Bug 1300659 P3 Make setTimeout() and setInterval() use the TabGroup ThrottledEventQueue. r=smaug

dom/base/Timeout.cpp

@@ -55,18 +55,17 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(Timeout, AddRef)
 NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(Timeout, Release)
 
-nsresult
-Timeout::InitTimer(uint32_t aDelay)
+namespace {
+
+void
+TimerCallback(nsITimer*, void* aClosure)
 {
-  return mTimer->InitWithNameableFuncCallback(
-    nsGlobalWindow::TimerCallback, this, aDelay,
-    nsITimer::TYPE_ONE_SHOT, Timeout::TimerNameCallback);
+  RefPtr<Timeout> timeout = (Timeout*)aClosure;
+  timeout->mWindow->RunTimeout(timeout);
 }
 
-// static
 void
-Timeout::TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
-                           size_t aLen)
+TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf, size_t aLen)
 {
   RefPtr<Timeout> timeout = (Timeout*)aClosure;
 
@@ -76,6 +75,28 @@ Timeout::TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
   snprintf(aBuf, aLen, "[content] %s:%u:%u", filename, lineNum, column);
 }
 
+} // anonymous namespace
+
+nsresult
+Timeout::InitTimer(nsIEventTarget* aTarget, uint32_t aDelay)
+{
+  // If the given target does not match the timer's current target
+  // then we need to override it before the Init.  Note that GetTarget()
+  // will return the current thread after setting the target to nullptr.
+  // So we need to special case the nullptr target comparison.
+  nsCOMPtr<nsIEventTarget> currentTarget;
+  MOZ_ALWAYS_SUCCEEDS(mTimer->GetTarget(getter_AddRefs(currentTarget)));
+  if ((aTarget && currentTarget != aTarget) ||
+      (!aTarget && currentTarget != NS_GetCurrentThread())) {
+    // Always call Cancel() in case we are re-using a timer.  Otherwise
+    // the subsequent SetTarget() may fail.
+    MOZ_ALWAYS_SUCCEEDS(mTimer->Cancel());
+    MOZ_ALWAYS_SUCCEEDS(mTimer->SetTarget(aTarget));
+  }
+
+  return mTimer->InitWithNameableFuncCallback(
+    TimerCallback, this, aDelay, nsITimer::TYPE_ONE_SHOT, TimerNameCallback);
+}
 
 // Return true if this timeout has a refcount of 1. This is used to check
 // that dummy_timeout doesn't leak from nsGlobalWindow::RunTimeout.

dom/base/Timeout.h

@@ -34,13 +34,13 @@ public:
   NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(Timeout)
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(Timeout)
 
-  nsresult InitTimer(uint32_t aDelay);
+  // The target may be specified to use a particular event queue for the
+  // resulting timer runnable.  A nullptr target will result in the
+  // default main thread being used.
+  nsresult InitTimer(nsIEventTarget* aTarget, uint32_t aDelay);
 
   enum class Reason { eTimeoutOrInterval, eIdleCallbackTimeout };
 
-  static void TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
-                                size_t aLen);
-
 #ifdef DEBUG
   bool HasRefCntOne() const;
 #endif // DEBUG

dom/base/nsGlobalWindow.cpp

@@ -11882,7 +11882,7 @@ nsGlobalWindow::Resume()
       continue;
     }
 
-    nsresult rv = t->InitTimer(delay);
+    nsresult rv = t->InitTimer(GetThrottledEventQueue(), delay);
     if (NS_FAILED(rv)) {
       t->mTimer = nullptr;
       t->remove();
@@ -12601,7 +12601,7 @@ nsGlobalWindow::SetTimeoutOrInterval(nsITimeoutHandler* aHandler,
 
     RefPtr<Timeout> copy = timeout;
 
-    rv = timeout->InitTimer(realInterval);
+    rv = timeout->InitTimer(GetThrottledEventQueue(), realInterval);
     if (NS_FAILED(rv)) {
       return rv;
     }
@@ -12874,7 +12874,8 @@ nsGlobalWindow::RescheduleTimeout(Timeout* aTimeout, const TimeStamp& now,
 
   // Reschedule the OS timer. Don't bother returning any error codes if
   // this fails since the callers of this method don't care about them.
-  nsresult rv = aTimeout->InitTimer(delay.ToMilliseconds());
+  nsresult rv = aTimeout->InitTimer(GetThrottledEventQueue(),
+                                    delay.ToMilliseconds());
 
   if (NS_FAILED(rv)) {
     NS_ERROR("Error initializing timer for DOM timeout!");
@@ -12949,6 +12950,20 @@ nsGlobalWindow::RunTimeout(Timeout* aTimeout)
       // firing depth so that we can reentrantly run timeouts
       timeout->mFiringDepth = firingDepth;
       last_expired_timeout = timeout;
+
+      // Run available timers until we see our target timer.  After
+      // that, however, stop coalescing timers so we can yield the
+      // main thread.  Further timers that are ready will get picked
+      // up by their own nsITimer runnables when they execute.
+      //
+      // For chrome windows, however, we do coalesce all timers and
+      // do not yield the main thread.  This is partly because we
+      // trust chrome windows not to misbehave and partly because a
+      // number of browser chrome tests have races that depend on this
+      // coalescing.
+      if (timeout == aTimeout && !IsChromeWindow()) {
+        break;
+      }
     }
   }
 
@@ -13167,7 +13182,8 @@ nsresult nsGlobalWindow::ResetTimersForNonBackgroundWindow()
       timeout->mFiringDepth = firingDepth;
       timeout->Release();
 
-      nsresult rv = timeout->InitTimer(delay.ToMilliseconds());
+      nsresult rv = timeout->InitTimer(GetThrottledEventQueue(),
+                                       delay.ToMilliseconds());
 
       if (NS_FAILED(rv)) {
         NS_WARNING("Error resetting non background timer for DOM timeout!");
@@ -13256,15 +13272,6 @@ nsGlobalWindow::InsertTimeoutIntoList(Timeout* aTimeout)
   aTimeout->AddRef();
 }
 
-// static
-void
-nsGlobalWindow::TimerCallback(nsITimer *aTimer, void *aClosure)
-{
-  RefPtr<Timeout> timeout = (Timeout*)aClosure;
-
-  timeout->mWindow->RunTimeout(timeout);
-}
-
 //*****************************************************************************
 // nsGlobalWindow: Helper Functions
 //*****************************************************************************

dom/base/nsGlobalWindow.h

@@ -1498,7 +1498,6 @@ public:
   // Insert aTimeout into the list, before all timeouts that would
   // fire after it, but no earlier than mTimeoutInsertionPoint, if any.
   void InsertTimeoutIntoList(mozilla::dom::Timeout* aTimeout);
-  static void TimerCallback(nsITimer *aTimer, void *aClosure);
   uint32_t GetTimeoutId(mozilla::dom::Timeout::Reason aReason);
 
   // Helper Functions