| /* |
| * 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<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(java.io.PipedWriter) |
| * connected}. It must be {@linkplain java.io.PipedWriter#connect( |
| * java.io.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(java.io.PipedWriter) connected} and uses |
| * the specified pipe size for the pipe's buffer. |
| * It must be {@linkplain java.io.PipedWriter#connect( |
| * java.io.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(java.io.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(java.io.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(java.io.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; |
| } |
| } |
