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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.hardware.automotive.evs@1.0;
     18 
     19 import types;
     20 import IEvsCamera;
     21 import IEvsDisplay;
     22 
     23 
     24 /**
     25  * Provides the mechanism for EVS camera discovery
     26  */
     27 interface IEvsEnumerator {
     28 
     29     /**
     30      * Returns a list of all EVS cameras available to the system
     31      */
     32     getCameraList() generates (vec<CameraDesc> cameras);
     33 
     34     /**
     35      * Get the IEvsCamera associated with a cameraId from a CameraDesc
     36      *
     37      * Given a camera's unique cameraId from CameraDesc, returns the
     38      * IEvsCamera interface associated with the specified camera. When
     39      * done using the camera, the caller may release it by calling closeCamera().
     40      * Note: Reliance on the sp<> going out of scope is not recommended
     41      * because the resources may not be released right away due to asynchronos
     42      * behavior in the hardware binder (ref b/36122635).
     43      */
     44     openCamera(string cameraId) generates (IEvsCamera carCamera);
     45 
     46     /**
     47      * Return the specified IEvsCamera interface as no longer in use
     48      *
     49      * When the IEvsCamera object is no longer required, it must be released.
     50      * NOTE: Video streaming must be cleanly stopped before making this call.
     51      */
     52     closeCamera(IEvsCamera carCamera);
     53 
     54 
     55     /**
     56      * Get exclusive access to IEvsDisplay for the system
     57      *
     58      * There can be at most one EVS display object for the system and this function
     59      * requests access to it. If the EVS display is not available or is already in use,
     60      * a null pointer is returned.
     61      * When done using the display, the caller may release it by calling closeDisplay().
     62      * TODO(b/36122635) Reliance on the sp<> going out of scope is not recommended because the
     63      * resources may not be released right away due to asynchronos behavior in the hardware binder.
     64      */
     65     openDisplay() generates (IEvsDisplay display);
     66 
     67     /**
     68      * Return the specified IEvsDisplay interface as no longer in use
     69      *
     70      * When the IEvsDisplay object is no longer required, it must be released.
     71      * NOTE: All buffers must have been returned to the display before making this call.
     72      */
     73     closeDisplay(IEvsDisplay display);
     74 
     75     /**
     76      * This call requests the current state of the display
     77      *
     78      * If there is no open display, this returns DisplayState::NOT_OPEN. otherwise, it returns
     79      * the actual state of the active display.  This call is replicated on the IEvsEnumerator
     80      * interface in order to allow secondary clients to monitor the state of the EVS display
     81      * without acquiring exclusive ownership of the display.
     82      */
     83     getDisplayState() generates (DisplayState state);
     84 };
     85 
     86