From a38531b21c7e2b0dc956e0ed1bfc9513f604273c Mon Sep 17 00:00:00 2001 From: Shawn Pearce Date: Fri, 4 Dec 2015 14:56:14 -0800 Subject: [PATCH] ProgressSpinner: Simple busy wait entertainment Keep a user amused while the server does work by spinning a little ASCII-art object on a single line. Change-Id: Ie8f181d1aa606d4ae69e5d3ca4db387cea739f38 --- .../jgit/transport/ProgressSpinner.java | 149 ++++++++++++++++++ 1 file changed, 149 insertions(+) create mode 100644 org.eclipse.jgit/src/org/eclipse/jgit/transport/ProgressSpinner.java diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProgressSpinner.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProgressSpinner.java new file mode 100644 index 0000000000..ac048a14a9 --- /dev/null +++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProgressSpinner.java @@ -0,0 +1,149 @@ +/* + * Copyright (C) 2015, Google Inc. + * and other copyright owners as documented in the project's IP log. + * + * This program and the accompanying materials are made available + * under the terms of the Eclipse Distribution License v1.0 which + * accompanies this distribution, is reproduced below, and is + * available at http://www.eclipse.org/org/documents/edl-v10.php + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials provided + * with the distribution. + * + * - Neither the name of the Eclipse Foundation, Inc. nor the + * names of its contributors may be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND + * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +package org.eclipse.jgit.transport; + +import static java.nio.charset.StandardCharsets.UTF_8; + +import java.io.IOException; +import java.io.OutputStream; +import java.util.concurrent.TimeUnit; + +/** + * A simple spinner connected to an {@code OutputStream}. + *

+ * This is class is not thread-safe. The update method may only be used from a + * single thread. Updates are sent only as frequently as {@link #update()} is + * invoked by the caller, and are capped at no more than 2 times per second by + * requiring at least 500 milliseconds between updates. + * + * @since 4.2 + */ +public class ProgressSpinner { + private static final long MIN_REFRESH_MILLIS = 500; + private static final char[] STATES = new char[] { '-', '\\', '|', '/' }; + + private final OutputStream out; + private String msg; + private int state; + private boolean write; + private boolean shown; + private long nextUpdateMillis; + + /** + * Initialize a new spinner. + * + * @param out + * where to send output to. + */ + public ProgressSpinner(OutputStream out) { + this.out = out; + this.write = true; + } + + /** + * Begin a time consuming task. + * + * @param title + * description of the task, suitable for human viewing. + * @param delay + * delay to wait before displaying anything at all. + * @param delayUnits + * unit for {@code delay}. + */ + public void beginTask(String title, long delay, TimeUnit delayUnits) { + msg = title; + state = 0; + shown = false; + + long now = System.currentTimeMillis(); + if (delay > 0) { + nextUpdateMillis = now + delayUnits.toMillis(delay); + } else { + send(now); + } + } + + /** Update the spinner if it is showing. */ + public void update() { + long now = System.currentTimeMillis(); + if (now >= nextUpdateMillis) { + send(now); + state = (state + 1) % STATES.length; + } + } + + private void send(long now) { + StringBuilder buf = new StringBuilder(msg.length() + 16); + buf.append('\r').append(msg).append("... ("); //$NON-NLS-1$ + buf.append(STATES[state]); + buf.append(") "); //$NON-NLS-1$ + shown = true; + write(buf.toString()); + nextUpdateMillis = now + MIN_REFRESH_MILLIS; + } + + /** + * Denote the current task completed. + * + * @param result + * text to print after the task's title + * {@code "$title ... $result"}. + */ + public void endTask(String result) { + if (shown) { + write('\r' + msg + "... " + result + "\n"); //$NON-NLS-1$ //$NON-NLS-2$ + } + } + + private void write(String s) { + if (write) { + try { + out.write(s.getBytes(UTF_8)); + out.flush(); + } catch (IOException e) { + write = false; + } + } + } +} -- 2.39.5