text: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // 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.
  
  #ifndef GOOGLE_PROTOBUF_IMPLICIT_WEAK_MESSAGE_H__
  #define GOOGLE_PROTOBUF_IMPLICIT_WEAK_MESSAGE_H__
  
  #include <google/protobuf/io/coded_stream.h>
  #include <google/protobuf/arena.h>
  #include <google/protobuf/message_lite.h>
  
  // 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 LIBPROTOBUF_EXPORT ImplicitWeakMessage : public MessageLite {
   public:
    ImplicitWeakMessage() : arena_(NULL) {}
    explicit ImplicitWeakMessage(Arena* arena) : arena_(arena) {}
  
    string GetTypeName() const { return ""; }
  
    MessageLite* New() const { return new ImplicitWeakMessage; }
    MessageLite* New(Arena* arena) const {
      return Arena::CreateMessage<ImplicitWeakMessage>(arena);
    }
  
    Arena* GetArena() const { return arena_; }
  
    void Clear() { data_.clear(); }
  
    bool IsInitialized() const { return true; }
  
    void CheckTypeAndMergeFrom(const MessageLite& other) {
      data_.append(static_cast<const ImplicitWeakMessage&>(other).data_);
    }
  
    bool MergePartialFromCodedStream(io::CodedInputStream* input);
  
    size_t ByteSizeLong() const { return data_.size(); }
  
    void SerializeWithCachedSizes(io::CodedOutputStream* output) const {
      output->WriteString(data_);
    }
  
    int GetCachedSize() const { return static_cast<int>(data_.size()); }
  
    typedef void InternalArenaConstructable_;
  
   private:
    Arena* const arena_;
    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 ::google::protobuf::MessageLite WeakType;
  #if LANG_CXX11
    static const bool Moveable = false;
  #endif
  
    // 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 ::google::protobuf::MessageLite* NewFromPrototype(
        const ::google::protobuf::MessageLite* prototype, ::google::protobuf::Arena* arena = NULL) {
      return prototype->New(arena);
    }
  
    static inline void Delete(::google::protobuf::MessageLite* value, Arena* arena) {
      if (arena == NULL) {
        delete value;
      }
    }
    static inline ::google::protobuf::Arena* GetArena(::google::protobuf::MessageLite* value) {
      return value->GetArena();
    }
    static inline void* GetMaybeArenaPointer(::google::protobuf::MessageLite* value) {
      return value->GetArena();
    }
    static inline void Clear(::google::protobuf::MessageLite* value) {
      value->Clear();
    }
    static void Merge(const ::google::protobuf::MessageLite& from,
                      ::google::protobuf::MessageLite* to) {
      to->CheckTypeAndMergeFrom(from);
    }
    static inline size_t SpaceUsedLong(const Type& value) {
      return value.SpaceUsedLong();
    }
  };
  
  extern ::google::protobuf::internal::ExplicitlyConstructed<ImplicitWeakMessage>
      implicit_weak_message_default_instance;
  
  }  // namespace internal
  }  // namespace protobuf
  
  }  // namespace google
  #endif  // GOOGLE_PROTOBUF_IMPLICIT_WEAK_MESSAGE_H__
  