cpp_type_generator.py revision b2df76ea8fec9e32f6f3718986dba0d95315b29c 
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    value = '%s_%s' % (self.FollowRef(type_).unix_name.upper(),
68                       cpp_util.Classname(enum_value.upper()))
69    # To avoid collisions with built-in OS_* preprocessor definitions, we add a
70    # trailing slash to enum names that start with OS_.
71    if value.startswith("OS_"):
72      value += "_"
73    return value
74
75  def GetCppType(self, type_, is_ptr=False, is_in_container=False):
76    """Translates a model.Property or model.Type into its C++ type.
77
78    If REF types from different namespaces are referenced, will resolve
79    using self._schema_loader.
80
81    Use |is_ptr| if the type is optional. This will wrap the type in a
82    scoped_ptr if possible (it is not possible to wrap an enum).
83
84    Use |is_in_container| if the type is appearing in a collection, e.g. a
85    std::vector or std::map. This will wrap it in the correct type with spacing.
86    """
87    cpp_type = None
88    if type_.property_type == PropertyType.REF:
89      ref_type = self._FindType(type_.ref_type)
90      if ref_type is None:
91        raise KeyError('Cannot find referenced type: %s' % type_.ref_type)
92      if self._default_namespace is ref_type.namespace:
93        cpp_type = ref_type.name
94      else:
95        cpp_type = '%s::%s' % (ref_type.namespace.unix_name, ref_type.name)
96    elif type_.property_type == PropertyType.BOOLEAN:
97      cpp_type = 'bool'
98    elif type_.property_type == PropertyType.INTEGER:
99      cpp_type = 'int'
100    elif type_.property_type == PropertyType.INT64:
101      cpp_type = 'int64'
102    elif type_.property_type == PropertyType.DOUBLE:
103      cpp_type = 'double'
104    elif type_.property_type == PropertyType.STRING:
105      cpp_type = 'std::string'
106    elif type_.property_type == PropertyType.ENUM:
107      cpp_type = cpp_util.Classname(type_.name)
108    elif type_.property_type == PropertyType.ANY:
109      cpp_type = 'base::Value'
110    elif (type_.property_type == PropertyType.OBJECT or
111          type_.property_type == PropertyType.CHOICES):
112      cpp_type = cpp_util.Classname(type_.name)
113    elif type_.property_type == PropertyType.FUNCTION:
114      # Functions come into the json schema compiler as empty objects. We can
115      # record these as empty DictionaryValues so that we know if the function
116      # was passed in or not.
117      cpp_type = 'base::DictionaryValue'
118    elif type_.property_type == PropertyType.ARRAY:
119      item_cpp_type = self.GetCppType(type_.item_type, is_in_container=True)
120      cpp_type = 'std::vector<%s>' % cpp_util.PadForGenerics(item_cpp_type)
121    elif type_.property_type == PropertyType.BINARY:
122      cpp_type = 'std::string'
123    else:
124      raise NotImplementedError('Cannot get type of %s' % type_.property_type)
125
126    # HACK: optional ENUM is represented elsewhere with a _NONE value, so it
127    # never needs to be wrapped in pointer shenanigans.
128    # TODO(kalman): change this - but it's an exceedingly far-reaching change.
129    if not self.FollowRef(type_).property_type == PropertyType.ENUM:
130      if is_in_container and (is_ptr or not self.IsCopyable(type_)):
131        cpp_type = 'linked_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
132      elif is_ptr:
133        cpp_type = 'scoped_ptr<%s>' % cpp_util.PadForGenerics(cpp_type)
134
135    return cpp_type
136
137  def IsCopyable(self, type_):
138    return not (self.FollowRef(type_).property_type in (PropertyType.ANY,
139                                                        PropertyType.ARRAY,
140                                                        PropertyType.OBJECT,
141                                                        PropertyType.CHOICES))
142
143  def GenerateForwardDeclarations(self):
144    """Returns the forward declarations for self._default_namespace.
145    """
146    c = Code()
147
148    for namespace, dependencies in self._NamespaceTypeDependencies().items():
149      c.Append('namespace %s {' % namespace.unix_name)
150      for dependency in dependencies:
151        # No point forward-declaring hard dependencies.
152        if dependency.hard:
153          continue
154        # Add more ways to forward declare things as necessary.
155        if dependency.type_.property_type == PropertyType.OBJECT:
156          c.Append('struct %s;' % dependency.type_.name)
157      c.Append('}')
158
159    return c
160
161  def GenerateIncludes(self, include_soft=False):
162    """Returns the #include lines for self._default_namespace.
163    """
164    c = Code()
165    for namespace, dependencies in self._NamespaceTypeDependencies().items():
166      for dependency in dependencies:
167        if dependency.hard or include_soft:
168          c.Append('#include "%s/%s.h"' % (namespace.source_file_dir,
169                                           namespace.unix_name))
170    return c
171
172  def _FindType(self, full_name):
173    """Finds the model.Type with name |qualified_name|. If it's not from
174    |self._default_namespace| then it needs to be qualified.
175    """
176    namespace = self._schema_loader.ResolveType(full_name,
177                                                self._default_namespace)
178    if namespace is None:
179      raise KeyError('Cannot resolve type %s. Maybe it needs a prefix '
180                     'if it comes from another namespace?' % full_name)
181    return namespace.types[schema_util.StripNamespace(full_name)]
182
183  def FollowRef(self, type_):
184    """Follows $ref link of types to resolve the concrete type a ref refers to.
185
186    If the property passed in is not of type PropertyType.REF, it will be
187    returned unchanged.
188    """
189    if type_.property_type != PropertyType.REF:
190      return type_
191    return self.FollowRef(self._FindType(type_.ref_type))
192
193  def _NamespaceTypeDependencies(self):
194    """Returns a dict ordered by namespace name containing a mapping of
195    model.Namespace to every _TypeDependency for |self._default_namespace|,
196    sorted by the type's name.
197    """
198    dependencies = set()
199    for function in self._default_namespace.functions.values():
200      for param in function.params:
201        dependencies |= self._TypeDependencies(param.type_,
202                                               hard=not param.optional)
203      if function.callback:
204        for param in function.callback.params:
205          dependencies |= self._TypeDependencies(param.type_,
206                                                 hard=not param.optional)
207    for type_ in self._default_namespace.types.values():
208      for prop in type_.properties.values():
209        dependencies |= self._TypeDependencies(prop.type_,
210                                               hard=not prop.optional)
211    for event in self._default_namespace.events.values():
212      for param in event.params:
213        dependencies |= self._TypeDependencies(param.type_,
214                                               hard=not param.optional)
215
216    # Make sure that the dependencies are returned in alphabetical order.
217    dependency_namespaces = OrderedDict()
218    for dependency in sorted(dependencies, key=_TypeDependency.GetSortKey):
219      namespace = dependency.type_.namespace
220      if namespace is self._default_namespace:
221        continue
222      if namespace not in dependency_namespaces:
223        dependency_namespaces[namespace] = []
224      dependency_namespaces[namespace].append(dependency)
225
226    return dependency_namespaces
227
228  def _TypeDependencies(self, type_, hard=False):
229    """Gets all the type dependencies of a property.
230    """
231    deps = set()
232    if type_.property_type == PropertyType.REF:
233      deps.add(_TypeDependency(self._FindType(type_.ref_type), hard=hard))
234    elif type_.property_type == PropertyType.ARRAY:
235      # Non-copyable types are not hard because they are wrapped in linked_ptrs
236      # when generated. Otherwise they're typedefs, so they're hard (though we
237      # could generate those typedefs in every dependent namespace, but that
238      # seems weird).
239      deps = self._TypeDependencies(type_.item_type,
240                                    hard=self.IsCopyable(type_.item_type))
241    elif type_.property_type == PropertyType.CHOICES:
242      for type_ in type_.choices:
243        deps |= self._TypeDependencies(type_, hard=self.IsCopyable(type_))
244    elif type_.property_type == PropertyType.OBJECT:
245      for p in type_.properties.values():
246        deps |= self._TypeDependencies(p.type_, hard=not p.optional)
247    return deps
248
249  def GeneratePropertyValues(self, property, line, nodoc=False):
250    """Generates the Code to display all value-containing properties.
251    """
252    c = Code()
253    if not nodoc:
254      c.Comment(property.description)
255
256    if property.value is not None:
257      c.Append(line % {
258          "type": self.GetCppType(property.type_),
259          "name": property.name,
260          "value": property.value
261        })
262    else:
263      has_child_code = False
264      c.Sblock('namespace %s {' % property.name)
265      for child_property in property.type_.properties.values():
266        child_code = self.GeneratePropertyValues(child_property,
267                                                 line,
268                                                 nodoc=nodoc)
269        if child_code:
270          has_child_code = True
271          c.Concat(child_code)
272      c.Eblock('}  // namespace %s' % property.name)
273      if not has_child_code:
274        c = None
275    return c
276