// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
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#ifndef GOOGLE_PROTOBUF_PYTHON_CPP_DESCRIPTOR_POOL_H__
#define GOOGLE_PROTOBUF_PYTHON_CPP_DESCRIPTOR_POOL_H__
#include <Python.h>
#include <google/protobuf/stubs/hash.h>
#include <google/protobuf/descriptor.h>
namespace google {
namespace protobuf {
class MessageFactory;
namespace python {
// Wraps operations to the global DescriptorPool which contains information
// about all messages and fields.
//
// There is normally one pool per process. We make it a Python object only
// because it contains many Python references.
// TODO(amauryfa): See whether such objects can appear in reference cycles, and
// consider adding support for the cyclic GC.
//
// "Methods" that interacts with this DescriptorPool are in the cdescriptor_pool
// namespace.
typedef struct PyDescriptorPool {
PyObject_HEAD
DescriptorPool* pool;
// DynamicMessageFactory used to create C++ instances of messages.
// This object cache the descriptors that were used, so the DescriptorPool
// needs to get rid of it before it can delete itself.
//
// Note: A C++ MessageFactory is different from the Python MessageFactory.
// The C++ one creates messages, when the Python one creates classes.
MessageFactory* message_factory;
// Make our own mapping to retrieve Python classes from C++ descriptors.
//
// Descriptor pointers stored here are owned by the DescriptorPool above.
// Python references to classes are owned by this PyDescriptorPool.
typedef hash_map<const Descriptor*, PyObject*> ClassesByMessageMap;
ClassesByMessageMap* classes_by_descriptor;
// Store interned descriptors, so that the same C++ descriptor yields the same
// Python object. Objects are not immortal: this map does not own the
// references, and items are deleted when the last reference to the object is
// released.
// This is enough to support the "is" operator on live objects.
// All descriptors are stored here.
hash_map<const void*, PyObject*>* interned_descriptors;
// Cache the options for any kind of descriptor.
// Descriptor pointers are owned by the DescriptorPool above.
// Python objects are owned by the map.
hash_map<const void*, PyObject*>* descriptor_options;
} PyDescriptorPool;
extern PyTypeObject PyDescriptorPool_Type;
namespace cdescriptor_pool {
// Builds a new DescriptorPool. Normally called only once per process.
PyDescriptorPool* NewDescriptorPool();
// Looks up a message by name.
// Returns a message Descriptor, or NULL if not found.
const Descriptor* FindMessageTypeByName(PyDescriptorPool* self,
const string& name);
// Registers a new Python class for the given message descriptor.
// Returns the message Descriptor.
// On error, returns NULL with a Python exception set.
const Descriptor* RegisterMessageClass(
PyDescriptorPool* self, PyObject* message_class, PyObject* descriptor);
// The function below are also exposed as methods of the DescriptorPool type.
// Retrieves the Python class registered with the given message descriptor.
//
// Returns a *borrowed* reference if found, otherwise returns NULL with an
// exception set.
PyObject* GetMessageClass(PyDescriptorPool* self,
const Descriptor* message_descriptor);
// Looks up a message by name. Returns a PyMessageDescriptor corresponding to
// the field on success, or NULL on failure.
//
// Returns a new reference.
PyObject* FindMessageByName(PyDescriptorPool* self, PyObject* name);
// Looks up a field by name. Returns a PyFieldDescriptor corresponding to
// the field on success, or NULL on failure.
//
// Returns a new reference.
PyObject* FindFieldByName(PyDescriptorPool* self, PyObject* name);
// Looks up an extension by name. Returns a PyFieldDescriptor corresponding
// to the field on success, or NULL on failure.
//
// Returns a new reference.
PyObject* FindExtensionByName(PyDescriptorPool* self, PyObject* arg);
// Looks up an enum type by name. Returns a PyEnumDescriptor corresponding
// to the field on success, or NULL on failure.
//
// Returns a new reference.
PyObject* FindEnumTypeByName(PyDescriptorPool* self, PyObject* arg);
// Looks up a oneof by name. Returns a COneofDescriptor corresponding
// to the oneof on success, or NULL on failure.
//
// Returns a new reference.
PyObject* FindOneofByName(PyDescriptorPool* self, PyObject* arg);
} // namespace cdescriptor_pool
// Retrieve the global descriptor pool owned by the _message module.
// Returns a *borrowed* reference.
PyDescriptorPool* GetDescriptorPool();
// Initialize objects used by this module.
bool InitDescriptorPool();
} // namespace python
} // namespace protobuf
} // namespace google
#endif // GOOGLE_PROTOBUF_PYTHON_CPP_DESCRIPTOR_POOL_H__
