add a layerStack attribute to Layers.

this attribute can be set through a regular transaction using
SurfaceComposerClient (just like any other attribute, eg: position or size)

Change-Id: I701a47c677ea6442ca713728a93335328cd2b172

include/gui/ISurfaceComposer.h

@@ -67,6 +67,7 @@ public:
         eMatrixChanged              = 0x00000010,
         eTransparentRegionChanged   = 0x00000020,
         eVisibilityChanged          = 0x00000040,
+        eLayerStackChanged          = 0x00000080,
         eCropChanged                = 0x00000100,
     };
 

include/gui/SurfaceComposerClient.h

@@ -119,6 +119,7 @@ public:
     status_t    setPosition(SurfaceID id, float x, float y);
     status_t    setSize(SurfaceID id, uint32_t w, uint32_t h);
     status_t    setCrop(SurfaceID id, const Rect& crop);
+    status_t    setLayerStack(SurfaceID id, uint32_t layerStack);
     status_t    destroySurface(SurfaceID sid);
 
 private:

include/private/gui/LayerState.h

@@ -35,7 +35,7 @@ struct layer_state_t {
 
     layer_state_t()
         :   surface(0), what(0),
-            x(0), y(0), z(0), w(0), h(0),
+            x(0), y(0), z(0), w(0), h(0), layerStack(0),
             alpha(0), flags(0), mask(0),
             reserved(0)
     {
@@ -60,6 +60,7 @@ struct layer_state_t {
             uint32_t        z;
             uint32_t        w;
             uint32_t        h;
+            uint32_t        layerStack;
             float           alpha;
             uint8_t         flags;
             uint8_t         mask;

libs/gui/SurfaceComposerClient.cpp

@@ -124,6 +124,8 @@ public:
     status_t setOrientation(int orientation);
     status_t setCrop(const sp<SurfaceComposerClient>& client, SurfaceID id,
             const Rect& crop);
+    status_t setLayerStack(const sp<SurfaceComposerClient>& client,
+            SurfaceID id, uint32_t layerStack);
 
     static void closeGlobalTransaction(bool synchronous) {
         Composer::getInstance().closeGlobalTransactionImpl(synchronous);
@@ -255,6 +257,17 @@ status_t Composer::setAlpha(const sp<SurfaceComposerClient>& client,
     return NO_ERROR;
 }
 
+status_t Composer::setLayerStack(const sp<SurfaceComposerClient>& client,
+        SurfaceID id, uint32_t layerStack) {
+    Mutex::Autolock _l(mLock);
+    layer_state_t* s = getLayerStateLocked(client, id);
+    if (!s)
+        return BAD_INDEX;
+    s->what |= ISurfaceComposer::eLayerStackChanged;
+    s->layerStack = layerStack;
+    return NO_ERROR;
+}
+
 status_t Composer::setMatrix(const sp<SurfaceComposerClient>& client,
         SurfaceID id, float dsdx, float dtdx,
         float dsdy, float dtdy) {
@@ -443,6 +456,10 @@ status_t SurfaceComposerClient::setAlpha(SurfaceID id, float alpha) {
     return getComposer().setAlpha(this, id, alpha);
 }
 
+status_t SurfaceComposerClient::setLayerStack(SurfaceID id, uint32_t layerStack) {
+    return getComposer().setLayerStack(this, id, layerStack);
+}
+
 status_t SurfaceComposerClient::setMatrix(SurfaceID id, float dsdx, float dtdx,
         float dsdy, float dtdy) {
     return getComposer().setMatrix(this, id, dsdx, dtdx, dsdy, dtdy);

services/surfaceflinger/LayerBase.cpp

@@ -77,6 +77,7 @@ void LayerBase::initStates(uint32_t w, uint32_t h, uint32_t flags)
     mCurrentState.active.crop.makeInvalid();
     mCurrentState.z = 0;
     mCurrentState.alpha = 0xFF;
+    mCurrentState.layerStack = 0;
     mCurrentState.flags = layerFlags;
     mCurrentState.sequence = 0;
     mCurrentState.transform.set(0, 0);
@@ -169,6 +170,15 @@ bool LayerBase::setCrop(const Rect& crop) {
     return true;
 }
 
+bool LayerBase::setLayerStack(uint32_t layerStack) {
+    if (mCurrentState.layerStack == layerStack)
+        return false;
+    mCurrentState.sequence++;
+    mCurrentState.layerStack = layerStack;
+    requestTransaction();
+    return true;
+}
+
 void LayerBase::setVisibleRegion(const Region& visibleRegion) {
     // always called from main thread
     this->visibleRegion = visibleRegion;

services/surfaceflinger/LayerBase.h

@@ -79,6 +79,7 @@ public:
                 Geometry        active;
                 Geometry        requested;
                 uint32_t        z;
+                uint32_t        layerStack;
                 uint8_t         alpha;
                 uint8_t         flags;
                 uint8_t         reserved[2];
@@ -113,7 +114,8 @@ public:
             bool setTransparentRegionHint(const Region& opaque);
             bool setFlags(uint8_t flags, uint8_t mask);
             bool setCrop(const Rect& crop);
-            
+            bool setLayerStack(uint32_t layerStack);
+
             void commitTransaction();
             bool requestTransaction();
             void forceVisibilityTransaction();

services/surfaceflinger/SurfaceFlinger.cpp

@@ -1572,6 +1572,10 @@ uint32_t SurfaceFlinger::setClientStateLocked(
             if (layer->setCrop(s.crop))
                 flags |= eTraversalNeeded;
         }
+        if (what & eLayerStackChanged) {
+            if (layer->setLayerStack(s.layerStack))
+                flags |= eTraversalNeeded;
+        }
     }
     return flags;
 }