src/google/protobuf/map_field.cc

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#include <google/protobuf/map_field.h>

#include <vector>

#include <google/protobuf/map_field_inl.h>

// Must be included last.
#include <google/protobuf/port_def.inc>

namespace google {
namespace protobuf {
namespace internal {

void MapFieldBase::Destruct() {
  if (arena_ == nullptr) {
    delete repeated_field_;
  }
  repeated_field_ = nullptr;
}

const RepeatedPtrFieldBase& MapFieldBase::GetRepeatedField() const {
  ConstAccess();
  SyncRepeatedFieldWithMap();
  return *reinterpret_cast<RepeatedPtrFieldBase*>(repeated_field_);
}

RepeatedPtrFieldBase* MapFieldBase::MutableRepeatedField() {
  MutableAccess();
  SyncRepeatedFieldWithMap();
  SetRepeatedDirty();
  return reinterpret_cast<RepeatedPtrFieldBase*>(repeated_field_);
}

void MapFieldBase::SwapState(MapFieldBase* other) {
  // a relaxed swap of the atomic
  auto other_state = other->state_.load(std::memory_order_relaxed);
  auto this_state = state_.load(std::memory_order_relaxed);
  other->state_.store(this_state, std::memory_order_relaxed);
  state_.store(other_state, std::memory_order_relaxed);
}

void SwapRepeatedPtrToNull(RepeatedPtrField<Message>** from,
                           RepeatedPtrField<Message>** to, Arena* from_arena,
                           Arena* to_arena) {
  GOOGLE_DCHECK(*from != nullptr);
  GOOGLE_DCHECK(*to == nullptr);
  *to = Arena::CreateMessage<RepeatedPtrField<Message> >(to_arena);
  **to = std::move(**from);
  if (from_arena == nullptr) {
    delete *from;
  }
  *from = nullptr;
}

void MapFieldBase::Swap(MapFieldBase* other) {
  if (arena_ == other->arena_) {
    InternalSwap(other);
    return;
  }
  if (repeated_field_ != nullptr || other->repeated_field_ != nullptr) {
    if (repeated_field_ == nullptr) {
      SwapRepeatedPtrToNull(&other->repeated_field_, &repeated_field_,
                            other->arena_, arena_);
    } else if (other->repeated_field_ == nullptr) {
      SwapRepeatedPtrToNull(&repeated_field_, &other->repeated_field_, arena_,
                            other->arena_);
    } else {
      repeated_field_->Swap(other->repeated_field_);
    }
  }
  SwapState(other);
}

void MapFieldBase::UnsafeShallowSwap(MapFieldBase* other) {
  GOOGLE_DCHECK_EQ(arena_, other->arena_);
  InternalSwap(other);
}

void MapFieldBase::InternalSwap(MapFieldBase* other) {
  std::swap(arena_, other->arena_);
  std::swap(repeated_field_, other->repeated_field_);
  SwapState(other);
}

size_t MapFieldBase::SpaceUsedExcludingSelfLong() const {
  ConstAccess();
  mutex_.Lock();
  size_t size = SpaceUsedExcludingSelfNoLock();
  mutex_.Unlock();
  ConstAccess();
  return size;
}

size_t MapFieldBase::SpaceUsedExcludingSelfNoLock() const {
  if (repeated_field_ != nullptr) {
    return repeated_field_->SpaceUsedExcludingSelfLong();
  } else {
    return 0;
  }
}

bool MapFieldBase::IsMapValid() const {
  ConstAccess();
  // "Acquire" insures the operation after SyncRepeatedFieldWithMap won't get
  // executed before state_ is checked.
  int state = state_.load(std::memory_order_acquire);
  return state != STATE_MODIFIED_REPEATED;
}

bool MapFieldBase::IsRepeatedFieldValid() const {
  ConstAccess();
  int state = state_.load(std::memory_order_acquire);
  return state != STATE_MODIFIED_MAP;
}

void MapFieldBase::SetMapDirty() {
  MutableAccess();
  // These are called by (non-const) mutator functions. So by our API it's the
  // callers responsibility to have these calls properly ordered.
  state_.store(STATE_MODIFIED_MAP, std::memory_order_relaxed);
}

void MapFieldBase::SetRepeatedDirty() {
  MutableAccess();
  // These are called by (non-const) mutator functions. So by our API it's the
  // callers responsibility to have these calls properly ordered.
  state_.store(STATE_MODIFIED_REPEATED, std::memory_order_relaxed);
}

void MapFieldBase::SyncRepeatedFieldWithMap() const {
  ConstAccess();
  // acquire here matches with release below to ensure that we can only see a
  // value of CLEAN after all previous changes have been synced.
  switch (state_.load(std::memory_order_acquire)) {
    case 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_.load(std::memory_order_relaxed) == STATE_MODIFIED_MAP) {
        SyncRepeatedFieldWithMapNoLock();
        state_.store(CLEAN, std::memory_order_release);
      }
      mutex_.Unlock();
      ConstAccess();
      break;
    case CLEAN:
      mutex_.Lock();
      // Double check state
      if (state_.load(std::memory_order_relaxed) == CLEAN) {
        if (repeated_field_ == nullptr) {
          repeated_field_ =
              Arena::CreateMessage<RepeatedPtrField<Message> >(arena_);
        }
        state_.store(CLEAN, std::memory_order_release);
      }
      mutex_.Unlock();
      ConstAccess();
      break;
    default:
      break;
  }
}

void MapFieldBase::SyncRepeatedFieldWithMapNoLock() const {
  if (repeated_field_ == nullptr) {
    repeated_field_ = Arena::CreateMessage<RepeatedPtrField<Message> >(arena_);
  }
}

void MapFieldBase::SyncMapWithRepeatedField() const {
  ConstAccess();
  // acquire here matches with release below to ensure that we can only see a
  // value of CLEAN after all previous changes have been synced.
  if (state_.load(std::memory_order_acquire) == 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_.load(std::memory_order_relaxed) == STATE_MODIFIED_REPEATED) {
      SyncMapWithRepeatedFieldNoLock();
      state_.store(CLEAN, std::memory_order_release);
    }
    mutex_.Unlock();
    ConstAccess();
  }
}

// ------------------DynamicMapField------------------
DynamicMapField::DynamicMapField(const Message* default_entry)
    : default_entry_(default_entry) {}

DynamicMapField::DynamicMapField(const Message* default_entry, Arena* arena)
    : TypeDefinedMapFieldBase<MapKey, MapValueRef>(arena),
      map_(arena),
      default_entry_(default_entry) {}

DynamicMapField::~DynamicMapField() {
  if (arena_ == nullptr) {
    // DynamicMapField owns map values. Need to delete them before clearing the
    // map.
    for (auto& kv : map_) {
      kv.second.DeleteData();
    }
    map_.clear();
  }
  Destruct();
}

int DynamicMapField::size() const { return GetMap().size(); }

void DynamicMapField::Clear() {
  Map<MapKey, MapValueRef>* map = &const_cast<DynamicMapField*>(this)->map_;
  if (MapFieldBase::arena_ == nullptr) {
    for (Map<MapKey, MapValueRef>::iterator iter = map->begin();
         iter != map->end(); ++iter) {
      iter->second.DeleteData();
    }
  }

  map->clear();

  if (MapFieldBase::repeated_field_ != nullptr) {
    MapFieldBase::repeated_field_->Clear();
  }
  // Data in map and repeated field are both empty, but we can't set status
  // CLEAN which will invalidate previous reference to map.
  MapFieldBase::SetMapDirty();
}

bool DynamicMapField::ContainsMapKey(const MapKey& map_key) const {
  const Map<MapKey, MapValueRef>& map = GetMap();
  Map<MapKey, MapValueRef>::const_iterator iter = map.find(map_key);
  return iter != map.end();
}

void DynamicMapField::AllocateMapValue(MapValueRef* map_val) {
  const FieldDescriptor* val_des = default_entry_->GetDescriptor()->map_value();
  map_val->SetType(val_des->cpp_type());
  // Allocate memory for the MapValueRef, and initialize to
  // default value.
  switch (val_des->cpp_type()) {
#define HANDLE_TYPE(CPPTYPE, TYPE)                           \
  case FieldDescriptor::CPPTYPE_##CPPTYPE: {                 \
    TYPE* value = Arena::Create<TYPE>(MapFieldBase::arena_); \
    map_val->SetValue(value);                                \
    break;                                                   \
  }
    HANDLE_TYPE(INT32, int32_t);
    HANDLE_TYPE(INT64, int64_t);
    HANDLE_TYPE(UINT32, uint32_t);
    HANDLE_TYPE(UINT64, uint64_t);
    HANDLE_TYPE(DOUBLE, double);
    HANDLE_TYPE(FLOAT, float);
    HANDLE_TYPE(BOOL, bool);
    HANDLE_TYPE(STRING, std::string);
    HANDLE_TYPE(ENUM, int32_t);
#undef HANDLE_TYPE
    case FieldDescriptor::CPPTYPE_MESSAGE: {
      const Message& message =
          default_entry_->GetReflection()->GetMessage(*default_entry_, val_des);
      Message* value = message.New(MapFieldBase::arena_);
      map_val->SetValue(value);
      break;
    }
  }
}

bool DynamicMapField::InsertOrLookupMapValue(const MapKey& map_key,
                                             MapValueRef* val) {
  // Always use mutable map because users may change the map value by
  // MapValueRef.
  Map<MapKey, MapValueRef>* map = MutableMap();
  Map<MapKey, MapValueRef>::iterator iter = map->find(map_key);
  if (iter == map->end()) {
    MapValueRef& map_val = map_[map_key];
    AllocateMapValue(&map_val);
    val->CopyFrom(map_val);
    return true;
  }
  // map_key is already in the map. Make sure (*map)[map_key] is not called.
  // [] may reorder the map and iterators.
  val->CopyFrom(iter->second);
  return false;
}

bool DynamicMapField::LookupMapValue(const MapKey& map_key,
                                     MapValueConstRef* val) const {
  const Map<MapKey, MapValueRef>& map = GetMap();
  Map<MapKey, MapValueRef>::const_iterator iter = map.find(map_key);
  if (iter == map.end()) {
    return false;
  }
  // map_key is already in the map. Make sure (*map)[map_key] is not called.
  // [] may reorder the map and iterators.
  val->CopyFrom(iter->second);
  return true;
}

bool DynamicMapField::DeleteMapValue(const MapKey& map_key) {
  MapFieldBase::SyncMapWithRepeatedField();
  Map<MapKey, MapValueRef>::iterator iter = map_.find(map_key);
  if (iter == map_.end()) {
    return false;
  }
  // Set map dirty only if the delete is successful.
  MapFieldBase::SetMapDirty();
  if (MapFieldBase::arena_ == nullptr) {
    iter->second.DeleteData();
  }
  map_.erase(iter);
  return true;
}

const Map<MapKey, MapValueRef>& DynamicMapField::GetMap() const {
  MapFieldBase::SyncMapWithRepeatedField();
  return map_;
}

Map<MapKey, MapValueRef>* DynamicMapField::MutableMap() {
  MapFieldBase::SyncMapWithRepeatedField();
  MapFieldBase::SetMapDirty();
  return &map_;
}

void DynamicMapField::SetMapIteratorValue(MapIterator* map_iter) const {
  Map<MapKey, MapValueRef>::const_iterator iter =
      TypeDefinedMapFieldBase<MapKey, MapValueRef>::InternalGetIterator(
          map_iter);
  if (iter == map_.end()) return;
  map_iter->key_.CopyFrom(iter->first);
  map_iter->value_.CopyFrom(iter->second);
}

void DynamicMapField::MergeFrom(const MapFieldBase& other) {
  GOOGLE_DCHECK(IsMapValid() && other.IsMapValid());
  Map<MapKey, MapValueRef>* map = MutableMap();
  const DynamicMapField& other_field =
      reinterpret_cast<const DynamicMapField&>(other);
  for (Map<MapKey, MapValueRef>::const_iterator other_it =
           other_field.map_.begin();
       other_it != other_field.map_.end(); ++other_it) {
    Map<MapKey, MapValueRef>::iterator iter = map->find(other_it->first);
    MapValueRef* map_val;
    if (iter == map->end()) {
      map_val = &map_[other_it->first];
      AllocateMapValue(map_val);
    } else {
      map_val = &iter->second;
    }

    // Copy map value
    const FieldDescriptor* field_descriptor =
        default_entry_->GetDescriptor()->map_value();
    switch (field_descriptor->cpp_type()) {
      case FieldDescriptor::CPPTYPE_INT32: {
        map_val->SetInt32Value(other_it->second.GetInt32Value());
        break;
      }
      case FieldDescriptor::CPPTYPE_INT64: {
        map_val->SetInt64Value(other_it->second.GetInt64Value());
        break;
      }
      case FieldDescriptor::CPPTYPE_UINT32: {
        map_val->SetUInt32Value(other_it->second.GetUInt32Value());
        break;
      }
      case FieldDescriptor::CPPTYPE_UINT64: {
        map_val->SetUInt64Value(other_it->second.GetUInt64Value());
        break;
      }
      case FieldDescriptor::CPPTYPE_FLOAT: {
        map_val->SetFloatValue(other_it->second.GetFloatValue());
        break;
      }
      case FieldDescriptor::CPPTYPE_DOUBLE: {
        map_val->SetDoubleValue(other_it->second.GetDoubleValue());
        break;
      }
      case FieldDescriptor::CPPTYPE_BOOL: {
        map_val->SetBoolValue(other_it->second.GetBoolValue());
        break;
      }
      case FieldDescriptor::CPPTYPE_STRING: {
        map_val->SetStringValue(other_it->second.GetStringValue());
        break;
      }
      case FieldDescriptor::CPPTYPE_ENUM: {
        map_val->SetEnumValue(other_it->second.GetEnumValue());
        break;
      }
      case FieldDescriptor::CPPTYPE_MESSAGE: {
        map_val->MutableMessageValue()->CopyFrom(
            other_it->second.GetMessageValue());
        break;
      }
    }
  }
}

void DynamicMapField::Swap(MapFieldBase* other) {
  DynamicMapField* other_field = down_cast<DynamicMapField*>(other);
  std::swap(this->MapFieldBase::repeated_field_, other_field->repeated_field_);
  map_.swap(other_field->map_);
  // a relaxed swap of the atomic
  auto other_state = other_field->state_.load(std::memory_order_relaxed);
  auto this_state = this->MapFieldBase::state_.load(std::memory_order_relaxed);
  other_field->state_.store(this_state, std::memory_order_relaxed);
  this->MapFieldBase::state_.store(other_state, std::memory_order_relaxed);
}

void DynamicMapField::SyncRepeatedFieldWithMapNoLock() const {
  const Reflection* reflection = default_entry_->GetReflection();
  const FieldDescriptor* key_des = default_entry_->GetDescriptor()->map_key();
  const FieldDescriptor* val_des = default_entry_->GetDescriptor()->map_value();
  if (MapFieldBase::repeated_field_ == nullptr) {
    MapFieldBase::repeated_field_ =
        Arena::CreateMessage<RepeatedPtrField<Message> >(MapFieldBase::arena_);
  }

  MapFieldBase::repeated_field_->Clear();

  for (Map<MapKey, MapValueRef>::const_iterator it = map_.begin();
       it != map_.end(); ++it) {
    Message* new_entry = default_entry_->New(MapFieldBase::arena_);
    MapFieldBase::repeated_field_->AddAllocated(new_entry);
    const MapKey& map_key = it->first;
    switch (key_des->cpp_type()) {
      case FieldDescriptor::CPPTYPE_STRING:
        reflection->SetString(new_entry, key_des, map_key.GetStringValue());
        break;
      case FieldDescriptor::CPPTYPE_INT64:
        reflection->SetInt64(new_entry, key_des, map_key.GetInt64Value());
        break;
      case FieldDescriptor::CPPTYPE_INT32:
        reflection->SetInt32(new_entry, key_des, map_key.GetInt32Value());
        break;
      case FieldDescriptor::CPPTYPE_UINT64:
        reflection->SetUInt64(new_entry, key_des, map_key.GetUInt64Value());
        break;
      case FieldDescriptor::CPPTYPE_UINT32:
        reflection->SetUInt32(new_entry, key_des, map_key.GetUInt32Value());
        break;
      case FieldDescriptor::CPPTYPE_BOOL:
        reflection->SetBool(new_entry, key_des, map_key.GetBoolValue());
        break;
      case FieldDescriptor::CPPTYPE_DOUBLE:
      case FieldDescriptor::CPPTYPE_FLOAT:
      case FieldDescriptor::CPPTYPE_ENUM:
      case FieldDescriptor::CPPTYPE_MESSAGE:
        GOOGLE_LOG(FATAL) << "Can't get here.";
        break;
    }
    const MapValueRef& map_val = it->second;
    switch (val_des->cpp_type()) {
      case FieldDescriptor::CPPTYPE_STRING:
        reflection->SetString(new_entry, val_des, map_val.GetStringValue());
        break;
      case FieldDescriptor::CPPTYPE_INT64:
        reflection->SetInt64(new_entry, val_des, map_val.GetInt64Value());
        break;
      case FieldDescriptor::CPPTYPE_INT32:
        reflection->SetInt32(new_entry, val_des, map_val.GetInt32Value());
        break;
      case FieldDescriptor::CPPTYPE_UINT64:
        reflection->SetUInt64(new_entry, val_des, map_val.GetUInt64Value());
        break;
      case FieldDescriptor::CPPTYPE_UINT32:
        reflection->SetUInt32(new_entry, val_des, map_val.GetUInt32Value());
        break;
      case FieldDescriptor::CPPTYPE_BOOL:
        reflection->SetBool(new_entry, val_des, map_val.GetBoolValue());
        break;
      case FieldDescriptor::CPPTYPE_DOUBLE:
        reflection->SetDouble(new_entry, val_des, map_val.GetDoubleValue());
        break;
      case FieldDescriptor::CPPTYPE_FLOAT:
        reflection->SetFloat(new_entry, val_des, map_val.GetFloatValue());
        break;
      case FieldDescriptor::CPPTYPE_ENUM:
        reflection->SetEnumValue(new_entry, val_des, map_val.GetEnumValue());
        break;
      case FieldDescriptor::CPPTYPE_MESSAGE: {
        const Message& message = map_val.GetMessageValue();
        reflection->MutableMessage(new_entry, val_des)->CopyFrom(message);
        break;
      }
    }
  }
}

void DynamicMapField::SyncMapWithRepeatedFieldNoLock() const {
  Map<MapKey, MapValueRef>* map = &const_cast<DynamicMapField*>(this)->map_;
  const Reflection* reflection = default_entry_->GetReflection();
  const FieldDescriptor* key_des = default_entry_->GetDescriptor()->map_key();
  const FieldDescriptor* val_des = default_entry_->GetDescriptor()->map_value();
  // DynamicMapField owns map values. Need to delete them before clearing
  // the map.
  if (MapFieldBase::arena_ == nullptr) {
    for (Map<MapKey, MapValueRef>::iterator iter = map->begin();
         iter != map->end(); ++iter) {
      iter->second.DeleteData();
    }
  }
  map->clear();
  for (RepeatedPtrField<Message>::iterator it =
           MapFieldBase::repeated_field_->begin();
       it != MapFieldBase::repeated_field_->end(); ++it) {
    // MapKey type will be set later.
    MapKey map_key;
    switch (key_des->cpp_type()) {
      case FieldDescriptor::CPPTYPE_STRING:
        map_key.SetStringValue(reflection->GetString(*it, key_des));
        break;
      case FieldDescriptor::CPPTYPE_INT64:
        map_key.SetInt64Value(reflection->GetInt64(*it, key_des));
        break;
      case FieldDescriptor::CPPTYPE_INT32:
        map_key.SetInt32Value(reflection->GetInt32(*it, key_des));
        break;
      case FieldDescriptor::CPPTYPE_UINT64:
        map_key.SetUInt64Value(reflection->GetUInt64(*it, key_des));
        break;
      case FieldDescriptor::CPPTYPE_UINT32:
        map_key.SetUInt32Value(reflection->GetUInt32(*it, key_des));
        break;
      case FieldDescriptor::CPPTYPE_BOOL:
        map_key.SetBoolValue(reflection->GetBool(*it, key_des));
        break;
      case FieldDescriptor::CPPTYPE_DOUBLE:
      case FieldDescriptor::CPPTYPE_FLOAT:
      case FieldDescriptor::CPPTYPE_ENUM:
      case FieldDescriptor::CPPTYPE_MESSAGE:
        GOOGLE_LOG(FATAL) << "Can't get here.";
        break;
    }

    if (MapFieldBase::arena_ == nullptr) {
      // Remove existing map value with same key.
      Map<MapKey, MapValueRef>::iterator iter = map->find(map_key);
      if (iter != map->end()) {
        iter->second.DeleteData();
      }
    }

    MapValueRef& map_val = (*map)[map_key];
    map_val.SetType(val_des->cpp_type());
    switch (val_des->cpp_type()) {
#define HANDLE_TYPE(CPPTYPE, TYPE, METHOD)                   \
  case FieldDescriptor::CPPTYPE_##CPPTYPE: {                 \
    TYPE* value = Arena::Create<TYPE>(MapFieldBase::arena_); \
    *value = reflection->Get##METHOD(*it, val_des);          \
    map_val.SetValue(value);                                 \
    break;                                                   \
  }
      HANDLE_TYPE(INT32, int32_t, Int32);
      HANDLE_TYPE(INT64, int64_t, Int64);
      HANDLE_TYPE(UINT32, uint32_t, UInt32);
      HANDLE_TYPE(UINT64, uint64_t, UInt64);
      HANDLE_TYPE(DOUBLE, double, Double);
      HANDLE_TYPE(FLOAT, float, Float);
      HANDLE_TYPE(BOOL, bool, Bool);
      HANDLE_TYPE(STRING, std::string, String);
      HANDLE_TYPE(ENUM, int32_t, EnumValue);
#undef HANDLE_TYPE
      case FieldDescriptor::CPPTYPE_MESSAGE: {
        const Message& message = reflection->GetMessage(*it, val_des);
        Message* value = message.New(MapFieldBase::arena_);
        value->CopyFrom(message);
        map_val.SetValue(value);
        break;
      }
    }
  }
}

size_t DynamicMapField::SpaceUsedExcludingSelfNoLock() const {
  size_t size = 0;
  if (MapFieldBase::repeated_field_ != nullptr) {
    size += MapFieldBase::repeated_field_->SpaceUsedExcludingSelfLong();
  }
  size += sizeof(map_);
  size_t map_size = map_.size();
  if (map_size) {
    Map<MapKey, MapValueRef>::const_iterator it = map_.begin();
    size += sizeof(it->first) * map_size;
    size += sizeof(it->second) * map_size;
    // If key is string, add the allocated space.
    if (it->first.type() == FieldDescriptor::CPPTYPE_STRING) {
      size += sizeof(std::string) * map_size;
    }
    // Add the allocated space in MapValueRef.
    switch (it->second.type()) {
#define HANDLE_TYPE(CPPTYPE, TYPE)           \
  case FieldDescriptor::CPPTYPE_##CPPTYPE: { \
    size += sizeof(TYPE) * map_size;         \
    break;                                   \
  }
      HANDLE_TYPE(INT32, int32_t);
      HANDLE_TYPE(INT64, int64_t);
      HANDLE_TYPE(UINT32, uint32_t);
      HANDLE_TYPE(UINT64, uint64_t);
      HANDLE_TYPE(DOUBLE, double);
      HANDLE_TYPE(FLOAT, float);
      HANDLE_TYPE(BOOL, bool);
      HANDLE_TYPE(STRING, std::string);
      HANDLE_TYPE(ENUM, int32_t);
#undef HANDLE_TYPE
      case FieldDescriptor::CPPTYPE_MESSAGE: {
        while (it != map_.end()) {
          const Message& message = it->second.GetMessageValue();
          size += message.GetReflection()->SpaceUsedLong(message);
          ++it;
        }
        break;
      }
    }
  }
  return size;
}

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

#include <google/protobuf/port_undef.inc>