From a6b32db164e7834e211261046f3229bf50bc0098 Mon Sep 17 00:00:00 2001
From: Jesse Hall <jessehall@google.com>
Date: Thu, 19 Jul 2012 16:44:38 -0700
Subject: [PATCH] Handle empty HWC layer list when composing

Bug: 6777877
Change-Id: I71e9b948d04dda33d45cfa986d9c7e28328cf749
---
 services/surfaceflinger/SurfaceFlinger.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 29ec1a7b7..693f24113 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1151,11 +1151,11 @@ void SurfaceFlinger::composeSurfaces(const DisplayHardware& hw, const Region& di
         const Vector< sp<LayerBase> >& layers(hw.getVisibleLayersSortedByZ());
         const size_t count = layers.size();
         const Transform& tr = hw.getTransform();
-        for (size_t i=0 ; cur!=end && i<count ; ++i, ++cur) {
+        for (size_t i=0 ; i<count ; ++i) {
             const sp<LayerBase>& layer(layers[i]);
             const Region clip(dirty.intersect(tr.transform(layer->visibleRegion)));
             if (!clip.isEmpty()) {
-                if (cur->getCompositionType() == HWC_OVERLAY) {
+                if (cur != end && cur->getCompositionType() == HWC_OVERLAY) {
                     if (i && (cur->getHints() & HWC_HINT_CLEAR_FB)
                             && layer->isOpaque()) {
                         // never clear the very first layer since we're
@@ -1167,6 +1167,9 @@ void SurfaceFlinger::composeSurfaces(const DisplayHardware& hw, const Region& di
                 // render the layer
                 layer->draw(hw, clip);
             }
+            if (cur != end) {
+                ++cur;
+            }
         }
     }
 }