/******************************************************************************
 *
 * This file is part of Log4Qt library.
 *
 * Copyright (C) 2007 - 2020 Log4Qt contributors
 *
 * Licensed 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 LOG4QT_ASYNCAPPENDER_H
#define LOG4QT_ASYNCAPPENDER_H

#include "appenderskeleton.h"
#include "helpers/appenderattachable.h"

namespace Log4Qt
{

class Dispatcher;

/*!
 * \brief The class AsyncAppender lets users log events asynchronously.
 *
 * The AsyncAppender will collect the events sent to it and then dispatch them to all the
 * appenders that are attached to it. You can attach multiple appenders to an AsyncAppender.
 *
 * The AsyncAppender uses a separate thread to serve the events fromthe event loop.
 *
 * \note All the functions declared in this class are thread-safe.
 *  
 * \note The ownership and lifetime of objects of this class are managed.
 *       See \ref Ownership "Object ownership" for more details.
 */
class LOG4QT_EXPORT AsyncAppender : public AppenderSkeleton, public AppenderAttachable
{
    Q_OBJECT

public:
    AsyncAppender(QObject *parent = nullptr);
    ~AsyncAppender() override;

    bool requiresLayout() const override;

    void activateOptions() override;
    void close() override;
    void callAppenders(const LoggingEvent &event) const;

    /*!
     * Tests if all entry conditions for using append() in this class are
     * met.
     *
     * If a conditions is not met, an error is logged and the function
     * returns false. Otherwise the result of
     * AppenderSkeleton::checkEntryConditions() is returned.
     *
     * The checked conditions are:
     * - dispatcher thread running (APPENDER_ASNC_DISPATCHER_NOT_RUNNING)
     *
     * The function is called as part of the checkEntryConditions() chain
     * started by AppenderSkeleton::doAppend().
     *
     * \sa AppenderSkeleton::doAppend(),
     *     AppenderSkeleton::checkEntryConditions()
     */
    bool checkEntryConditions() const override;

protected:
    void append(const LoggingEvent &event) override;

private:
    Q_DISABLE_COPY(AsyncAppender)

    //! Event dispatcher trhead
    QThread       *mThread;
    Dispatcher    *mDispatcher;
    void closeInternal();
};


} // namespace Log4Qt

#endif // LOG4QT_AsyncAppender_H