cpp_type_generator.py revision 2a99a7e74a7f215066514fe81d2bfa6639d9eddd 
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
5from code import Code
6from model import Namespace, PropertyType, Type
7import cpp_util
8from json_parse import OrderedDict
9from operator import attrgetter
10import schema_util
11
12class _TypeDependency(object):
13  """Contains information about a dependency a namespace has on a type: the
14  type's model, and whether that dependency is "hard" meaning that it cannot be
15  forward declared.
16  """
17  def __init__(self, type_, hard=False):
18    self.type_ = type_
19    self.hard = hard
20
21  def GetSortKey(self):
22    return '%s.%s' % (self.type_.namespace.name, self.type_.name)
23
24class 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    return '%s_%s' % (self.FollowRef(type_).unix_name.upper(),
68                      cpp_util.Classname(enum_value.upper()))
69
70  def GetCppType(self, type_, is_ptr=False, is_in_container=False):
71    """Translates a model.Property or model.Type into its C++ type.
72
73    If REF types from different namespaces are referenced, will resolve
74    using self._schema_loader.
75
76    Use |is_ptr| if the type is optional. This will wrap the type in a
77    scoped_ptr if possible (it is not possible to wrap an enum).
78
79    Use |is_in_container| if the type is appearing in a collection, e.g. a
80    std::vector or std::map. This will wrap it in the correct type with spacing.
81    """
82    cpp_type = None
83    if type_.property_type == PropertyType.REF:
84      ref_type = self._FindType(type_.ref_type)
85      if ref_type is None:
86        raise KeyError('Cannot find referenced type: %s' % type_.ref_type)
87      if self._default_namespace is ref_type.namespace:
88        cpp_type = ref_type.name
89      else:
90        cpp_type = '%s::%s' % (ref_type.namespace.unix_name, ref_type.name)
91    elif type_.property_type == PropertyType.BOOLEAN:
92      cpp_type = 'bool'
93    elif type_.property_type == PropertyType.INTEGER:
94      cpp_type = 'int'
95    elif type_.property_type == PropertyType.INT64:
96      cpp_type = 'int64'
97    elif type_.property_type == PropertyType.DOUBLE:
98      cpp_type = 'double'
99    elif type_.property_type == PropertyType.STRING:
100      cpp_type = 'std::string'
101    elif type_.property_type == PropertyType.ENUM:
102      cpp_type = cpp_util.Classname(type_.name)
103    elif type_.property_type == PropertyType.ANY:
104      cpp_type = 'base::Value'
105    elif (type_.property_type == PropertyType.OBJECT or
106          type_.property_type == PropertyType.CHOICES):
107      cpp_type = cpp_util.Classname(type_.name)
108    elif type_.property_type == PropertyType.FUNCTION:
109      # Functions come into the json schema compiler as empty objects. We can
110      # record these as empty DictionaryValues so that we know if the function
111      # was passed in or not.
112      cpp_type = 'base::DictionaryValue'
113    elif type_.property_type == PropertyType.ARRAY:
114      item_cpp_type = self.GetCppType(type_.item_type, is_in_container=True)
115      cpp_type = 'std::vector<%s>' % cpp_util.PadForGenerics(item_cpp_type)
116    elif type_.property_type == PropertyType.BINARY:
117      cpp_type = 'std::string'
118    else:
119      raise NotImplementedError('Cannot get type of %s' % type_.property_type)
120
121    # HACK: optional ENUM is represented elsewhere with a _NONE value, so it
122    # never needs to be wrapped in pointer shenanigans.
123    # TODO(kalman): change this - but it's an exceedingly far-reaching change.
124    if not self.FollowRef(type_).property_type == PropertyType.ENUM:
125      if is_in_container and (is_ptr or not self.IsCopyable(type_)):
126        cpp_type = 'linked_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
127      elif is_ptr:
128        cpp_type = 'scoped_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
129
130    return cpp_type
131
132  def IsCopyable(self, type_):
133    return not (self.FollowRef(type_).property_type in (PropertyType.ANY,
134                                                        PropertyType.ARRAY,
135                                                        PropertyType.OBJECT,
136                                                        PropertyType.CHOICES))
137
138  def GenerateForwardDeclarations(self):
139    """Returns the forward declarations for self._default_namespace.
140    """
141    c = Code()
142
143    for namespace, dependencies in self._NamespaceTypeDependencies().items():
144      c.Append('namespace %s {' % namespace.unix_name)
145      for dependency in dependencies:
146        # No point forward-declaring hard dependencies.
147        if dependency.hard:
148          continue
149        # Add more ways to forward declare things as necessary.
150        if dependency.type_.property_type == PropertyType.OBJECT:
151          c.Append('struct %s;' % dependency.type_.name)
152      c.Append('}')
153
154    return c
155
156  def GenerateIncludes(self, include_soft=False):
157    """Returns the #include lines for self._default_namespace.
158    """
159    c = Code()
160    for namespace, dependencies in self._NamespaceTypeDependencies().items():
161      for dependency in dependencies:
162        if dependency.hard or include_soft:
163          c.Append('#include "%s/%s.h"' % (namespace.source_file_dir,
164                                           namespace.unix_name))
165    return c
166
167  def _FindType(self, full_name):
168    """Finds the model.Type with name |qualified_name|. If it's not from
169    |self._default_namespace| then it needs to be qualified.
170    """
171    namespace = self._schema_loader.ResolveType(full_name,
172                                                self._default_namespace)
173    if namespace is None:
174      raise KeyError('Cannot resolve type %s. Maybe it needs a prefix '
175                     'if it comes from another namespace?' % full_name)
176    return namespace.types[schema_util.StripNamespace(full_name)]
177
178  def FollowRef(self, type_):
179    """Follows $ref link of types to resolve the concrete type a ref refers to.
180
181    If the property passed in is not of type PropertyType.REF, it will be
182    returned unchanged.
183    """
184    if type_.property_type != PropertyType.REF:
185      return type_
186    return self.FollowRef(self._FindType(type_.ref_type))
187
188  def _NamespaceTypeDependencies(self):
189    """Returns a dict ordered by namespace name containing a mapping of
190    model.Namespace to every _TypeDependency for |self._default_namespace|,
191    sorted by the type's name.
192    """
193    dependencies = set()
194    for function in self._default_namespace.functions.values():
195      for param in function.params:
196        dependencies |= self._TypeDependencies(param.type_,
197                                               hard=not param.optional)
198      if function.callback:
199        for param in function.callback.params:
200          dependencies |= self._TypeDependencies(param.type_,
201                                                 hard=not param.optional)
202    for type_ in self._default_namespace.types.values():
203      for prop in type_.properties.values():
204        dependencies |= self._TypeDependencies(prop.type_,
205                                               hard=not prop.optional)
206    for event in self._default_namespace.events.values():
207      for param in event.params:
208        dependencies |= self._TypeDependencies(param.type_,
209                                               hard=not param.optional)
210
211    # Make sure that the dependencies are returned in alphabetical order.
212    dependency_namespaces = OrderedDict()
213    for dependency in sorted(dependencies, key=_TypeDependency.GetSortKey):
214      namespace = dependency.type_.namespace
215      if namespace is self._default_namespace:
216        continue
217      if namespace not in dependency_namespaces:
218        dependency_namespaces[namespace] = []
219      dependency_namespaces[namespace].append(dependency)
220
221    return dependency_namespaces
222
223  def _TypeDependencies(self, type_, hard=False):
224    """Gets all the type dependencies of a property.
225    """
226    deps = set()
227    if type_.property_type == PropertyType.REF:
228      deps.add(_TypeDependency(self._FindType(type_.ref_type), hard=hard))
229    elif type_.property_type == PropertyType.ARRAY:
230      # Non-copyable types are not hard because they are wrapped in linked_ptrs
231      # when generated. Otherwise they're typedefs, so they're hard (though we
232      # could generate those typedefs in every dependent namespace, but that
233      # seems weird).
234      deps = self._TypeDependencies(type_.item_type,
235                                    hard=self.IsCopyable(type_.item_type))
236    elif type_.property_type == PropertyType.CHOICES:
237      for type_ in type_.choices:
238        deps |= self._TypeDependencies(type_, hard=self.IsCopyable(type_))
239    elif type_.property_type == PropertyType.OBJECT:
240      for p in type_.properties.values():
241        deps |= self._TypeDependencies(p.type_, hard=not p.optional)
242    return deps
243
244  def GeneratePropertyValues(self, property, line, nodoc=False):
245    """Generates the Code to display all value-containing properties.
246    """
247    c = Code()
248    if not nodoc:
249      c.Comment(property.description)
250
251    if property.value is not None:
252      c.Append(line % {
253          "type": self.GetCppType(property.type_),
254          "name": property.name,
255          "value": property.value
256        })
257    else:
258      has_child_code = False
259      c.Sblock('namespace %s {' % property.name)
260      for child_property in property.type_.properties.values():
261        child_code = self.GeneratePropertyValues(child_property,
262                                                 line,
263                                                 nodoc=nodoc)
264        if child_code:
265          has_child_code = True
266          c.Concat(child_code)
267      c.Eblock('}  // namespace %s' % property.name)
268      if not has_child_code:
269        c = None
270    return c
271