From ea882b6f161409ff439b93dfa146431944a42d9d Mon Sep 17 00:00:00 2001
From: Alexander Blom <blom@fb.com>
Date: Fri, 4 Mar 2016 09:30:38 -0800
Subject: [PATCH] Immediate dispatch 0 time timers

Summary: Calling setTimeout(f, 0) will currently schedule f to be called the next frame instead of immediately (which is how it behaves on iOS). This immediately calls back to JS and invokes the function.

Reviewed By: astreet, tadeuzagallo

Differential Revision: D3006125

fb-gh-sync-id: 9fa109ed82836a718cbb2e8cb21da4943d96f5f6
shipit-source-id: 9fa109ed82836a718cbb2e8cb21da4943d96f5f6
---
 .../com/facebook/react/modules/core/Timing.java    |  8 ++++++++
 .../react/modules/timing/TimingModuleTest.java     | 14 ++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/core/Timing.java b/ReactAndroid/src/main/java/com/facebook/react/modules/core/Timing.java
index b0bf332da..79a5b6b3f 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/core/Timing.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/core/Timing.java
@@ -217,6 +217,14 @@ public final class Timing extends ReactContextBaseJavaModule implements Lifecycl
     long adjustedDuration = (long) Math.max(
         0,
         jsSchedulingTime - SystemClock.currentTimeMillis() + duration);
+    if (duration == 0 && !repeat) {
+      WritableArray timerToCall = Arguments.createArray();
+      timerToCall.pushInt(callbackID);
+      getReactApplicationContext().getJSModule(executorToken, JSTimersExecution.class)
+        .callTimers(timerToCall);
+      return;
+    }
+
     long initialTargetTime = SystemClock.nanoTime() / 1000000 + adjustedDuration;
     Timer timer = new Timer(executorToken, callbackID, initialTargetTime, duration, repeat);
     synchronized (mTimerGuard) {
diff --git a/ReactAndroid/src/test/java/com/facebook/react/modules/timing/TimingModuleTest.java b/ReactAndroid/src/test/java/com/facebook/react/modules/timing/TimingModuleTest.java
index 1597d84e3..e6185a8f0 100644
--- a/ReactAndroid/src/test/java/com/facebook/react/modules/timing/TimingModuleTest.java
+++ b/ReactAndroid/src/test/java/com/facebook/react/modules/timing/TimingModuleTest.java
@@ -110,7 +110,7 @@ public class TimingModuleTest {
   @Test
   public void testSimpleTimer() {
     mTiming.onHostResume();
-    mTiming.createTimer(mExecutorTokenMock, 1, 0, 0, false);
+    mTiming.createTimer(mExecutorTokenMock, 1, 1, 0, false);
     stepChoreographerFrame();
     verify(mJSTimersMock).callTimers(JavaOnlyArray.of(1));
     reset(mJSTimersMock);
@@ -120,7 +120,7 @@ public class TimingModuleTest {
 
   @Test
   public void testSimpleRecurringTimer() {
-    mTiming.createTimer(mExecutorTokenMock, 100, 0, 0, true);
+    mTiming.createTimer(mExecutorTokenMock, 100, 1, 0, true);
     mTiming.onHostResume();
     stepChoreographerFrame();
     verify(mJSTimersMock).callTimers(JavaOnlyArray.of(100));
@@ -133,7 +133,7 @@ public class TimingModuleTest {
   @Test
   public void testCancelRecurringTimer() {
     mTiming.onHostResume();
-    mTiming.createTimer(mExecutorTokenMock, 105, 0, 0, true);
+    mTiming.createTimer(mExecutorTokenMock, 105, 1, 0, true);
 
     stepChoreographerFrame();
     verify(mJSTimersMock).callTimers(JavaOnlyArray.of(105));
@@ -147,7 +147,7 @@ public class TimingModuleTest {
   @Test
   public void testPausingAndResuming() {
     mTiming.onHostResume();
-    mTiming.createTimer(mExecutorTokenMock, 41, 0, 0, true);
+    mTiming.createTimer(mExecutorTokenMock, 41, 1, 0, true);
 
     stepChoreographerFrame();
     verify(mJSTimersMock).callTimers(JavaOnlyArray.of(41));
@@ -163,6 +163,12 @@ public class TimingModuleTest {
     verify(mJSTimersMock).callTimers(JavaOnlyArray.of(41));
   }
 
+  @Test
+  public void testSetTimeoutZero() {
+    mTiming.createTimer(mExecutorTokenMock, 100, 0, 0, false);
+    verify(mJSTimersMock).callTimers(JavaOnlyArray.of(100));
+  }
+
   private static class PostFrameCallbackHandler implements Answer<Void> {
 
     private Choreographer.FrameCallback mFrameCallback;