python/google/protobuf/pyext/message.h

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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
// Author: anuraag@google.com (Anuraag Agrawal)
// Author: tibell@google.com (Johan Tibell)
 
#ifndef GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_H__
#define GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_H__
 
#include <Python.h>
 
#include <memory>
#include <string>
#include <unordered_map>
 
#include <google/protobuf/stubs/common.h>
 
namespace google {
namespace protobuf {
 
class Message;
class Reflection;
class FieldDescriptor;
class Descriptor;
class DescriptorPool;
class MessageFactory;
 
namespace python {
 
struct ExtensionDict;
struct PyMessageFactory;
struct CMessageClass;
 
// Most of the complexity of the Message class comes from the "Release"
// behavior:
//
// When a field is cleared, it is only detached from its message. Existing
// references to submessages, to repeated container etc. won't see any change,
// as if the data was effectively managed by these containers.
//
// ExtensionDicts and UnknownFields containers do NOT follow this rule. They
// don't store any data, and always refer to their parent message.
 
struct ContainerBase {
  PyObject_HEAD;
 
  // Strong reference to a parent message object. For a CMessage there are three
  // cases:
  // - For a top-level message, this pointer is NULL.
  // - For a sub-message, this points to the parent message.
  // - For a message managed externally, this is a owned reference to Py_None.
  //
  // For all other types: repeated containers, maps, it always point to a
  // valid parent CMessage.
  struct CMessage* parent;
 
  // If this object belongs to a parent message, describes which field it comes
  // from.
  // The pointer is owned by the DescriptorPool (which is kept alive
  // through the message's Python class)
  const FieldDescriptor* parent_field_descriptor;
 
  PyObject* AsPyObject() { return reinterpret_cast<PyObject*>(this); }
 
  // The Three methods below are only used by Repeated containers, and Maps.
 
  // This implementation works for all containers which have a parent.
  PyObject* DeepCopy();
  // Delete this container object from its parent. Does not work for messages.
  void RemoveFromParentCache();
};
 
typedef struct CMessage : public ContainerBase {
  // Pointer to the C++ Message object for this CMessage.
  // - If this object has no parent, we own this pointer.
  // - If this object has a parent message, the parent owns this pointer.
  Message* message;
 
  // Indicates this submessage is pointing to a default instance of a message.
  // Submessages are always first created as read only messages and are then
  // made writable, at which point this field is set to false.
  bool read_only;
 
  // A mapping indexed by field, containing weak references to contained objects
  // which need to implement the "Release" mechanism:
  // direct submessages, RepeatedCompositeContainer, RepeatedScalarContainer
  // and MapContainer.
  typedef std::unordered_map<const FieldDescriptor*, ContainerBase*>
      CompositeFieldsMap;
  CompositeFieldsMap* composite_fields;
 
  // A mapping containing weak references to indirect child messages, accessed
  // through containers: repeated messages, and values of message maps.
  // This avoid the creation of similar maps in each of those containers.
  typedef std::unordered_map<const Message*, CMessage*> SubMessagesMap;
  SubMessagesMap* child_submessages;
 
  // A reference to PyUnknownFields.
  PyObject* unknown_field_set;
 
  // Implements the "weakref" protocol for this object.
  PyObject* weakreflist;
 
  // Return a *borrowed* reference to the message class.
  CMessageClass* GetMessageClass() {
    return reinterpret_cast<CMessageClass*>(Py_TYPE(this));
  }
 
  // For container containing messages, return a Python object for the given
  // pointer to a message.
  CMessage* BuildSubMessageFromPointer(const FieldDescriptor* field_descriptor,
                                       Message* sub_message,
                                       CMessageClass* message_class);
  CMessage* MaybeReleaseSubMessage(Message* sub_message);
} CMessage;
 
// The (meta) type of all Messages classes.
// It allows us to cache some C++ pointers in the class object itself, they are
// faster to extract than from the type's dictionary.
 
struct CMessageClass {
  // This is how CPython subclasses C structures: the base structure must be
  // the first member of the object.
  PyHeapTypeObject super;
 
  // C++ descriptor of this message.
  const Descriptor* message_descriptor;
 
  // Owned reference, used to keep the pointer above alive.
  // This reference must stay alive until all message pointers are destructed.
  PyObject* py_message_descriptor;
 
  // The Python MessageFactory used to create the class. It is needed to resolve
  // fields descriptors, including extensions fields; its C++ MessageFactory is
  // used to instantiate submessages.
  // This reference must stay alive until all message pointers are destructed.
  PyMessageFactory* py_message_factory;
 
  PyObject* AsPyObject() {
    return reinterpret_cast<PyObject*>(this);
  }
};
 
extern PyTypeObject* CMessageClass_Type;
extern PyTypeObject* CMessage_Type;
 
namespace cmessage {
 
// Internal function to create a new empty Message Python object, but with empty
// pointers to the C++ objects.
// The caller must fill self->message, self->owner and eventually self->parent.
CMessage* NewEmptyMessage(CMessageClass* type);
 
// Retrieves the C++ descriptor of a Python Extension descriptor.
// On error, return NULL with an exception set.
const FieldDescriptor* GetExtensionDescriptor(PyObject* extension);
 
// Initializes a new CMessage instance for a submessage. Only called once per
// submessage as the result is cached in composite_fields.
//
// Corresponds to reflection api method GetMessage.
CMessage* InternalGetSubMessage(
    CMessage* self, const FieldDescriptor* field_descriptor);
 
// Deletes a range of items in a repeated field (following a
// removal in a RepeatedCompositeContainer).
//
// Corresponds to reflection api method RemoveLast.
int DeleteRepeatedField(CMessage* self,
                        const FieldDescriptor* field_descriptor,
                        PyObject* slice);
 
// Sets the specified scalar value to the message.
int InternalSetScalar(CMessage* self,
                      const FieldDescriptor* field_descriptor,
                      PyObject* value);
 
// Sets the specified scalar value to the message.  Requires it is not a Oneof.
int InternalSetNonOneofScalar(Message* message,
                              const FieldDescriptor* field_descriptor,
                              PyObject* arg);
 
// Retrieves the specified scalar value from the message.
//
// Returns a new python reference.
PyObject* InternalGetScalar(const Message* message,
                            const FieldDescriptor* field_descriptor);
 
bool SetCompositeField(CMessage* self, const FieldDescriptor* field,
                       ContainerBase* value);
 
bool SetSubmessage(CMessage* self, CMessage* submessage);
 
// Clears the message, removing all contained data. Extension dictionary and
// submessages are released first if there are remaining external references.
//
// Corresponds to message api method Clear.
PyObject* Clear(CMessage* self);
 
// Clears the data described by the given descriptor. Used to clear extensions
// (which don't have names). Extension release is handled by ExtensionDict
// class, not this function.
// TODO(anuraag): Try to make this discrepancy in release semantics with
//                ClearField less confusing.
//
// Corresponds to reflection api method ClearField.
PyObject* ClearFieldByDescriptor(
    CMessage* self, const FieldDescriptor* descriptor);
 
// Clears the data for the given field name. The message is released if there
// are any external references.
//
// Corresponds to reflection api method ClearField.
PyObject* ClearField(CMessage* self, PyObject* arg);
 
// Checks if the message has the field described by the descriptor. Used for
// extensions (which have no name).
//
// Corresponds to reflection api method HasField
PyObject* HasFieldByDescriptor(
    CMessage* self, const FieldDescriptor* field_descriptor);
 
// Checks if the message has the named field.
//
// Corresponds to reflection api method HasField.
PyObject* HasField(CMessage* self, PyObject* arg);
 
// Initializes values of fields on a newly constructed message.
// Note that positional arguments are disallowed: 'args' must be NULL or the
// empty tuple.
int InitAttributes(CMessage* self, PyObject* args, PyObject* kwargs);
 
PyObject* MergeFrom(CMessage* self, PyObject* arg);
 
// This method does not do anything beyond checking that no other extension
// has been registered with the same field number on this class.
PyObject* RegisterExtension(PyObject* cls, PyObject* extension_handle);
 
// Get a field from a message.
PyObject* GetFieldValue(CMessage* self,
                        const FieldDescriptor* field_descriptor);
// Sets the value of a scalar field in a message.
// On error, return -1 with an extension set.
int SetFieldValue(CMessage* self, const FieldDescriptor* field_descriptor,
                  PyObject* value);
 
PyObject* FindInitializationErrors(CMessage* self);
 
int AssureWritable(CMessage* self);
 
// Returns the message factory for the given message.
// This is equivalent to message.MESSAGE_FACTORY
//
// The returned factory is suitable for finding fields and building submessages,
// even in the case of extensions.
// Returns a *borrowed* reference, and never fails because we pass a CMessage.
PyMessageFactory* GetFactoryForMessage(CMessage* message);
 
PyObject* SetAllowOversizeProtos(PyObject* m, PyObject* arg);
 
}  // namespace cmessage
 
 
/* Is 64bit */
#define IS_64BIT (SIZEOF_LONG == 8)
 
#define FIELD_IS_REPEATED(field_descriptor)                 \
    ((field_descriptor)->label() == FieldDescriptor::LABEL_REPEATED)
 
#define GOOGLE_CHECK_GET_INT32(arg, value, err)                        \
    int32 value;                                            \
    if (!CheckAndGetInteger(arg, &value)) { \
      return err;                                          \
    }
 
#define GOOGLE_CHECK_GET_INT64(arg, value, err)                        \
    int64 value;                                            \
    if (!CheckAndGetInteger(arg, &value)) { \
      return err;                                          \
    }
 
#define GOOGLE_CHECK_GET_UINT32(arg, value, err)                       \
    uint32 value;                                           \
    if (!CheckAndGetInteger(arg, &value)) { \
      return err;                                          \
    }
 
#define GOOGLE_CHECK_GET_UINT64(arg, value, err)                       \
    uint64 value;                                           \
    if (!CheckAndGetInteger(arg, &value)) { \
      return err;                                          \
    }
 
#define GOOGLE_CHECK_GET_FLOAT(arg, value, err)                        \
    float value;                                            \
    if (!CheckAndGetFloat(arg, &value)) {                   \
      return err;                                          \
    }                                                       \
 
#define GOOGLE_CHECK_GET_DOUBLE(arg, value, err)                       \
    double value;                                           \
    if (!CheckAndGetDouble(arg, &value)) {                  \
      return err;                                          \
    }
 
#define GOOGLE_CHECK_GET_BOOL(arg, value, err)                         \
    bool value;                                             \
    if (!CheckAndGetBool(arg, &value)) {                    \
      return err;                                          \
    }
 
 
#define FULL_MODULE_NAME "google.protobuf.pyext._message"
 
void FormatTypeError(PyObject* arg, char* expected_types);
template<class T>
bool CheckAndGetInteger(PyObject* arg, T* value);
bool CheckAndGetDouble(PyObject* arg, double* value);
bool CheckAndGetFloat(PyObject* arg, float* value);
bool CheckAndGetBool(PyObject* arg, bool* value);
PyObject* CheckString(PyObject* arg, const FieldDescriptor* descriptor);
bool CheckAndSetString(
    PyObject* arg, Message* message,
    const FieldDescriptor* descriptor,
    const Reflection* reflection,
    bool append,
    int index);
PyObject* ToStringObject(const FieldDescriptor* descriptor,
                         const string& value);
 
// Check if the passed field descriptor belongs to the given message.
// If not, return false and set a Python exception (a KeyError)
bool CheckFieldBelongsToMessage(const FieldDescriptor* field_descriptor,
                                const Message* message);
 
extern PyObject* PickleError_class;
 
const Message* PyMessage_GetMessagePointer(PyObject* msg);
Message* PyMessage_GetMutableMessagePointer(PyObject* msg);
PyObject* PyMessage_NewMessageOwnedExternally(Message* message,
                                              PyObject* message_factory);
 
bool InitProto2MessageModule(PyObject *m);
 
// These are referenced by repeated_scalar_container, and must
// be explicitly instantiated.
extern template bool CheckAndGetInteger<int32>(PyObject*, int32*);
extern template bool CheckAndGetInteger<int64>(PyObject*, int64*);
extern template bool CheckAndGetInteger<uint32>(PyObject*, uint32*);
extern template bool CheckAndGetInteger<uint64>(PyObject*, uint64*);
 
}  // namespace python
}  // namespace protobuf
}  // namespace google
 
#endif  // GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_H__