org.robolectric.shadows.ShadowPausedLooper Maven / Gradle / Ivy
package org.robolectric.shadows;
import static com.google.common.base.Preconditions.checkState;
import static org.robolectric.shadow.api.Shadow.invokeConstructor;
import static org.robolectric.util.ReflectionHelpers.ClassParameter.from;
import static org.robolectric.util.reflector.Reflector.reflector;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.MessageQueue.IdleHandler;
import android.os.SystemClock;
import android.util.Log;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import org.robolectric.annotation.Implementation;
import org.robolectric.annotation.Implements;
import org.robolectric.annotation.LooperMode;
import org.robolectric.annotation.RealObject;
import org.robolectric.annotation.Resetter;
import org.robolectric.config.ConfigurationRegistry;
import org.robolectric.shadow.api.Shadow;
import org.robolectric.util.Scheduler;
import org.robolectric.util.reflector.Direct;
import org.robolectric.util.reflector.ForType;
import org.robolectric.util.reflector.Static;
/**
* The shadow Looper for {@link LooperMode.Mode.PAUSED}.
*
* This shadow differs from the legacy {@link ShadowLegacyLooper} in the following ways:\ - Has
* no connection to {@link org.robolectric.util.Scheduler}. Its APIs are standalone - The main
* looper is always paused. Posted messages are not executed unless {@link #idle()} is called. -
* Just like in real Android, each looper has its own thread, and posted tasks get executed in that
* thread. - - There is only a single {@link SystemClock} value that all loopers read from. Unlike
* legacy behavior where each {@link org.robolectric.util.Scheduler} kept their own clock value.
*
*
This class should not be used directly; use {@link ShadowLooper} instead.
*/
@Implements(
value = Looper.class,
// turn off shadowOf generation.
isInAndroidSdk = false)
@SuppressWarnings("NewApi")
public final class ShadowPausedLooper extends ShadowLooper {
// Keep reference to all created Loopers so they can be torn down after test
private static Set loopingLoopers =
Collections.synchronizedSet(Collections.newSetFromMap(new WeakHashMap()));
@RealObject private Looper realLooper;
private boolean isPaused = false;
// the Executor that executes looper messages. Must be written to on looper thread
private Executor looperExecutor;
@Implementation
protected void __constructor__(boolean quitAllowed) {
invokeConstructor(Looper.class, realLooper, from(boolean.class, quitAllowed));
loopingLoopers.add(realLooper);
looperExecutor = new HandlerExecutor(new Handler(realLooper));
}
protected static Collection getLoopers() {
List loopers = new ArrayList<>(loopingLoopers);
return Collections.unmodifiableCollection(loopers);
}
@Override
public void quitUnchecked() {
throw new UnsupportedOperationException(
"this action is not" + " supported" + " in " + looperMode() + " mode.");
}
@Override
public boolean hasQuit() {
throw new UnsupportedOperationException(
"this action is not" + " supported" + " in " + looperMode() + " mode.");
}
@Override
public void idle() {
executeOnLooper(new IdlingRunnable());
}
@Override
public void idleFor(long time, TimeUnit timeUnit) {
long endingTimeMs = SystemClock.uptimeMillis() + timeUnit.toMillis(time);
long nextScheduledTimeMs = getNextScheduledTaskTime().toMillis();
while (nextScheduledTimeMs != 0 && nextScheduledTimeMs <= endingTimeMs) {
SystemClock.setCurrentTimeMillis(nextScheduledTimeMs);
idle();
nextScheduledTimeMs = getNextScheduledTaskTime().toMillis();
}
SystemClock.setCurrentTimeMillis(endingTimeMs);
// the last SystemClock update might have added new tasks to the main looper via Choreographer
// so idle once more.
idle();
}
@Override
public boolean isIdle() {
if (Thread.currentThread() == realLooper.getThread() || isPaused) {
return shadowQueue().isIdle();
} else {
return shadowQueue().isIdle() && shadowQueue().isPolling();
}
}
@Override
public void unPause() {
if (realLooper == Looper.getMainLooper()) {
throw new UnsupportedOperationException("main looper cannot be unpaused");
}
executeOnLooper(new UnPauseRunnable());
}
@Override
public void pause() {
if (!isPaused()) {
executeOnLooper(new PausedLooperExecutor());
}
}
@Override
public boolean isPaused() {
return isPaused;
}
@Override
public boolean setPaused(boolean shouldPause) {
if (shouldPause) {
pause();
} else {
unPause();
}
return true;
}
@Override
public void resetScheduler() {
throw new UnsupportedOperationException(
"this action is not" + " supported" + " in " + looperMode() + " mode.");
}
@Override
public void reset() {
throw new UnsupportedOperationException(
"this action is not" + " supported" + " in " + looperMode() + " mode.");
}
@Override
public void idleIfPaused() {
idle();
}
@Override
public void idleConstantly(boolean shouldIdleConstantly) {
throw new UnsupportedOperationException(
"this action is not" + " supported" + " in " + looperMode() + " mode.");
}
@Override
public void runToEndOfTasks() {
idleFor(Duration.ofMillis(getLastScheduledTaskTime().toMillis() - SystemClock.uptimeMillis()));
}
@Override
public void runToNextTask() {
idleFor(Duration.ofMillis(getNextScheduledTaskTime().toMillis() - SystemClock.uptimeMillis()));
}
@Override
public void runOneTask() {
executeOnLooper(new RunOneRunnable());
}
@Override
public boolean post(Runnable runnable, long delayMillis) {
return new Handler(realLooper).postDelayed(runnable, delayMillis);
}
@Override
public boolean postAtFrontOfQueue(Runnable runnable) {
return new Handler(realLooper).postAtFrontOfQueue(runnable);
}
// this API doesn't make sense in LooperMode.PAUSED, but just retain it for backwards
// compatibility for now
@Override
public void runPaused(Runnable runnable) {
if (isPaused && Thread.currentThread() == realLooper.getThread()) {
// just run
runnable.run();
} else {
throw new UnsupportedOperationException();
}
}
/**
* Polls the message queue waiting until a message is posted to the head of the queue. This will
* suspend the thread until a new message becomes available. Returns immediately if the queue is
* not idle. There's no guarantee that the message queue will not still be idle when returning,
* but if the message queue becomes not idle it will return immediately.
*
* This method is only applicable for the main looper's queue when called on the main thread,
* as the main looper in Robolectric is processed manually (it doesn't loop)--looper threads are
* using the native polling of their loopers. Throws an exception if called for another looper's
* queue. Non-main thread loopers should use {@link #unPause()}.
*
*
This should be used with care, it can be used to suspend the main (i.e. test) thread while
* worker threads perform some work, and then resumed by posting to the main looper. Used in a
* loop to wait on some condition it can process messages on the main looper, simulating the
* behavior of the real looper, for example:
*
*
{@code
* while (!condition) {
* shadowMainLooper.poll(timeout);
* shadowMainLooper.idle();
* }
* }
*
* Beware though that a message must be posted to the main thread after the condition is
* satisfied, or the condition satisfied while idling the main thread, otherwise the main thread
* will continue to be suspended until the timeout.
*
* @param timeout Timeout in milliseconds, the maximum time to wait before returning, or 0 to wait
* indefinitely,
*/
public void poll(long timeout) {
checkState(Looper.myLooper() == Looper.getMainLooper() && Looper.myLooper() == realLooper);
shadowQueue().poll(timeout);
}
@Override
public Duration getNextScheduledTaskTime() {
return shadowQueue().getNextScheduledTaskTime();
}
@Override
public Duration getLastScheduledTaskTime() {
return shadowQueue().getLastScheduledTaskTime();
}
@Resetter
public static synchronized void resetLoopers() {
// do not use looperMode() here, because its cached value might already have been reset
if (ConfigurationRegistry.get(LooperMode.Mode.class) != LooperMode.Mode.PAUSED) {
// ignore if not realistic looper
return;
}
Collection loopersCopy = new ArrayList(loopingLoopers);
for (Looper looper : loopersCopy) {
ShadowPausedMessageQueue shadowQueue = Shadow.extract(looper.getQueue());
shadowQueue.reset();
}
}
@Implementation
protected static void prepareMainLooper() {
reflector(LooperReflector.class).prepareMainLooper();
ShadowPausedLooper pausedLooper = Shadow.extract(Looper.getMainLooper());
pausedLooper.isPaused = true;
}
@Implementation
protected void quit() {
if (isPaused()) {
executeOnLooper(new UnPauseRunnable());
}
reflector(LooperReflector.class, realLooper).quit();
}
@Implementation(minSdk = Build.VERSION_CODES.JELLY_BEAN_MR2)
protected void quitSafely() {
if (isPaused()) {
executeOnLooper(new UnPauseRunnable());
}
reflector(LooperReflector.class, realLooper).quitSafely();
}
@Override
public Scheduler getScheduler() {
throw new UnsupportedOperationException(
String.format("this action is not supported in %s mode.", looperMode()));
}
private static ShadowPausedMessage shadowMsg(Message msg) {
return Shadow.extract(msg);
}
private ShadowPausedMessageQueue shadowQueue() {
return Shadow.extract(realLooper.getQueue());
}
private void setLooperExecutor(Executor executor) {
looperExecutor = executor;
}
/** Retrieves the next message or null if the queue is idle. */
private Message getNextExecutableMessage() {
synchronized (realLooper.getQueue()) {
// Use null if the queue is idle, otherwise getNext() will block.
return shadowQueue().isIdle() ? null : shadowQueue().getNext();
}
}
/**
* If the given {@code lastMessageRead} is not null and the queue is now idle, get the idle
* handlers and run them. This synchronization mirrors what happens in the real message queue
* next() method, but does not block after running the idle handlers.
*/
private void triggerIdleHandlersIfNeeded(Message lastMessageRead) {
List idleHandlers;
// Mirror the synchronization of MessageQueue.next(). If a message was read on the last call
// to next() and the queue is now idle, make a copy of the idle handlers and release the lock.
// Run the idle handlers without holding the lock, removing those that return false from their
// queueIdle() method.
synchronized (realLooper.getQueue()) {
if (lastMessageRead == null || !shadowQueue().isIdle()) {
return;
}
idleHandlers = shadowQueue().getIdleHandlersCopy();
}
for (IdleHandler idleHandler : idleHandlers) {
if (!idleHandler.queueIdle()) {
// This method already has synchronization internally.
realLooper.getQueue().removeIdleHandler(idleHandler);
}
}
}
/** A runnable that changes looper state, and that must be run from looper's thread */
private abstract static class ControlRunnable implements Runnable {
protected final CountDownLatch runLatch = new CountDownLatch(1);
public void waitTillComplete() {
try {
runLatch.await();
} catch (InterruptedException e) {
Log.w("ShadowPausedLooper", "wait till idle interrupted");
}
}
}
private class IdlingRunnable extends ControlRunnable {
@Override
public void run() {
try {
while (true) {
Message msg = getNextExecutableMessage();
if (msg == null) {
break;
}
msg.getTarget().dispatchMessage(msg);
shadowMsg(msg).recycleUnchecked();
triggerIdleHandlersIfNeeded(msg);
}
} finally {
runLatch.countDown();
}
}
}
private class RunOneRunnable extends ControlRunnable {
@Override
public void run() {
try {
Message msg = shadowQueue().getNextIgnoringWhen();
if (msg != null) {
SystemClock.setCurrentTimeMillis(shadowMsg(msg).getWhen());
msg.getTarget().dispatchMessage(msg);
triggerIdleHandlersIfNeeded(msg);
}
} finally {
runLatch.countDown();
}
}
}
/** Executes the given runnable on the loopers thread, and waits for it to complete. */
private void executeOnLooper(ControlRunnable runnable) {
if (Thread.currentThread() == realLooper.getThread()) {
if (runnable instanceof UnPauseRunnable) {
// Need to trigger the unpause action in PausedLooperExecutor
looperExecutor.execute(runnable);
} else {
runnable.run();
}
} else {
if (realLooper.equals(Looper.getMainLooper())) {
throw new UnsupportedOperationException(
"main looper can only be controlled from main thread");
}
looperExecutor.execute(runnable);
runnable.waitTillComplete();
}
}
/**
* A runnable that will block normal looper execution of messages aka will 'pause' the looper.
*
* Message execution can be triggered by posting messages to this runnable.
*/
private class PausedLooperExecutor extends ControlRunnable implements Executor {
private final LinkedBlockingQueue executionQueue = new LinkedBlockingQueue<>();
@Override
public void execute(Runnable runnable) {
executionQueue.add(runnable);
}
@Override
public void run() {
setLooperExecutor(this);
isPaused = true;
runLatch.countDown();
while (isPaused) {
try {
Runnable runnable = executionQueue.take();
runnable.run();
} catch (InterruptedException e) {
// ignore
}
}
}
}
private class UnPauseRunnable extends ControlRunnable {
@Override
public void run() {
setLooperExecutor(new HandlerExecutor(new Handler(realLooper)));
isPaused = false;
runLatch.countDown();
}
}
private static class HandlerExecutor implements Executor {
private final Handler handler;
private HandlerExecutor(Handler handler) {
this.handler = handler;
}
@Override
public void execute(Runnable runnable) {
if (!handler.post(runnable)) {
throw new IllegalStateException(
String.format("post to %s failed. Is handler thread dead?", handler));
}
}
}
@ForType(Looper.class)
interface LooperReflector {
@Static
@Direct
void prepareMainLooper();
@Direct
void quit();
@Direct
void quitSafely();
}
}