src/google/protobuf/map_field.cc

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
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#include <google/protobuf/map_field.h>

#include <vector>

namespace google {
namespace protobuf {
namespace internal {

ProtobufOnceType map_entry_default_instances_once_;
Mutex* map_entry_default_instances_mutex_;
vector<MessageLite*>* map_entry_default_instances_;

void DeleteMapEntryDefaultInstances() {
  for (int i = 0; i < map_entry_default_instances_->size(); ++i) {
    delete map_entry_default_instances_->at(i);
  }
  delete map_entry_default_instances_mutex_;
  delete map_entry_default_instances_;
}

void InitMapEntryDefaultInstances() {
  map_entry_default_instances_mutex_ = new Mutex();
  map_entry_default_instances_ = new vector<MessageLite*>();
  OnShutdown(&DeleteMapEntryDefaultInstances);
}

void RegisterMapEntryDefaultInstance(MessageLite* default_instance) {
  ::google::protobuf::GoogleOnceInit(&map_entry_default_instances_once_,
                 &InitMapEntryDefaultInstances);
  MutexLock lock(map_entry_default_instances_mutex_);
  map_entry_default_instances_->push_back(default_instance);
}

MapFieldBase::~MapFieldBase() {
  if (repeated_field_ != NULL && arena_ == NULL) delete repeated_field_;
}

const RepeatedPtrFieldBase& MapFieldBase::GetRepeatedField() const {
  SyncRepeatedFieldWithMap();
  return *repeated_field_;
}

RepeatedPtrFieldBase* MapFieldBase::MutableRepeatedField() {
  SyncRepeatedFieldWithMap();
  SetRepeatedDirty();
  return repeated_field_;
}

int MapFieldBase::SpaceUsedExcludingSelf() const {
  mutex_.Lock();
  int size = SpaceUsedExcludingSelfNoLock();
  mutex_.Unlock();
  return size;
}

int MapFieldBase::SpaceUsedExcludingSelfNoLock() const {
  if (repeated_field_ != NULL) {
    return repeated_field_->SpaceUsedExcludingSelf();
  } else {
    return 0;
  }
}

void MapFieldBase::InitMetadataOnce() const {
  GOOGLE_CHECK(entry_descriptor_ != NULL);
  GOOGLE_CHECK(assign_descriptor_callback_ != NULL);
  (*assign_descriptor_callback_)();
}

void MapFieldBase::SetMapDirty() { state_ = STATE_MODIFIED_MAP; }

void MapFieldBase::SetRepeatedDirty() { state_ = STATE_MODIFIED_REPEATED; }

void* MapFieldBase::MutableRepeatedPtrField() const { return repeated_field_; }

void MapFieldBase::SyncRepeatedFieldWithMap() const {
  Atomic32 state = google::protobuf::internal::NoBarrier_Load(&state_);
  if (state == STATE_MODIFIED_MAP) {
    mutex_.Lock();
    // Double check state, because another thread may have seen the same state
    // and done the synchronization before the current thread.
    if (state_ == STATE_MODIFIED_MAP) {
      SyncRepeatedFieldWithMapNoLock();
      google::protobuf::internal::NoBarrier_Store(&state_, CLEAN);
    }
    mutex_.Unlock();
  }
}

void MapFieldBase::SyncRepeatedFieldWithMapNoLock() const {
  if (repeated_field_ == NULL) {
    repeated_field_ = Arena::Create<RepeatedPtrField<Message> >(arena_, arena_);
  }
}

void MapFieldBase::SyncMapWithRepeatedField() const {
  Atomic32 state = google::protobuf::internal::NoBarrier_Load(&state_);
  if (state == STATE_MODIFIED_REPEATED) {
    mutex_.Lock();
    // Double check state, because another thread may have seen the same state
    // and done the synchronization before the current thread.
    if (state_ == STATE_MODIFIED_REPEATED) {
      SyncMapWithRepeatedFieldNoLock();
      google::protobuf::internal::NoBarrier_Store(&state_, CLEAN);
    }
    mutex_.Unlock();
  }
}

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