protobuf/python/google/protobuf/pyext/message.h

// Protocol Buffers - Google's data interchange format
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// 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 <google/protobuf/stubs/common.h>
#include <google/protobuf/pyext/thread_unsafe_shared_ptr.h>

namespace google {
namespace protobuf {

class Message;
class Reflection;
class FieldDescriptor;
class Descriptor;
class DescriptorPool;
class MessageFactory;

namespace python {

struct ExtensionDict;
struct PyMessageFactory;

typedef struct CMessage {
  PyObject_HEAD;

  // This is the top-level C++ Message object that owns the whole
  // proto tree.  Every Python CMessage holds a reference to it in
  // order to keep it alive as long as there's a Python object that
  // references any part of the tree.

  typedef ThreadUnsafeSharedPtr<Message> OwnerRef;
  OwnerRef owner;

  // Weak reference to a parent CMessage object. This is NULL for any top-level
  // message and is set for any child message (i.e. a child submessage or a
  // part of a repeated composite field).
  //
  // Used to make sure all ancestors are also mutable when first modifying
  // a child submessage (in other words, turning a default message instance
  // into a mutable one).
  //
  // If a submessage is released (becomes a new top-level message), this field
  // MUST be set to NULL. The parent may get deallocated and further attempts
  // to use this pointer will result in a crash.
  struct CMessage* parent;

  // Pointer to the parent's descriptor that describes this submessage.
  // Used together with the parent's message when making a default message
  // instance mutable.
  // The pointer is owned by the global DescriptorPool.
  const FieldDescriptor* parent_field_descriptor;

  // Pointer to the C++ Message object for this CMessage.  The
  // CMessage does not own 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 reference to a Python dictionary containing CMessage,
  // RepeatedCompositeContainer, and RepeatedScalarContainer
  // objects. Used as a cache to make sure we don't have to make a
  // Python wrapper for the C++ Message objects on every access, or
  // deal with the synchronization nightmare that could create.
  PyObject* composite_fields;

  // A reference to the dictionary containing the message's extensions.
  // Similar to composite_fields, acting as a cache, but also contains the
  // required extension dict logic.
  ExtensionDict* extensions;

  // Implements the "weakref" protocol for this object.
  PyObject* weakreflist;
} CMessage;

extern PyTypeObject CMessageClass_Type;
extern PyTypeObject CMessage_Type;


// 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.
  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.
  // We own the reference, because it's important to keep the factory alive.
  PyMessageFactory* py_message_factory;

  PyObject* AsPyObject() {
    return reinterpret_cast<PyObject*>(this);
  }
};


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.
PyObject* InternalGetSubMessage(
    CMessage* self, const FieldDescriptor* field_descriptor);

// Deletes a range of C++ submessages in a repeated field (following a
// removal in a RepeatedCompositeContainer).
//
// Releases messages to the provided cmessage_list if it is not NULL rather
// than just removing them from the underlying proto. This cmessage_list must
// have a CMessage for each underlying submessage. The CMessages referred to
// by slice will be removed from cmessage_list by this function.
//
// Corresponds to reflection api method RemoveLast.
int InternalDeleteRepeatedField(CMessage* self,
                                const FieldDescriptor* field_descriptor,
                                PyObject* slice, PyObject* cmessage_list);

// 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);

// 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);

// Retrieves an attribute named 'name' from 'self', which is interpreted as a
// CMessage. Returns the attribute value on success, or null on failure.
//
// Returns a new reference.
PyObject* GetAttr(PyObject* self, PyObject* name);

// Set the value of the attribute named 'name', for 'self', which is interpreted
// as a CMessage, to the value 'value'. Returns -1 on failure.
int SetAttr(PyObject* self, PyObject* name, PyObject* value);

PyObject* FindInitializationErrors(CMessage* self);

// Set the owner field of self and any children of self, recursively.
// Used when self is being released and thus has a new owner (the
// released Message.)
int SetOwner(CMessage* self, const CMessage::OwnerRef& new_owner);

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);

bool InitProto2MessageModule(PyObject *m);

#if LANG_CXX11
// 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*);
#endif

}  // namespace python
}  // namespace protobuf

}  // namespace google
#endif  // GOOGLE_PROTOBUF_PYTHON_CPP_MESSAGE_H__