pagespeed/kernel/base/json_writer.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */


#ifndef PAGESPEED_KERNEL_BASE_JSON_WRITER_H_
#define PAGESPEED_KERNEL_BASE_JSON_WRITER_H_

#include <utility>
#include <vector>

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/base/writer.h"

namespace Json {
class Value;
}  // namespace Json

namespace net_instaweb {

static const char kInstanceHtml[] = "instance_html";

class HtmlElement;
class MessageHandler;

// Pair of panel json and start Element corresponding to the panel.
typedef std::pair<HtmlElement*, Json::Value*> ElementJsonPair;

// Writes bytes to top json of the stack.
class JsonWriter : public Writer {
 public:
  // It is assumed that the element_json_stack is available till the destruction
  // of the writer
  JsonWriter(Writer* writer,
             const std::vector<ElementJsonPair>* element_json_stack);
  virtual ~JsonWriter();

  virtual bool Write(const StringPiece& str, MessageHandler* message_handler);
  virtual bool Flush(MessageHandler* message_handler);
  // Updates the json dictionary with the buffer content so far.
  void UpdateDictionary();

 private:
  Writer* writer_;
  GoogleString buffer_;
  const std::vector<ElementJsonPair>* element_json_stack_;

  DISALLOW_COPY_AND_ASSIGN(JsonWriter);
};

}  // namespace net_instaweb

#endif  // PAGESPEED_KERNEL_BASE_JSON_WRITER_H_