evs/manager/Enumerator.cpp

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "EvsManager"

#include "Enumerator.h"

namespace android {
namespace automotive {
namespace evs {
namespace V1_0 {
namespace implementation {


bool Enumerator::init(const char* hardwareServiceName) {
    ALOGD("init");

    // Connect with the underlying hardware enumerator
    mHwEnumerator = IEvsEnumerator::getService(hardwareServiceName);
    bool result = (mHwEnumerator.get() != nullptr);

    return result;
}


// Methods from ::android::hardware::evs::V1_0::IEvsEnumerator follow.
Return<void> Enumerator::getCameraList(getCameraList_cb list_cb)  {
    ALOGD("getCameraList");

    // Simply pass through to hardware layer
    return mHwEnumerator->getCameraList(list_cb);
}


Return<sp<IEvsCamera>> Enumerator::openCamera(const hidl_string& cameraId) {
    ALOGD("openCamera");

    // Is the underlying hardware camera already open?
    sp<HalCamera> hwCamera;
    for (auto &&cam : mCameras) {
        bool match = false;
        cam->getHwCamera()->getId([cameraId, &match](hidl_string id) {
                                      if (id == cameraId) {
                                          match = true;
                                      }
                                  }
        );
        if (match) {
            hwCamera = cam;
            break;
        }
    }

    // Do we need to open a new hardware camera?
    if (hwCamera == nullptr) {
        // Is the hardware camera available?
        sp<IEvsCamera> device = mHwEnumerator->openCamera(cameraId);
        if (device == nullptr) {
            ALOGE("Failed to open hardware camera %s", cameraId.c_str());
        } else {
            hwCamera = new HalCamera(device);
            if (hwCamera == nullptr) {
                ALOGE("Failed to allocate camera wrapper object");
                mHwEnumerator->closeCamera(device);
            }
        }
    }

    // Construct a virtual camera wrapper for this hardware camera
    sp<VirtualCamera> clientCamera;
    if (hwCamera != nullptr) {
        clientCamera = hwCamera->makeVirtualCamera();
    }

    // Add the hardware camera to our list, which will keep the object alive via ref count
    if (clientCamera != nullptr) {
        mCameras.push_back(hwCamera);
    } else {
        ALOGE("Requested camera %s not found or not available", cameraId.c_str());
    }

    // Send the virtual camera object (also owned by our hwCamera) back to the client
    return clientCamera;
}


Return<void> Enumerator::closeCamera(const ::android::sp<IEvsCamera>& clientCamera) {
    ALOGD("closeCamera");

    if (clientCamera.get() == nullptr) {
        ALOGE("Ignoring call with null camera pointer.");
        return Void();
    }

    // All our client cameras are actually VirtualCamera objects
    // TODO (b/33492405):  This will likely crash until pointers make proper round trips
    sp<VirtualCamera> virtualCamera = reinterpret_cast<VirtualCamera*>(clientCamera.get());

    // Find the parent camera that backs this virtual camera
    sp<HalCamera> halCamera = virtualCamera->getHalCamera();

    // Tell the virtual camera's parent to clean it up and drop it
    // NOTE:  The camera objects will only actually destruct when the sp<> ref counts get to
    //        zero, so it is important to break all cyclic references.
    halCamera->disownVirtualCamera(virtualCamera);

    // Did we just remove the last client of this camera?
    if (halCamera->getClientCount() == 0) {
        // Close the hardware camera before we go any further
        mHwEnumerator->closeCamera(halCamera->getHwCamera());

        // Take this now closed camera out of our list
        // NOTE:  This should drop our last reference to the camera, resulting in its
        //        destruction.
        mCameras.remove(halCamera);
    }

    return Void();
}


Return<sp<IEvsDisplay>> Enumerator::openDisplay() {
    ALOGD("openDisplay");

    // If we already have a display active, then this request must be denied
    if (mActiveDisplay != nullptr) {
        ALOGW("Rejecting openDisplay request because the display is already in use.");
        return nullptr;
    } else {
        // Request exclusive access to the EVS display
        ALOGI("Acquiring EVS Display");

        mActiveDisplay = mHwEnumerator->openDisplay();
        if (mActiveDisplay.get() == nullptr) {
            ALOGE("EVS Display unavailable");
        }

        return mActiveDisplay;
    }
}


Return<void> Enumerator::closeDisplay(const ::android::sp<IEvsDisplay>& display) {
    ALOGD("closeDisplay");

    // Drop the active display
    if (display != mActiveDisplay) {
        ALOGW("Ignoring call to closeDisplay with a display object we don't recognize.");
    } else {
        // Pass this request through to the hardware layer
        mHwEnumerator->closeDisplay(display);
        mActiveDisplay = nullptr;
    }

    return Void();
}


Return<DisplayState> Enumerator::getDisplayState()  {
    ALOGD("getDisplayState");

    // Pass this request through to the hardware layer
    if (mHwEnumerator == nullptr) {
        // If we haven't even been initialized, this should not be called
        ALOGE("getDisplayState called on incompletely initialized EvsEnumerator");
        return DisplayState::NOT_OPEN;
    } else if (mActiveDisplay == nullptr) {
        // We actually DO hold the underlying hardware display open (in order to reserve it)
        // but the application hasn't opened it, so we know it isn't actually doing anything.
        return DisplayState::NOT_OPEN;
    } else {
        return mActiveDisplay->getDisplayState();
    }
}


// TODO(b/31632518):  Need to get notification when our client dies so we can close the camera.
// As possible work around would be to give the client a HIDL object to exclusively hold
// and use it's destructor to perform some work in the server side.


} // namespace implementation
} // namespace V1_0
} // namespace evs
} // namespace automotive
} // namespace android