Code drop from //branches/cupcake/...@124589

1 files changed, 95 insertions, 18 deletions

diff --git a/WebCore/platform/win/SharedTimerWin.cpp b/WebCore/platform/win/SharedTimerWin.cpp
index 8ff7734..b611659 100644
--- a/WebCore/platform/win/SharedTimerWin.cpp
+++ b/WebCore/platform/win/SharedTimerWin.cpp
@@ -39,6 +39,21 @@
 #endif
 
 #include <windows.h>
+#include <mmsystem.h>
+
+// These aren't in winuser.h with the MSVS 2003 Platform SDK, 
+// so use default values in that case.
+#ifndef USER_TIMER_MINIMUM
+#define USER_TIMER_MINIMUM 0x0000000A
+#endif
+
+#ifndef USER_TIMER_MAXIMUM
+#define USER_TIMER_MAXIMUM 0x7FFFFFFF
+#endif
+
+#ifndef QS_RAWINPUT
+#define QS_RAWINPUT         0x0400
+#endif
 
 #if PLATFORM(WIN)
 #include "PluginView.h"
@@ -51,9 +66,22 @@ static void (*sharedTimerFiredFunction)();
 
 static HWND timerWindowHandle = 0;
 static UINT timerFiredMessage = 0;
-const LPCWSTR kTimerWindowClassName = L"TimerWindowClass";
+static HANDLE timerQueue;
+static HANDLE timer;
+static Mutex timerMutex;
+static bool highResTimerActive;
 static bool processingCustomTimerMessage = false;
-const int sharedTimerID = 1000;
+static LONG pendingTimers;
+
+const LPCWSTR kTimerWindowClassName = L"TimerWindowClass";
+const int timerResolution = 1; // To improve timer resolution, we call timeBeginPeriod/timeEndPeriod with this value to increase timer resolution to 1ms.
+const int highResolutionThresholdMsec = 16; // Only activate high-res timer for sub-16ms timers (Windows can fire timers at 16ms intervals without changing the system resolution).
+const int stopHighResTimerInMsec = 300; // Stop high-res timer after 0.3 seconds to lessen power consumption (we don't use a smaller time since oscillating between high and low resolution breaks timer accuracy on XP).
+
+enum {
+    sharedTimerID = 1000,
+    endHighResTimerID = 1001,
+};
 
 LRESULT CALLBACK TimerWindowWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
@@ -69,13 +97,22 @@ LRESULT CALLBACK TimerWindowWndProc(HWND hWnd, UINT message, WPARAM wParam, LPAR
 #endif
 
     if (message == timerFiredMessage) {
+        InterlockedExchange(&pendingTimers, 0);
         processingCustomTimerMessage = true;
         sharedTimerFiredFunction();
         processingCustomTimerMessage = false;
-    } else if (message == WM_TIMER && wParam == sharedTimerID)
-        sharedTimerFiredFunction();
-    else
+    } else if (message == WM_TIMER) {
+        if (wParam == sharedTimerID) {
+            KillTimer(timerWindowHandle, sharedTimerID);
+            sharedTimerFiredFunction();
+        } else if (wParam == endHighResTimerID) {
+            KillTimer(timerWindowHandle, endHighResTimerID);
+            highResTimerActive = false;
+            timeEndPeriod(timerResolution);
+        }
+    } else
         return DefWindowProc(hWnd, message, wParam, lParam);
+
     return 0;
 }
 
@@ -102,6 +139,21 @@ void setSharedTimerFiredFunction(void (*f)())
     sharedTimerFiredFunction = f;
 }
 
+static void clearTimer()
+{
+    MutexLocker locker(timerMutex);
+    if (timerQueue && timer)
+        DeleteTimerQueueTimer(timerQueue, timer, 0);
+    timer = 0;
+}
+
+static void NTAPI queueTimerProc(PVOID, BOOLEAN)
+{
+    clearTimer();
+    if (InterlockedIncrement(&pendingTimers) == 1)
+        PostMessage(timerWindowHandle, timerFiredMessage, 0, 0);
+}
+
 void setSharedTimerFireTime(double fireTime)
 {
     ASSERT(sharedTimerFiredFunction);
@@ -118,29 +170,54 @@ void setSharedTimerFireTime(double fireTime)
             intervalInMS = (unsigned)interval;
     }
 
-    if (timerID) {
-        KillTimer(0, timerID);
-        timerID = 0;
+    if (interval < highResolutionThresholdMsec) {
+        if (!highResTimerActive) {
+            highResTimerActive = true;
+            timeBeginPeriod(timerResolution);
+        }
+        SetTimer(timerWindowHandle, endHighResTimerID, stopHighResTimerInMsec, 0);
     }
 
-    // We don't allow nested PostMessages, since the custom messages will effectively starve
-    // painting and user input. (Win32 has a tri-level queue with application messages > 
-    // user input > WM_PAINT/WM_TIMER.)
-    // In addition, if the queue contains input events that have been there since the last call to
-    // GetQueueStatus, PeekMessage or GetMessage we favor timers.
     initializeOffScreenTimerWindow();
-    if (intervalInMS < USER_TIMER_MINIMUM && !processingCustomTimerMessage && 
-        !LOWORD(::GetQueueStatus(QS_ALLINPUT))) {
-        // Windows SetTimer does not allow timeouts smaller than 10ms (USER_TIMER_MINIMUM)
-        PostMessage(timerWindowHandle, timerFiredMessage, 0, 0);
+    bool timerSet = false;
+    DWORD queueStatus = LOWORD(GetQueueStatus(QS_PAINT | QS_MOUSEBUTTON | QS_KEY | QS_RAWINPUT));
+
+    // Win32 has a tri-level queue with application messages > user input > WM_PAINT/WM_TIMER.
+
+    // If the queue doesn't contains input events, we use a higher priorty timer event posting mechanism.
+    if (!(queueStatus & (QS_MOUSEBUTTON | QS_KEY | QS_RAWINPUT))) {
+        if (intervalInMS < USER_TIMER_MINIMUM && !processingCustomTimerMessage && !(queueStatus & QS_PAINT)) {
+            // Call PostMessage immediately if the timer is already expired, unless a paint is pending.
+            // (we prioritize paints over timers)
+            if (InterlockedIncrement(&pendingTimers) == 1)
+                PostMessage(timerWindowHandle, timerFiredMessage, 0, 0);
+            timerSet = true;
+        } else {
+            // Otherwise, delay the PostMessage via a CreateTimerQueueTimer
+            if (!timerQueue)
+                timerQueue = CreateTimerQueue();
+            MutexLocker locker(timerMutex);
+            if (timer)
+                timerSet = ChangeTimerQueueTimer(timerQueue, timer, intervalInMS, 0);
+            else
+                timerSet = CreateTimerQueueTimer(&timer, timerQueue, queueTimerProc, 0, intervalInMS, 0, WT_EXECUTEINTIMERTHREAD | WT_EXECUTEONLYONCE);
+        }
+    }
+
+    if (timerSet) {
+        if (timerID) {
+            KillTimer(timerWindowHandle, timerID);
+            timerID = 0;
+        }
     } else
         timerID = SetTimer(timerWindowHandle, sharedTimerID, intervalInMS, 0);
 }
 
 void stopSharedTimer()
 {
+    clearTimer();
     if (timerID) {
-        KillTimer(0, timerID);
+        KillTimer(timerWindowHandle, timerID);
         timerID = 0;
     }
 }