Remove usage of SharedBuffer

- Remove getSharedBuffer() from Region
- Don't use SharedBuffer for memory management in HWCLayerVersion1,
  instead keep shallow copies of the Regions.

Bug 23962051

(cherry picked from commit d814cf2a3e3a2fdb73efa80539fe8af0a93da1db)

Change-Id: I8fa17beed57936648c7b4defc9219dff1d5b337f

3 files changed, 13 insertions, 45 deletions

diff --git a/include/ui/Region.h b/include/ui/Region.h
index 2a1491837d..e9b3a0bad7 100644
--- a/include/ui/Region.h
+++ b/include/ui/Region.h
@@ -130,11 +130,6 @@ public:
     // Region object.
     Rect const* getArray(size_t* count) const;
 
-    // returns a SharedBuffer as well as the number of rects.
-    // ownership is transfered to the caller.
-    // the caller must call SharedBuffer::release() to free the memory.
-    SharedBuffer const* getSharedBuffer(size_t* count) const;
-
     /* no user serviceable parts here... */
 
             // add a rectangle to the internal list. This rectangle must
diff --git a/libs/ui/Region.cpp b/libs/ui/Region.cpp
index 3810da4049..a3558bd5c2 100644
--- a/libs/ui/Region.cpp
+++ b/libs/ui/Region.cpp
@@ -835,18 +835,6 @@ Rect const* Region::getArray(size_t* count) const {
     return begin();
 }
 
-SharedBuffer const* Region::getSharedBuffer(size_t* count) const {
-    // We can get to the SharedBuffer of a Vector<Rect> because Rect has
-    // a trivial destructor.
-    SharedBuffer const* sb = SharedBuffer::bufferFromData(mStorage.array());
-    if (count) {
-        size_t numRects = isRect() ? 1 : mStorage.size() - 1;
-        count[0] = numRects;
-    }
-    sb->acquire();
-    return sb;
-}
-
 // ----------------------------------------------------------------------------
 
 void Region::dump(String8& out, const char* what, uint32_t /* flags */) const
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 2dad005171..3208990459 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -1017,12 +1017,10 @@ public:
         }
     }
     virtual void setVisibleRegionScreen(const Region& reg) {
-        // Region::getSharedBuffer creates a reference to the underlying
-        // SharedBuffer of this Region, this reference is freed
-        // in onDisplayed()
         hwc_region_t& visibleRegion = getLayer()->visibleRegionScreen;
-        SharedBuffer const* sb = reg.getSharedBuffer(&visibleRegion.numRects);
-        visibleRegion.rects = reinterpret_cast<hwc_rect_t const *>(sb->data());
+        mVisibleRegion = reg;
+        visibleRegion.rects = reinterpret_cast<hwc_rect_t const *>(
+                mVisibleRegion.getArray(&visibleRegion.numRects));
     }
     virtual void setSurfaceDamage(const Region& reg) {
         if (!hwcHasApiVersion(mHwc, HWC_DEVICE_API_VERSION_1_5)) {
@@ -1036,8 +1034,9 @@ public:
             surfaceDamage.rects = NULL;
             return;
         }
-        SharedBuffer const* sb = reg.getSharedBuffer(&surfaceDamage.numRects);
-        surfaceDamage.rects = reinterpret_cast<hwc_rect_t const *>(sb->data());
+        mSurfaceDamage = reg;
+        surfaceDamage.rects = reinterpret_cast<hwc_rect_t const *>(
+                mSurfaceDamage.getArray(&surfaceDamage.numRects));
     }
     virtual void setSidebandStream(const sp<NativeHandle>& stream) {
         ALOG_ASSERT(stream->handle() != NULL);
@@ -1059,29 +1058,15 @@ public:
         }
     }
     virtual void onDisplayed() {
-        hwc_region_t& visibleRegion = getLayer()->visibleRegionScreen;
-        SharedBuffer const* sb = SharedBuffer::bufferFromData(visibleRegion.rects);
-        if (sb) {
-            sb->release();
-            // not technically needed but safer
-            visibleRegion.numRects = 0;
-            visibleRegion.rects = NULL;
-        }
-
         getLayer()->acquireFenceFd = -1;
-
-        if (!hwcHasApiVersion(mHwc, HWC_DEVICE_API_VERSION_1_5)) {
-            return;
-        }
-
-        hwc_region_t& surfaceDamage = getLayer()->surfaceDamage;
-        sb = SharedBuffer::bufferFromData(surfaceDamage.rects);
-        if (sb) {
-            sb->release();
-            surfaceDamage.numRects = 0;
-            surfaceDamage.rects = NULL;
-        }
     }
+
+protected:
+    // We need to hold "copies" of these for memory management purposes. The
+    // actual hwc_layer_1_t holds pointers to the memory within. Vector<>
+    // internally doesn't copy the memory unless one of the copies is modified.
+    Region mVisibleRegion;
+    Region mSurfaceDamage;
 };
 
 /*