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Commit c5686802 authored by Valerie Hau's avatar Valerie Hau
Browse files

When destroying layer, add children to offscreen layers 

If a layer is destroyed, make sure all children are added to the
offscreen layers.  Otherwise, we may dangle a layer that is neither in
current state nor in offscreen layers.
Bug: 141111965
Test: build, boot, manual

Change-Id: Iec6788f10a24cb63faa9b40f246cbde3770d24a7
parent d0d28e31

services/surfaceflinger/Layer.h

+9 −0
Original line number Diff line number Diff line
@@ -664,6 +664,15 @@ public: 
                                  const LayerVector::Visitor& visitor);



    size_t getChildrenCount() const;



    // ONLY CALL THIS FROM THE LAYER DTOR!

    // See b/141111965.  We need to add current children to offscreen layers in

    // the layer dtor so as not to dangle layers.  Since the layer has not

    // committed its transaction when the layer is destroyed, we must add

    // current children.  This is safe in the dtor as we will no longer update

    // the current state, but should not be called anywhere else!

    LayerVector& getCurrentChildren() { return mCurrentChildren; }



    void addChild(const sp<Layer>& layer);

    // Returns index if removed, or negative value otherwise

    // for symmetry with Vector::remove

services/surfaceflinger/SurfaceFlinger.cpp

+14 −3
Original line number Diff line number Diff line
@@ -3717,9 +3717,6 @@ void SurfaceFlinger::setPowerModeInternal(const sp<DisplayDevice>& display, int 
    }



    if (currentMode == HWC_POWER_MODE_OFF) {

        // Turn on the display

        // TODO: @vhau temp fix only!  See b/141111965

        mTransactionCompletedThread.clearAllPending();

        getHwComposer().setPowerMode(*displayId, mode);

        if (display->isPrimary() && mode != HWC_POWER_MODE_DOZE_SUSPEND) {

            setVsyncEnabledInHWC(*displayId, mHWCVsyncPendingState);
@@ -5500,6 +5497,20 @@ void SurfaceFlinger::onLayerFirstRef(Layer* layer) { 


void SurfaceFlinger::onLayerDestroyed(Layer* layer) {

    mNumLayers--;

    removeFromOffscreenLayers(layer);

}



// WARNING: ONLY CALL THIS FROM LAYER DTOR

// Here we add children in the current state to offscreen layers and remove the

// layer itself from the offscreen layer list.  Since

// this is the dtor, it is safe to access the current state.  This keeps us

// from dangling children layers such that they are not reachable from the

// Drawing state nor the offscreen layer list

// See b/141111965

void SurfaceFlinger::removeFromOffscreenLayers(Layer* layer) {

    for (auto& child : layer->getCurrentChildren()) {

        mOffscreenLayers.emplace(child.get());

    }

    mOffscreenLayers.erase(layer);

}

services/surfaceflinger/SurfaceFlinger.h

+2 −0
Original line number Diff line number Diff line
@@ -313,6 +313,8 @@ public: 
    void onLayerFirstRef(Layer*);

    void onLayerDestroyed(Layer*);



    void removeFromOffscreenLayers(Layer* layer);



    TransactionCompletedThread& getTransactionCompletedThread() {

        return mTransactionCompletedThread;

    }

services/surfaceflinger/TransactionCompletedThread.cpp

+0 −9
Original line number Diff line number Diff line
@@ -189,15 +189,6 @@ status_t TransactionCompletedThread::finalizePendingCallbackHandles( 
    return NO_ERROR;

}



void TransactionCompletedThread::clearAllPending() {

    std::lock_guard lock(mMutex);

    if (!mRunning) {

        return;

    }

    mPendingTransactions.clear();

    mConditionVariable.notify_all();

}



status_t TransactionCompletedThread::registerUnpresentedCallbackHandle(

        const sp<CallbackHandle>& handle) {

    std::lock_guard lock(mMutex);

services/surfaceflinger/TransactionCompletedThread.h

+0 −2
Original line number Diff line number Diff line
@@ -70,8 +70,6 @@ public: 
    // Notifies the TransactionCompletedThread that a pending CallbackHandle has been presented.

    status_t finalizePendingCallbackHandles(const std::deque<sp<CallbackHandle>>& handles);



    void clearAllPending();



    // Adds the Transaction CallbackHandle from a layer that does not need to be relatched and

    // presented this frame.

    status_t registerUnpresentedCallbackHandle(const sp<CallbackHandle>& handle);