Fix crash due to texture view callback threading invariants.

Allow the client of a SurfaceTexture to specify the Handler to
which the update callback should be directed to avoid unnecessary
scheduling ping-pong between threads.

Fixed an invalid assumption in TextureView that it is attached
to the main looper which could result in a crash under certain
circumstances.  In normal app processes, it is true that TextureViews
must be created on the main looper since hardware rendering is
currently only supported on the main looper.  However, in the
system server, UI components run a different thread.  Although
hardware rendering is normally disabled in the system server,
it may be enabled for certain developer features.

Bug: 14445309
Change-Id: I5ae17ad018b9ef05ba87ec2f972c7c82e2bca70a

4 files changed, 72 insertions, 68 deletions

diff --git a/api/current.txt b/api/current.txt
index a711896062ea..d787c9a0c1ad 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -10734,6 +10734,7 @@ package android.graphics {
     method public void releaseTexImage();
     method public void setDefaultBufferSize(int, int);
     method public void setOnFrameAvailableListener(android.graphics.SurfaceTexture.OnFrameAvailableListener);
+    method public void setOnFrameAvailableListener(android.graphics.SurfaceTexture.OnFrameAvailableListener, android.os.Handler);
     method public void updateTexImage();
   }
 
diff --git a/core/java/android/view/TextureView.java b/core/java/android/view/TextureView.java
index 3cfe5e916937..1765c4341b58 100644
--- a/core/java/android/view/TextureView.java
+++ b/core/java/android/view/TextureView.java
@@ -23,7 +23,6 @@ import android.graphics.Matrix;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
-import android.os.Looper;
 import android.util.AttributeSet;
 import android.util.Log;
 
@@ -119,8 +118,6 @@ public class TextureView extends View {
     private boolean mUpdateLayer;
     private boolean mUpdateSurface;
 
-    private SurfaceTexture.OnFrameAvailableListener mUpdateListener;
-
     private Canvas mCanvas;
     private int mSaveCount;
 
@@ -370,21 +367,7 @@ public class TextureView extends View {
             mSurface.setDefaultBufferSize(getWidth(), getHeight());
             nCreateNativeWindow(mSurface);
 
-            mUpdateListener = new SurfaceTexture.OnFrameAvailableListener() {
-                @Override
-                public void onFrameAvailable(SurfaceTexture surfaceTexture) {
-                    // Per SurfaceTexture's documentation, the callback may be invoked
-                    // from an arbitrary thread
-                    updateLayer();
-
-                    if (Looper.myLooper() == Looper.getMainLooper()) {
-                        invalidate();
-                    } else {
-                        postInvalidate();
-                    }
-                }
-            };
-            mSurface.setOnFrameAvailableListener(mUpdateListener);
+            mSurface.setOnFrameAvailableListener(mUpdateListener, mAttachInfo.mHandler);
 
             if (mListener != null && !mUpdateSurface) {
                 mListener.onSurfaceTextureAvailable(mSurface, getWidth(), getHeight());
@@ -422,7 +405,7 @@ public class TextureView extends View {
             // To cancel updates, the easiest thing to do is simply to remove the
             // updates listener
             if (visibility == VISIBLE) {
-                mSurface.setOnFrameAvailableListener(mUpdateListener);
+                mSurface.setOnFrameAvailableListener(mUpdateListener, mAttachInfo.mHandler);
                 updateLayerAndInvalidate();
             } else {
                 mSurface.setOnFrameAvailableListener(null);
@@ -767,6 +750,15 @@ public class TextureView extends View {
         mListener = listener;
     }
 
+    private final SurfaceTexture.OnFrameAvailableListener mUpdateListener =
+            new SurfaceTexture.OnFrameAvailableListener() {
+        @Override
+        public void onFrameAvailable(SurfaceTexture surfaceTexture) {
+            updateLayer();
+            invalidate();
+        }
+    };
+
     /**
      * This listener can be used to be notified when the surface texture
      * associated with this texture view is available.
diff --git a/core/jni/android/graphics/SurfaceTexture.cpp b/core/jni/android/graphics/SurfaceTexture.cpp
index b78b131fc1e0..621534e64cd8 100644
--- a/core/jni/android/graphics/SurfaceTexture.cpp
+++ b/core/jni/android/graphics/SurfaceTexture.cpp
@@ -221,7 +221,7 @@ static void SurfaceTexture_classInit(JNIEnv* env, jclass clazz)
     }
 
     fields.postEvent = env->GetStaticMethodID(clazz, "postEventFromNative",
-            "(Ljava/lang/Object;)V");
+            "(Ljava/lang/ref/WeakReference;)V");
     if (fields.postEvent == NULL) {
         ALOGE("can't find android/graphics/SurfaceTexture.postEventFromNative");
     }
@@ -338,7 +338,7 @@ static void SurfaceTexture_release(JNIEnv* env, jobject thiz)
 
 static JNINativeMethod gSurfaceTextureMethods[] = {
     {"nativeClassInit",            "()V",   (void*)SurfaceTexture_classInit },
-    {"nativeInit",                 "(IZLjava/lang/Object;)V", (void*)SurfaceTexture_init },
+    {"nativeInit",                 "(IZLjava/lang/ref/WeakReference;)V", (void*)SurfaceTexture_init },
     {"nativeFinalize",             "()V",   (void*)SurfaceTexture_finalize },
     {"nativeSetDefaultBufferSize", "(II)V", (void*)SurfaceTexture_setDefaultBufferSize },
     {"nativeUpdateTexImage",       "()V",   (void*)SurfaceTexture_updateTexImage },
diff --git a/graphics/java/android/graphics/SurfaceTexture.java b/graphics/java/android/graphics/SurfaceTexture.java
index d877502e2779..3f8c45c82e5a 100644
--- a/graphics/java/android/graphics/SurfaceTexture.java
+++ b/graphics/java/android/graphics/SurfaceTexture.java
@@ -62,9 +62,8 @@ import android.view.Surface;
  * #updateTexImage} should not be called directly from the callback.
  */
 public class SurfaceTexture {
-
-    private EventHandler mEventHandler;
-    private OnFrameAvailableListener mOnFrameAvailableListener;
+    private final Looper mCreatorLooper;
+    private Handler mOnFrameAvailableHandler;
 
     /**
      * These fields are used by native code, do not access or modify.
@@ -83,7 +82,8 @@ public class SurfaceTexture {
     /**
      * Exception thrown when a SurfaceTexture couldn't be created or resized.
      *
-     * @deprecated No longer thrown. {@link Surface.OutOfResourcesException} is used instead.
+     * @deprecated No longer thrown. {@link android.view.Surface.OutOfResourcesException}
+     * is used instead.
      */
     @SuppressWarnings("serial")
     @Deprecated
@@ -100,10 +100,10 @@ public class SurfaceTexture {
      *
      * @param texName the OpenGL texture object name (e.g. generated via glGenTextures)
      *
-     * @throws OutOfResourcesException If the SurfaceTexture cannot be created.
+     * @throws Surface.OutOfResourcesException If the SurfaceTexture cannot be created.
      */
     public SurfaceTexture(int texName) {
-        init(texName, false);
+        this(texName, false);
     }
 
     /**
@@ -121,20 +121,58 @@ public class SurfaceTexture {
      * @param texName the OpenGL texture object name (e.g. generated via glGenTextures)
      * @param singleBufferMode whether the SurfaceTexture will be in single buffered mode.
      *
-     * @throws throws OutOfResourcesException If the SurfaceTexture cannot be created.
+     * @throws Surface.OutOfResourcesException If the SurfaceTexture cannot be created.
      */
     public SurfaceTexture(int texName, boolean singleBufferMode) {
-        init(texName, singleBufferMode);
+        mCreatorLooper = Looper.myLooper();
+        nativeInit(texName, singleBufferMode, new WeakReference<SurfaceTexture>(this));
     }
 
     /**
      * Register a callback to be invoked when a new image frame becomes available to the
-     * SurfaceTexture.  Note that this callback may be called on an arbitrary thread, so it is not
+     * SurfaceTexture.
+     * <p>
+     * This callback may be called on an arbitrary thread, so it is not
      * safe to call {@link #updateTexImage} without first binding the OpenGL ES context to the
      * thread invoking the callback.
+     * </p>
+     *
+     * @param listener The listener to set.
      */
-    public void setOnFrameAvailableListener(OnFrameAvailableListener l) {
-        mOnFrameAvailableListener = l;
+    public void setOnFrameAvailableListener(OnFrameAvailableListener listener) {
+        setOnFrameAvailableListener(listener, null);
+    }
+
+    /**
+     * Register a callback to be invoked when a new image frame becomes available to the
+     * SurfaceTexture.
+     * <p>
+     * If no handler is specified, then this callback may be called on an arbitrary thread,
+     * so it is not safe to call {@link #updateTexImage} without first binding the OpenGL ES
+     * context to the thread invoking the callback.
+     * </p>
+     *
+     * @param listener The listener to set.
+     * @param handler The handler on which the listener should be invoked, or null
+     * to use an arbitrary thread.
+     */
+    public void setOnFrameAvailableListener(final OnFrameAvailableListener listener,
+            Handler handler) {
+        if (listener != null) {
+            // Although we claim the thread is arbitrary, earlier implementation would
+            // prefer to send the callback on the creating looper or the main looper
+            // so we preserve this behavior here.
+            Looper looper = handler != null ? handler.getLooper() :
+                    mCreatorLooper != null ? mCreatorLooper : Looper.getMainLooper();
+            mOnFrameAvailableHandler = new Handler(looper, null, true /*async*/) {
+                @Override
+                public void handleMessage(Message msg) {
+                    listener.onFrameAvailable(SurfaceTexture.this);
+                }
+            };
+        } else {
+            mOnFrameAvailableHandler = null;
+        }
     }
 
     /**
@@ -285,49 +323,22 @@ public class SurfaceTexture {
         }
     }
 
-    private class EventHandler extends Handler {
-        public EventHandler(Looper looper) {
-            super(looper);
-        }
-
-        @Override
-        public void handleMessage(Message msg) {
-            if (mOnFrameAvailableListener != null) {
-                mOnFrameAvailableListener.onFrameAvailable(SurfaceTexture.this);
-            }
-        }
-    }
-
     /**
      * This method is invoked from native code only.
      */
     @SuppressWarnings({"UnusedDeclaration"})
-    private static void postEventFromNative(Object selfRef) {
-        WeakReference weakSelf = (WeakReference)selfRef;
-        SurfaceTexture st = (SurfaceTexture)weakSelf.get();
-        if (st == null) {
-            return;
-        }
-
-        if (st.mEventHandler != null) {
-            Message m = st.mEventHandler.obtainMessage();
-            st.mEventHandler.sendMessage(m);
-        }
-    }
-
-    private void init(int texName, boolean singleBufferMode) throws Surface.OutOfResourcesException {
-        Looper looper;
-        if ((looper = Looper.myLooper()) != null) {
-            mEventHandler = new EventHandler(looper);
-        } else if ((looper = Looper.getMainLooper()) != null) {
-            mEventHandler = new EventHandler(looper);
-        } else {
-            mEventHandler = null;
+    private static void postEventFromNative(WeakReference<SurfaceTexture> weakSelf) {
+        SurfaceTexture st = weakSelf.get();
+        if (st != null) {
+            Handler handler = st.mOnFrameAvailableHandler;
+            if (handler != null) {
+                handler.sendEmptyMessage(0);
+            }
         }
-        nativeInit(texName, singleBufferMode, new WeakReference<SurfaceTexture>(this));
     }
 
-    private native void nativeInit(int texName, boolean singleBufferMode, Object weakSelf)
+    private native void nativeInit(int texName, boolean singleBufferMode,
+            WeakReference<SurfaceTexture> weakSelf)
             throws Surface.OutOfResourcesException;
     private native void nativeFinalize();
     private native void nativeGetTransformMatrix(float[] mtx);