Don't call prepare more than necessary

Store the memory address of our last QRasterBuffer::prepare() call to
make sure we reprepare if someone has unlocked and locked the device
behind our back.

Also optimize QDirectFBDevice::memory() since it might get called a fair
bit.

Reviewed-by: Donald <qt-info@nokia.com>

3 files changed, 37 insertions, 22 deletions

diff --git a/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.cpp b/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.cpp
index 9796280..72e0ce5 100644
--- a/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.cpp
+++ b/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.cpp
@@ -58,18 +58,18 @@ IDirectFBSurface *QDirectFBPaintDevice::directFBSurface() const
 
 void QDirectFBPaintDevice::lockDirectFB(uint flags)
 {
-    if (lockedImage) {
-        if (lockFlags & flags)
-            return;
-        unlockDirectFB();
-    }
-    if (uchar *mem = QDirectFBScreen::lockSurface(dfbSurface, flags, &bpl)) {
-        const QSize s = size();
-        lockedImage = new QImage(mem, s.width(), s.height(), bpl,
-                                 QDirectFBScreen::getImageFormat(dfbSurface));
-        lockFlags = flags;
-    } else {
-        lockFlags = 0;
+    if (!(lock & flags)) {
+        if (lock)
+            unlockDirectFB();
+        if ((mem = QDirectFBScreen::lockSurface(dfbSurface, flags, &bpl))) {
+            const QSize s = size();
+            lockedImage = new QImage(mem, s.width(), s.height(), bpl,
+                                     QDirectFBScreen::getImageFormat(dfbSurface));
+            lock = flags;
+            Q_ASSERT(mem);
+        } else {
+            lock = 0;
+        }
     }
 }
 
@@ -82,15 +82,19 @@ void QDirectFBPaintDevice::unlockDirectFB()
     dfbSurface->Unlock(dfbSurface);
     delete lockedImage;
     lockedImage = 0;
+    mem = 0;
+    lock = 0;
 }
 
 
 void *QDirectFBPaintDevice::memory() const
 {
-    QDirectFBPaintDevice* that = const_cast<QDirectFBPaintDevice*>(this);
-    that->lockDirectFB(DSLF_READ|DSLF_WRITE);
-    Q_ASSERT(that->lockedImage);
-    return that->lockedImage->bits();
+    if (lock != (DSLF_READ|DSLF_WRITE)) {
+        QDirectFBPaintDevice *that = const_cast<QDirectFBPaintDevice*>(this);
+        that->lockDirectFB(DSLF_READ|DSLF_WRITE);
+        Q_ASSERT(that->lockedImage);
+    }
+    return mem;
 }
 
 
diff --git a/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.h b/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.h
index 1709d69..13f0a8f 100644
--- a/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.h
+++ b/src/plugins/gfxdrivers/directfb/qdirectfbpaintdevice.h
@@ -69,6 +69,7 @@ public:
     int bytesPerLine() const;
     QSize size() const;
     int metric(QPaintDevice::PaintDeviceMetric metric) const;
+    uint lockFlags() const { return lock; }
 protected:
     // Shouldn't create QDirectFBPaintDevice by itself but only sub-class it:
     QDirectFBPaintDevice(QDirectFBScreen *scr = QDirectFBScreen::instance())
@@ -77,7 +78,8 @@ protected:
           lockedImage(0),
           screen(scr),
           forceRaster(false),
-          lockFlags(0)
+          lock(0),
+          mem(0)
     {}
 
     inline int dotsPerMeterX() const
@@ -94,7 +96,8 @@ protected:
     QDirectFBScreen *screen;
     int bpl;
     bool forceRaster;
-    uint lockFlags;
+    uint lock;
+    uchar *mem;
 private:
     Q_DISABLE_COPY(QDirectFBPaintDevice)
 };
diff --git a/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp b/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp
index c77632c..c9752e9 100644
--- a/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp
+++ b/src/plugins/gfxdrivers/directfb/qdirectfbpaintengine.cpp
@@ -336,6 +336,7 @@ private:
     bool dfbHandledClip;
     bool ignoreSystemClip;
     QDirectFBPaintDevice *dfbDevice;
+    void *lockedMemory;
 
     QDirectFBPaintEngine *q;
 };
@@ -345,7 +346,7 @@ QDirectFBPaintEnginePrivate::QDirectFBPaintEnginePrivate(QDirectFBPaintEngine *p
       matrixRotShear(false), scale(NoScale), lastLockedHeight(-1),
       fbWidth(-1), fbHeight(-1), opacity(255), drawFlagsFromCompositionMode(0),
       blitFlagsFromCompositionMode(0), porterDuffRule(DSPD_SRC_OVER), dirtyClip(true),
-      dfbHandledClip(false), dfbDevice(0), q(p)
+      dfbHandledClip(false), dfbDevice(0), lockedMemory(0), q(p)
 {
     fb = QDirectFBScreen::instance()->dfb();
     ignoreSystemClip = QDirectFBScreen::instance()->directFBFlags() & QDirectFBScreen::IgnoreSystemClip;
@@ -392,16 +393,21 @@ void QDirectFBPaintEnginePrivate::lock()
     // We will potentially get a new pointer to the buffer after a
     // lock so we need to call the base implementation of prepare so
     // it updates its rasterBuffer to point to the new buffer address.
-    lastLockedHeight = dfbDevice->height();
-
     Q_ASSERT(dfbDevice);
-    prepare(dfbDevice);
+    if (dfbDevice->lockFlags() != (DSLF_WRITE|DSLF_READ)
+        || dfbDevice->height() != lastLockedHeight
+        || dfbDevice->memory() != lockedMemory) {
+        prepare(dfbDevice);
+        lastLockedHeight = dfbDevice->height();
+        lockedMemory = dfbDevice->memory();
+    }
 }
 
 void QDirectFBPaintEnginePrivate::unlock()
 {
     Q_ASSERT(dfbDevice);
     dfbDevice->unlockDirectFB();
+    lockedMemory = 0;
 }
 
 void QDirectFBPaintEnginePrivate::setTransform(const QTransform &m)
@@ -436,6 +442,7 @@ void QDirectFBPaintEnginePrivate::begin(QPaintDevice *device)
         qFatal("QDirectFBPaintEngine used on an invalid device: 0x%x",
                device->devType());
     }
+    lockedMemory = 0;
     forceRasterPrimitives = dfbDevice->forceRasterPrimitives();
 
     surface->GetSize(surface, &fbWidth, &fbHeight);
@@ -451,6 +458,7 @@ void QDirectFBPaintEnginePrivate::begin(QPaintDevice *device)
 
 void QDirectFBPaintEnginePrivate::end()
 {
+    lockedMemory = 0;
     dfbDevice = 0;
     surface->ReleaseSource(surface);
     surface->SetClip(surface, NULL);