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Commit 2c1782c6 authored by Garfield Tan's avatar Garfield Tan
Browse files

Hide layers that have irreversible transforms 

Surface API doesn't prohibit putting interesting values in transforms.
It's especially possible to scale something to 0 at the begining or the
end of an animation, but we should guard SF against ill-intentioned
apps.

Bug: 210837722
Test: KeyguardTests#testDismissKeyguardActivity doesn't crash SF on CF
PC and the warning log is in logcat.

Change-Id: Idaa1cdb0676102a580c4478c860327796c8213f3
parent 8798a484

libs/ui/Transform.cpp

+5 −1
Original line number Diff line number Diff line
@@ -134,6 +134,10 @@ float Transform::dsdy() const { 
    return mMatrix[1][1];

}



float Transform::det() const {

    return mMatrix[0][0] * mMatrix[1][1] - mMatrix[0][1] * mMatrix[1][0];

}



float Transform::getScaleX() const {

    return sqrt((dsdx() * dsdx()) + (dtdx() * dtdx()));

}
@@ -390,7 +394,7 @@ Transform Transform::inverse() const { 
        const float x = M[2][0];

        const float y = M[2][1];



        const float idet = 1.0f / (a*d - b*c);

        const float idet = 1.0f / det();

        result.mMatrix[0][0] =  d*idet;

        result.mMatrix[0][1] = -c*idet;

        result.mMatrix[1][0] = -b*idet;

libs/ui/include/ui/Transform.h

+1 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ public: 
    float dtdx() const;

    float dtdy() const;

    float dsdy() const;

    float det() const;



    float getScaleX() const;

    float getScaleY() const;

services/surfaceflinger/Layer.cpp

+15 −0
Original line number Diff line number Diff line
@@ -338,6 +338,12 @@ void Layer::computeBounds(FloatRect parentBounds, ui::Transform parentTransform, 
    // Calculate effective layer transform

    mEffectiveTransform = parentTransform * getActiveTransform(s);



    if (CC_UNLIKELY(!isTransformValid())) {

        ALOGW("Stop computing bounds for %s because it has invalid transformation.",

              getDebugName());

        return;

    }



    // Transform parent bounds to layer space

    parentBounds = getActiveTransform(s).inverse().transform(parentBounds);
@@ -1326,6 +1332,10 @@ bool Layer::isHiddenByPolicy() const { 
            }

        }

    }

    if (CC_UNLIKELY(!isTransformValid())) {

        ALOGW("Hide layer %s because it has invalid transformation.", getDebugName());

        return true;

    }

    return s.flags & layer_state_t::eLayerHidden;

}
@@ -1858,6 +1868,11 @@ ui::Transform Layer::getTransform() const { 
    return mEffectiveTransform;

}



bool Layer::isTransformValid() const {

    float transformDet = getTransform().det();

    return transformDet != 0 && !isinf(transformDet) && !isnan(transformDet);

}



half Layer::getAlpha() const {

    const auto& p = mDrawingParent.promote();

services/surfaceflinger/Layer.h

+1 −0
Original line number Diff line number Diff line
@@ -752,6 +752,7 @@ public: 
                                  FrameEventHistoryDelta* outDelta);



    ui::Transform getTransform() const;

    bool isTransformValid() const;



    // Returns the Alpha of the Surface, accounting for the Alpha

    // of parent Surfaces in the hierarchy (alpha's will be multiplied