content: /*
   * Copyright (C) 2014 The Android Open Source Project
   * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.io;
  
  import libcore.io.IoUtils;
  
  /**
   * Piped character-input streams.
   *
   * @author      Mark Reinhold
   * @since       JDK1.1
   */
  
  public class PipedReader extends Reader {
      boolean closedByWriter = false;
      boolean closedByReader = false;
      boolean connected = false;
  
      /* REMIND: identification of the read and write sides needs to be
         more sophisticated.  Either using thread groups (but what about
         pipes within a thread?) or using finalization (but it may be a
         long time until the next GC). */
      Thread readSide;
      Thread writeSide;
  
     /**
      * The size of the pipe's circular input buffer.
      */
      private static final int DEFAULT_PIPE_SIZE = 1024;
  
      /**
       * The circular buffer into which incoming data is placed.
       */
      char buffer[];
  
      /**
       * The index of the position in the circular buffer at which the
       * next character of data will be stored when received from the connected
       * piped writer. <code>in&lt;0</code> implies the buffer is empty,
       * <code>in==out</code> implies the buffer is full
       */
      int in = -1;
  
      /**
       * The index of the position in the circular buffer at which the next
       * character of data will be read by this piped reader.
       */
      int out = 0;
  
      /**
       * Creates a <code>PipedReader</code> so
       * that it is connected to the piped writer
       * <code>src</code>. Data written to <code>src</code>
       * will then be available as input from this stream.
       *
       * @param      src   the stream to connect to.
       * @exception  IOException  if an I/O error occurs.
       */
      public PipedReader(PipedWriter src) throws IOException {
          this(src, DEFAULT_PIPE_SIZE);
      }
  
      /**
       * Creates a <code>PipedReader</code> so that it is connected
       * to the piped writer <code>src</code> and uses the specified
       * pipe size for the pipe's buffer. Data written to <code>src</code>
       * will then be  available as input from this stream.
  
       * @param      src       the stream to connect to.
       * @param      pipeSize  the size of the pipe's buffer.
       * @exception  IOException  if an I/O error occurs.
       * @exception  IllegalArgumentException if {@code pipeSize <= 0}.
       * @since      1.6
       */
      public PipedReader(PipedWriter src, int pipeSize) throws IOException {
          initPipe(pipeSize);
          connect(src);
      }
  
  
      /**
       * Creates a <code>PipedReader</code> so
       * that it is not yet {@linkplain #connect(PipedWriter)
       * connected}. It must be {@linkplain PipedWriter#connect(
       * PipedReader) connected} to a <code>PipedWriter</code>
       * before being used.
       */
      public PipedReader() {
          initPipe(DEFAULT_PIPE_SIZE);
      }
  
      /**
       * Creates a <code>PipedReader</code> so that it is not yet
       * {@link #connect(PipedWriter) connected} and uses
       * the specified pipe size for the pipe's buffer.
       * It must be  {@linkplain PipedWriter#connect(
       * PipedReader) connected} to a <code>PipedWriter</code>
       * before being used.
       *
       * @param   pipeSize the size of the pipe's buffer.
       * @exception  IllegalArgumentException if {@code pipeSize <= 0}.
       * @since      1.6
       */
      public PipedReader(int pipeSize) {
          initPipe(pipeSize);
      }
  
      private void initPipe(int pipeSize) {
          if (pipeSize <= 0) {
              throw new IllegalArgumentException("Pipe size <= 0");
          }
          buffer = new char[pipeSize];
      }
  
      /**
       * Causes this piped reader to be connected
       * to the piped  writer <code>src</code>.
       * If this object is already connected to some
       * other piped writer, an <code>IOException</code>
       * is thrown.
       * <p>
       * If <code>src</code> is an
       * unconnected piped writer and <code>snk</code>
       * is an unconnected piped reader, they
       * may be connected by either the call:
       *
       * <pre><code>snk.connect(src)</code> </pre>
       * <p>
       * or the call:
       *
       * <pre><code>src.connect(snk)</code> </pre>
       * <p>
       * The two calls have the same effect.
       *
       * @param      src   The piped writer to connect to.
       * @exception  IOException  if an I/O error occurs.
       */
      public void connect(PipedWriter src) throws IOException {
          src.connect(this);
      }
  
      /**
       * Receives a char of data. This method will block if no input is
       * available.
       */
      synchronized void receive(int c) throws IOException {
          if (!connected) {
              throw new IOException("Pipe not connected");
          } else if (closedByWriter || closedByReader) {
              throw new IOException("Pipe closed");
          } else if (readSide != null && !readSide.isAlive()) {
              throw new IOException("Read end dead");
          }
  
          writeSide = Thread.currentThread();
          while (in == out) {
              if ((readSide != null) && !readSide.isAlive()) {
                  throw new IOException("Pipe broken");
              }
              /* full: kick any waiting readers */
              notifyAll();
              try {
                  wait(1000);
              } catch (InterruptedException ex) {
                  // Android-changed: re-set the thread's interrupt status
                  // throw new java.io.InterruptedIOException();
                  IoUtils.throwInterruptedIoException();
              }
          }
          if (in < 0) {
              in = 0;
              out = 0;
          }
          buffer[in++] = (char) c;
          if (in >= buffer.length) {
              in = 0;
          }
      }
  
      /**
       * Receives data into an array of characters.  This method will
       * block until some input is available.
       */
      synchronized void receive(char c[], int off, int len)  throws IOException {
          while (--len >= 0) {
              receive(c[off++]);
          }
      }
  
      /**
       * Notifies all waiting threads that the last character of data has been
       * received.
       */
      synchronized void receivedLast() {
          closedByWriter = true;
          notifyAll();
      }
  
      /**
       * Reads the next character of data from this piped stream.
       * If no character is available because the end of the stream
       * has been reached, the value <code>-1</code> is returned.
       * This method blocks until input data is available, the end of
       * the stream is detected, or an exception is thrown.
       *
       * @return     the next character of data, or <code>-1</code> if the end of the
       *             stream is reached.
       * @exception  IOException  if the pipe is
       *          <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
       *          {@link #connect(PipedWriter) unconnected}, closed,
       *          or an I/O error occurs.
       */
      public synchronized int read()  throws IOException {
          if (!connected) {
              throw new IOException("Pipe not connected");
          } else if (closedByReader) {
              throw new IOException("Pipe closed");
          } else if (writeSide != null && !writeSide.isAlive()
                     && !closedByWriter && (in < 0)) {
              throw new IOException("Write end dead");
          }
  
          readSide = Thread.currentThread();
          int trials = 2;
          while (in < 0) {
              if (closedByWriter) {
                  /* closed by writer, return EOF */
                  return -1;
              }
              if ((writeSide != null) && (!writeSide.isAlive()) && (--trials < 0)) {
                  throw new IOException("Pipe broken");
              }
              /* might be a writer waiting */
              notifyAll();
              try {
                  wait(1000);
              } catch (InterruptedException ex) {
                // Android-changed: re-set the thread's interrupt status
                // throw new java.io.InterruptedIOException();
                IoUtils.throwInterruptedIoException();
              }
          }
          int ret = buffer[out++];
          if (out >= buffer.length) {
              out = 0;
          }
          if (in == out) {
              /* now empty */
              in = -1;
          }
          return ret;
      }
  
      /**
       * Reads up to <code>len</code> characters of data from this piped
       * stream into an array of characters. Less than <code>len</code> characters
       * will be read if the end of the data stream is reached or if
       * <code>len</code> exceeds the pipe's buffer size. This method
       * blocks until at least one character of input is available.
       *
       * @param      cbuf     the buffer into which the data is read.
       * @param      off   the start offset of the data.
       * @param      len   the maximum number of characters read.
       * @return     the total number of characters read into the buffer, or
       *             <code>-1</code> if there is no more data because the end of
       *             the stream has been reached.
       * @exception  IOException  if the pipe is
       *                  <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
       *                  {@link #connect(PipedWriter) unconnected}, closed,
       *                  or an I/O error occurs.
       */
      public synchronized int read(char cbuf[], int off, int len)  throws IOException {
          if (!connected) {
              throw new IOException("Pipe not connected");
          } else if (closedByReader) {
              throw new IOException("Pipe closed");
          } else if (writeSide != null && !writeSide.isAlive()
                     && !closedByWriter && (in < 0)) {
              throw new IOException("Write end dead");
          }
  
          if ((off < 0) || (off > cbuf.length) || (len < 0) ||
              ((off + len) > cbuf.length) || ((off + len) < 0)) {
              throw new IndexOutOfBoundsException();
          } else if (len == 0) {
              return 0;
          }
  
          /* possibly wait on the first character */
          int c = read();
          if (c < 0) {
              return -1;
          }
          cbuf[off] =  (char)c;
          int rlen = 1;
          while ((in >= 0) && (--len > 0)) {
              cbuf[off + rlen] = buffer[out++];
              rlen++;
              if (out >= buffer.length) {
                  out = 0;
              }
              if (in == out) {
                  /* now empty */
                  in = -1;
              }
          }
          return rlen;
      }
  
      /**
       * Tell whether this stream is ready to be read.  A piped character
       * stream is ready if the circular buffer is not empty.
       *
       * @exception  IOException  if the pipe is
       *                  <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
       *                  {@link #connect(PipedWriter) unconnected}, or closed.
       */
      public synchronized boolean ready() throws IOException {
          if (!connected) {
              throw new IOException("Pipe not connected");
          } else if (closedByReader) {
              throw new IOException("Pipe closed");
          } else if (writeSide != null && !writeSide.isAlive()
                     && !closedByWriter && (in < 0)) {
              throw new IOException("Write end dead");
          }
          if (in < 0) {
              return false;
          } else {
              return true;
          }
      }
  
      /**
       * Closes this piped stream and releases any system resources
       * associated with the stream.
       *
       * @exception  IOException  if an I/O error occurs.
       */
      public void close()  throws IOException {
          in = -1;
          closedByReader = true;
      }
  }
  