FM / protobuf

/usr/include/google/protobuf

Name	Size	Mode	Actions
io/	-	0755	rm
stubs/	-	0755	rm
util/	-	0755	rm
any.h	6181	0644	edit dl rm
any.pb.h	17726	0644	edit dl rm
any.proto	5878	0644	edit dl rm
api.pb.h	64196	0644	edit dl rm
api.proto	7734	0644	edit dl rm
arena.h	31329	0644	edit dl rm
arenastring.h	14674	0644	edit dl rm
arena_impl.h	14316	0644	edit dl rm
descriptor.h	96357	0644	edit dl rm
descriptor.pb.h	587894	0644	edit dl rm
descriptor.proto	37986	0644	edit dl rm
descriptor_database.h	19379	0644	edit dl rm
duration.pb.h	9865	0644	edit dl rm
duration.proto	4888	0644	edit dl rm
dynamic_message.h	9986	0644	edit dl rm
empty.pb.h	7683	0644	edit dl rm
empty.proto	2422	0644	edit dl rm
extension_set.h	78461	0644	edit dl rm
extension_set_inl.h	12756	0644	edit dl rm
field_mask.pb.h	11825	0644	edit dl rm
field_mask.proto	8192	0644	edit dl rm
generated_enum_reflection.h	3954	0644	edit dl rm
generated_enum_util.h	3266	0644	edit dl rm
generated_message_reflection.h	12880	0644	edit dl rm
generated_message_table_driven.h	12610	0644	edit dl rm
generated_message_util.h	9560	0644	edit dl rm
has_bits.h	3528	0644	edit dl rm
implicit_weak_message.h	7014	0644	edit dl rm
inlined_string_field.h	9332	0644	edit dl rm
map.h	46287	0644	edit dl rm
map_entry.h	7276	0644	edit dl rm
map_entry_lite.h	26016	0644	edit dl rm
map_field.h	31208	0644	edit dl rm
map_field_inl.h	14512	0644	edit dl rm
map_field_lite.h	7559	0644	edit dl rm
map_type_handler.h	39082	0644	edit dl rm
message.h	61613	0644	edit dl rm
message_lite.h	25964	0644	edit dl rm
metadata.h	1857	0644	edit dl rm
metadata_lite.h	8260	0644	edit dl rm
parse_context.h	29812	0644	edit dl rm
port.h	2050	0644	edit dl rm
port_def.inc	17039	0644	edit dl rm
port_undef.inc	3498	0644	edit dl rm
reflection.h	22717	0644	edit dl rm
reflection_ops.h	3686	0644	edit dl rm
repeated_field.h	101032	0644	edit dl rm
service.h	13159	0644	edit dl rm
source_context.pb.h	12740	0644	edit dl rm
source_context.proto	2352	0644	edit dl rm
struct.pb.h	43629	0644	edit dl rm
struct.proto	3780	0644	edit dl rm
text_format.h	28948	0644	edit dl rm
timestamp.pb.h	9928	0644	edit dl rm
timestamp.proto	6200	0644	edit dl rm
type.pb.h	105722	0644	edit dl rm
type.proto	6129	0644	edit dl rm
unknown_field_set.h	14401	0644	edit dl rm
wire_format.h	17660	0644	edit dl rm
wire_format_lite.h	84033	0644	edit dl rm
wrappers.pb.h	61421	0644	edit dl rm
wrappers.proto	4035	0644	edit dl rm

Edit: /usr/include/google/protobuf/extension_set.h (78461B)

// 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.

// Author: kenton@google.com (Kenton Varda)
//  Based on original Protocol Buffers design by
//  Sanjay Ghemawat, Jeff Dean, and others.
//
// This header is logically internal, but is made public because it is used
// from protocol-compiler-generated code, which may reside in other components.

#ifndef GOOGLE_PROTOBUF_EXTENSION_SET_H__
#define GOOGLE_PROTOBUF_EXTENSION_SET_H__

#include <algorithm>
#include <cassert>
#include <map>
#include <string>
#include <utility>
#include <vector>

#include <google/protobuf/stubs/common.h>
#include <google/protobuf/stubs/logging.h>
#include <google/protobuf/parse_context.h>
#include <google/protobuf/io/coded_stream.h>
#include <google/protobuf/port.h>
#include <google/protobuf/repeated_field.h>
#include <google/protobuf/wire_format_lite.h>

#include <google/protobuf/port_def.inc>

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

namespace google {
namespace protobuf {
class Arena;
class Descriptor;       // descriptor.h
class FieldDescriptor;  // descriptor.h
class DescriptorPool;   // descriptor.h
class MessageLite;      // message_lite.h
class Message;          // message.h
class MessageFactory;   // message.h
class UnknownFieldSet;  // unknown_field_set.h
namespace internal {
class FieldSkipper;  // wire_format_lite.h
}  // namespace internal
}  // namespace protobuf
}  // namespace google

namespace google {
namespace protobuf {
namespace internal {

class InternalMetadata;

// Used to store values of type WireFormatLite::FieldType without having to
// #include wire_format_lite.h.  Also, ensures that we use only one byte to
// store these values, which is important to keep the layout of
// ExtensionSet::Extension small.
typedef uint8 FieldType;

// A function which, given an integer value, returns true if the number
// matches one of the defined values for the corresponding enum type.  This
// is used with RegisterEnumExtension, below.
typedef bool EnumValidityFunc(int number);

// Version of the above which takes an argument.  This is needed to deal with
// extensions that are not compiled in.
typedef bool EnumValidityFuncWithArg(const void* arg, int number);

// Information about a registered extension.
struct ExtensionInfo {
  inline ExtensionInfo() {}
  inline ExtensionInfo(FieldType type_param, bool isrepeated, bool ispacked)
      : type(type_param),
        is_repeated(isrepeated),
        is_packed(ispacked),
        descriptor(NULL) {}

FieldType type;
  bool is_repeated;
  bool is_packed;

struct EnumValidityCheck {
    EnumValidityFuncWithArg* func;
    const void* arg;
  };

struct MessageInfo {
    const MessageLite* prototype;
  };

union {
    EnumValidityCheck enum_validity_check;
    MessageInfo message_info;
  };

// The descriptor for this extension, if one exists and is known.  May be
  // NULL.  Must not be NULL if the descriptor for the extension does not
  // live in the same pool as the descriptor for the containing type.
  const FieldDescriptor* descriptor;
};

// Abstract interface for an object which looks up extension definitions.  Used
// when parsing.
class PROTOBUF_EXPORT ExtensionFinder {
 public:
  virtual ~ExtensionFinder();

// Find the extension with the given containing type and number.
  virtual bool Find(int number, ExtensionInfo* output) = 0;
};

// Implementation of ExtensionFinder which finds extensions defined in .proto
// files which have been compiled into the binary.
class PROTOBUF_EXPORT GeneratedExtensionFinder : public ExtensionFinder {
 public:
  GeneratedExtensionFinder(const MessageLite* containing_type)
      : containing_type_(containing_type) {}
  ~GeneratedExtensionFinder() override {}

// Returns true and fills in *output if found, otherwise returns false.
  bool Find(int number, ExtensionInfo* output) override;

private:
  const MessageLite* containing_type_;
};

// A FieldSkipper used for parsing MessageSet.
class MessageSetFieldSkipper;

// Note:  extension_set_heavy.cc defines DescriptorPoolExtensionFinder for
// finding extensions from a DescriptorPool.

// This is an internal helper class intended for use within the protocol buffer
// library and generated classes.  Clients should not use it directly.  Instead,
// use the generated accessors such as GetExtension() of the class being
// extended.
//
// This class manages extensions for a protocol message object.  The
// message's HasExtension(), GetExtension(), MutableExtension(), and
// ClearExtension() methods are just thin wrappers around the embedded
// ExtensionSet.  When parsing, if a tag number is encountered which is
// inside one of the message type's extension ranges, the tag is passed
// off to the ExtensionSet for parsing.  Etc.
class PROTOBUF_EXPORT ExtensionSet {
 public:
  ExtensionSet();
  explicit ExtensionSet(Arena* arena);
  ~ExtensionSet();

// These are called at startup by protocol-compiler-generated code to
  // register known extensions.  The registrations are used by ParseField()
  // to look up extensions for parsed field numbers.  Note that dynamic parsing
  // does not use ParseField(); only protocol-compiler-generated parsing
  // methods do.
  static void RegisterExtension(const MessageLite* containing_type, int number,
                                FieldType type, bool is_repeated,
                                bool is_packed);
  static void RegisterEnumExtension(const MessageLite* containing_type,
                                    int number, FieldType type,
                                    bool is_repeated, bool is_packed,
                                    EnumValidityFunc* is_valid);
  static void RegisterMessageExtension(const MessageLite* containing_type,
                                       int number, FieldType type,
                                       bool is_repeated, bool is_packed,
                                       const MessageLite* prototype);

// =================================================================

// Add all fields which are currently present to the given vector.  This
  // is useful to implement Reflection::ListFields().
  void AppendToList(const Descriptor* containing_type,
                    const DescriptorPool* pool,
                    std::vector<const FieldDescriptor*>* output) const;

// =================================================================
  // Accessors
  //
  // Generated message classes include type-safe templated wrappers around
  // these methods.  Generally you should use those rather than call these
  // directly, unless you are doing low-level memory management.
  //
  // When calling any of these accessors, the extension number requested
  // MUST exist in the DescriptorPool provided to the constructor.  Otherwise,
  // the method will fail an assert.  Normally, though, you would not call
  // these directly; you would either call the generated accessors of your
  // message class (e.g. GetExtension()) or you would call the accessors
  // of the reflection interface.  In both cases, it is impossible to
  // trigger this assert failure:  the generated accessors only accept
  // linked-in extension types as parameters, while the Reflection interface
  // requires you to provide the FieldDescriptor describing the extension.
  //
  // When calling any of these accessors, a protocol-compiler-generated
  // implementation of the extension corresponding to the number MUST
  // be linked in, and the FieldDescriptor used to refer to it MUST be
  // the one generated by that linked-in code.  Otherwise, the method will
  // die on an assert failure.  The message objects returned by the message
  // accessors are guaranteed to be of the correct linked-in type.
  //
  // These methods pretty much match Reflection except that:
  // - They're not virtual.
  // - They identify fields by number rather than FieldDescriptors.
  // - They identify enum values using integers rather than descriptors.
  // - Strings provide Mutable() in addition to Set() accessors.

bool Has(int number) const;
  int ExtensionSize(int number) const;  // Size of a repeated extension.
  int NumExtensions() const;            // The number of extensions
  FieldType ExtensionType(int number) const;
  void ClearExtension(int number);

// singular fields -------------------------------------------------

int32 GetInt32(int number, int32 default_value) const;
  int64 GetInt64(int number, int64 default_value) const;
  uint32 GetUInt32(int number, uint32 default_value) const;
  uint64 GetUInt64(int number, uint64 default_value) const;
  float GetFloat(int number, float default_value) const;
  double GetDouble(int number, double default_value) const;
  bool GetBool(int number, bool default_value) const;
  int GetEnum(int number, int default_value) const;
  const std::string& GetString(int number,
                               const std::string& default_value) const;
  const MessageLite& GetMessage(int number,
                                const MessageLite& default_value) const;
  const MessageLite& GetMessage(int number, const Descriptor* message_type,
                                MessageFactory* factory) const;

// |descriptor| may be NULL so long as it is known that the descriptor for
  // the extension lives in the same pool as the descriptor for the containing
  // type.
#define desc const FieldDescriptor* descriptor  // avoid line wrapping
  void SetInt32(int number, FieldType type, int32 value, desc);
  void SetInt64(int number, FieldType type, int64 value, desc);
  void SetUInt32(int number, FieldType type, uint32 value, desc);
  void SetUInt64(int number, FieldType type, uint64 value, desc);
  void SetFloat(int number, FieldType type, float value, desc);
  void SetDouble(int number, FieldType type, double value, desc);
  void SetBool(int number, FieldType type, bool value, desc);
  void SetEnum(int number, FieldType type, int value, desc);
  void SetString(int number, FieldType type, std::string value, desc);
  std::string* MutableString(int number, FieldType type, desc);
  MessageLite* MutableMessage(int number, FieldType type,
                              const MessageLite& prototype, desc);
  MessageLite* MutableMessage(const FieldDescriptor* descriptor,
                              MessageFactory* factory);
  // Adds the given message to the ExtensionSet, taking ownership of the
  // message object. Existing message with the same number will be deleted.
  // If "message" is NULL, this is equivalent to "ClearExtension(number)".
  void SetAllocatedMessage(int number, FieldType type,
                           const FieldDescriptor* descriptor,
                           MessageLite* message);
  void UnsafeArenaSetAllocatedMessage(int number, FieldType type,
                                      const FieldDescriptor* descriptor,
                                      MessageLite* message);
  MessageLite* ReleaseMessage(int number, const MessageLite& prototype);
  MessageLite* UnsafeArenaReleaseMessage(int number,
                                         const MessageLite& prototype);

MessageLite* ReleaseMessage(const FieldDescriptor* descriptor,
                              MessageFactory* factory);
  MessageLite* UnsafeArenaReleaseMessage(const FieldDescriptor* descriptor,
                                         MessageFactory* factory);
#undef desc
  Arena* GetArena() const { return arena_; }

// repeated fields -------------------------------------------------

// Fetches a RepeatedField extension by number; returns |default_value|
  // if no such extension exists. User should not touch this directly; it is
  // used by the GetRepeatedExtension() method.
  const void* GetRawRepeatedField(int number, const void* default_value) const;
  // Fetches a mutable version of a RepeatedField extension by number,
  // instantiating one if none exists. Similar to above, user should not use
  // this directly; it underlies MutableRepeatedExtension().
  void* MutableRawRepeatedField(int number, FieldType field_type, bool packed,
                                const FieldDescriptor* desc);

// This is an overload of MutableRawRepeatedField to maintain compatibility
  // with old code using a previous API. This version of
  // MutableRawRepeatedField() will GOOGLE_CHECK-fail on a missing extension.
  // (E.g.: borg/clients/internal/proto1/proto2_reflection.cc.)
  void* MutableRawRepeatedField(int number);

int32 GetRepeatedInt32(int number, int index) const;
  int64 GetRepeatedInt64(int number, int index) const;
  uint32 GetRepeatedUInt32(int number, int index) const;
  uint64 GetRepeatedUInt64(int number, int index) const;
  float GetRepeatedFloat(int number, int index) const;
  double GetRepeatedDouble(int number, int index) const;
  bool GetRepeatedBool(int number, int index) const;
  int GetRepeatedEnum(int number, int index) const;
  const std::string& GetRepeatedString(int number, int index) const;
  const MessageLite& GetRepeatedMessage(int number, int index) const;

void SetRepeatedInt32(int number, int index, int32 value);
  void SetRepeatedInt64(int number, int index, int64 value);
  void SetRepeatedUInt32(int number, int index, uint32 value);
  void SetRepeatedUInt64(int number, int index, uint64 value);
  void SetRepeatedFloat(int number, int index, float value);
  void SetRepeatedDouble(int number, int index, double value);
  void SetRepeatedBool(int number, int index, bool value);
  void SetRepeatedEnum(int number, int index, int value);
  void SetRepeatedString(int number, int index, std::string value);
  std::string* MutableRepeatedString(int number, int index);
  MessageLite* MutableRepeatedMessage(int number, int index);

#define desc const FieldDescriptor* descriptor  // avoid line wrapping
  void AddInt32(int number, FieldType type, bool packed, int32 value, desc);
  void AddInt64(int number, FieldType type, bool packed, int64 value, desc);
  void AddUInt32(int number, FieldType type, bool packed, uint32 value, desc);
  void AddUInt64(int number, FieldType type, bool packed, uint64 value, desc);
  void AddFloat(int number, FieldType type, bool packed, float value, desc);
  void AddDouble(int number, FieldType type, bool packed, double value, desc);
  void AddBool(int number, FieldType type, bool packed, bool value, desc);
  void AddEnum(int number, FieldType type, bool packed, int value, desc);
  void AddString(int number, FieldType type, std::string value, desc);
  std::string* AddString(int number, FieldType type, desc);
  MessageLite* AddMessage(int number, FieldType type,
                          const MessageLite& prototype, desc);
  MessageLite* AddMessage(const FieldDescriptor* descriptor,
                          MessageFactory* factory);
  void AddAllocatedMessage(const FieldDescriptor* descriptor,
                           MessageLite* new_entry);
#undef desc

void RemoveLast(int number);
  MessageLite* ReleaseLast(int number);
  void SwapElements(int number, int index1, int index2);

// -----------------------------------------------------------------
  // TODO(kenton):  Hardcore memory management accessors

// =================================================================
  // convenience methods for implementing methods of Message
  //
  // These could all be implemented in terms of the other methods of this
  // class, but providing them here helps keep the generated code size down.

void Clear();
  void MergeFrom(const ExtensionSet& other);
  void Swap(ExtensionSet* other);
  void SwapExtension(ExtensionSet* other, int number);
  bool IsInitialized() const;

// Parses a single extension from the input. The input should start out
  // positioned immediately after the tag.
  bool ParseField(uint32 tag, io::CodedInputStream* input,
                  ExtensionFinder* extension_finder,
                  FieldSkipper* field_skipper);

// Specific versions for lite or full messages (constructs the appropriate
  // FieldSkipper automatically).  |containing_type| is the default
  // instance for the containing message; it is used only to look up the
  // extension by number.  See RegisterExtension(), above.  Unlike the other
  // methods of ExtensionSet, this only works for generated message types --
  // it looks up extensions registered using RegisterExtension().
  bool ParseField(uint32 tag, io::CodedInputStream* input,
                  const MessageLite* containing_type);
  bool ParseField(uint32 tag, io::CodedInputStream* input,
                  const Message* containing_type,
                  UnknownFieldSet* unknown_fields);
  bool ParseField(uint32 tag, io::CodedInputStream* input,
                  const MessageLite* containing_type,
                  io::CodedOutputStream* unknown_fields);

// Lite parser
  const char* ParseField(uint64 tag, const char* ptr,
                         const MessageLite* containing_type,
                         internal::InternalMetadata* metadata,
                         internal::ParseContext* ctx);
  // Full parser
  const char* ParseField(uint64 tag, const char* ptr,
                         const Message* containing_type,
                         internal::InternalMetadata* metadata,
                         internal::ParseContext* ctx);
  template <typename Msg>
  const char* ParseMessageSet(const char* ptr, const Msg* containing_type,
                              InternalMetadata* metadata,
                              internal::ParseContext* ctx) {
    struct MessageSetItem {
      const char* _InternalParse(const char* ptr, ParseContext* ctx) {
        return me->ParseMessageSetItem(ptr, containing_type, metadata, ctx);
      }
      ExtensionSet* me;
      const Msg* containing_type;
      InternalMetadata* metadata;
    } item{this, containing_type, metadata};
    while (!ctx->Done(&ptr)) {
      uint32 tag;
      ptr = ReadTag(ptr, &tag);
      GOOGLE_PROTOBUF_PARSER_ASSERT(ptr);
      if (tag == WireFormatLite::kMessageSetItemStartTag) {
        ptr = ctx->ParseGroup(&item, ptr, tag);
        GOOGLE_PROTOBUF_PARSER_ASSERT(ptr);
      } else {
        if (tag == 0 || (tag & 7) == 4) {
          ctx->SetLastTag(tag);
          return ptr;
        }
        ptr = ParseField(tag, ptr, containing_type, metadata, ctx);
        GOOGLE_PROTOBUF_PARSER_ASSERT(ptr);
      }
    }
    return ptr;
  }

// Parse an entire message in MessageSet format.  Such messages have no
  // fields, only extensions.
  bool ParseMessageSetLite(io::CodedInputStream* input,
                           ExtensionFinder* extension_finder,
                           FieldSkipper* field_skipper);
  bool ParseMessageSet(io::CodedInputStream* input,
                       ExtensionFinder* extension_finder,
                       MessageSetFieldSkipper* field_skipper);

// Specific versions for lite or full messages (constructs the appropriate
  // FieldSkipper automatically).
  bool ParseMessageSet(io::CodedInputStream* input,
                       const MessageLite* containing_type,
                       std::string* unknown_fields);
  bool ParseMessageSet(io::CodedInputStream* input,
                       const Message* containing_type,
                       UnknownFieldSet* unknown_fields);

// Write all extension fields with field numbers in the range
  //   [start_field_number, end_field_number)
  // to the output stream, using the cached sizes computed when ByteSize() was
  // last called.  Note that the range bounds are inclusive-exclusive.
  void SerializeWithCachedSizes(int start_field_number, int end_field_number,
                                io::CodedOutputStream* output) const {
    output->SetCur(_InternalSerialize(start_field_number, end_field_number,
                                      output->Cur(), output->EpsCopy()));
  }

// Same as SerializeWithCachedSizes, but without any bounds checking.
  // The caller must ensure that target has sufficient capacity for the
  // serialized extensions.
  //
  // Returns a pointer past the last written byte.
  uint8* _InternalSerialize(int start_field_number, int end_field_number,
                            uint8* target,
                            io::EpsCopyOutputStream* stream) const;

// Like above but serializes in MessageSet format.
  void SerializeMessageSetWithCachedSizes(io::CodedOutputStream* output) const {
    output->SetCur(InternalSerializeMessageSetWithCachedSizesToArray(
        output->Cur(), output->EpsCopy()));
  }
  uint8* InternalSerializeMessageSetWithCachedSizesToArray(
      uint8* target, io::EpsCopyOutputStream* stream) const;

// For backward-compatibility, versions of two of the above methods that
  // serialize deterministically iff SetDefaultSerializationDeterministic()
  // has been called.
  uint8* SerializeWithCachedSizesToArray(int start_field_number,
                                         int end_field_number,
                                         uint8* target) const;
  uint8* SerializeMessageSetWithCachedSizesToArray(uint8* target) const;

// Returns the total serialized size of all the extensions.
  size_t ByteSize() const;

// Like ByteSize() but uses MessageSet format.
  size_t MessageSetByteSize() const;

// Returns (an estimate of) the total number of bytes used for storing the
  // extensions in memory, excluding sizeof(*this).  If the ExtensionSet is
  // for a lite message (and thus possibly contains lite messages), the results
  // are undefined (might work, might crash, might corrupt data, might not even
  // be linked in).  It's up to the protocol compiler to avoid calling this on
  // such ExtensionSets (easy enough since lite messages don't implement
  // SpaceUsed()).
  size_t SpaceUsedExcludingSelfLong() const;

// This method just calls SpaceUsedExcludingSelfLong() but it can not be
  // inlined because the definition of SpaceUsedExcludingSelfLong() is not
  // included in lite runtime and when an inline method refers to it MSVC
  // will complain about unresolved symbols when building the lite runtime
  // as .dll.
  int SpaceUsedExcludingSelf() const;

private:
  // Interface of a lazily parsed singular message extension.
  class PROTOBUF_EXPORT LazyMessageExtension {
   public:
    LazyMessageExtension() {}
    virtual ~LazyMessageExtension() {}

virtual LazyMessageExtension* New(Arena* arena) const = 0;
    virtual const MessageLite& GetMessage(
        const MessageLite& prototype) const = 0;
    virtual MessageLite* MutableMessage(const MessageLite& prototype) = 0;
    virtual void SetAllocatedMessage(MessageLite* message) = 0;
    virtual void UnsafeArenaSetAllocatedMessage(MessageLite* message) = 0;
    virtual MessageLite* ReleaseMessage(const MessageLite& prototype) = 0;
    virtual MessageLite* UnsafeArenaReleaseMessage(
        const MessageLite& prototype) = 0;

virtual bool IsInitialized() const = 0;

PROTOBUF_DEPRECATED_MSG("Please use ByteSizeLong() instead")
    virtual int ByteSize() const { return internal::ToIntSize(ByteSizeLong()); }
    virtual size_t ByteSizeLong() const = 0;
    virtual size_t SpaceUsedLong() const = 0;

virtual void MergeFrom(const LazyMessageExtension& other) = 0;
    virtual void Clear() = 0;

virtual bool ReadMessage(const MessageLite& prototype,
                             io::CodedInputStream* input) = 0;
    virtual const char* _InternalParse(const char* ptr, ParseContext* ctx) = 0;
    virtual uint8* WriteMessageToArray(
        int number, uint8* target, io::EpsCopyOutputStream* stream) const = 0;

private:
    virtual void UnusedKeyMethod();  // Dummy key method to avoid weak vtable.

GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(LazyMessageExtension);
  };
  struct Extension {
    // The order of these fields packs Extension into 24 bytes when using 8
    // byte alignment. Consider this when adding or removing fields here.
    union {
      int32 int32_value;
      int64 int64_value;
      uint32 uint32_value;
      uint64 uint64_value;
      float float_value;
      double double_value;
      bool bool_value;
      int enum_value;
      std::string* string_value;
      MessageLite* message_value;
      LazyMessageExtension* lazymessage_value;

RepeatedField<int32>* repeated_int32_value;
      RepeatedField<int64>* repeated_int64_value;
      RepeatedField<uint32>* repeated_uint32_value;
      RepeatedField<uint64>* repeated_uint64_value;
      RepeatedField<float>* repeated_float_value;
      RepeatedField<double>* repeated_double_value;
      RepeatedField<bool>* repeated_bool_value;
      RepeatedField<int>* repeated_enum_value;
      RepeatedPtrField<std::string>* repeated_string_value;
      RepeatedPtrField<MessageLite>* repeated_message_value;
    };

FieldType type;
    bool is_repeated;

// For singular types, indicates if the extension is "cleared".  This
    // happens when an extension is set and then later cleared by the caller.
    // We want to keep the Extension object around for reuse, so instead of
    // removing it from the map, we just set is_cleared = true.  This has no
    // meaning for repeated types; for those, the size of the RepeatedField
    // simply becomes zero when cleared.
    bool is_cleared : 4;

// For singular message types, indicates whether lazy parsing is enabled
    // for this extension. This field is only valid when type == TYPE_MESSAGE
    // and !is_repeated because we only support lazy parsing for singular
    // message types currently. If is_lazy = true, the extension is stored in
    // lazymessage_value. Otherwise, the extension will be message_value.
    bool is_lazy : 4;

// For repeated types, this indicates if the [packed=true] option is set.
    bool is_packed;

// For packed fields, the size of the packed data is recorded here when
    // ByteSize() is called then used during serialization.
    // TODO(kenton):  Use atomic<int> when C++ supports it.
    mutable int cached_size;

// The descriptor for this extension, if one exists and is known.  May be
    // NULL.  Must not be NULL if the descriptor for the extension does not
    // live in the same pool as the descriptor for the containing type.
    const FieldDescriptor* descriptor;

// Some helper methods for operations on a single Extension.
    uint8* InternalSerializeFieldWithCachedSizesToArray(
        int number, uint8* target, io::EpsCopyOutputStream* stream) const;
    uint8* InternalSerializeMessageSetItemWithCachedSizesToArray(
        int number, uint8* target, io::EpsCopyOutputStream* stream) const;
    size_t ByteSize(int number) const;
    size_t MessageSetItemByteSize(int number) const;
    void Clear();
    int GetSize() const;
    void Free();
    size_t SpaceUsedExcludingSelfLong() const;
    bool IsInitialized() const;
  };

// The Extension struct is small enough to be passed by value, so we use it
  // directly as the value type in mappings rather than use pointers.  We use
  // sorted maps rather than hash-maps because we expect most ExtensionSets will
  // only contain a small number of extension.  Also, we want AppendToList and
  // deterministic serialization to order fields by field number.

struct KeyValue {
    int first;
    Extension second;

struct FirstComparator {
      bool operator()(const KeyValue& lhs, const KeyValue& rhs) const {
        return lhs.first < rhs.first;
      }
      bool operator()(const KeyValue& lhs, int key) const {
        return lhs.first < key;
      }
      bool operator()(int key, const KeyValue& rhs) const {
        return key < rhs.first;
      }
    };
  };

typedef std::map<int, Extension> LargeMap;

// Wrapper API that switches between flat-map and LargeMap.

// Finds a key (if present) in the ExtensionSet.
  const Extension* FindOrNull(int key) const;
  Extension* FindOrNull(int key);

// Helper-functions that only inspect the LargeMap.
  const Extension* FindOrNullInLargeMap(int key) const;
  Extension* FindOrNullInLargeMap(int key);

// Inserts a new (key, Extension) into the ExtensionSet (and returns true), or
  // finds the already-existing Extension for that key (returns false).
  // The Extension* will point to the new-or-found Extension.
  std::pair<Extension*, bool> Insert(int key);

// Grows the flat_capacity_.
  // If flat_capacity_ > kMaximumFlatCapacity, converts to LargeMap.
  void GrowCapacity(size_t minimum_new_capacity);
  static constexpr uint16 kMaximumFlatCapacity = 256;
  bool is_large() const { return flat_capacity_ > kMaximumFlatCapacity; }

// Removes a key from the ExtensionSet.
  void Erase(int key);

size_t Size() const {
    return PROTOBUF_PREDICT_FALSE(is_large()) ? map_.large->size() : flat_size_;
  }

// Similar to std::for_each.
  // Each Iterator is decomposed into ->first and ->second fields, so
  // that the KeyValueFunctor can be agnostic vis-a-vis KeyValue-vs-std::pair.
  template <typename Iterator, typename KeyValueFunctor>
  static KeyValueFunctor ForEach(Iterator begin, Iterator end,
                                 KeyValueFunctor func) {
    for (Iterator it = begin; it != end; ++it) func(it->first, it->second);
    return std::move(func);
  }

// Applies a functor to the <int, Extension&> pairs in sorted order.
  template <typename KeyValueFunctor>
  KeyValueFunctor ForEach(KeyValueFunctor func) {
    if (PROTOBUF_PREDICT_FALSE(is_large())) {
      return ForEach(map_.large->begin(), map_.large->end(), std::move(func));
    }
    return ForEach(flat_begin(), flat_end(), std::move(func));
  }

// Applies a functor to the <int, const Extension&> pairs in sorted order.
  template <typename KeyValueFunctor>
  KeyValueFunctor ForEach(KeyValueFunctor func) const {
    if (PROTOBUF_PREDICT_FALSE(is_large())) {
      return ForEach(map_.large->begin(), map_.large->end(), std::move(func));
    }
    return ForEach(flat_begin(), flat_end(), std::move(func));
  }

// Merges existing Extension from other_extension
  void InternalExtensionMergeFrom(int number, const Extension& other_extension);

// Returns true and fills field_number and extension if extension is found.
  // Note to support packed repeated field compatibility, it also fills whether
  // the tag on wire is packed, which can be different from
  // extension->is_packed (whether packed=true is specified).
  bool FindExtensionInfoFromTag(uint32 tag, ExtensionFinder* extension_finder,
                                int* field_number, ExtensionInfo* extension,
                                bool* was_packed_on_wire);

// Returns true and fills extension if extension is found.
  // Note to support packed repeated field compatibility, it also fills whether
  // the tag on wire is packed, which can be different from
  // extension->is_packed (whether packed=true is specified).
  bool FindExtensionInfoFromFieldNumber(int wire_type, int field_number,
                                        ExtensionFinder* extension_finder,
                                        ExtensionInfo* extension,
                                        bool* was_packed_on_wire);

// Parses a single extension from the input. The input should start out
  // positioned immediately after the wire tag. This method is called in
  // ParseField() after field number and was_packed_on_wire is extracted from
  // the wire tag and ExtensionInfo is found by the field number.
  bool ParseFieldWithExtensionInfo(int field_number, bool was_packed_on_wire,
                                   const ExtensionInfo& extension,
                                   io::CodedInputStream* input,
                                   FieldSkipper* field_skipper);

// Like ParseField(), but this method may parse singular message extensions
  // lazily depending on the value of FLAGS_eagerly_parse_message_sets.
  bool ParseFieldMaybeLazily(int wire_type, int field_number,
                             io::CodedInputStream* input,
                             ExtensionFinder* extension_finder,
                             MessageSetFieldSkipper* field_skipper);

// Gets the extension with the given number, creating it if it does not
  // already exist.  Returns true if the extension did not already exist.
  bool MaybeNewExtension(int number, const FieldDescriptor* descriptor,
                         Extension** result);

// Gets the repeated extension for the given descriptor, creating it if
  // it does not exist.
  Extension* MaybeNewRepeatedExtension(const FieldDescriptor* descriptor);

// Parse a single MessageSet item -- called just after the item group start
  // tag has been read.
  bool ParseMessageSetItemLite(io::CodedInputStream* input,
                               ExtensionFinder* extension_finder,
                               FieldSkipper* field_skipper);
  // Parse a single MessageSet item -- called just after the item group start
  // tag has been read.
  bool ParseMessageSetItem(io::CodedInputStream* input,
                           ExtensionFinder* extension_finder,
                           MessageSetFieldSkipper* field_skipper);

bool FindExtension(int wire_type, uint32 field,
                     const MessageLite* containing_type,
                     const internal::ParseContext* /*ctx*/,
                     ExtensionInfo* extension, bool* was_packed_on_wire) {
    GeneratedExtensionFinder finder(containing_type);
    return FindExtensionInfoFromFieldNumber(wire_type, field, &finder,
                                            extension, was_packed_on_wire);
  }
  inline bool FindExtension(int wire_type, uint32 field,
                            const Message* containing_type,
                            const internal::ParseContext* ctx,
                            ExtensionInfo* extension, bool* was_packed_on_wire);
  // Used for MessageSet only
  const char* ParseFieldMaybeLazily(uint64 tag, const char* ptr,
                                    const MessageLite* containing_type,
                                    internal::InternalMetadata* metadata,
                                    internal::ParseContext* ctx) {
    // Lite MessageSet doesn't implement lazy.
    return ParseField(tag, ptr, containing_type, metadata, ctx);
  }
  const char* ParseFieldMaybeLazily(uint64 tag, const char* ptr,
                                    const Message* containing_type,
                                    internal::InternalMetadata* metadata,
                                    internal::ParseContext* ctx);
  const char* ParseMessageSetItem(const char* ptr,
                                  const MessageLite* containing_type,
                                  internal::InternalMetadata* metadata,
                                  internal::ParseContext* ctx);
  const char* ParseMessageSetItem(const char* ptr,
                                  const Message* containing_type,
                                  internal::InternalMetadata* metadata,
                                  internal::ParseContext* ctx);

// Implemented in extension_set_inl.h to keep code out of the header file.
  template <typename T>
  const char* ParseFieldWithExtensionInfo(int number, bool was_packed_on_wire,
                                          const ExtensionInfo& info,
                                          internal::InternalMetadata* metadata,
                                          const char* ptr,
                                          internal::ParseContext* ctx);
  template <typename Msg, typename T>
  const char* ParseMessageSetItemTmpl(const char* ptr,
                                      const Msg* containing_type,
                                      internal::InternalMetadata* metadata,
                                      internal::ParseContext* ctx);

// Hack:  RepeatedPtrFieldBase declares ExtensionSet as a friend.  This
  //   friendship should automatically extend to ExtensionSet::Extension, but
  //   unfortunately some older compilers (e.g. GCC 3.4.4) do not implement this
  //   correctly.  So, we must provide helpers for calling methods of that
  //   class.

// Defined in extension_set_heavy.cc.
  static inline size_t RepeatedMessage_SpaceUsedExcludingSelfLong(
      RepeatedPtrFieldBase* field);

KeyValue* flat_begin() {
    assert(!is_large());
    return map_.flat;
  }
  const KeyValue* flat_begin() const {
    assert(!is_large());
    return map_.flat;
  }
  KeyValue* flat_end() {
    assert(!is_large());
    return map_.flat + flat_size_;
  }
  const KeyValue* flat_end() const {
    assert(!is_large());
    return map_.flat + flat_size_;
  }

Arena* arena_;

// Manual memory-management:
  // map_.flat is an allocated array of flat_capacity_ elements.
  // [map_.flat, map_.flat + flat_size_) is the currently-in-use prefix.
  uint16 flat_capacity_;
  uint16 flat_size_;
  union AllocatedData {
    KeyValue* flat;

// If flat_capacity_ > kMaximumFlatCapacity, switch to LargeMap,
    // which guarantees O(n lg n) CPU but larger constant factors.
    LargeMap* large;
  } map_;

static void DeleteFlatMap(const KeyValue* flat, uint16 flat_capacity);

GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ExtensionSet);
};

// These are just for convenience...
inline void ExtensionSet::SetString(int number, FieldType type,
                                    std::string value,
                                    const FieldDescriptor* descriptor) {
  MutableString(number, type, descriptor)->assign(std::move(value));
}
inline void ExtensionSet::SetRepeatedString(int number, int index,
                                            std::string value) {
  MutableRepeatedString(number, index)->assign(std::move(value));
}
inline void ExtensionSet::AddString(int number, FieldType type,
                                    std::string value,
                                    const FieldDescriptor* descriptor) {
  AddString(number, type, descriptor)->assign(std::move(value));
}
// ===================================================================
// Glue for generated extension accessors

// -------------------------------------------------------------------
// Template magic

// First we have a set of classes representing "type traits" for different
// field types.  A type traits class knows how to implement basic accessors
// for extensions of a particular type given an ExtensionSet.  The signature
// for a type traits class looks like this:
//
//   class TypeTraits {
//    public:
//     typedef ? ConstType;
//     typedef ? MutableType;
//     // TypeTraits for singular fields and repeated fields will define the
//     // symbol "Singular" or "Repeated" respectively. These two symbols will
//     // be used in extension accessors to distinguish between singular
//     // extensions and repeated extensions. If the TypeTraits for the passed
//     // in extension doesn't have the expected symbol defined, it means the
//     // user is passing a repeated extension to a singular accessor, or the
//     // opposite. In that case the C++ compiler will generate an error
//     // message "no matching member function" to inform the user.
//     typedef ? Singular
//     typedef ? Repeated
//
//     static inline ConstType Get(int number, const ExtensionSet& set);
//     static inline void Set(int number, ConstType value, ExtensionSet* set);
//     static inline MutableType Mutable(int number, ExtensionSet* set);
//
//     // Variants for repeated fields.
//     static inline ConstType Get(int number, const ExtensionSet& set,
//                                 int index);
//     static inline void Set(int number, int index,
//                            ConstType value, ExtensionSet* set);
//     static inline MutableType Mutable(int number, int index,
//                                       ExtensionSet* set);
//     static inline void Add(int number, ConstType value, ExtensionSet* set);
//     static inline MutableType Add(int number, ExtensionSet* set);
//     This is used by the ExtensionIdentifier constructor to register
//     the extension at dynamic initialization.
//     template <typename ExtendeeT>
//     static void Register(int number, FieldType type, bool is_packed);
//   };
//
// Not all of these methods make sense for all field types.  For example, the
// "Mutable" methods only make sense for strings and messages, and the
// repeated methods only make sense for repeated types.  So, each type
// traits class implements only the set of methods from this signature that it
// actually supports.  This will cause a compiler error if the user tries to
// access an extension using a method that doesn't make sense for its type.
// For example, if "foo" is an extension of type "optional int32", then if you
// try to write code like:
//   my_message.MutableExtension(foo)
// you will get a compile error because PrimitiveTypeTraits<int32> does not
// have a "Mutable()" method.

// -------------------------------------------------------------------
// PrimitiveTypeTraits

// Since the ExtensionSet has different methods for each primitive type,
// we must explicitly define the methods of the type traits class for each
// known type.
template <typename Type>
class PrimitiveTypeTraits {
 public:
  typedef Type ConstType;
  typedef Type MutableType;
  typedef PrimitiveTypeTraits<Type> Singular;

static inline ConstType Get(int number, const ExtensionSet& set,
                              ConstType default_value);
  static inline void Set(int number, FieldType field_type, ConstType value,
                         ExtensionSet* set);
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterExtension(&ExtendeeT::default_instance(), number,
                                    type, false, is_packed);
  }
};

template <typename Type>
class RepeatedPrimitiveTypeTraits {
 public:
  typedef Type ConstType;
  typedef Type MutableType;
  typedef RepeatedPrimitiveTypeTraits<Type> Repeated;

typedef RepeatedField<Type> RepeatedFieldType;

static inline Type Get(int number, const ExtensionSet& set, int index);
  static inline void Set(int number, int index, Type value, ExtensionSet* set);
  static inline void Add(int number, FieldType field_type, bool is_packed,
                         Type value, ExtensionSet* set);

static inline const RepeatedField<ConstType>& GetRepeated(
      int number, const ExtensionSet& set);
  static inline RepeatedField<Type>* MutableRepeated(int number,
                                                     FieldType field_type,
                                                     bool is_packed,
                                                     ExtensionSet* set);

static const RepeatedFieldType* GetDefaultRepeatedField();
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterExtension(&ExtendeeT::default_instance(), number,
                                    type, true, is_packed);
  }
};

class PROTOBUF_EXPORT RepeatedPrimitiveDefaults {
 private:
  template <typename Type>
  friend class RepeatedPrimitiveTypeTraits;
  static const RepeatedPrimitiveDefaults* default_instance();
  RepeatedField<int32> default_repeated_field_int32_;
  RepeatedField<int64> default_repeated_field_int64_;
  RepeatedField<uint32> default_repeated_field_uint32_;
  RepeatedField<uint64> default_repeated_field_uint64_;
  RepeatedField<double> default_repeated_field_double_;
  RepeatedField<float> default_repeated_field_float_;
  RepeatedField<bool> default_repeated_field_bool_;
};

#define PROTOBUF_DEFINE_PRIMITIVE_TYPE(TYPE, METHOD)                           \
  template <>                                                                  \
  inline TYPE PrimitiveTypeTraits<TYPE>::Get(                                  \
      int number, const ExtensionSet& set, TYPE default_value) {               \
    return set.Get##METHOD(number, default_value);                             \
  }                                                                            \
  template <>                                                                  \
  inline void PrimitiveTypeTraits<TYPE>::Set(int number, FieldType field_type, \
                                             TYPE value, ExtensionSet* set) {  \
    set->Set##METHOD(number, field_type, value, NULL);                         \
  }                                                                            \
                                                                               \
  template <>                                                                  \
  inline TYPE RepeatedPrimitiveTypeTraits<TYPE>::Get(                          \
      int number, const ExtensionSet& set, int index) {                        \
    return set.GetRepeated##METHOD(number, index);                             \
  }                                                                            \
  template <>                                                                  \
  inline void RepeatedPrimitiveTypeTraits<TYPE>::Set(                          \
      int number, int index, TYPE value, ExtensionSet* set) {                  \
    set->SetRepeated##METHOD(number, index, value);                            \
  }                                                                            \
  template <>                                                                  \
  inline void RepeatedPrimitiveTypeTraits<TYPE>::Add(                          \
      int number, FieldType field_type, bool is_packed, TYPE value,            \
      ExtensionSet* set) {                                                     \
    set->Add##METHOD(number, field_type, is_packed, value, NULL);              \
  }                                                                            \
  template <>                                                                  \
  inline const RepeatedField<TYPE>*                                            \
  RepeatedPrimitiveTypeTraits<TYPE>::GetDefaultRepeatedField() {               \
    return &RepeatedPrimitiveDefaults::default_instance()                      \
                ->default_repeated_field_##TYPE##_;                            \
  }                                                                            \
  template <>                                                                  \
  inline const RepeatedField<TYPE>&                                            \
  RepeatedPrimitiveTypeTraits<TYPE>::GetRepeated(int number,                   \
                                                 const ExtensionSet& set) {    \
    return *reinterpret_cast<const RepeatedField<TYPE>*>(                      \
        set.GetRawRepeatedField(number, GetDefaultRepeatedField()));           \
  }                                                                            \
  template <>                                                                  \
  inline RepeatedField<TYPE>*                                                  \
  RepeatedPrimitiveTypeTraits<TYPE>::MutableRepeated(                          \
      int number, FieldType field_type, bool is_packed, ExtensionSet* set) {   \
    return reinterpret_cast<RepeatedField<TYPE>*>(                             \
        set->MutableRawRepeatedField(number, field_type, is_packed, NULL));    \
  }

PROTOBUF_DEFINE_PRIMITIVE_TYPE(int32, Int32)
PROTOBUF_DEFINE_PRIMITIVE_TYPE(int64, Int64)
PROTOBUF_DEFINE_PRIMITIVE_TYPE(uint32, UInt32)
PROTOBUF_DEFINE_PRIMITIVE_TYPE(uint64, UInt64)
PROTOBUF_DEFINE_PRIMITIVE_TYPE(float, Float)
PROTOBUF_DEFINE_PRIMITIVE_TYPE(double, Double)
PROTOBUF_DEFINE_PRIMITIVE_TYPE(bool, Bool)

#undef PROTOBUF_DEFINE_PRIMITIVE_TYPE

// -------------------------------------------------------------------
// StringTypeTraits

// Strings support both Set() and Mutable().
class PROTOBUF_EXPORT StringTypeTraits {
 public:
  typedef const std::string& ConstType;
  typedef std::string* MutableType;
  typedef StringTypeTraits Singular;

static inline const std::string& Get(int number, const ExtensionSet& set,
                                       ConstType default_value) {
    return set.GetString(number, default_value);
  }
  static inline void Set(int number, FieldType field_type,
                         const std::string& value, ExtensionSet* set) {
    set->SetString(number, field_type, value, NULL);
  }
  static inline std::string* Mutable(int number, FieldType field_type,
                                     ExtensionSet* set) {
    return set->MutableString(number, field_type, NULL);
  }
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterExtension(&ExtendeeT::default_instance(), number,
                                    type, false, is_packed);
  }
};

class PROTOBUF_EXPORT RepeatedStringTypeTraits {
 public:
  typedef const std::string& ConstType;
  typedef std::string* MutableType;
  typedef RepeatedStringTypeTraits Repeated;

typedef RepeatedPtrField<std::string> RepeatedFieldType;

static inline const std::string& Get(int number, const ExtensionSet& set,
                                       int index) {
    return set.GetRepeatedString(number, index);
  }
  static inline void Set(int number, int index, const std::string& value,
                         ExtensionSet* set) {
    set->SetRepeatedString(number, index, value);
  }
  static inline std::string* Mutable(int number, int index, ExtensionSet* set) {
    return set->MutableRepeatedString(number, index);
  }
  static inline void Add(int number, FieldType field_type, bool /*is_packed*/,
                         const std::string& value, ExtensionSet* set) {
    set->AddString(number, field_type, value, NULL);
  }
  static inline std::string* Add(int number, FieldType field_type,
                                 ExtensionSet* set) {
    return set->AddString(number, field_type, NULL);
  }
  static inline const RepeatedPtrField<std::string>& GetRepeated(
      int number, const ExtensionSet& set) {
    return *reinterpret_cast<const RepeatedPtrField<std::string>*>(
        set.GetRawRepeatedField(number, GetDefaultRepeatedField()));
  }

static inline RepeatedPtrField<std::string>* MutableRepeated(
      int number, FieldType field_type, bool is_packed, ExtensionSet* set) {
    return reinterpret_cast<RepeatedPtrField<std::string>*>(
        set->MutableRawRepeatedField(number, field_type, is_packed, NULL));
  }

static const RepeatedFieldType* GetDefaultRepeatedField();

template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterExtension(&ExtendeeT::default_instance(), number,
                                    type, true, is_packed);
  }

private:
  static void InitializeDefaultRepeatedFields();
  static void DestroyDefaultRepeatedFields();
};

// -------------------------------------------------------------------
// EnumTypeTraits

// ExtensionSet represents enums using integers internally, so we have to
// static_cast around.
template <typename Type, bool IsValid(int)>
class EnumTypeTraits {
 public:
  typedef Type ConstType;
  typedef Type MutableType;
  typedef EnumTypeTraits<Type, IsValid> Singular;

static inline ConstType Get(int number, const ExtensionSet& set,
                              ConstType default_value) {
    return static_cast<Type>(set.GetEnum(number, default_value));
  }
  static inline void Set(int number, FieldType field_type, ConstType value,
                         ExtensionSet* set) {
    GOOGLE_DCHECK(IsValid(value));
    set->SetEnum(number, field_type, value, NULL);
  }
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterEnumExtension(&ExtendeeT::default_instance(), number,
                                        type, false, is_packed, IsValid);
  }
};

template <typename Type, bool IsValid(int)>
class RepeatedEnumTypeTraits {
 public:
  typedef Type ConstType;
  typedef Type MutableType;
  typedef RepeatedEnumTypeTraits<Type, IsValid> Repeated;

typedef RepeatedField<Type> RepeatedFieldType;

static inline ConstType Get(int number, const ExtensionSet& set, int index) {
    return static_cast<Type>(set.GetRepeatedEnum(number, index));
  }
  static inline void Set(int number, int index, ConstType value,
                         ExtensionSet* set) {
    GOOGLE_DCHECK(IsValid(value));
    set->SetRepeatedEnum(number, index, value);
  }
  static inline void Add(int number, FieldType field_type, bool is_packed,
                         ConstType value, ExtensionSet* set) {
    GOOGLE_DCHECK(IsValid(value));
    set->AddEnum(number, field_type, is_packed, value, NULL);
  }
  static inline const RepeatedField<Type>& GetRepeated(
      int number, const ExtensionSet& set) {
    // Hack: the `Extension` struct stores a RepeatedField<int> for enums.
    // RepeatedField<int> cannot implicitly convert to RepeatedField<EnumType>
    // so we need to do some casting magic. See message.h for similar
    // contortions for non-extension fields.
    return *reinterpret_cast<const RepeatedField<Type>*>(
        set.GetRawRepeatedField(number, GetDefaultRepeatedField()));
  }

static inline RepeatedField<Type>* MutableRepeated(int number,
                                                     FieldType field_type,
                                                     bool is_packed,
                                                     ExtensionSet* set) {
    return reinterpret_cast<RepeatedField<Type>*>(
        set->MutableRawRepeatedField(number, field_type, is_packed, NULL));
  }

static const RepeatedFieldType* GetDefaultRepeatedField() {
    // Hack: as noted above, repeated enum fields are internally stored as a
    // RepeatedField<int>. We need to be able to instantiate global static
    // objects to return as default (empty) repeated fields on non-existent
    // extensions. We would not be able to know a-priori all of the enum types
    // (values of |Type|) to instantiate all of these, so we just re-use int32's
    // default repeated field object.
    return reinterpret_cast<const RepeatedField<Type>*>(
        RepeatedPrimitiveTypeTraits<int32>::GetDefaultRepeatedField());
  }
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterEnumExtension(&ExtendeeT::default_instance(), number,
                                        type, true, is_packed, IsValid);
  }
};

// -------------------------------------------------------------------
// MessageTypeTraits

// ExtensionSet guarantees that when manipulating extensions with message
// types, the implementation used will be the compiled-in class representing
// that type.  So, we can static_cast down to the exact type we expect.
template <typename Type>
class MessageTypeTraits {
 public:
  typedef const Type& ConstType;
  typedef Type* MutableType;
  typedef MessageTypeTraits<Type> Singular;

static inline ConstType Get(int number, const ExtensionSet& set,
                              ConstType default_value) {
    return static_cast<const Type&>(set.GetMessage(number, default_value));
  }
  static inline MutableType Mutable(int number, FieldType field_type,
                                    ExtensionSet* set) {
    return static_cast<Type*>(set->MutableMessage(
        number, field_type, Type::default_instance(), NULL));
  }
  static inline void SetAllocated(int number, FieldType field_type,
                                  MutableType message, ExtensionSet* set) {
    set->SetAllocatedMessage(number, field_type, NULL, message);
  }
  static inline void UnsafeArenaSetAllocated(int number, FieldType field_type,
                                             MutableType message,
                                             ExtensionSet* set) {
    set->UnsafeArenaSetAllocatedMessage(number, field_type, NULL, message);
  }
  static inline MutableType Release(int number, FieldType /* field_type */,
                                    ExtensionSet* set) {
    return static_cast<Type*>(
        set->ReleaseMessage(number, Type::default_instance()));
  }
  static inline MutableType UnsafeArenaRelease(int number,
                                               FieldType /* field_type */,
                                               ExtensionSet* set) {
    return static_cast<Type*>(
        set->UnsafeArenaReleaseMessage(number, Type::default_instance()));
  }
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterMessageExtension(&ExtendeeT::default_instance(),
                                           number, type, false, is_packed,
                                           &Type::default_instance());
  }
};

// forward declaration
class RepeatedMessageGenericTypeTraits;

template <typename Type>
class RepeatedMessageTypeTraits {
 public:
  typedef const Type& ConstType;
  typedef Type* MutableType;
  typedef RepeatedMessageTypeTraits<Type> Repeated;

typedef RepeatedPtrField<Type> RepeatedFieldType;

static inline ConstType Get(int number, const ExtensionSet& set, int index) {
    return static_cast<const Type&>(set.GetRepeatedMessage(number, index));
  }
  static inline MutableType Mutable(int number, int index, ExtensionSet* set) {
    return static_cast<Type*>(set->MutableRepeatedMessage(number, index));
  }
  static inline MutableType Add(int number, FieldType field_type,
                                ExtensionSet* set) {
    return static_cast<Type*>(
        set->AddMessage(number, field_type, Type::default_instance(), NULL));
  }
  static inline const RepeatedPtrField<Type>& GetRepeated(
      int number, const ExtensionSet& set) {
    // See notes above in RepeatedEnumTypeTraits::GetRepeated(): same
    // casting hack applies here, because a RepeatedPtrField<MessageLite>
    // cannot naturally become a RepeatedPtrType<Type> even though Type is
    // presumably a message. google::protobuf::Message goes through similar contortions
    // with a reinterpret_cast<>.
    return *reinterpret_cast<const RepeatedPtrField<Type>*>(
        set.GetRawRepeatedField(number, GetDefaultRepeatedField()));
  }
  static inline RepeatedPtrField<Type>* MutableRepeated(int number,
                                                        FieldType field_type,
                                                        bool is_packed,
                                                        ExtensionSet* set) {
    return reinterpret_cast<RepeatedPtrField<Type>*>(
        set->MutableRawRepeatedField(number, field_type, is_packed, NULL));
  }

static const RepeatedFieldType* GetDefaultRepeatedField();
  template <typename ExtendeeT>
  static void Register(int number, FieldType type, bool is_packed) {
    ExtensionSet::RegisterMessageExtension(&ExtendeeT::default_instance(),
                                           number, type, true, is_packed,
                                           &Type::default_instance());
  }
};

template <typename Type>
inline const typename RepeatedMessageTypeTraits<Type>::RepeatedFieldType*
RepeatedMessageTypeTraits<Type>::GetDefaultRepeatedField() {
  static auto instance = OnShutdownDelete(new RepeatedFieldType);
  return instance;
}

// -------------------------------------------------------------------
// ExtensionIdentifier

// This is the type of actual extension objects.  E.g. if you have:
//   extends Foo with optional int32 bar = 1234;
// then "bar" will be defined in C++ as:
//   ExtensionIdentifier<Foo, PrimitiveTypeTraits<int32>, 5, false> bar(1234);
//
// Note that we could, in theory, supply the field number as a template
// parameter, and thus make an instance of ExtensionIdentifier have no
// actual contents.  However, if we did that, then using an extension
// identifier would not necessarily cause the compiler to output any sort
// of reference to any symbol defined in the extension's .pb.o file.  Some
// linkers will actually drop object files that are not explicitly referenced,
// but that would be bad because it would cause this extension to not be
// registered at static initialization, and therefore using it would crash.

template <typename ExtendeeType, typename TypeTraitsType, FieldType field_type,
          bool is_packed>
class ExtensionIdentifier {
 public:
  typedef TypeTraitsType TypeTraits;
  typedef ExtendeeType Extendee;

ExtensionIdentifier(int number, typename TypeTraits::ConstType default_value)
      : number_(number), default_value_(default_value) {
    Register(number);
  }
  inline int number() const { return number_; }
  typename TypeTraits::ConstType default_value() const {
    return default_value_;
  }

static void Register(int number) {
    TypeTraits::template Register<ExtendeeType>(number, field_type, is_packed);
  }

private:
  const int number_;
  typename TypeTraits::ConstType default_value_;
};

// -------------------------------------------------------------------
// Generated accessors

// This macro should be expanded in the context of a generated type which
// has extensions.
//
// We use "_proto_TypeTraits" as a type name below because "TypeTraits"
// causes problems if the class has a nested message or enum type with that
// name and "_TypeTraits" is technically reserved for the C++ library since
// it starts with an underscore followed by a capital letter.
//
// For similar reason, we use "_field_type" and "_is_packed" as parameter names
// below, so that "field_type" and "is_packed" can be used as field names.
#define GOOGLE_PROTOBUF_EXTENSION_ACCESSORS(CLASSNAME)                       \
  /* Has, Size, Clear */                                                      \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline bool HasExtension(                                                   \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) const { \
    return _extensions_.Has(id.number());                                     \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline void ClearExtension(                                                 \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) {       \
    _extensions_.ClearExtension(id.number());                                 \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline int ExtensionSize(                                                   \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) const { \
    return _extensions_.ExtensionSize(id.number());                           \
  }                                                                           \
                                                                              \
  /* Singular accessors */                                                    \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Singular::ConstType GetExtension(        \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) const { \
    return _proto_TypeTraits::Get(id.number(), _extensions_,                  \
                                  id.default_value());                        \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Singular::MutableType MutableExtension(  \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) {       \
    return _proto_TypeTraits::Mutable(id.number(), _field_type,               \
                                      &_extensions_);                         \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline void SetExtension(                                                   \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      typename _proto_TypeTraits::Singular::ConstType value) {                \
    _proto_TypeTraits::Set(id.number(), _field_type, value, &_extensions_);   \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline void SetAllocatedExtension(                                          \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      typename _proto_TypeTraits::Singular::MutableType value) {              \
    _proto_TypeTraits::SetAllocated(id.number(), _field_type, value,          \
                                    &_extensions_);                           \
  }                                                                           \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline void UnsafeArenaSetAllocatedExtension(                               \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      typename _proto_TypeTraits::Singular::MutableType value) {              \
    _proto_TypeTraits::UnsafeArenaSetAllocated(id.number(), _field_type,      \
                                               value, &_extensions_);         \
  }                                                                           \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Singular::MutableType ReleaseExtension(  \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) {       \
    return _proto_TypeTraits::Release(id.number(), _field_type,               \
                                      &_extensions_);                         \
  }                                                                           \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Singular::MutableType                    \
  UnsafeArenaReleaseExtension(                                                \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) {       \
    return _proto_TypeTraits::UnsafeArenaRelease(id.number(), _field_type,    \
                                                 &_extensions_);              \
  }                                                                           \
                                                                              \
  /* Repeated accessors */                                                    \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Repeated::ConstType GetExtension(        \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      int index) const {                                                      \
    return _proto_TypeTraits::Get(id.number(), _extensions_, index);          \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Repeated::MutableType MutableExtension(  \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      int index) {                                                            \
    return _proto_TypeTraits::Mutable(id.number(), index, &_extensions_);     \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline void SetExtension(                                                   \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      int index, typename _proto_TypeTraits::Repeated::ConstType value) {     \
    _proto_TypeTraits::Set(id.number(), index, value, &_extensions_);         \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Repeated::MutableType AddExtension(      \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) {       \
    return _proto_TypeTraits::Add(id.number(), _field_type, &_extensions_);   \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline void AddExtension(                                                   \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id,         \
      typename _proto_TypeTraits::Repeated::ConstType value) {                \
    _proto_TypeTraits::Add(id.number(), _field_type, _is_packed, value,       \
                           &_extensions_);                                    \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline const typename _proto_TypeTraits::Repeated::RepeatedFieldType&       \
  GetRepeatedExtension(                                                       \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) const { \
    return _proto_TypeTraits::GetRepeated(id.number(), _extensions_);         \
  }                                                                           \
                                                                              \
  template <typename _proto_TypeTraits,                                       \
            ::PROTOBUF_NAMESPACE_ID::internal::FieldType _field_type,         \
            bool _is_packed>                                                  \
  inline typename _proto_TypeTraits::Repeated::RepeatedFieldType*             \
  MutableRepeatedExtension(                                                   \
      const ::PROTOBUF_NAMESPACE_ID::internal::ExtensionIdentifier<           \
          CLASSNAME, _proto_TypeTraits, _field_type, _is_packed>& id) {       \
    return _proto_TypeTraits::MutableRepeated(id.number(), _field_type,       \
                                              _is_packed, &_extensions_);     \
  }

}  // namespace internal

// Call this function to ensure that this extensions's reflection is linked into
// the binary:
//
//   google::protobuf::LinkExtensionReflection(Foo::my_extension);
//
// This will ensure that the following lookup will succeed:
//
//   DescriptorPool::generated_pool()->FindExtensionByName("Foo.my_extension");
//
// This is often relevant for parsing extensions in text mode.
//
// As a side-effect, it will also guarantee that anything else from the same
// .proto file will also be available for lookup in the generated pool.
//
// This function does not actually register the extension, so it does not need
// to be called before the lookup.  However it does need to occur in a function
// that cannot be stripped from the binary (ie. it must be reachable from main).
//
// Best practice is to call this function as close as possible to where the
// reflection is actually needed.  This function is very cheap to call, so you
// should not need to worry about its runtime overhead except in tight loops (on
// x86-64 it compiles into two "mov" instructions).
template <typename ExtendeeType, typename TypeTraitsType,
          internal::FieldType field_type, bool is_packed>
void LinkExtensionReflection(
    const google::protobuf::internal::ExtensionIdentifier<
        ExtendeeType, TypeTraitsType, field_type, is_packed>& extension) {
  internal::StrongReference(extension);
}

}  // namespace protobuf
}  // namespace google

#include <google/protobuf/port_undef.inc>

#endif  // GOOGLE_PROTOBUF_EXTENSION_SET_H__

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