Merge "Add a new camera open API that allows taking the ownership."

Author: Wu-cheng Li

core/java/android/hardware/Camera.java

@@ -236,6 +236,50 @@ public static class CameraInfo {
     /**
      * Creates a new Camera object to access a particular hardware camera.
      *
+     * <p>When <code>force</code> is set to false, this will throw an exception
+     * if the same camera is already opened by other clients. If true, the other
+     * client will be disconnected from the camera they opened. If the device
+     * can only support one camera running at a time, all camera-using clients
+     * will be disconnected from their cameras.
+     *
+     * <p>A camera being held by an application can be taken away by other
+     * applications at any time. Before the camera is taken, applications will
+     * get {@link #CAMERA_ERROR_RELEASED} and have some time to clean up. Apps
+     * receiving this callback must immediately stop video recording and then
+     * call {@link #release()} on their camera object. Otherwise, it will be
+     * released by the frameworks in a short time. After receiving
+     * CAMERA_ERROR_RELEASED, apps should not call any method except <code>
+     * release</code> and {@link #isReleased()}. After a camera is taken away,
+     * all methods will throw exceptions except <code>isReleased</code> and
+     * <code>release</code>. Apps can use <code>isReleased</code> to see if the
+     * camera has been taken away. If the camera is taken away, the apps can
+     * silently finish themselves or show a dialog.
+     *
+     * <p>Applications with android.permission.KEEP_CAMERA can request to keep
+     * the camera. That is, the camera will not be taken by other applications
+     * while it is opened. The permission can only be obtained by trusted
+     * platform applications, such as those implementing lock screen security
+     * features.
+     *
+     * @param cameraId the hardware camera to access, between 0 and
+     *     {@link #getNumberOfCameras()}-1.
+     * @param force true to take the ownership from the existing client if the
+     *     camera has been opened by other clients.
+     * @param keep true if the applications do not want other apps to take the
+     *     camera. Only the apps with android.permission.KEEP_CAMERA can keep
+     *     the camera.
+     * @return a new Camera object, connected, locked and ready for use.
+     * @hide
+     */
+    public static Camera open(int cameraId, boolean force, boolean keep) {
+        return new Camera(cameraId, force, keep);
+    }
+
+    /**
+     * Creates a new Camera object to access a particular hardware camera. If
+     * the same camera is opened by other applications, this will throw a
+     * RuntimeException.
+     *
      * <p>You must call {@link #release()} when you are done using the camera,
      * otherwise it will remain locked and be unavailable to other applications.
      *
@@ -255,13 +299,13 @@ public static class CameraInfo {
      * @param cameraId the hardware camera to access, between 0 and
      *     {@link #getNumberOfCameras()}-1.
      * @return a new Camera object, connected, locked and ready for use.
-     * @throws RuntimeException if connection to the camera service fails (for
-     *     example, if the camera is in use by another process or device policy
-     *     manager has disabled the camera).
+     * @throws RuntimeException if opening the camera fails (for example, if the
+     *     camera is in use by another process or device policy manager has
+     *     disabled the camera).
      * @see android.app.admin.DevicePolicyManager#getCameraDisabled(android.content.ComponentName)
      */
     public static Camera open(int cameraId) {
-        return new Camera(cameraId);
+        return new Camera(cameraId, false, false);
     }
 
     /**
@@ -276,13 +320,13 @@ public static Camera open() {
         for (int i = 0; i < numberOfCameras; i++) {
             getCameraInfo(i, cameraInfo);
             if (cameraInfo.facing == CameraInfo.CAMERA_FACING_BACK) {
-                return new Camera(i);
+                return new Camera(i, false, false);
             }
         }
         return null;
     }
 
-    Camera(int cameraId) {
+    Camera(int cameraId, boolean force, boolean keep) {
         mShutterCallback = null;
         mRawImageCallback = null;
         mJpegCallback = null;
@@ -299,7 +343,7 @@ public static Camera open() {
             mEventHandler = null;
         }
 
-        native_setup(new WeakReference<Camera>(this), cameraId);
+        native_setup(new WeakReference<Camera>(this), cameraId, force, keep);
     }
 
     /**
@@ -312,7 +356,8 @@ protected void finalize() {
         release();
     }
 
-    private native final void native_setup(Object camera_this, int cameraId);
+    private native final void native_setup(Object camera_this, int cameraId,
+            boolean force, boolean keep);
     private native final void native_release();
 
 
@@ -326,6 +371,18 @@ public final void release() {
         mFaceDetectionRunning = false;
     }
 
+    /**
+     * Whether the camera is released. When any camera method throws an
+     * exception, applications can use this to check whether the camera has been
+     * taken by other clients. If true, it means other clients have taken the
+     * camera. The applications can silently finish themselves or show a dialog.
+     *
+     * @return whether the camera is released.
+     * @see #open(int, boolean, boolean)
+     * @hide
+     */
+    public native final boolean isReleased();
+
     /**
      * Unlocks the camera to allow another process to access it.
      * Normally, the camera is locked to the process with an active Camera
@@ -1321,6 +1378,17 @@ public Face() {
      */
     public static final int CAMERA_ERROR_UNKNOWN = 1;
 
+    /**
+     * Camera was released because another client has opened the camera. The
+     * application should call {@link #release()} after getting this. The apps
+     * should not call any method except <code>release</code> and {@link #isReleased()}
+     * after this.
+     *
+     * @see Camera.ErrorCallback
+     * @hide
+     */
+    public static final int CAMERA_ERROR_RELEASED = 2;
+
     /**
      * Media server died. In this case, the application must release the
      * Camera object and instantiate a new one.

core/jni/android_hardware_Camera.cpp

@@ -457,9 +457,9 @@ static void android_hardware_Camera_getCameraInfo(JNIEnv *env, jobject thiz,
 
 // connect to camera service
 static void android_hardware_Camera_native_setup(JNIEnv *env, jobject thiz,
-    jobject weak_this, jint cameraId)
+    jobject weak_this, jint cameraId, jboolean force, jboolean keep)
 {
-    sp<Camera> camera = Camera::connect(cameraId);
+    sp<Camera> camera = Camera::connect(cameraId, force, keep);
 
     if (camera == NULL) {
         jniThrowRuntimeException(env, "Fail to connect to camera service");
@@ -700,7 +700,12 @@ static jstring android_hardware_Camera_getParameters(JNIEnv *env, jobject thiz)
     sp<Camera> camera = get_native_camera(env, thiz, NULL);
     if (camera == 0) return 0;
 
-    return env->NewStringUTF(camera->getParameters().string());
+    String8 params8 = camera->getParameters();
+    if (params8.isEmpty()) {
+        jniThrowRuntimeException(env, "getParameters failed (empty parameters)");
+        return 0;
+    }
+    return env->NewStringUTF(params8.string());
 }
 
 static void android_hardware_Camera_reconnect(JNIEnv *env, jobject thiz)
@@ -816,6 +821,15 @@ static void android_hardware_Camera_enableFocusMoveCallback(JNIEnv *env, jobject
     }
 }
 
+static bool android_hardware_Camera_isReleased(JNIEnv *env, jobject thiz)
+{
+    ALOGV("isReleased");
+    sp<Camera> camera = get_native_camera(env, thiz, NULL);
+    if (camera == 0) return true;
+
+    return (camera->sendCommand(CAMERA_CMD_PING, 0, 0) != NO_ERROR);
+}
+
 //-------------------------------------------------
 
 static JNINativeMethod camMethods[] = {
@@ -826,7 +840,7 @@ static JNINativeMethod camMethods[] = {
     "(ILandroid/hardware/Camera$CameraInfo;)V",
     (void*)android_hardware_Camera_getCameraInfo },
   { "native_setup",
-    "(Ljava/lang/Object;I)V",
+    "(Ljava/lang/Object;IZZ)V",
     (void*)android_hardware_Camera_native_setup },
   { "native_release",
     "()V",
@@ -894,6 +908,9 @@ static JNINativeMethod camMethods[] = {
   { "enableFocusMoveCallback",
     "(I)V",
     (void *)android_hardware_Camera_enableFocusMoveCallback},
+  { "isReleased",
+    "()Z",
+    (void *)android_hardware_Camera_isReleased},
 };
 
 struct field {

include/camera/Camera.h

@@ -72,7 +72,7 @@ class Camera : public BnCameraClient, public IBinder::DeathRecipient
     static  int32_t     getNumberOfCameras();
     static  status_t    getCameraInfo(int cameraId,
                                       struct CameraInfo* cameraInfo);
-    static  sp<Camera>  connect(int cameraId);
+    static  sp<Camera>  connect(int cameraId, bool force, bool keep);
             virtual     ~Camera();
             void        init();
 

include/camera/ICameraService.h

@@ -42,7 +42,7 @@ class ICameraService : public IInterface
     virtual status_t        getCameraInfo(int cameraId,
                                           struct CameraInfo* cameraInfo) = 0;
     virtual sp<ICamera>     connect(const sp<ICameraClient>& cameraClient,
-                                    int cameraId) = 0;
+                                    int cameraId, bool force, bool keep) = 0;
 };
 
 // ----------------------------------------------------------------------------

libs/camera/Camera.cpp

@@ -116,13 +116,13 @@ status_t Camera::getCameraInfo(int cameraId,
     return cs->getCameraInfo(cameraId, cameraInfo);
 }
 
-sp<Camera> Camera::connect(int cameraId)
+sp<Camera> Camera::connect(int cameraId, bool force, bool keep)
 {
     ALOGV("connect");
     sp<Camera> c = new Camera();
     const sp<ICameraService>& cs = getCameraService();
     if (cs != 0) {
-        c->mCamera = cs->connect(c, cameraId);
+        c->mCamera = cs->connect(c, cameraId, force, keep);
     }
     if (c->mCamera != 0) {
         c->mCamera->asBinder()->linkToDeath(c);

libs/camera/ICameraService.cpp

@@ -56,12 +56,15 @@ class BpCameraService: public BpInterface<ICameraService>
     }
 
     // connect to camera service
-    virtual sp<ICamera> connect(const sp<ICameraClient>& cameraClient, int cameraId)
+    virtual sp<ICamera> connect(const sp<ICameraClient>& cameraClient, int cameraId,
+                                bool force, bool keep)
     {
         Parcel data, reply;
         data.writeInterfaceToken(ICameraService::getInterfaceDescriptor());
         data.writeStrongBinder(cameraClient->asBinder());
         data.writeInt32(cameraId);
+        data.writeInt32(force);
+        data.writeInt32(keep);
         remote()->transact(BnCameraService::CONNECT, data, &reply);
         return interface_cast<ICamera>(reply.readStrongBinder());
     }
@@ -93,7 +96,10 @@ status_t BnCameraService::onTransact(
         case CONNECT: {
             CHECK_INTERFACE(ICameraService, data, reply);
             sp<ICameraClient> cameraClient = interface_cast<ICameraClient>(data.readStrongBinder());
-            sp<ICamera> camera = connect(cameraClient, data.readInt32());
+            const int cameraId = data.readInt32();
+            const int force = data.readInt32();
+            const int keep = data.readInt32();
+            sp<ICamera> camera = connect(cameraClient, cameraId, force, keep);
             reply->writeStrongBinder(camera->asBinder());
             return NO_ERROR;
         } break;
@@ -105,4 +111,3 @@ status_t BnCameraService::onTransact(
 // ----------------------------------------------------------------------------
 
 }; // namespace android
-

media/libstagefright/CameraSource.cpp

@@ -182,7 +182,7 @@ status_t CameraSource::isCameraAvailable(
     int32_t cameraId) {
 
     if (camera == 0) {
-        mCamera = Camera::connect(cameraId);
+        mCamera = Camera::connect(cameraId, false, false);
         if (mCamera == 0) return -EBUSY;
         mCameraFlags &= ~FLAGS_HOT_CAMERA;
     } else {