp_util.PadForGenerics(item_cpp_type)
 122     elif type_.property_type == PropertyType.BINARY:
 123       cpp_type = 'std::string'
 124     else:
 125       raise NotImplementedError('Cannot get type of %s' % type_.property_type)
 126
 127     # HACK: optional ENUM is represented elsewhere with a _NONE value, so it
 128     # never needs to be wrapped in pointer shenanigans.
 129     # TODO(kalman): change this - but it's an exceedingly far-reaching change.
 130     if not self.FollowRef(type_).property_type == PropertyType.ENUM:
 131       if is_in_container and (is_ptr or not self.IsCopyable(type_)):
 132         cpp_type = 'linked_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
 133       elif is_ptr:
 134         cpp_type = 'scoped_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
 135
 136     return cpp_type
 137
 138   def IsCopyable(self, type_):
 139     return not (self.FollowRef(type_).property_type in (PropertyType.ANY,
 140                                                         PropertyType.ARRAY,
 141                                                         PropertyType.OBJECT,
 142                                                         PropertyType.CHOICES))
 143
 144   def GenerateForwardDeclarations(self):
 145     """Returns the forward declarations for self._default_namespace.
 146     """
 147     c = Code()
 148
 149     for namespace, dependencies in self._NamespaceTypeDependencies().items():
 150       c.Append('namespace %s {' % namespace.unix_name)
 151       for dependency in dependencies:
 152         # No point forward-declaring hard dependencies.
 153         if dependency.hard:
 154           continue
 155         # Add more ways to forward declare things as necessary.
 156         if dependency.type_.property_type in (PropertyType.CHOICES,
 157                                               PropertyType.OBJECT):
 158           c.Append('struct %s;' % dependency.type_.name)
 159       c.Append('}')
 160
 161     return c
 162
 163   def GenerateIncludes(self, include_soft=False):
 164     """Returns the #include lines for self._default_namespace.
 165     """
 166     c = Code()
 167     for namespace, dependencies in self._NamespaceTypeDependencies().items():
 168       for dependency in dependencies:
 169         if dependency.hard or include_soft:
 170           c.Append('#include "%s/%s.h"' % (namespace.source_file_dir,
 171                                            namespace.unix_name))
 172     return c
 173
 174   def _FindType(self, full_name):
 175     """Finds the model.Type with name |qualified_name|. If it's not from
 176     |self._default_namespace| then it needs to be qualified.
 177     """
 178     namespace = self._schema_loader.ResolveType(full_name,
 179                                                 self._default_namespace)
 180     if namespace is None:
 181       raise KeyError('Cannot resolve type %s. Maybe it needs a prefix '
 182                      'if it comes from another namespace?' % full_name)
 183     return namespace.types[schema_util.StripNamespace(full_name)]
 184
 185   def FollowRef(self, type_):
 186     """Follows $ref link of types to resolve the concrete type a ref refers to.
 187
 188     If the property passed in is not of type PropertyType.REF, it will be
 189     returned unchanged.
 190     """
 191     if type_.property_type != PropertyType.REF:
 192       return type_
 193     return self.FollowRef(self._FindType(type_.ref_type))
 194
 195   def _NamespaceTypeDependencies(self):
 196     """Returns a dict ordered by namespace name containing a mapping of
 197     model.Namespace to every _TypeDependency for |self._default_namespace|,
 198     sorted by the type's name.
 199     """
 200     dependencies = set()
 201     for function in self._default_namespace.functions.values():
 202       for param in function.params:
 203         dependencies |= self._TypeDependencies(param.type_,
 204                                                hard=not param.optional)
 205       if function.callback:
 206         for param in function.callback.params:
 207           dependencies |= self._TypeDependencies(param.type_,
 208                                                  hard=not param.optional)
 209     for type_ in self._default_namespace.types.values():
 210       for prop in type_.properties.values():
 211         dependencies |= self._TypeDependencies(prop.type_,
 212                                                hard=not prop.optional)
 213     for event in self._default_namespace.events.values():
 214       for param in event.params:
 215         dependencies |= self._TypeDependencies(param.type_,
 216                                                hard=not param.optional)
 217
 218     # Make sure that the dependencies are returned in alphabetical order.
 219     dependency_namespaces = OrderedDict()
 220     for dependency in sorted(dependencies, key=_TypeDependency.GetSortKey):
 221       namespace = dependency.type_.namespace
 222       if namespace is self._default_namespace:
 223         continue
 224       if namespace not in dependency_namespaces:
 225         dependency_namespaces[namespace] = []
 226       dependency_namespaces[namespace].append(dependency)
 227
 228     return dependency_namespaces
 229
 230   def _TypeDependencies(self, type_, hard=False):
 231     """Gets all the type dependencies of a property.
 232     """
 233     deps = set()
 234     if type_.property_type == PropertyType.REF:
 235       deps.add(_TypeDependency(self._FindType(type_.ref_type), hard=hard))
 236     elif type_.property_type == PropertyType.ARRAY:
 237       # Non-copyable types are not hard because they are wrapped in linked_ptrs
 238       # when generated. Otherwise they're typedefs, so they're hard (though we
 239       # could generate those typedefs in every dependent namespace, but that
 240       # seems weird).
 241       deps = self._TypeDependencies(type_.item_type,
 242                                     hard=self.IsCopyable(type_.item_type))
 243     elif type_.property_type == PropertyType.CHOICES:
 244       for type_ in type_.choices:
 245         deps |= self._TypeDependencies(type_, hard=self.IsCopyable(type_))
 246     elif type_.property_type == PropertyType.OBJECT:
 247       for p in type_.properties.values():
 248         deps |= self._TypeDependencies(p.type_, hard=not p.optional)
 249     return deps
 250
 251   def GeneratePropertyValues(self, property, line, nodoc=False):
 252     """Generates the Code to display all value-containing properties.
 253     """
 254     c = Code()
 255     if not nodoc:
 256       c.Comment(property.description)
 257
 258     if property.value is not None:
 259       c.Append(line % {
 260           "type": self.GetCppType(property.type_),
 261           "name": property.name,
 262           "value": property.value
 263         })
 264     else:
 265       has_child_code = False
 266       c.Sblock('namespace %s {' % property.name)
 267       for child_property in property.type_.properties.values():
 268         child_code = self.GeneratePropertyValues(child_property,
 269                                                  line,
 270                                                  nodoc=nodoc)
 271         if child_code:
 272           has_child_code = True
 273           c.Concat(child_code)
 274       c.Eblock('}  // namespace %s' % property.name)
 275       if not has_child_code:
 276         c = None
 277     return c