path: root/src/google/protobuf/implicit_weak_message.h

// Protocol Buffers - Google's data interchange format
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// https://developers.google.com/protocol-buffers/
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#ifndef GOOGLE_PROTOBUF_IMPLICIT_WEAK_MESSAGE_H__
#define GOOGLE_PROTOBUF_IMPLICIT_WEAK_MESSAGE_H__

#include <string>
#include <google/protobuf/io/coded_stream.h>
#include <google/protobuf/arena.h>
#include <google/protobuf/message_lite.h>

#include <google/protobuf/port_def.inc>

#ifdef SWIG
#error "You cannot SWIG proto headers"
#endif

// This file is logically internal-only and should only be used by protobuf
// generated code.

namespace google {
namespace protobuf {
namespace internal {

// An implementation of MessageLite that treats all data as unknown. This type
// acts as a placeholder for an implicit weak field in the case where the true
// message type does not get linked into the binary.
class PROTOBUF_EXPORT ImplicitWeakMessage : public MessageLite {
 public:
  ImplicitWeakMessage() : arena_(NULL) {}
  explicit ImplicitWeakMessage(Arena* arena) : arena_(arena) {}

  static const ImplicitWeakMessage* default_instance();

  std::string GetTypeName() const override { return ""; }

  MessageLite* New() const override { return new ImplicitWeakMessage; }
  MessageLite* New(Arena* arena) const override {
    return Arena::CreateMessage<ImplicitWeakMessage>(arena);
  }

  Arena* GetArena() const override { return arena_; }

  void Clear() override { data_.clear(); }

  bool IsInitialized() const override { return true; }

  void CheckTypeAndMergeFrom(const MessageLite& other) override {
    data_.append(static_cast<const ImplicitWeakMessage&>(other).data_);
  }

  bool MergePartialFromCodedStream(io::CodedInputStream* input) override;

#if GOOGLE_PROTOBUF_ENABLE_EXPERIMENTAL_PARSER
  ParseFunc _ParseFunc() const override { return _InternalParse; }

  static const char* _InternalParse(const char* begin, const char* end,
                                    void* object, ParseContext* ctx);
#endif

  size_t ByteSizeLong() const override { return data_.size(); }

  void SerializeWithCachedSizes(io::CodedOutputStream* output) const override {
    output->WriteString(data_);
  }

  int GetCachedSize() const override { return static_cast<int>(data_.size()); }

  typedef void InternalArenaConstructable_;

 private:
  Arena* const arena_;
  std::string data_;
  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ImplicitWeakMessage);
};

// A type handler for use with implicit weak repeated message fields.
template <typename ImplicitWeakType>
class ImplicitWeakTypeHandler {
 public:
  typedef ImplicitWeakType Type;
  typedef MessageLite WeakType;
  static const bool Moveable = false;

  // With implicit weak fields, we need separate NewFromPrototype and
  // NewFromPrototypeWeak functions. The former is used when we want to create a
  // strong dependency on the message type, and it just delegates to the
  // GenericTypeHandler. The latter avoids creating a strong dependency, by
  // simply calling MessageLite::New.
  static inline MessageLite* NewFromPrototype(const MessageLite* prototype,
                                              Arena* arena = NULL) {
    return prototype->New(arena);
  }

  static inline void Delete(MessageLite* value, Arena* arena) {
    if (arena == NULL) {
      delete value;
    }
  }
  static inline Arena* GetArena(MessageLite* value) {
    return value->GetArena();
  }
  static inline void* GetMaybeArenaPointer(MessageLite* value) {
    return value->GetArena();
  }
  static inline void Clear(MessageLite* value) { value->Clear(); }
  static void Merge(const MessageLite& from, MessageLite* to) {
    to->CheckTypeAndMergeFrom(from);
  }
  static inline size_t SpaceUsedLong(const Type& value) {
    return value.SpaceUsedLong();
  }
};

}  // namespace internal
}  // namespace protobuf
}  // namespace google

#include <google/protobuf/port_undef.inc>

#endif  // GOOGLE_PROTOBUF_IMPLICIT_WEAK_MESSAGE_H__