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1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc.  All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 //     * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 //     * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 //     * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 
31 #ifndef GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_FACTORY_H__
32 #define GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_FACTORY_H__
33 
34 #include <Python.h>
35 
36 #include <unordered_map>
37 #include <google/protobuf/descriptor.h>
38 #include <google/protobuf/pyext/descriptor_pool.h>
39 
40 namespace google {
41 namespace protobuf {
42 class MessageFactory;
43 
44 namespace python {
45 
46 // The (meta) type of all Messages classes.
47 struct CMessageClass;
48 
49 struct PyMessageFactory {
50   PyObject_HEAD
51 
52   // DynamicMessageFactory used to create C++ instances of messages.
53   // This object cache the descriptors that were used, so the DescriptorPool
54   // needs to get rid of it before it can delete itself.
55   //
56   // Note: A C++ MessageFactory is different from the PyMessageFactory.
57   // The C++ one creates messages, when the Python one creates classes.
58   MessageFactory* message_factory;
59 
60   // Owned reference to a Python DescriptorPool.
61   // This reference must stay until the message_factory is destructed.
62   PyDescriptorPool* pool;
63 
64   // Make our own mapping to retrieve Python classes from C++ descriptors.
65   //
66   // Descriptor pointers stored here are owned by the DescriptorPool above.
67   // Python references to classes are owned by this PyDescriptorPool.
68   typedef std::unordered_map<const Descriptor*, CMessageClass*>
69       ClassesByMessageMap;
70   ClassesByMessageMap* classes_by_descriptor;
71 };
72 
73 extern PyTypeObject PyMessageFactory_Type;
74 
75 namespace message_factory {
76 
77 // Creates a new MessageFactory instance.
78 PyMessageFactory* NewMessageFactory(PyTypeObject* type, PyDescriptorPool* pool);
79 
80 // Registers a new Python class for the given message descriptor.
81 // On error, returns -1 with a Python exception set.
82 int RegisterMessageClass(PyMessageFactory* self,
83                          const Descriptor* message_descriptor,
84                          CMessageClass* message_class);
85 // Retrieves the Python class registered with the given message descriptor, or
86 // fail with a TypeError. Returns a *borrowed* reference.
87 CMessageClass* GetMessageClass(PyMessageFactory* self,
88                                const Descriptor* message_descriptor);
89 // Retrieves the Python class registered with the given message descriptor.
90 // The class is created if not done yet. Returns a *new* reference.
91 CMessageClass* GetOrCreateMessageClass(PyMessageFactory* self,
92                                        const Descriptor* message_descriptor);
93 }  // namespace message_factory
94 
95 // Initialize objects used by this module.
96 // On error, returns false with a Python exception set.
97 bool InitMessageFactory();
98 
99 }  // namespace python
100 }  // namespace protobuf
101 }  // namespace google
102 
103 #endif  // GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_FACTORY_H__
104