Remove StringSerializer and implement StringCodec

Author: swift-kim

shell/platform/tizen/channels/lifecycle_channel.cc

@@ -4,9 +4,7 @@
 
 #include "lifecycle_channel.h"
 
-#include <variant>
-
-#include "flutter/shell/platform/common/client_wrapper/include/flutter/standard_message_codec.h"
+#include "flutter/shell/platform/tizen/channels/string_codec.h"
 #include "flutter/shell/platform/tizen/tizen_log.h"
 
 namespace flutter {
@@ -20,38 +18,13 @@ constexpr char kResumed[] = "AppLifecycleState.resumed";
 constexpr char kPaused[] = "AppLifecycleState.paused";
 constexpr char kDetached[] = "AppLifecycleState.detached";
 
-// Codec extension for UTF-8 strings.
-class StringSerializer : public StandardCodecSerializer {
- public:
-  StringSerializer() = default;
-  virtual ~StringSerializer() = default;
-
-  // Returns the shared serializer instance.
-  static const StringSerializer& GetInstance() {
-    static StringSerializer sInstance;
-    return sInstance;
-  }
-
-  virtual void WriteValue(const EncodableValue& value,
-                          ByteStreamWriter* stream) const override {
-    if (auto string_value = std::get_if<std::string>(&value)) {
-      size_t size = string_value->size();
-      if (size > 0) {
-        stream->WriteBytes(
-            reinterpret_cast<const uint8_t*>(string_value->data()), size);
-      }
-    }
-  }
-};
-
 }  // namespace
 
 LifecycleChannel::LifecycleChannel(BinaryMessenger* messenger)
     : channel_(std::make_unique<BasicMessageChannel<EncodableValue>>(
           messenger,
           kChannelName,
-          &StandardMessageCodec::GetInstance(
-              &StringSerializer::GetInstance()))) {}
+          &StringCodec::GetInstance())) {}
 
 LifecycleChannel::~LifecycleChannel() {}
 

shell/platform/tizen/channels/string_codec.h

@@ -0,0 +1,58 @@
+// Copyright 2021 Samsung Electronics Co., Ltd. All rights reserved.
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef EMBEDDER_STRING_CODEC_H_
+#define EMBEDDER_STRING_CODEC_H_
+
+#include <memory>
+#include <string>
+#include <variant>
+
+#include "flutter/shell/platform/common/client_wrapper/include/flutter/encodable_value.h"
+#include "flutter/shell/platform/common/client_wrapper/include/flutter/message_codec.h"
+
+namespace flutter {
+
+// A string message encoding/decoding mechanism for communications to/from the
+// Flutter engine via message channels.
+class StringCodec : public MessageCodec<EncodableValue> {
+ public:
+  ~StringCodec() = default;
+
+  // Returns an instance of the codec.
+  static const StringCodec& GetInstance() {
+    static StringCodec sInstance;
+    return sInstance;
+  }
+
+  // Prevent copying.
+  StringCodec(StringCodec const&) = delete;
+  StringCodec& operator=(StringCodec const&) = delete;
+
+ protected:
+  // |flutter::MessageCodec|
+  std::unique_ptr<EncodableValue> DecodeMessageInternal(
+      const uint8_t* binary_message,
+      const size_t message_size) const override {
+    return std::make_unique<EncodableValue>(std::string(
+        reinterpret_cast<const char*>(binary_message), message_size));
+  }
+
+  // |flutter::MessageCodec|
+  std::unique_ptr<std::vector<uint8_t>> EncodeMessageInternal(
+      const EncodableValue& message) const override {
+    auto string_value = std::get<std::string>(message);
+    return std::make_unique<std::vector<uint8_t>>(string_value.begin(),
+                                                  string_value.end());
+  }
+
+ private:
+  // Instances should be obtained via GetInstance.
+  explicit StringCodec() = default;
+};
+
+}  // namespace flutter
+
+#endif  // EMBEDDER_STRING_CODEC_H_