/*
    * 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.
   */
  package org.apache.logging.log4j.core.impl;
  
  import java.io.InvalidObjectException;
  import java.io.ObjectInputStream;
  import java.util.Arrays;
  import java.util.Map;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.Marker;
  import org.apache.logging.log4j.ThreadContext;
  import org.apache.logging.log4j.util.ReadOnlyStringMap;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.util.Constants;
  import org.apache.logging.log4j.message.Message;
  import org.apache.logging.log4j.message.ParameterizedMessage;
  import org.apache.logging.log4j.message.ReusableMessage;
  import org.apache.logging.log4j.message.SimpleMessage;
  import org.apache.logging.log4j.util.StringMap;
  import org.apache.logging.log4j.util.Strings;
  
  /**
   * Mutable implementation of the {@code LogEvent} interface.
   * @since 2.6
   */
  public class MutableLogEvent implements LogEvent, ReusableMessage {
      private static final Message EMPTY = new SimpleMessage(Strings.EMPTY);
  
      private int threadPriority;
      private long threadId;
      private long timeMillis;
      private long nanoTime;
      private short parameterCount;
      private boolean includeLocation;
      private boolean endOfBatch = false;
      private Level level;
      private String threadName;
      private String loggerName;
      private Message message;
      private StringBuilder messageText;
      private Object[] parameters;
      private Throwable thrown;
      private ThrowableProxy thrownProxy;
      private StringMap contextData = ContextDataFactory.createContextData();
      private Marker marker;
      private String loggerFqcn;
      private StackTraceElement source;
      private ThreadContext.ContextStack contextStack;
      transient boolean reserved = false;
  
      public MutableLogEvent() {
          this(new StringBuilder(Constants.INITIAL_REUSABLE_MESSAGE_SIZE), new Object[10]);
      }
  
      public MutableLogEvent(final StringBuilder msgText, final Object[] replacementParameters) {
          this.messageText = msgText;
          this.parameters = replacementParameters;
      }
  
      /**
       * Initialize the fields of this {@code MutableLogEvent} from another event.
       * Similar in purpose and usage as {@link org.apache.logging.log4j.core.impl.Log4jLogEvent.LogEventProxy},
       * but a mutable version.
       * <p>
       * This method is used on async logger ringbuffer slots holding MutableLogEvent objects in each slot.
       * </p>
       *
       * @param event the event to copy data from
       */
      public void initFrom(final LogEvent event) {
          this.loggerFqcn = event.getLoggerFqcn();
          this.marker = event.getMarker();
          this.level = event.getLevel();
          this.loggerName = event.getLoggerName();
          this.timeMillis = event.getTimeMillis();
          this.thrown = event.getThrown();
          this.thrownProxy = event.getThrownProxy();
  
          // NOTE: this ringbuffer event SHOULD NOT keep a reference to the specified
          // thread-local MutableLogEvent's context data, because then two threads would call
          // ReadOnlyStringMap.clear() on the same shared instance, resulting in data corruption.
          this.contextData.putAll(event.getContextData());
  
          this.contextStack = event.getContextStack();
         this.source = event.isIncludeLocation() ? event.getSource() : null;
         this.threadId = event.getThreadId();
         this.threadName = event.getThreadName();
         this.threadPriority = event.getThreadPriority();
         this.endOfBatch = event.isEndOfBatch();
         this.includeLocation = event.isIncludeLocation();
         this.nanoTime = event.getNanoTime();
         setMessage(event.getMessage());
     }
 
     /**
      * Clears all references this event has to other objects.
      *
      */
     public void clear() {
         loggerFqcn = null;
         marker = null;
         level = null;
         loggerName = null;
         message = null;
         thrown = null;
         thrownProxy = null;
         source = null;
         if (contextData != null) {
             if (contextData.isFrozen()) { // came from CopyOnWrite thread context
                 contextData = null;
             } else {
                 contextData.clear();
             }
         }
         contextStack = null;
 
         // ThreadName should not be cleared: this field is set in the ReusableLogEventFactory
         // where this instance is kept in a ThreadLocal, so it usually does not change.
         // threadName = null; // no need to clear threadName
 
         trimMessageText();
         if (parameters != null) {
             for (int i = 0; i < parameters.length; i++) {
                 parameters[i] = null;
             }
         }
 
         // primitive fields that cannot be cleared:
         //timeMillis;
         //threadId;
         //threadPriority;
         //includeLocation;
         //endOfBatch;
         //nanoTime;
     }
 
     // ensure that excessively long char[] arrays are not kept in memory forever
     private void trimMessageText() {
         if (messageText != null && messageText.length() > Constants.MAX_REUSABLE_MESSAGE_SIZE) {
             messageText.setLength(Constants.MAX_REUSABLE_MESSAGE_SIZE);
             messageText.trimToSize();
         }
     }
 
     @Override
     public String getLoggerFqcn() {
         return loggerFqcn;
     }
 
     public void setLoggerFqcn(final String loggerFqcn) {
         this.loggerFqcn = loggerFqcn;
     }
 
     @Override
     public Marker getMarker() {
         return marker;
     }
 
     public void setMarker(final Marker marker) {
         this.marker = marker;
     }
 
     @Override
     public Level getLevel() {
         if (level == null) {
             level = Level.OFF; // LOG4J2-462, LOG4J2-465
         }
         return level;
     }
 
     public void setLevel(final Level level) {
         this.level = level;
     }
 
     @Override
     public String getLoggerName() {
         return loggerName;
     }
 
     public void setLoggerName(final String loggerName) {
         this.loggerName = loggerName;
     }
 
     @Override
     public Message getMessage() {
         if (message == null) {
             return (messageText == null) ? EMPTY : this;
         }
         return message;
     }
 
     public void setMessage(final Message msg) {
         if (msg instanceof ReusableMessage) {
             final ReusableMessage reusable = (ReusableMessage) msg;
             reusable.formatTo(getMessageTextForWriting());
             if (parameters != null) {
                 parameters = reusable.swapParameters(parameters);
                 parameterCount = reusable.getParameterCount();
             }
         } else {
             // if the Message instance is reused, there is no point in freezing its message here
             if (!Constants.FORMAT_MESSAGES_IN_BACKGROUND && msg != null) { // LOG4J2-898: user may choose
                 msg.getFormattedMessage(); // LOG4J2-763: ask message to freeze parameters
             }
             this.message = msg;
         }
     }
 
     private StringBuilder getMessageTextForWriting() {
         if (messageText == null) {
             // Should never happen:
             // only happens if user logs a custom reused message when Constants.ENABLE_THREADLOCALS is false
             messageText = new StringBuilder(Constants.INITIAL_REUSABLE_MESSAGE_SIZE);
         }
         messageText.setLength(0);
         return messageText;
     }
 
     /**
      * @see ReusableMessage#getFormattedMessage()
      */
     @Override
     public String getFormattedMessage() {
         return messageText.toString();
     }
 
     /**
      * @see ReusableMessage#getFormat()
      */
     @Override
     public String getFormat() {
         return null;
     }
 
     /**
      * @see ReusableMessage#getParameters()
      */
     @Override
     public Object[] getParameters() {
         return parameters == null ? null : Arrays.copyOf(parameters, parameterCount);
     }
 
     /**
      * @see ReusableMessage#getThrowable()
      */
     @Override
     public Throwable getThrowable() {
         return getThrown();
     }
 
     /**
      * @see ReusableMessage#formatTo(StringBuilder)
      */
     @Override
     public void formatTo(final StringBuilder buffer) {
         buffer.append(messageText);
     }
 
     /**
      * Replaces this ReusableMessage's parameter array with the specified value and return the original array
      * @param emptyReplacement the parameter array that can be used for subsequent uses of this reusable message
      * @return the original parameter array
      * @see ReusableMessage#swapParameters(Object[])
      */
     @Override
     public Object[] swapParameters(final Object[] emptyReplacement) {
         final Object[] result = this.parameters;
         this.parameters = emptyReplacement;
         return result;
     }
 
     /*
      * @see ReusableMessage#getParameterCount
      */
     @Override
     public short getParameterCount() {
         return parameterCount;
     }
 
     @Override
     public Message memento() {
         if (message != null) {
             return message;
         }
         final Object[] params = parameters == null ? new Object[0] : Arrays.copyOf(parameters, parameterCount);
         return new ParameterizedMessage(messageText.toString(), params);
     }
 
     @Override
     public Throwable getThrown() {
         return thrown;
     }
 
     public void setThrown(final Throwable thrown) {
         this.thrown = thrown;
     }
 
     @Override
     public long getTimeMillis() {
         return timeMillis;
     }
 
     public void setTimeMillis(final long timeMillis) {
         this.timeMillis = timeMillis;
     }
 
     /**
      * Returns the ThrowableProxy associated with the event, or null.
      * @return The ThrowableProxy associated with the event.
      */
     @Override
     public ThrowableProxy getThrownProxy() {
         if (thrownProxy == null && thrown != null) {
             thrownProxy = new ThrowableProxy(thrown);
         }
         return thrownProxy;
     }
 
     /**
      * Returns the StackTraceElement for the caller. This will be the entry that occurs right
      * before the first occurrence of FQCN as a class name.
      * @return the StackTraceElement for the caller.
      */
     @Override
     public StackTraceElement getSource() {
         if (source != null) {
             return source;
         }
         if (loggerFqcn == null || !includeLocation) {
             return null;
         }
         source = Log4jLogEvent.calcLocation(loggerFqcn);
         return source;
     }
 
     @SuppressWarnings("unchecked")
     @Override
     public ReadOnlyStringMap getContextData() {
         return contextData;
     }
 
     @Override
     public Map<String, String> getContextMap() {
         return contextData.toMap();
     }
 
     public void setContextData(final StringMap mutableContextData) {
         this.contextData = mutableContextData;
     }
 
     @Override
     public ThreadContext.ContextStack getContextStack() {
         return contextStack;
     }
 
     public void setContextStack(final ThreadContext.ContextStack contextStack) {
         this.contextStack = contextStack;
     }
 
     @Override
     public long getThreadId() {
         return threadId;
     }
 
     public void setThreadId(final long threadId) {
         this.threadId = threadId;
     }
 
     @Override
     public String getThreadName() {
         return threadName;
     }
 
     public void setThreadName(final String threadName) {
         this.threadName = threadName;
     }
 
     @Override
     public int getThreadPriority() {
         return threadPriority;
     }
 
     public void setThreadPriority(final int threadPriority) {
         this.threadPriority = threadPriority;
     }
 
     @Override
     public boolean isIncludeLocation() {
         return includeLocation;
     }
 
     @Override
     public void setIncludeLocation(final boolean includeLocation) {
         this.includeLocation = includeLocation;
     }
 
     @Override
     public boolean isEndOfBatch() {
         return endOfBatch;
     }
 
     @Override
     public void setEndOfBatch(final boolean endOfBatch) {
         this.endOfBatch = endOfBatch;
     }
 
     @Override
     public long getNanoTime() {
         return nanoTime;
     }
 
     public void setNanoTime(final long nanoTime) {
         this.nanoTime = nanoTime;
     }
 
     /**
      * Creates a LogEventProxy that can be serialized.
      * @return a LogEventProxy.
      */
     protected Object writeReplace() {
         return new Log4jLogEvent.LogEventProxy(this, this.includeLocation);
     }
 
     private void readObject(final ObjectInputStream stream) throws InvalidObjectException {
         throw new InvalidObjectException("Proxy required");
     }
 
     /**
      * Creates and returns a new immutable copy of this {@code MutableLogEvent}.
      * If {@link #isIncludeLocation()} is true, this will obtain caller location information.
      *
      * @return a new immutable copy of the data in this {@code MutableLogEvent}
      */
     public Log4jLogEvent createMemento() {
         return Log4jLogEvent.deserialize(Log4jLogEvent.serialize(this, includeLocation));
     }
 
     /**
      * Initializes the specified {@code Log4jLogEvent.Builder} from this {@code MutableLogEvent}.
      * @param builder the builder whose fields to populate
      */
     public void initializeBuilder(final Log4jLogEvent.Builder builder) {
         builder.setContextData(contextData) //
                 .setContextStack(contextStack) //
                 .setEndOfBatch(endOfBatch) //
                 .setIncludeLocation(includeLocation) //
                 .setLevel(getLevel()) // ensure non-null
                 .setLoggerFqcn(loggerFqcn) //
                 .setLoggerName(loggerName) //
                 .setMarker(marker) //
                 .setMessage(getNonNullImmutableMessage()) // ensure non-null & immutable
                 .setNanoTime(nanoTime) //
                 .setSource(source) //
                 .setThreadId(threadId) //
                 .setThreadName(threadName) //
                 .setThreadPriority(threadPriority) //
                 .setThrown(getThrown()) // may deserialize from thrownProxy
                 .setThrownProxy(thrownProxy) // avoid unnecessarily creating thrownProxy
                 .setTimeMillis(timeMillis);
     }
 
     private Message getNonNullImmutableMessage() {
         return message != null ? message : new SimpleMessage(String.valueOf(messageText));
     }
 }