cpp_type_generator.py revision cedac228d2dd51db4b79ea1e72c7f249408ee061 
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 PropertyType
7import cpp_util
8from json_parse import OrderedDict
9import schema_util
10
11class _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
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 GetEnumLastValue(self, type_):
63    """Gets the enum value in the given model.Property indicating the last value
64    for the type.
65    """
66    return '%s_LAST' % self.FollowRef(type_).unix_name.upper()
67
68  def GetEnumValue(self, type_, enum_value):
69    """Gets the enum value of the given model.Property of the given type.
70
71    e.g VAR_STRING
72    """
73    value = cpp_util.Classname(enum_value.name.upper())
74    prefix = (type_.cpp_enum_prefix_override or
75              self.FollowRef(type_).unix_name)
76    value = '%s_%s' % (prefix.upper(), value)
77    # To avoid collisions with built-in OS_* preprocessor definitions, we add a
78    # trailing slash to enum names that start with OS_.
79    if value.startswith("OS_"):
80      value += "_"
81    return value
82
83  def GetCppType(self, type_, is_ptr=False, is_in_container=False):
84    """Translates a model.Property or model.Type into its C++ type.
85
86    If REF types from different namespaces are referenced, will resolve
87    using self._schema_loader.
88
89    Use |is_ptr| if the type is optional. This will wrap the type in a
90    scoped_ptr if possible (it is not possible to wrap an enum).
91
92    Use |is_in_container| if the type is appearing in a collection, e.g. a
93    std::vector or std::map. This will wrap it in the correct type with spacing.
94    """
95    cpp_type = None
96    if type_.property_type == PropertyType.REF:
97      ref_type = self._FindType(type_.ref_type)
98      if ref_type is None:
99        raise KeyError('Cannot find referenced type: %s' % type_.ref_type)
100      cpp_type = self.GetCppType(ref_type)
101    elif type_.property_type == PropertyType.BOOLEAN:
102      cpp_type = 'bool'
103    elif type_.property_type == PropertyType.INTEGER:
104      cpp_type = 'int'
105    elif type_.property_type == PropertyType.INT64:
106      cpp_type = 'int64'
107    elif type_.property_type == PropertyType.DOUBLE:
108      cpp_type = 'double'
109    elif type_.property_type == PropertyType.STRING:
110      cpp_type = 'std::string'
111    elif type_.property_type in (PropertyType.ENUM,
112                                 PropertyType.OBJECT,
113                                 PropertyType.CHOICES):
114      if self._default_namespace is type_.namespace:
115        cpp_type = cpp_util.Classname(type_.name)
116      else:
117        cpp_type = '%s::%s' % (type_.namespace.unix_name,
118                               cpp_util.Classname(type_.name))
119    elif type_.property_type == PropertyType.ANY:
120      cpp_type = 'base::Value'
121    elif type_.property_type == PropertyType.FUNCTION:
122      # Functions come into the json schema compiler as empty objects. We can
123      # record these as empty DictionaryValues so that we know if the function
124      # was passed in or not.
125      cpp_type = 'base::DictionaryValue'
126    elif type_.property_type == PropertyType.ARRAY:
127      item_cpp_type = self.GetCppType(type_.item_type, is_in_container=True)
128      cpp_type = 'std::vector<%s>' % cpp_util.PadForGenerics(item_cpp_type)
129    elif type_.property_type == PropertyType.BINARY:
130      cpp_type = 'std::string'
131    else:
132      raise NotImplementedError('Cannot get type of %s' % type_.property_type)
133
134    # HACK: optional ENUM is represented elsewhere with a _NONE value, so it
135    # never needs to be wrapped in pointer shenanigans.
136    # TODO(kalman): change this - but it's an exceedingly far-reaching change.
137    if not self.FollowRef(type_).property_type == PropertyType.ENUM:
138      if is_in_container and (is_ptr or not self.IsCopyable(type_)):
139        cpp_type = 'linked_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
140      elif is_ptr:
141        cpp_type = 'scoped_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
142
143    return cpp_type
144
145  def IsCopyable(self, type_):
146    return not (self.FollowRef(type_).property_type in (PropertyType.ANY,
147                                                        PropertyType.ARRAY,
148                                                        PropertyType.OBJECT,
149                                                        PropertyType.CHOICES))
150
151  def GenerateForwardDeclarations(self):
152    """Returns the forward declarations for self._default_namespace.
153    """
154    c = Code()
155
156    for namespace, dependencies in self._NamespaceTypeDependencies().items():
157      c.Append('namespace %s {' % namespace.unix_name)
158      for dependency in dependencies:
159        # No point forward-declaring hard dependencies.
160        if dependency.hard:
161          continue
162        # Add more ways to forward declare things as necessary.
163        if dependency.type_.property_type in (PropertyType.CHOICES,
164                                              PropertyType.OBJECT):
165          c.Append('struct %s;' % dependency.type_.name)
166      c.Append('}')
167
168    return c
169
170  def GenerateIncludes(self, include_soft=False):
171    """Returns the #include lines for self._default_namespace.
172    """
173    c = Code()
174    for namespace, dependencies in self._NamespaceTypeDependencies().items():
175      for dependency in dependencies:
176        if dependency.hard or include_soft:
177          c.Append('#include "%s/%s.h"' % (namespace.source_file_dir,
178                                           namespace.unix_name))
179    return c
180
181  def _FindType(self, full_name):
182    """Finds the model.Type with name |qualified_name|. If it's not from
183    |self._default_namespace| then it needs to be qualified.
184    """
185    namespace = self._schema_loader.ResolveType(full_name,
186                                                self._default_namespace)
187    if namespace is None:
188      raise KeyError('Cannot resolve type %s. Maybe it needs a prefix '
189                     'if it comes from another namespace?' % full_name)
190    return namespace.types[schema_util.StripNamespace(full_name)]
191
192  def FollowRef(self, type_):
193    """Follows $ref link of types to resolve the concrete type a ref refers to.
194
195    If the property passed in is not of type PropertyType.REF, it will be
196    returned unchanged.
197    """
198    if type_.property_type != PropertyType.REF:
199      return type_
200    return self.FollowRef(self._FindType(type_.ref_type))
201
202  def _NamespaceTypeDependencies(self):
203    """Returns a dict ordered by namespace name containing a mapping of
204    model.Namespace to every _TypeDependency for |self._default_namespace|,
205    sorted by the type's name.
206    """
207    dependencies = set()
208    for function in self._default_namespace.functions.values():
209      for param in function.params:
210        dependencies |= self._TypeDependencies(param.type_,
211                                               hard=not param.optional)
212      if function.callback:
213        for param in function.callback.params:
214          dependencies |= self._TypeDependencies(param.type_,
215                                                 hard=not param.optional)
216    for type_ in self._default_namespace.types.values():
217      for prop in type_.properties.values():
218        dependencies |= self._TypeDependencies(prop.type_,
219                                               hard=not prop.optional)
220    for event in self._default_namespace.events.values():
221      for param in event.params:
222        dependencies |= self._TypeDependencies(param.type_,
223                                               hard=not param.optional)
224
225    # Make sure that the dependencies are returned in alphabetical order.
226    dependency_namespaces = OrderedDict()
227    for dependency in sorted(dependencies, key=_TypeDependency.GetSortKey):
228      namespace = dependency.type_.namespace
229      if namespace is self._default_namespace:
230        continue
231      if namespace not in dependency_namespaces:
232        dependency_namespaces[namespace] = []
233      dependency_namespaces[namespace].append(dependency)
234
235    return dependency_namespaces
236
237  def _TypeDependencies(self, type_, hard=False):
238    """Gets all the type dependencies of a property.
239    """
240    deps = set()
241    if type_.property_type == PropertyType.REF:
242      deps.add(_TypeDependency(self._FindType(type_.ref_type), hard=hard))
243    elif type_.property_type == PropertyType.ARRAY:
244      # Non-copyable types are not hard because they are wrapped in linked_ptrs
245      # when generated. Otherwise they're typedefs, so they're hard (though we
246      # could generate those typedefs in every dependent namespace, but that
247      # seems weird).
248      deps = self._TypeDependencies(type_.item_type,
249                                    hard=self.IsCopyable(type_.item_type))
250    elif type_.property_type == PropertyType.CHOICES:
251      for type_ in type_.choices:
252        deps |= self._TypeDependencies(type_, hard=self.IsCopyable(type_))
253    elif type_.property_type == PropertyType.OBJECT:
254      for p in type_.properties.values():
255        deps |= self._TypeDependencies(p.type_, hard=not p.optional)
256    return deps
257
258  def GeneratePropertyValues(self, property, line, nodoc=False):
259    """Generates the Code to display all value-containing properties.
260    """
261    c = Code()
262    if not nodoc:
263      c.Comment(property.description)
264
265    if property.value is not None:
266      c.Append(line % {
267          "type": self.GetCppType(property.type_),
268          "name": property.name,
269          "value": property.value
270        })
271    else:
272      has_child_code = False
273      c.Sblock('namespace %s {' % property.name)
274      for child_property in property.type_.properties.values():
275        child_code = self.GeneratePropertyValues(child_property,
276                                                 line,
277                                                 nodoc=nodoc)
278        if child_code:
279          has_child_code = True
280          c.Concat(child_code)
281      c.Eblock('}  // namespace %s' % property.name)
282      if not has_child_code:
283        c = None
284    return c
285