optimize Surface.readFromParcel()

this is called for each relayout() and used to create a full Surface (cpp)
which in turn did some heavy work (including an IPC with surfaceflinger),
most of the time to destroy it immediatelly when the returned surface
(the one in the parcel) was the same.

we now more intelligentely read from the parcel and construct the new
object only if needed.

Change-Id: Idfd40d9ac96ffc6d4ae5fd99bcc0773e131e2267

core/jni/android_view_Surface.cpp

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#define LOG_TAG "Surface"
+
 #include <stdio.h>
 
 #include "android_util_Binder.h"
@@ -226,8 +228,9 @@ static void Surface_initParcel(JNIEnv* env, jobject clazz, jobject argParcel)
         doThrow(env, "java/lang/NullPointerException", NULL);
         return;
     }
-    sp<Surface> rhs = new Surface(*parcel);
-    setSurface(env, clazz, rhs);
+
+    sp<Surface> sur(Surface::readFromParcel(*parcel, 0));
+    setSurface(env, clazz, sur);
 }
 
 static jint Surface_getIdentity(JNIEnv* env, jobject clazz)
@@ -586,7 +589,7 @@ static void Surface_copyFrom(
      * a Surface and is necessary for returning the Surface reference to
      * the caller. At this point, we should only have a SurfaceControl.
      */
-    
+
     const sp<SurfaceControl>& surface = getSurfaceControl(env, clazz);
     const sp<SurfaceControl>& rhs = getSurfaceControl(env, other);
     if (!SurfaceControl::isSameSurface(surface, rhs)) {
@@ -605,13 +608,9 @@ static void Surface_readFromParcel(
         return;
     }
 
-    const sp<Surface>& control(getSurface(env, clazz));
-    sp<Surface> rhs = new Surface(*parcel);
-    if (!Surface::isSameSurface(control, rhs)) {
-        // we reassign the surface only if it's a different one
-        // otherwise we would loose our client-side state.
-        setSurface(env, clazz, rhs);
-    }
+    const sp<Surface>& curr(getSurface(env, clazz));
+    sp<Surface> sur(Surface::readFromParcel(*parcel, curr));
+    setSurface(env, clazz, sur);
 }
 
 static void Surface_writeToParcel(

include/surfaceflinger/Surface.h

@@ -145,15 +145,13 @@ public:
         uint32_t    reserved[2];
     };
 
-    Surface(const Parcel& data);
+    static sp<Surface> readFromParcel(
+            const Parcel& data, const sp<Surface>& other);
 
     static bool isValid(const sp<Surface>& surface) {
         return (surface != 0) && surface->isValid();
     }
 
-    static bool isSameSurface(
-            const sp<Surface>& lhs, const sp<Surface>& rhs);
-
     bool        isValid();
     SurfaceID   ID() const          { return mToken; }
     uint32_t    getFlags() const    { return mFlags; }
@@ -191,6 +189,7 @@ private:
     Surface(const Surface& rhs);
 
     Surface(const sp<SurfaceControl>& control);
+    Surface(const Parcel& data, const sp<IBinder>& ref);
     ~Surface();
 
 

libs/surfaceflinger_client/Surface.cpp

@@ -334,13 +334,13 @@ Surface::Surface(const sp<SurfaceControl>& surface)
     init();
 }
 
-Surface::Surface(const Parcel& parcel)
+Surface::Surface(const Parcel& parcel, const sp<IBinder>& ref)
     : mBufferMapper(GraphicBufferMapper::get()),
       mClient(SurfaceClient::getInstance()),
       mSharedBufferClient(NULL),
       mInitCheck(NO_INIT)
 {
-    mSurface    = interface_cast<ISurface>(parcel.readStrongBinder());
+    mSurface    = interface_cast<ISurface>(ref);
     mIdentity   = parcel.readInt32();
     mWidth      = parcel.readInt32();
     mHeight     = parcel.readInt32();
@@ -349,6 +349,17 @@ Surface::Surface(const Parcel& parcel)
     init();
 }
 
+sp<Surface> Surface::readFromParcel(
+        const Parcel& data, const sp<Surface>& other)
+{
+    sp<Surface> result(other);
+    sp<IBinder> binder(data.readStrongBinder());
+    if (other==0 || binder != other->mSurface->asBinder()) {
+        result = new Surface(data, binder);
+    }
+    return result;
+}
+
 void Surface::init()
 {
     android_native_window_t::setSwapInterval  = setSwapInterval;
@@ -443,12 +454,6 @@ status_t Surface::validate() const
     return NO_ERROR;
 }
 
-bool Surface::isSameSurface(const sp<Surface>& lhs, const sp<Surface>& rhs) {
-    if (lhs == 0 || rhs == 0)
-        return false;
-    return lhs->mSurface->asBinder() == rhs->mSurface->asBinder();
-}
-
 sp<ISurface> Surface::getISurface() const {
     return mSurface;
 }