| /* |
| * Copyright (c) 2015, 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 jdk.internal.jshell.tool; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.function.Consumer; |
| |
| public final class StopDetectingInputStream extends InputStream { |
| public static final int INITIAL_SIZE = 128; |
| |
| private final Runnable stop; |
| private final Consumer<Exception> errorHandler; |
| |
| private boolean initialized; |
| private int[] buffer = new int[INITIAL_SIZE]; |
| private int start; |
| private int end; |
| private State state = State.WAIT; |
| |
| public StopDetectingInputStream(Runnable stop, Consumer<Exception> errorHandler) { |
| this.stop = stop; |
| this.errorHandler = errorHandler; |
| } |
| |
| public synchronized InputStream setInputStream(InputStream input) { |
| if (initialized) |
| throw new IllegalStateException("Already initialized."); |
| initialized = true; |
| |
| Thread reader = new Thread() { |
| @Override |
| public void run() { |
| try { |
| int read; |
| while (true) { |
| //to support external terminal editors, the "cmdin.read" must not run when |
| //an external editor is running. At the same time, it needs to run while the |
| //user's code is running (so Ctrl-C is detected). Hence waiting here until |
| //there is a confirmed need for input. |
| waitInputNeeded(); |
| if ((read = input.read()) == (-1)) { |
| break; |
| } |
| if (read == 3 && state == StopDetectingInputStream.State.BUFFER) { |
| stop.run(); |
| } else { |
| write(read); |
| } |
| } |
| } catch (IOException ex) { |
| errorHandler.accept(ex); |
| } finally { |
| state = StopDetectingInputStream.State.CLOSED; |
| } |
| } |
| }; |
| reader.setDaemon(true); |
| reader.start(); |
| |
| return this; |
| } |
| |
| @Override |
| public synchronized int read() { |
| while (start == end) { |
| if (state == State.CLOSED) { |
| return -1; |
| } |
| if (state == State.WAIT) { |
| state = State.READ; |
| } |
| notifyAll(); |
| try { |
| wait(); |
| } catch (InterruptedException ex) { |
| //ignore |
| } |
| } |
| try { |
| return buffer[start]; |
| } finally { |
| start = (start + 1) % buffer.length; |
| } |
| } |
| |
| public synchronized void write(int b) { |
| if (state != State.BUFFER) { |
| state = State.WAIT; |
| } |
| int newEnd = (end + 1) % buffer.length; |
| if (newEnd == start) { |
| //overflow: |
| int[] newBuffer = new int[buffer.length * 2]; |
| int rightPart = (end > start ? end : buffer.length) - start; |
| int leftPart = end > start ? 0 : start - 1; |
| System.arraycopy(buffer, start, newBuffer, 0, rightPart); |
| System.arraycopy(buffer, 0, newBuffer, rightPart, leftPart); |
| buffer = newBuffer; |
| start = 0; |
| end = rightPart + leftPart; |
| newEnd = end + 1; |
| } |
| buffer[end] = b; |
| end = newEnd; |
| notifyAll(); |
| } |
| |
| public synchronized void setState(State state) { |
| this.state = state; |
| notifyAll(); |
| } |
| |
| private synchronized void waitInputNeeded() { |
| while (state == State.WAIT) { |
| try { |
| wait(); |
| } catch (InterruptedException ex) { |
| //ignore |
| } |
| } |
| } |
| |
| public enum State { |
| /* No reading from the input should happen. This is the default state. The StopDetectingInput |
| * must be in this state when an external editor is being run, so that the external editor |
| * can read from the input. |
| */ |
| WAIT, |
| /* A single input character should be read. Reading from the StopDetectingInput will move it |
| * into this state, and the state will be automatically changed back to WAIT when a single |
| * input character is obtained. This state is typically used while the user is editing the |
| * input line. |
| */ |
| READ, |
| /* Continuously read from the input. Forward Ctrl-C ((int) 3) to the "stop" Runnable, buffer |
| * all other input. This state is typically used while the user's code is running, to provide |
| * the ability to detect Ctrl-C in order to stop the execution. |
| */ |
| BUFFER, |
| /* The input is closed. |
| */ |
| CLOSED |
| } |
| |
| } |