/*

 * 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 _LOG4CXX_WRITER_APPENDER_H

#define _LOG4CXX_WRITER_APPENDER_H

#include <log4cxx/appenderskeleton.h>

#include <log4cxx/helpers/outputstreamwriter.h>

#include <atomic>

namespace LOG4CXX_NS

{

namespace helpers

{

class Transcoder;

}

/**

WriterAppender appends log events to a standard output stream

*/

class LOG4CXX_EXPORT WriterAppender : public AppenderSkeleton

{

  protected:

    struct WriterAppenderPriv;

  public:

    DECLARE_ABSTRACT_LOG4CXX_OBJECT(WriterAppender)

    BEGIN_LOG4CXX_CAST_MAP()

    LOG4CXX_CAST_ENTRY(WriterAppender)

    LOG4CXX_CAST_ENTRY_CHAIN(AppenderSkeleton)

    END_LOG4CXX_CAST_MAP()

    /**

    This default constructor does nothing.*/

    WriterAppender();

  protected:

    WriterAppender(const LayoutPtr& layout,

      LOG4CXX_NS::helpers::WriterPtr& writer);

    WriterAppender(const LayoutPtr& layout);

    WriterAppender(std::unique_ptr<WriterAppenderPriv> priv);

  public:

    ~WriterAppender();

    /**

    Derived appenders should override this method if option structure

    requires it.

    */

    void activateOptions(helpers::Pool& pool) override;

    /**

    If the <b>ImmediateFlush</b> option is set to

    <code>true</code>, the appender will flush at the end of each

    write. This is the default behavior. If the option is set to

    <code>false</code>, then the underlying stream can defer writing

    to physical medium to a later time.

    <p>Avoiding the flush operation at the end of each append results in

    a performance gain of 10 to 20 percent. However, there is safety

    tradeoff involved in skipping flushing. Indeed, when flushing is

    skipped, then it is likely that the last few log events will not

    be recorded on disk when the application exits. This is a high

    price to pay even for a 20% performance gain.

    */

    void setImmediateFlush(bool value);

    /**

    Returns value of the <b>ImmediateFlush</b> option.

    */

    bool getImmediateFlush() const;

    /**

    This method is called by the AppenderSkeleton#doAppend

    method.

    <p>If the output stream exists and is writable then write a log

    statement to the output stream. Otherwise, write a single warning

    message to <code>stderr</code>.

    <p>The format of the output will depend on this appender's

    layout.

    */

    void append(const spi::LoggingEventPtr& event, helpers::Pool& p) override;

  protected:

    /**

    This method determines if there is a sense in attempting to append.

    <p>It checks whether there is a set output target and also if

    there is a set layout. If these checks fail, then the boolean

    value <code>false</code> is returned. */

    virtual bool checkEntryConditions() const;

  public:

    /**

    Close this appender instance. The underlying stream or writer is

    also closed.

    <p>Closed appenders cannot be reused.

    */

    void close() override;

  protected:

    /**

     * Close the underlying {@link log4cxx::helpers::Writer}.

     * */

    void closeWriter();

    /**

        Returns an OutputStreamWriter when passed an OutputStream.  The

        encoding used will depend on the value of the

        <code>encoding</code> property.  If the encoding value is

        specified incorrectly the writer will be opened using the default

        system encoding (an error message will be printed to the loglog.  */

    virtual helpers::WriterPtr createWriter(helpers::OutputStreamPtr& os);

  public:

    /**

    The current encoding value.

    \sa setOption

     */

    LogString getEncoding() const;

    /**

    Set the encoding to \c value.

    \sa setOption

     */

    void setEncoding(const LogString& value);

    /**

    \copybrief AppenderSkeleton::setOption()

    Supported options | Supported values | Default value

    -------------- | ---------------- | ---------------

    Encoding | C,UTF-8,UTF-16,UTF-16BE,UTF-16LE,646,US-ASCII,ISO646-US,ANSI_X3.4-1968,ISO-8859-1,ISO-LATIN-1 | UTF-8

    \sa AppenderSkeleton::setOption()

     */

    void setOption(const LogString& option, const LogString& value) override;

    /**

      <p>Send log output to \c writer which must be open and be writable.

      <p>The helpers::Writer will be closed when the

      appender instance is closed.

      <b>WARNING:</b> Logging to an unopened Writer will fail.

      @param writer An already opened Writer.

    */

    void setWriter(const LOG4CXX_NS::helpers::WriterPtr& writer);

    const LOG4CXX_NS::helpers::WriterPtr getWriter() const;

    bool requiresLayout() const override;

  protected:

    /**

     Actual writing occurs here.

    */

    virtual void subAppend(const spi::LoggingEventPtr& event, LOG4CXX_NS::helpers::Pool& p);

    /**

    Write a footer as produced by the embedded layout's

    Layout#appendFooter method.  */

    virtual void writeFooter(LOG4CXX_NS::helpers::Pool& p);

    /**

    Write a header as produced by the embedded layout's

    Layout#appendHeader method.  */

    virtual void writeHeader(LOG4CXX_NS::helpers::Pool& p);

    /**

     * Set the writer.  Mutex must already be held.

     */

    void setWriterInternal(const LOG4CXX_NS::helpers::WriterPtr& writer);

  private:

    //

    //  prevent copy and assignment

    WriterAppender(const WriterAppender&);

    WriterAppender& operator=(const WriterAppender&);

};

LOG4CXX_PTR_DEF(WriterAppender);

}  //namespace log4cxx

#endif //_LOG4CXX_WRITER_APPENDER_H