michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.util;
michael@0: 
michael@0: import java.util.Map;
michael@0: 
michael@0: import android.os.Handler;
michael@0: import android.os.MessageQueue;
michael@0: import android.util.Log;
michael@0: 
michael@0: public final class ThreadUtils {
michael@0:     private static final String LOGTAG = "ThreadUtils";
michael@0: 
michael@0:     /**
michael@0:      * Controls the action taken when a method like
michael@0:      * {@link ThreadUtils#assertOnUiThread(AssertBehavior)} detects a problem.
michael@0:      */
michael@0:     public static enum AssertBehavior {
michael@0:         NONE,
michael@0:         THROW,
michael@0:     }
michael@0: 
michael@0:     private static volatile Thread sUiThread;
michael@0:     private static volatile Thread sBackgroundThread;
michael@0: 
michael@0:     private static Handler sUiHandler;
michael@0: 
michael@0:     // Referenced directly from GeckoAppShell in highly performance-sensitive code (The extra
michael@0:     // function call of the getter was harming performance. (Bug 897123))
michael@0:     // Once Bug 709230 is resolved we should reconsider this as ProGuard should be able to optimise
michael@0:     // this out at compile time.
michael@0:     public static Handler sGeckoHandler;
michael@0:     public static MessageQueue sGeckoQueue;
michael@0:     public static Thread sGeckoThread;
michael@0: 
michael@0:     // Delayed Runnable that resets the Gecko thread priority.
michael@0:     private static final Runnable sPriorityResetRunnable = new Runnable() {
michael@0:         @Override
michael@0:         public void run() {
michael@0:             resetGeckoPriority();
michael@0:         }
michael@0:     };
michael@0: 
michael@0:     private static boolean sIsGeckoPriorityReduced;
michael@0: 
michael@0:     @SuppressWarnings("serial")
michael@0:     public static class UiThreadBlockedException extends RuntimeException {
michael@0:         public UiThreadBlockedException() {
michael@0:             super();
michael@0:         }
michael@0: 
michael@0:         public UiThreadBlockedException(String msg) {
michael@0:             super(msg);
michael@0:         }
michael@0: 
michael@0:         public UiThreadBlockedException(String msg, Throwable e) {
michael@0:             super(msg, e);
michael@0:         }
michael@0: 
michael@0:         public UiThreadBlockedException(Throwable e) {
michael@0:             super(e);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public static void dumpAllStackTraces() {
michael@0:         Log.w(LOGTAG, "Dumping ALL the threads!");
michael@0:         Map<Thread, StackTraceElement[]> allStacks = Thread.getAllStackTraces();
michael@0:         for (Thread t : allStacks.keySet()) {
michael@0:             Log.w(LOGTAG, t.toString());
michael@0:             for (StackTraceElement ste : allStacks.get(t)) {
michael@0:                 Log.w(LOGTAG, ste.toString());
michael@0:             }
michael@0:             Log.w(LOGTAG, "----");
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public static void setUiThread(Thread thread, Handler handler) {
michael@0:         sUiThread = thread;
michael@0:         sUiHandler = handler;
michael@0:     }
michael@0: 
michael@0:     public static void setBackgroundThread(Thread thread) {
michael@0:         sBackgroundThread = thread;
michael@0:     }
michael@0: 
michael@0:     public static Thread getUiThread() {
michael@0:         return sUiThread;
michael@0:     }
michael@0: 
michael@0:     public static Handler getUiHandler() {
michael@0:         return sUiHandler;
michael@0:     }
michael@0: 
michael@0:     public static void postToUiThread(Runnable runnable) {
michael@0:         sUiHandler.post(runnable);
michael@0:     }
michael@0: 
michael@0:     public static Thread getBackgroundThread() {
michael@0:         return sBackgroundThread;
michael@0:     }
michael@0: 
michael@0:     public static Handler getBackgroundHandler() {
michael@0:         return GeckoBackgroundThread.getHandler();
michael@0:     }
michael@0: 
michael@0:     public static void postToBackgroundThread(Runnable runnable) {
michael@0:         GeckoBackgroundThread.post(runnable);
michael@0:     }
michael@0: 
michael@0:     public static void assertOnUiThread(final AssertBehavior assertBehavior) {
michael@0:         assertOnThread(getUiThread(), assertBehavior);
michael@0:     }
michael@0: 
michael@0:     public static void assertOnUiThread() {
michael@0:         assertOnThread(getUiThread(), AssertBehavior.THROW);
michael@0:     }
michael@0: 
michael@0:     public static void assertOnGeckoThread() {
michael@0:         assertOnThread(sGeckoThread, AssertBehavior.THROW);
michael@0:     }
michael@0: 
michael@0:     public static void assertOnBackgroundThread() {
michael@0:         assertOnThread(getBackgroundThread(), AssertBehavior.THROW);
michael@0:     }
michael@0: 
michael@0:     public static void assertOnThread(final Thread expectedThread) {
michael@0:         assertOnThread(expectedThread, AssertBehavior.THROW);
michael@0:     }
michael@0: 
michael@0:     public static void assertOnThread(final Thread expectedThread, AssertBehavior behavior) {
michael@0:         final Thread currentThread = Thread.currentThread();
michael@0:         final long currentThreadId = currentThread.getId();
michael@0:         final long expectedThreadId = expectedThread.getId();
michael@0: 
michael@0:         if (currentThreadId == expectedThreadId) {
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         final String message = "Expected thread " +
michael@0:                                expectedThreadId + " (\"" + expectedThread.getName() +
michael@0:                                "\"), but running on thread " +
michael@0:                                currentThreadId + " (\"" + currentThread.getName() + ")";
michael@0:         final IllegalThreadStateException e = new IllegalThreadStateException(message);
michael@0: 
michael@0:         switch (behavior) {
michael@0:         case THROW:
michael@0:             throw e;
michael@0:         default:
michael@0:             Log.e(LOGTAG, "Method called on wrong thread!", e);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public static boolean isOnUiThread() {
michael@0:         return isOnThread(getUiThread());
michael@0:     }
michael@0: 
michael@0:     public static boolean isOnBackgroundThread() {
michael@0:         if (sBackgroundThread == null) {
michael@0:             return false;
michael@0:         }
michael@0: 
michael@0:         return isOnThread(sBackgroundThread);
michael@0:     }
michael@0: 
michael@0:     public static boolean isOnThread(Thread thread) {
michael@0:         return (Thread.currentThread().getId() == thread.getId());
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Reduces the priority of the Gecko thread, allowing other operations
michael@0:      * (such as those related to the UI and database) to take precedence.
michael@0:      *
michael@0:      * Note that there are no guards in place to prevent multiple calls
michael@0:      * to this method from conflicting with each other.
michael@0:      *
michael@0:      * @param timeout Timeout in ms after which the priority will be reset
michael@0:      */
michael@0:     public static void reduceGeckoPriority(long timeout) {
michael@0:         if (!sIsGeckoPriorityReduced) {
michael@0:             sIsGeckoPriorityReduced = true;
michael@0:             sGeckoThread.setPriority(Thread.MIN_PRIORITY);
michael@0:             getUiHandler().postDelayed(sPriorityResetRunnable, timeout);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Resets the priority of a thread whose priority has been reduced
michael@0:      * by reduceGeckoPriority.
michael@0:      */
michael@0:     public static void resetGeckoPriority() {
michael@0:         if (sIsGeckoPriorityReduced) {
michael@0:             sIsGeckoPriorityReduced = false;
michael@0:             sGeckoThread.setPriority(Thread.NORM_PRIORITY);
michael@0:             getUiHandler().removeCallbacks(sPriorityResetRunnable);
michael@0:         }
michael@0:     }
michael@0: }