content: /*
   * Copyright (C) 2006 The Android Open Source Project
   *
   * 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.
   */
  
  package android.util;
  
  import android.annotation.UnsupportedAppUsage;
  
  import java.io.FileDescriptor;
  import java.io.PrintWriter;
  import java.time.LocalDateTime;
  import java.util.ArrayDeque;
  import java.util.Deque;
  import java.util.Iterator;
  
  /**
   * @hide
   */
  public final class LocalLog {
  
      private final Deque<String> mLog;
      private final int mMaxLines;
  
      @UnsupportedAppUsage
      public LocalLog(int maxLines) {
          mMaxLines = Math.max(0, maxLines);
          mLog = new ArrayDeque<>(mMaxLines);
      }
  
      @UnsupportedAppUsage
      public void log(String msg) {
          if (mMaxLines <= 0) {
              return;
          }
          append(String.format("%s - %s", LocalDateTime.now(), msg));
      }
  
      private synchronized void append(String logLine) {
          while (mLog.size() >= mMaxLines) {
              mLog.remove();
          }
          mLog.add(logLine);
      }
  
      @UnsupportedAppUsage
      public synchronized void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
          dump(pw);
      }
  
      public synchronized void dump(PrintWriter pw) {
          Iterator<String> itr = mLog.iterator();
          while (itr.hasNext()) {
              pw.println(itr.next());
          }
      }
  
      public synchronized void reverseDump(FileDescriptor fd, PrintWriter pw, String[] args) {
          reverseDump(pw);
      }
  
      public synchronized void reverseDump(PrintWriter pw) {
          Iterator<String> itr = mLog.descendingIterator();
          while (itr.hasNext()) {
              pw.println(itr.next());
          }
      }
  
      public static class ReadOnlyLocalLog {
          private final LocalLog mLog;
          ReadOnlyLocalLog(LocalLog log) {
              mLog = log;
          }
          @UnsupportedAppUsage
          public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
              mLog.dump(pw);
          }
          public void dump(PrintWriter pw) {
              mLog.dump(pw);
          }
          public void reverseDump(FileDescriptor fd, PrintWriter pw, String[] args) {
              mLog.reverseDump(pw);
          }
          public void reverseDump(PrintWriter pw) {
              mLog.reverseDump(pw);
          }
      }
  
      @UnsupportedAppUsage
      public ReadOnlyLocalLog readOnlyLocalLog() {
          return new ReadOnlyLocalLog(this);
      }
  }
  