CameraManager: Separate service listener into a singleton (4c9c7a58) · Commits · e / os / android_frameworks_base

core/java/android/hardware/camera2/CameraManager.java

+191 −144

Original line number	Diff line number	Diff line
		@@ -54,29 +54,17 @@ public final class CameraManager {
		private static final String TAG = "CameraManager";
		private final boolean DEBUG;

		/**
		* This should match the ICameraService definition
		*/
		private static final String CAMERA_SERVICE_BINDER_NAME = "media.camera";
		private static final int USE_CALLING_UID = -1;

		@SuppressWarnings("unused")
		private static final int API_VERSION_1 = 1;
		private static final int API_VERSION_2 = 2;

		// Access only through getCameraServiceLocked to deal with binder death
		private ICameraService mCameraService;

		private ArrayList<String> mDeviceIdList;

		private final ArrayMap<AvailabilityCallback, Handler> mCallbackMap =
		new ArrayMap<AvailabilityCallback, Handler>();

		private final Context mContext;
		private final Object mLock = new Object();

		private final CameraServiceListener mServiceListener = new CameraServiceListener();

		/**
		* @hide
		*/
		@@ -84,8 +72,6 @@ public final class CameraManager {
		DEBUG = Log.isLoggable(TAG, Log.DEBUG);
		synchronized(mLock) {
		mContext = context;

		connectCameraServiceLocked();
		}
		}

		@@ -116,6 +102,12 @@ public final class CameraManager {
		* <p>The first time a callback is registered, it is immediately called
		* with the availability status of all currently known camera devices.</p>
		*
		* <p>Since this callback will be registered with the camera service, remember to unregister it
		* once it is no longer needed; otherwise the callback will continue to receive events
		* indefinitely and it may prevent other resources from being released. Specifically, the
		* callbacks will be invoked independently of the general activity lifecycle and independently
		* of the state of individual CameraManager instances.</p>
		*
		* @param callback the new callback to send camera availability notices to
		* @param handler The handler on which the callback should be invoked, or
		* {@code null} to use the current thread's {@link android.os.Looper looper}.
		@@ -130,13 +122,7 @@ public final class CameraManager {
		handler = new Handler(looper);
		}

		synchronized (mLock) {
		Handler oldHandler = mCallbackMap.put(callback, handler);
		// For new callbacks, provide initial availability information
		if (oldHandler == null) {
		mServiceListener.updateCallbackLocked(callback, handler);
		}
		}
		CameraManagerGlobal.get().registerAvailabilityCallback(callback, handler);
		}

		/**
		@@ -148,9 +134,7 @@ public final class CameraManager {
		* @param callback The callback to remove from the notification list
		*/
		public void unregisterAvailabilityCallback(AvailabilityCallback callback) {
		synchronized (mLock) {
		mCallbackMap.remove(callback);
		}
		CameraManagerGlobal.get().unregisterAvailabilityCallback(callback);
		}

		/**
		@@ -187,7 +171,7 @@ public final class CameraManager {
		* otherwise get them from the legacy shim instead.
		*/

		ICameraService cameraService = getCameraServiceLocked();
		ICameraService cameraService = CameraManagerGlobal.get().getCameraService();
		if (cameraService == null) {
		throw new CameraAccessException(CameraAccessException.CAMERA_DISCONNECTED,
		"Camera service is currently unavailable");
		@@ -268,7 +252,7 @@ public final class CameraManager {
		try {
		if (supportsCamera2ApiLocked(cameraId)) {
		// Use cameraservice's cameradeviceclient implementation for HAL3.2+ devices
		ICameraService cameraService = getCameraServiceLocked();
		ICameraService cameraService = CameraManagerGlobal.get().getCameraService();
		if (cameraService == null) {
		throw new CameraRuntimeException(
		CameraAccessException.CAMERA_DISCONNECTED,
		@@ -443,13 +427,6 @@ public final class CameraManager {
		}
		}

		/**
		* Temporary for migrating to Callback naming
		* @hide
		*/
		public static abstract class AvailabilityListener extends AvailabilityCallback {
		}

		/**
		* Return or create the list of currently connected camera devices.
		*
		@@ -458,7 +435,7 @@ public final class CameraManager {
		private ArrayList<String> getOrCreateDeviceIdListLocked() throws CameraAccessException {
		if (mDeviceIdList == null) {
		int numCameras = 0;
		ICameraService cameraService = getCameraServiceLocked();
		ICameraService cameraService = CameraManagerGlobal.get().getCameraService();
		ArrayList<String> deviceIdList = new ArrayList<>();

		// If no camera service, then no devices
		@@ -515,18 +492,6 @@ public final class CameraManager {
		return mDeviceIdList;
		}

		private void handleRecoverableSetupErrors(CameraRuntimeException e, String msg) {
		int problem = e.getReason();
		switch (problem) {
		case CameraAccessException.CAMERA_DISCONNECTED:
		String errorMsg = CameraAccessException.getDefaultMessage(problem);
		Log.w(TAG, msg + ": " + errorMsg);
		break;
		default:
		throw new IllegalStateException(msg, e.asChecked());
		}
		}

		/**
		* Queries the camera service if it supports the camera2 api directly, or needs a shim.
		*
		@@ -556,7 +521,7 @@ public final class CameraManager {
		* Anything else is an unexpected error we don't want to recover from.
		*/
		try {
		ICameraService cameraService = getCameraServiceLocked();
		ICameraService cameraService = CameraManagerGlobal.get().getCameraService();
		// If no camera service, no support
		if (cameraService == null) return false;

		@@ -577,6 +542,85 @@ public final class CameraManager {
		return false;
		}

		/**
		* A per-process global camera manager instance, to retain a connection to the camera service,
		* and to distribute camera availability notices to API-registered callbacks
		*/
		private static final class CameraManagerGlobal extends ICameraServiceListener.Stub
		implements IBinder.DeathRecipient {

		private static final String TAG = "CameraManagerGlobal";
		private final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);

		// Singleton instance
		private static final CameraManagerGlobal gCameraManager =
		new CameraManagerGlobal();

		/**
		* This must match the ICameraService definition
		*/
		private static final String CAMERA_SERVICE_BINDER_NAME = "media.camera";

		// Keep up-to-date with ICameraServiceListener.h

		// Device physically unplugged
		public static final int STATUS_NOT_PRESENT = 0;
		// Device physically has been plugged in
		// and the camera can be used exclusively
		public static final int STATUS_PRESENT = 1;
		// Device physically has been plugged in
		// but it will not be connect-able until enumeration is complete
		public static final int STATUS_ENUMERATING = 2;
		// Camera is in use by another app and cannot be used exclusively
		public static final int STATUS_NOT_AVAILABLE = 0x80000000;

		// End enums shared with ICameraServiceListener.h

		// Camera ID -> Status map
		private final ArrayMap<String, Integer> mDeviceStatus = new ArrayMap<String, Integer>();

		// Registered availablility callbacks and their handlers
		private final ArrayMap<AvailabilityCallback, Handler> mCallbackMap =
		new ArrayMap<AvailabilityCallback, Handler>();

		private final Object mLock = new Object();

		// Access only through getCameraService to deal with binder death
		private ICameraService mCameraService;

		// Singleton, don't allow construction
		private CameraManagerGlobal() {
		}

		public static CameraManagerGlobal get() {
		return gCameraManager;
		}

		@Override
		public IBinder asBinder() {
		return this;
		}

		/**
		* Return a best-effort ICameraService.
		*
		* <p>This will be null if the camera service is not currently available. If the camera
		* service has died since the last use of the camera service, will try to reconnect to the
		* service.</p>
		*/
		public ICameraService getCameraService() {
		synchronized(mLock) {
		if (mCameraService == null) {
		Log.i(TAG, "getCameraService: Reconnecting to camera service");
		connectCameraServiceLocked();
		if (mCameraService == null) {
		Log.e(TAG, "Camera service is unavailable");
		}
		}
		return mCameraService;
		}
		}

		/**
		* Connect to the camera service if it's available, and set up listeners.
		*
		@@ -590,7 +634,7 @@ public final class CameraManager {
		return;
		}
		try {
		cameraServiceBinder.linkToDeath(new CameraServiceDeathListener(), /flags/ 0);
		cameraServiceBinder.linkToDeath(this, /flags/ 0);
		} catch (RemoteException e) {
		// Camera service is now down, leave mCameraService as null
		return;
		@@ -602,7 +646,8 @@ public final class CameraManager {
		* Wrap the camera service in a decorator which automatically translates return codes
		* into exceptions.
		*/
		ICameraService cameraService = CameraServiceBinderDecorator.newInstance(cameraServiceRaw);
		ICameraService cameraService =
		CameraServiceBinderDecorator.newInstance(cameraServiceRaw);

		try {
		CameraServiceBinderDecorator.throwOnError(
		@@ -612,7 +657,7 @@ public final class CameraManager {
		}

		try {
		cameraService.addListener(mServiceListener);
		cameraService.addListener(this);
		mCameraService = cameraService;
		} catch(CameraRuntimeException e) {
		// Unexpected failure
		@@ -623,74 +668,16 @@ public final class CameraManager {
		}
		}

		/**
		* Return a best-effort ICameraService.
		*
		* <p>This will be null if the camera service
		* is not currently available. If the camera service has died since the last
		* use of the camera service, will try to reconnect to the service.</p>
		*/
		private ICameraService getCameraServiceLocked() {
		if (mCameraService == null) {
		Log.i(TAG, "getCameraServiceLocked: Reconnecting to camera service");
		connectCameraServiceLocked();
		if (mCameraService == null) {
		Log.e(TAG, "Camera service is unavailable");
		}
		}
		return mCameraService;
		}

		/**
		* Listener for camera service death.
		*
		* <p>The camera service isn't supposed to die under any normal circumstances, but can be turned
		* off during debug, or crash due to bugs. So detect that and null out the interface object, so
		* that the next calls to the manager can try to reconnect.</p>
		*/
		private class CameraServiceDeathListener implements IBinder.DeathRecipient {
		public void binderDied() {
		synchronized(mLock) {
		mCameraService = null;
		// Tell listeners that the cameras are _available_, because any existing clients
		// will have gotten disconnected. This is optimistic under the assumption that the
		// service will be back shortly.
		//
		// Without this, a camera service crash while a camera is open will never signal to
		// listeners that previously in-use cameras are now available.
		for (String cameraId : mDeviceIdList) {
		mServiceListener.onStatusChangedLocked(CameraServiceListener.STATUS_PRESENT,
		cameraId);
		}
		}
		}
		private void handleRecoverableSetupErrors(CameraRuntimeException e, String msg) {
		int problem = e.getReason();
		switch (problem) {
		case CameraAccessException.CAMERA_DISCONNECTED:
		String errorMsg = CameraAccessException.getDefaultMessage(problem);
		Log.w(TAG, msg + ": " + errorMsg);
		break;
		default:
		throw new IllegalStateException(msg, e.asChecked());
		}

		// TODO: this class needs unit tests
		// TODO: extract class into top level
		private class CameraServiceListener extends ICameraServiceListener.Stub {

		// Keep up-to-date with ICameraServiceListener.h

		// Device physically unplugged
		public static final int STATUS_NOT_PRESENT = 0;
		// Device physically has been plugged in
		// and the camera can be used exclusively
		public static final int STATUS_PRESENT = 1;
		// Device physically has been plugged in
		// but it will not be connect-able until enumeration is complete
		public static final int STATUS_ENUMERATING = 2;
		// Camera is in use by another app and cannot be used exclusively
		public static final int STATUS_NOT_AVAILABLE = 0x80000000;

		// Camera ID -> Status map
		private final ArrayMap<String, Integer> mDeviceStatus = new ArrayMap<String, Integer>();

		private static final String TAG = "CameraServiceListener";

		@Override
		public IBinder asBinder() {
		return this;
		}

		private boolean isAvailable(int status) {
		@@ -739,7 +726,7 @@ public final class CameraManager {
		* Send the state of all known cameras to the provided listener, to initialize
		* the listener's knowledge of camera state.
		*/
		public void updateCallbackLocked(AvailabilityCallback callback, Handler handler) {
		private void updateCallbackLocked(AvailabilityCallback callback, Handler handler) {
		for (int i = 0; i < mDeviceStatus.size(); i++) {
		String id = mDeviceStatus.keyAt(i);
		Integer status = mDeviceStatus.valueAt(i);
		@@ -747,14 +734,7 @@ public final class CameraManager {
		}
		}

		@Override
		public void onStatusChanged(int status, int cameraId) throws RemoteException {
		synchronized(CameraManager.this.mLock) {
		onStatusChangedLocked(status, String.valueOf(cameraId));
		}
		}

		public void onStatusChangedLocked(int status, String id) {
		private void onStatusChangedLocked(int status, String id) {
		if (DEBUG) {
		Log.v(TAG,
		String.format("Camera id %s has status changed to 0x%x", id, status));
		@@ -811,5 +791,72 @@ public final class CameraManager {
		}
		} // onStatusChangedLocked

		} // CameraServiceListener
		/**
		* Register a callback to be notified about camera device availability with the
		* global listener singleton.
		*
		* @param callback the new callback to send camera availability notices to
		* @param handler The handler on which the callback should be invoked. May not be null.
		*/
		public void registerAvailabilityCallback(AvailabilityCallback callback, Handler handler) {
		synchronized (mLock) {
		Handler oldHandler = mCallbackMap.put(callback, handler);
		// For new callbacks, provide initial availability information
		if (oldHandler == null) {
		updateCallbackLocked(callback, handler);
		}
		}
		}

		/**
		* Remove a previously-added callback; the callback will no longer receive connection and
		* disconnection callbacks, and is no longer referenced by the global listener singleton.
		*
		* @param callback The callback to remove from the notification list
		*/
		public void unregisterAvailabilityCallback(AvailabilityCallback callback) {
		synchronized (mLock) {
		mCallbackMap.remove(callback);
		}
		}

		/**
		* Callback from camera service notifying the process about camera availability changes
		*/
		@Override
		public void onStatusChanged(int status, int cameraId) throws RemoteException {
		synchronized(mLock) {
		onStatusChangedLocked(status, String.valueOf(cameraId));
		}
		}

		/**
		* Listener for camera service death.
		*
		* <p>The camera service isn't supposed to die under any normal circumstances, but can be
		* turned off during debug, or crash due to bugs. So detect that and null out the interface
		* object, so that the next calls to the manager can try to reconnect.</p>
		*/
		public void binderDied() {
		synchronized(mLock) {
		// Only do this once per service death
		if (mCameraService == null) return;

		mCameraService = null;

		// Tell listeners that the cameras are _available_, because any existing clients
		// will have gotten disconnected. This is optimistic under the assumption that
		// the service will be back shortly.
		//
		// Without this, a camera service crash while a camera is open will never signal
		// to listeners that previously in-use cameras are now available.
		for (int i = 0; i < mDeviceStatus.size(); i++) {
		String cameraId = mDeviceStatus.keyAt(i);
		onStatusChangedLocked(STATUS_PRESENT, cameraId);
		}
		}
		}

		} // CameraManagerGlobal

		} // CameraManager