Down integrate from Google internal branch for C++ and Java.

- Maps for C++ lite
- C++ Arena optimizations.
- Java Lite runtime code size optimization.

Change-Id: I7537a4357c1cb385d23f9e8aa7ffdfeefe079f13

1 files changed, 409 insertions, 0 deletions

diff --git a/src/google/protobuf/map_entry_lite.h b/src/google/protobuf/map_entry_lite.h
new file mode 100644
index 00000000..0602d847
--- /dev/null
+++ b/src/google/protobuf/map_entry_lite.h
@@ -0,0 +1,409 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_MAP_ENTRY_LITE_H__
+#define GOOGLE_PROTOBUF_MAP_ENTRY_LITE_H__
+
+#include <google/protobuf/map_type_handler.h>
+#include <google/protobuf/wire_format_lite_inl.h>
+
+namespace google {
+namespace protobuf {
+class Arena;
+namespace internal {
+template <typename Key, typename Value,
+          WireFormatLite::FieldType kKeyFieldType,
+          WireFormatLite::FieldType kValueFieldType,
+          int default_enum_value>
+class MapEntry;
+template <typename Key, typename Value,
+          WireFormatLite::FieldType kKeyFieldType,
+          WireFormatLite::FieldType kValueFieldType,
+          int default_enum_value>
+class MapFieldLite;
+}  // namespace internal
+}  // namespace protobuf
+
+namespace protobuf {
+namespace internal {
+
+// MapEntryLite is used to implement parsing and serialization of map for lite
+// runtime.
+template <typename Key, typename Value,
+          WireFormatLite::FieldType kKeyFieldType,
+          WireFormatLite::FieldType kValueFieldType,
+          int default_enum_value>
+class LIBPROTOBUF_EXPORT MapEntryLite : public MessageLite {
+  // Handlers for key/value wire type. Provide utilities to parse/serialize
+  // key/value.
+  typedef MapWireFieldTypeHandler<kKeyFieldType> KeyWireHandler;
+  typedef MapWireFieldTypeHandler<kValueFieldType> ValueWireHandler;
+
+  // Define key/value's internal stored type. Message is the only one whose
+  // internal stored type cannot be inferred from its proto type
+  static const bool kIsKeyMessage = KeyWireHandler::kIsMessage;
+  static const bool kIsValueMessage = ValueWireHandler::kIsMessage;
+  typedef typename KeyWireHandler::CppType KeyInternalType;
+  typedef typename ValueWireHandler::CppType ValueInternalType;
+  typedef typename MapIf<kIsKeyMessage, Key, KeyInternalType>::type
+      KeyCppType;
+  typedef typename MapIf<kIsValueMessage, Value, ValueInternalType>::type
+      ValCppType;
+
+  // Handlers for key/value's internal stored type. Provide utilities to
+  // manipulate internal stored type. We need it because some types are stored
+  // as values and others are stored as pointers (Message and string), but we
+  // need to keep the code in MapEntry unified instead of providing different
+  // codes for each type.
+  typedef MapCppTypeHandler<KeyCppType> KeyCppHandler;
+  typedef MapCppTypeHandler<ValCppType> ValueCppHandler;
+
+  // Define internal memory layout. Strings and messages are stored as
+  // pointers, while other types are stored as values.
+  static const bool kKeyIsStringOrMessage = KeyCppHandler::kIsStringOrMessage;
+  static const bool kValIsStringOrMessage = ValueCppHandler::kIsStringOrMessage;
+  typedef typename MapIf<kKeyIsStringOrMessage, KeyCppType*, KeyCppType>::type
+      KeyBase;
+  typedef typename MapIf<kValIsStringOrMessage, ValCppType*, ValCppType>::type
+      ValueBase;
+
+  // Constants for field number.
+  static const int kKeyFieldNumber = 1;
+  static const int kValueFieldNumber = 2;
+
+  // Constants for field tag.
+  static const uint8 kKeyTag = GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(
+      kKeyFieldNumber, KeyWireHandler::kWireType);
+  static const uint8 kValueTag = GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(
+      kValueFieldNumber, ValueWireHandler::kWireType);
+  static const int kTagSize = 1;
+
+ public:
+  ~MapEntryLite() {
+    if (this != default_instance_) {
+      KeyCppHandler::Delete(key_);
+      ValueCppHandler::Delete(value_);
+    }
+  }
+
+  // accessors ======================================================
+
+  virtual inline const KeyCppType& key() const {
+    return KeyCppHandler::Reference(key_);
+  }
+  inline KeyCppType* mutable_key() {
+    set_has_key();
+    KeyCppHandler::EnsureMutable(&key_, GetArenaNoVirtual());
+    return KeyCppHandler::Pointer(key_);
+  }
+  virtual inline const ValCppType& value() const {
+    GOOGLE_CHECK(default_instance_ != NULL);
+    return ValueCppHandler::DefaultIfNotInitialized(value_,
+                                                    default_instance_->value_);
+  }
+  inline ValCppType* mutable_value() {
+    set_has_value();
+    ValueCppHandler::EnsureMutable(&value_, GetArenaNoVirtual());
+    return ValueCppHandler::Pointer(value_);
+  }
+
+  // implements MessageLite =========================================
+
+  // MapEntryLite is for implementation only and this function isn't called
+  // anywhere. Just provide a fake implementation here for MessageLite.
+  string GetTypeName() const { return ""; }
+
+  void CheckTypeAndMergeFrom(const MessageLite& other) {
+    MergeFrom(*::google::protobuf::down_cast<const MapEntryLite*>(&other));
+  }
+
+  bool MergePartialFromCodedStream(::google::protobuf::io::CodedInputStream* input) {
+    uint32 tag;
+
+    for (;;) {
+      // 1) corrupted data: return false;
+      // 2) unknown field: skip without putting into unknown field set;
+      // 3) unknown enum value: keep it in parsing. In proto2, caller should
+      // check the value and put this entry into containing message's unknown
+      // field set if the value is an unknown enum. In proto3, caller doesn't
+      // need to care whether the value is unknown enum;
+      // 4) missing key/value: missed key/value will have default value. caller
+      // should take this entry as if key/value is set to default value.
+      tag = input->ReadTag();
+      switch (tag) {
+        case kKeyTag:
+          if (!KeyWireHandler::Read(input, mutable_key())) return false;
+          set_has_key();
+          if (!input->ExpectTag(kValueTag)) break;
+          GOOGLE_FALLTHROUGH_INTENDED;
+
+        case kValueTag:
+          if (!ValueWireHandler::Read(input, mutable_value())) return false;
+          set_has_value();
+          if (input->ExpectAtEnd()) return true;
+          break;
+
+        default:
+          if (tag == 0 ||
+              WireFormatLite::GetTagWireType(tag) ==
+              WireFormatLite::WIRETYPE_END_GROUP) {
+            return true;
+          }
+          if (!WireFormatLite::SkipField(input, tag)) return false;
+          break;
+      }
+    }
+  }
+
+  int ByteSize() const {
+    int size = 0;
+    size += has_key() ? kTagSize + KeyWireHandler::ByteSize(key()) : 0;
+    size += has_value() ? kTagSize + ValueWireHandler::ByteSize(value()) : 0;
+    return size;
+  }
+
+  void SerializeWithCachedSizes(::google::protobuf::io::CodedOutputStream* output) const {
+    KeyWireHandler::Write(kKeyFieldNumber, key(), output);
+    ValueWireHandler::Write(kValueFieldNumber, value(), output);
+  }
+
+  ::google::protobuf::uint8* SerializeWithCachedSizesToArray(::google::protobuf::uint8* output) const {
+    output = KeyWireHandler::WriteToArray(kKeyFieldNumber, key(), output);
+    output =
+        ValueWireHandler::WriteToArray(kValueFieldNumber, value(), output);
+    return output;
+  }
+
+  int GetCachedSize() const {
+    int size = 0;
+    size += has_key() ? kTagSize + KeyWireHandler::GetCachedSize(key()) : 0;
+    size +=
+        has_value() ? kTagSize + ValueWireHandler::GetCachedSize(value()) : 0;
+    return size;
+  }
+
+  bool IsInitialized() const { return ValueCppHandler::IsInitialized(value_); }
+
+  MessageLite* New() const {
+    MapEntryLite* entry = new MapEntryLite;
+    entry->default_instance_ = default_instance_;
+    return entry;
+  }
+
+  MessageLite* New(Arena* arena) const {
+    MapEntryLite* entry = Arena::CreateMessage<MapEntryLite>(arena);
+    entry->default_instance_ = default_instance_;
+    return entry;
+  }
+
+  int SpaceUsed() const {
+    int size = sizeof(MapEntryLite);
+    size += KeyCppHandler::SpaceUsedInMapEntry(key_);
+    size += ValueCppHandler::SpaceUsedInMapEntry(value_);
+    return size;
+  }
+
+  void MergeFrom(const MapEntryLite& from) {
+    if (from._has_bits_[0]) {
+      if (from.has_key()) {
+        KeyCppHandler::EnsureMutable(&key_, GetArenaNoVirtual());
+        KeyCppHandler::Merge(from.key(), &key_);
+        set_has_key();
+      }
+      if (from.has_value()) {
+        ValueCppHandler::EnsureMutable(&value_, GetArenaNoVirtual());
+        ValueCppHandler::Merge(from.value(), &value_);
+        set_has_value();
+      }
+    }
+  }
+
+  void Clear() {
+    KeyCppHandler::Clear(&key_);
+    ValueCppHandler::ClearMaybeByDefaultEnum(&value_, default_enum_value);
+    clear_has_key();
+    clear_has_value();
+  }
+
+  void InitAsDefaultInstance() {
+    KeyCppHandler::AssignDefaultValue(&key_);
+    ValueCppHandler::AssignDefaultValue(&value_);
+  }
+
+  Arena* GetArena() const {
+    return GetArenaNoVirtual();
+  }
+
+  // Create a MapEntryLite for given key and value from google::protobuf::Map in
+  // serialization. This function is only called when value is enum. Enum is
+  // treated differently because its type in MapEntry is int and its type in
+  // google::protobuf::Map is enum. We cannot create a reference to int from an enum.
+  static MapEntryLite* EnumWrap(const Key& key, const Value value,
+                                Arena* arena) {
+    return Arena::Create<MapEnumEntryWrapper<
+        Key, Value, kKeyFieldType, kValueFieldType, default_enum_value> >(
+        arena, key, value, arena);
+  }
+
+  // Like above, but for all the other types. This avoids value copy to create
+  // MapEntryLite from google::protobuf::Map in serialization.
+  static MapEntryLite* Wrap(const Key& key, const Value& value, Arena* arena) {
+    return Arena::Create<MapEntryWrapper<Key, Value, kKeyFieldType,
+                                         kValueFieldType, default_enum_value> >(
+        arena, key, value, arena);
+  }
+
+ protected:
+  void set_has_key() { _has_bits_[0] |= 0x00000001u; }
+  bool has_key() const { return (_has_bits_[0] & 0x00000001u) != 0; }
+  void clear_has_key() { _has_bits_[0] &= ~0x00000001u; }
+  void set_has_value() { _has_bits_[0] |= 0x00000002u; }
+  bool has_value() const { return (_has_bits_[0] & 0x00000002u) != 0; }
+  void clear_has_value() { _has_bits_[0] &= ~0x00000002u; }
+
+ private:
+  // Serializing a generated message containing map field involves serializing
+  // key-value pairs from google::protobuf::Map. The wire format of each key-value pair
+  // after serialization should be the same as that of a MapEntry message
+  // containing the same key and value inside it.  However, google::protobuf::Map doesn't
+  // store key and value as MapEntry message, which disables us to use existing
+  // code to serialize message. In order to use existing code to serialize
+  // message, we need to construct a MapEntry from key-value pair. But it
+  // involves copy of key and value to construct a MapEntry. In order to avoid
+  // this copy in constructing a MapEntry, we need the following class which
+  // only takes references of given key and value.
+  template <typename K, typename V, WireFormatLite::FieldType k_wire_type,
+            WireFormatLite::FieldType v_wire_type, int default_enum>
+  class LIBPROTOBUF_EXPORT MapEntryWrapper
+      : public MapEntryLite<K, V, k_wire_type, v_wire_type, default_enum> {
+    typedef MapEntryLite<K, V, k_wire_type, v_wire_type, default_enum> Base;
+    typedef typename Base::KeyCppType KeyCppType;
+    typedef typename Base::ValCppType ValCppType;
+
+   public:
+    MapEntryWrapper(const K& key, const V& value, Arena* arena)
+        : MapEntryLite<K, V, k_wire_type, v_wire_type, default_enum>(arena),
+          key_(key),
+          value_(value) {
+      Base::set_has_key();
+      Base::set_has_value();
+    }
+    inline const KeyCppType& key() const { return key_; }
+    inline const ValCppType& value() const { return value_; }
+
+   private:
+    const Key& key_;
+    const Value& value_;
+
+    friend class ::google::protobuf::Arena;
+    typedef void DestructorSkippable_;
+  };
+
+  // Like above, but for enum value only, which stores value instead of
+  // reference of value field inside. This is needed because the type of value
+  // field in constructor is an enum, while we need to store it as an int. If we
+  // initialize a reference to int with a reference to enum, compiler will
+  // generate a temporary int from enum and initialize the reference to int with
+  // the temporary.
+  template <typename K, typename V, WireFormatLite::FieldType k_wire_type,
+            WireFormatLite::FieldType v_wire_type, int default_enum>
+  class LIBPROTOBUF_EXPORT MapEnumEntryWrapper
+      : public MapEntryLite<K, V, k_wire_type, v_wire_type, default_enum> {
+    typedef MapEntryLite<K, V, k_wire_type, v_wire_type, default_enum> Base;
+    typedef typename Base::KeyCppType KeyCppType;
+    typedef typename Base::ValCppType ValCppType;
+
+   public:
+    MapEnumEntryWrapper(const K& key, const V& value, Arena* arena)
+        : MapEntryLite<K, V, k_wire_type, v_wire_type, default_enum>(arena),
+          key_(key),
+          value_(value) {
+      Base::set_has_key();
+      Base::set_has_value();
+    }
+    inline const KeyCppType& key() const { return key_; }
+    inline const ValCppType& value() const { return value_; }
+
+   private:
+    const KeyCppType& key_;
+    const ValCppType value_;
+
+    friend class ::google::protobuf::Arena;
+    typedef void DestructorSkippable_;
+  };
+
+  MapEntryLite() : arena_(NULL) {
+    KeyCppHandler::Initialize(&key_, NULL);
+    ValueCppHandler::InitializeMaybeByDefaultEnum(
+        &value_, default_enum_value, NULL);
+    _has_bits_[0] = 0;
+  }
+
+  explicit MapEntryLite(Arena* arena)
+      : arena_(arena) {
+    KeyCppHandler::Initialize(&key_, arena);
+    ValueCppHandler::InitializeMaybeByDefaultEnum(
+        &value_, default_enum_value, arena);
+    _has_bits_[0] = 0;
+  }
+
+  inline Arena* GetArenaNoVirtual() const {
+    return arena_;
+  }
+
+  void set_default_instance(MapEntryLite* default_instance) {
+    default_instance_ = default_instance;
+  }
+
+  MapEntryLite* default_instance_ = NULL;
+
+  KeyBase key_;
+  ValueBase value_;
+  Arena* arena_;
+  uint32 _has_bits_[1];
+
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
+  template <typename K, typename V, WireFormatLite::FieldType,
+            WireFormatLite::FieldType, int>
+  friend class LIBPROTOBUF_EXPORT internal::MapEntry;
+  template <typename K, typename V, WireFormatLite::FieldType,
+            WireFormatLite::FieldType, int>
+  friend class LIBPROTOBUF_EXPORT internal::MapFieldLite;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MapEntryLite);
+};
+
+}  // namespace internal
+}  // namespace protobuf
+
+}  // namespace google
+#endif  // GOOGLE_PROTOBUF_MAP_ENTRY_LITE_H__