Use a ref-counted callback interface for Camera.
This allows the camera service to hang onto the callback interface
until all callbacks have been processed. This prevents problems
where pending callbacks in binder worker threads are processed
after the Java camera object and its associated native resources
have been released.
Bug 1884362
diff --git a/include/ui/Camera.h b/include/ui/Camera.h
index 048bdd5..bd4855c 100644
--- a/include/ui/Camera.h
+++ b/include/ui/Camera.h
@@ -86,6 +86,14 @@
 class Mutex;
 class String8;
 
+// ref-counted object for callbacks
+class CameraListener: virtual public RefBase
+{
+public:
+    virtual void notify(int32_t msgType, int32_t ext1, int32_t ext2) = 0;
+    virtual void postData(int32_t msgType, const sp<IMemory>& dataPtr) = 0;
+};
+
 typedef void (*shutter_callback)(void *cookie);
 typedef void (*frame_callback)(const sp<IMemory>& mem, void *cookie);
 typedef void (*autofocus_callback)(bool focused, void *cookie);
@@ -152,6 +160,9 @@
             void        setErrorCallback(error_callback cb, void *cookie);
             void        setAutoFocusCallback(autofocus_callback cb, void *cookie);
 
+            void        setListener(const sp<CameraListener>& listener);
+            void        setPreviewCallbackFlags(int preview_callback_flag);
+
     // ICameraClient interface
     virtual void        notifyCallback(int32_t msgType, int32_t ext, int32_t ext2);
     virtual void        dataCallback(int32_t msgType, const sp<IMemory>& dataPtr);
@@ -194,6 +205,8 @@
             autofocus_callback  mAutoFocusCallback;
             void                *mAutoFocusCallbackCookie;
 
+            sp<CameraListener>  mListener;
+
             friend class DeathNotifier;
 
             static  Mutex               mLock;