manager/1.1/VirtualCamera.cpp

/*
 * Copyright (C) 2019 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.
 */

#include "VirtualCamera.h"
#include "HalCamera.h"
#include "Enumerator.h"

#include <android/hardware_buffer.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>

using ::android::base::StringAppendF;
using ::android::base::StringPrintf;
using ::android::base::WriteStringToFd;
using ::android::hardware::automotive::evs::V1_0::DisplayState;


namespace android {
namespace automotive {
namespace evs {
namespace V1_1 {
namespace implementation {


VirtualCamera::VirtualCamera(const std::vector<sp<HalCamera>>& halCameras) :
    mStreamState(STOPPED) {
    for (auto&& cam : halCameras) {
        mHalCamera.try_emplace(cam->getId(), cam);
    }
}


VirtualCamera::~VirtualCamera() {
    shutdown();
}


void VirtualCamera::shutdown() {
    // In normal operation, the stream should already be stopped by the time we get here
    if (mStreamState == RUNNING) {
        // Note that if we hit this case, no terminating frame will be sent to the client,
        // but they're probably already dead anyway.
        LOG(WARNING) << "Virtual camera being shutdown while stream is running";

        // Tell the frame delivery pipeline we don't want any more frames
        mStreamState = STOPPING;

        // Awakes the capture thread; this thread will terminate.
        mFramesReadySignal.notify_all();

        // Returns buffers held by this client
        for (auto&& [key, hwCamera] : mHalCamera) {
            auto pHwCamera = hwCamera.promote();
            if (pHwCamera == nullptr) {
                LOG(WARNING) << "Camera device " << key << " is not alive.";
                continue;
            }

            if (mFramesHeld[key].size() > 0) {
                LOG(WARNING) << "VirtualCamera destructing with frames in flight.";

                // Return to the underlying hardware camera any buffers the client was holding
                for (auto&& heldBuffer : mFramesHeld[key]) {
                    // Tell our parent that we're done with this buffer
                    pHwCamera->doneWithFrame(heldBuffer);
                }
                mFramesHeld[key].clear();
            }

            // Retire from a primary client
            pHwCamera->unsetMaster(this);

            // Give the underlying hardware camera the heads up that it might be time to stop
            pHwCamera->clientStreamEnding(this);

            // Retire from the participating HW camera's client list
            pHwCamera->disownVirtualCamera(this);
        }

        // Join a capture thread
        if (mCaptureThread.joinable()) {
            mCaptureThread.join();
        }

        mFramesHeld.clear();

        // Drop our reference to our associated hardware camera
        mHalCamera.clear();
    }
}


std::vector<sp<HalCamera>> VirtualCamera::getHalCameras() {
    std::vector<sp<HalCamera>> cameras;
    for (auto&& [key, cam] : mHalCamera) {
        auto ptr = cam.promote();
        if (ptr != nullptr) {
            cameras.emplace_back(ptr);
        }
    }

    return cameras;
}


bool VirtualCamera::deliverFrame(const BufferDesc_1_1& bufDesc) {
    if (mStreamState == STOPPED) {
        // A stopped stream gets no frames
        LOG(ERROR) << "A stopped stream should not get any frames";
        return false;
    } else if (mFramesHeld[bufDesc.deviceId].size() >= mFramesAllowed) {
        // Indicate that we declined to send the frame to the client because they're at quota
        LOG(INFO) << "Skipping new frame as we hold " << mFramesHeld[bufDesc.deviceId].size()
                  << " of " << mFramesAllowed;

        if (mStream_1_1 != nullptr) {
            // Report a frame drop to v1.1 client.
            EvsEventDesc event;
            event.deviceId = bufDesc.deviceId;
            event.aType = EvsEventType::FRAME_DROPPED;
            auto result = mStream_1_1->notify(event);
            if (!result.isOk()) {
                LOG(ERROR) << "Error delivering end of stream event";
            }
        }

        // Marks that a new frame has arrived though it was not accepted
        {
            std::lock_guard<std::mutex> lock(mFrameDeliveryMutex);
            mSourceCameras.erase(bufDesc.deviceId);
            mFramesReadySignal.notify_all();
        }

        return false;
    } else {
        // Keep a record of this frame so we can clean up if we have to in case of client death
        mFramesHeld[bufDesc.deviceId].emplace_back(bufDesc);

        // v1.0 client uses an old frame-delivery mechanism.
        if (mStream_1_1 == nullptr) {
            // Forward a frame to v1.0 client
            BufferDesc_1_0 frame_1_0 = {};
            const AHardwareBuffer_Desc* pDesc =
                reinterpret_cast<const AHardwareBuffer_Desc *>(&bufDesc.buffer.description);
            frame_1_0.width     = pDesc->width;
            frame_1_0.height    = pDesc->height;
            frame_1_0.format    = pDesc->format;
            frame_1_0.usage     = pDesc->usage;
            frame_1_0.stride    = pDesc->stride;
            frame_1_0.memHandle = bufDesc.buffer.nativeHandle;
            frame_1_0.pixelSize = bufDesc.pixelSize;
            frame_1_0.bufferId  = bufDesc.bufferId;

            mStream->deliverFrame(frame_1_0);
        } else if (mCaptureThread.joinable()) {
            // Keep forwarding frames as long as a capture thread is alive
            if (mFramesHeld.size() > 0 && mStream_1_1 != nullptr) {
                // Notify a new frame receipt
                std::lock_guard<std::mutex> lock(mFrameDeliveryMutex);
                mSourceCameras.erase(bufDesc.deviceId);
                mFramesReadySignal.notify_all();
            }
        }

        return true;
    }
}


bool VirtualCamera::notify(const EvsEventDesc& event) {
    switch(event.aType) {
        case EvsEventType::STREAM_STOPPED:
            if (mStreamState != STOPPING) {
                // Warn if we got an unexpected stream termination
                LOG(WARNING) << "Stream unexpectedly stopped, current status "
                             << mStreamState;

                // Clean up the resource and forward an event to the client
                stopVideoStream();

                // This event is handled properly.
                return true;
            }

            if (mStream_1_1 == nullptr) {
                // Send a null frame instead, for v1.0 client
                auto result = mStream->deliverFrame({});
                if (!result.isOk()) {
                    LOG(ERROR) << "Error delivering end of stream marker";
                }
            }
            break;

        // v1.0 client will ignore all other events.
        case EvsEventType::PARAMETER_CHANGED:
            LOG(DEBUG) << "A camera parameter " << event.payload[0]
                       << " is set to " << event.payload[1];
            break;

        case EvsEventType::MASTER_RELEASED:
            LOG(DEBUG) << "The primary client has been released";
            break;

        default:
            LOG(WARNING) << "Unknown event id " << static_cast<int32_t>(event.aType);
            break;
    }

    if (mStream_1_1 != nullptr) {
        // Forward a received event to the v1.1 client
        auto result = mStream_1_1->notify(event);
        if (!result.isOk()) {
            LOG(ERROR) << "Failed to forward an event";
            return false;
        }
    }

    return true;
}


// Methods from ::android::hardware::automotive::evs::V1_0::IEvsCamera follow.
Return<void> VirtualCamera::getCameraInfo(getCameraInfo_cb info_cb) {
    // Straight pass through to hardware layer
    if (mHalCamera.size() > 1) {
        LOG(ERROR) << __FUNCTION__
                   << " must NOT be called on a logical camera object.";
        info_cb({});
        return Void();
    }

    auto halCamera = mHalCamera.begin()->second.promote();
    if (halCamera != nullptr) {
        return halCamera->getHwCamera()->getCameraInfo(info_cb);
    } else {
        info_cb({});
        return Void();
    }
}


Return<EvsResult> VirtualCamera::setMaxFramesInFlight(uint32_t bufferCount) {
    // How many buffers are we trying to add (or remove if negative)
    int bufferCountChange = bufferCount - mFramesAllowed;

    // Ask our parent for more buffers
    bool result = true;
    std::vector<sp<HalCamera>> changedCameras;
    for (auto&& [key, hwCamera] : mHalCamera) {
        auto pHwCam = hwCamera.promote();
        if (pHwCam == nullptr) {
            continue;
        }

        result = pHwCam->changeFramesInFlight(bufferCountChange);
        if (!result) {
            LOG(ERROR) << key
                       << ": Failed to change buffer count by " << bufferCountChange
                       << " to " << bufferCount;
            break;
        }

        changedCameras.emplace_back(pHwCam);
    }

    // Update our notion of how many frames we're allowed
    mFramesAllowed = bufferCount;

    if (!result) {
        // Rollback changes because we failed to update all cameras
        for (auto&& hwCamera : changedCameras) {
            LOG(WARNING) << "Rollback a change on  " << hwCamera->getId();
            hwCamera->changeFramesInFlight(-bufferCountChange);
        }

        // Restore the original buffer count
        mFramesAllowed -= bufferCountChange;
        return EvsResult::BUFFER_NOT_AVAILABLE;
    } else {
        return EvsResult::OK;
    }
}


Return<EvsResult> VirtualCamera::startVideoStream(const ::android::sp<IEvsCameraStream_1_0>& stream)  {
    // We only support a single stream at a time
    if (mStreamState != STOPPED) {
        LOG(ERROR) << "Ignoring startVideoStream call when a stream is already running.";
        return EvsResult::STREAM_ALREADY_RUNNING;
    }

    // Validate our held frame count is starting out at zero as we expect
    assert(mFramesHeld.size() == 0);

    // Record the user's callback for use when we have a frame ready
    mStream = stream;
    mStream_1_1 = IEvsCameraStream_1_1::castFrom(stream).withDefault(nullptr);
    if (mStream_1_1 == nullptr) {
        LOG(INFO) << "Start video stream for v1.0 client.";
    } else {
        LOG(INFO) << "Start video stream for v1.1 client.";
    }

    mStreamState = RUNNING;

    // Tell the underlying camera hardware that we want to stream
    auto iter = mHalCamera.begin();
    while (iter != mHalCamera.end()) {
        auto pHwCamera = iter->second.promote();
        if (pHwCamera == nullptr) {
            LOG(ERROR) << "Failed to start a video stream on " << iter->first;
            continue;
        }

        LOG(INFO) << __FUNCTION__
                  << " starts a video stream on " << iter->first;
        Return<EvsResult> result = pHwCamera->clientStreamStarting();
        if ((!result.isOk()) || (result != EvsResult::OK)) {
            // If we failed to start the underlying stream, then we're not actually running
            mStream = mStream_1_1 = nullptr;
            mStreamState = STOPPED;

            // Request to stop streams started by this client.
            auto rb = mHalCamera.begin();
            while (rb != iter) {
                auto ptr = rb->second.promote();
                if (ptr != nullptr) {
                    ptr->clientStreamEnding(this);
                }
                ++rb;
            }
            return EvsResult::UNDERLYING_SERVICE_ERROR;
        }
        ++iter;
    }

    // Start a thread that waits on the fence and forwards collected frames
    // to the v1.1 client.
    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (mStream_1_1 != nullptr && pHwCamera != nullptr) {
        mCaptureThread = std::thread([this]() {
            // TODO(b/145466570): With a proper camera hang handler, we may want
            // to reduce an amount of timeout.
            constexpr auto kFrameTimeout = 5s; // timeout in seconds.
            int64_t lastFrameTimestamp = -1;
            while (mStreamState == RUNNING) {
                unsigned count = 0;
                for (auto&& [key, hwCamera] : mHalCamera) {
                    auto pHwCamera = hwCamera.promote();
                    if (pHwCamera == nullptr) {
                        LOG(WARNING) << "Invalid camera " << key << " is ignored.";
                        continue;
                    }

                    pHwCamera->requestNewFrame(this, lastFrameTimestamp);
                    {
                        std::lock_guard<std::mutex> lock(mFrameDeliveryMutex);
                        mSourceCameras.emplace(pHwCamera->getId());
                    }
                    ++count;
                }

                std::unique_lock<std::mutex> lock(mFrameDeliveryMutex);
                if (!mFramesReadySignal.wait_for(lock,
                                                 kFrameTimeout,
                                                 [this]() REQUIRES(mFrameDeliveryMutex) {
                                                     // Stops waiting if
                                                     // 1) we've requested to stop capturing
                                                     //    new frames
                                                     // 2) or, we've got all frames
                                                     return mStreamState != RUNNING ||
                                                            mSourceCameras.empty();
                                                 })) {
                    // This happens when either a new frame does not arrive
                    // before a timer expires or we're requested to stop
                    // capturing frames.
                    break;
                } else if (mStreamState == RUNNING) {
                    // Fetch frames and forward to the client
                    if (mFramesHeld.size() > 0 && mStream_1_1 != nullptr) {
                        // Pass this buffer through to our client
                        hardware::hidl_vec<BufferDesc_1_1> frames;
                        frames.resize(count);
                        unsigned i = 0;
                        for (auto&& [key, hwCamera] : mHalCamera) {
                            auto pHwCamera = hwCamera.promote();
                            if (pHwCamera == nullptr) {
                                continue;
                            }
                            if (mFramesHeld[key].size() == 0) {
                                continue;
                            }

                            const auto frame = mFramesHeld[key].back();
                            if (frame.timestamp > lastFrameTimestamp) {
                                lastFrameTimestamp = frame.timestamp;
                            }
                            frames[i++] = frame;
                        }

                        auto ret = mStream_1_1->deliverFrame_1_1(frames);
                        if (!ret.isOk()) {
                            LOG(WARNING) << "Failed to forward frames";
                        }
                    }
                } else if (mStreamState != RUNNING) {
                    LOG(DEBUG) << "Requested to stop capturing frames";
                }
            }

            LOG(DEBUG) << "Exiting a capture thread";
        });
    }

    // TODO(changyeon):
    // Detect and exit if we encounter a stalled stream or unresponsive driver?
    // Consider using a timer and watching for frame arrival?

    return EvsResult::OK;
}


Return<void> VirtualCamera::doneWithFrame(const BufferDesc_1_0& buffer) {
    if (buffer.memHandle == nullptr) {
        LOG(ERROR) << "Ignoring doneWithFrame called with invalid handle";
    } else if (mFramesHeld.size() > 1) {
        LOG(ERROR) << __FUNCTION__
                   << " must NOT be called on a logical camera object.";
    } else {
        // Find this buffer in our "held" list
        auto& frameQueue = mFramesHeld.begin()->second;
        auto it = frameQueue.begin();
        while (it != frameQueue.end()) {
            if (it->bufferId == buffer.bufferId) {
                // found it!
                break;
            }
            ++it;
        }
        if (it == frameQueue.end()) {
            // We should always find the frame in our "held" list
            LOG(ERROR) << "Ignoring doneWithFrame called with unrecognized frameID "
                       << buffer.bufferId;
        } else {
            // Take this frame out of our "held" list
            frameQueue.erase(it);

            // Tell our parent that we're done with this buffer
            auto pHwCamera = mHalCamera.begin()->second.promote();
            if (pHwCamera != nullptr) {
                pHwCamera->doneWithFrame(buffer);
            } else {
                LOG(WARNING) << "Possible memory leak because a device "
                             << mHalCamera.begin()->first
                             << " is not valid.";
            }
        }
    }

    return Void();
}


Return<void> VirtualCamera::stopVideoStream()  {
    if (mStreamState == RUNNING) {
        // Tell the frame delivery pipeline we don't want any more frames
        mStreamState = STOPPING;

        // Awake the capture thread; this thread will terminate.
        mFramesReadySignal.notify_all();

        // Deliver the stream-ending notification
        if (mStream_1_1 != nullptr) {
            // v1.1 client waits for a stream stopped event
            EvsEventDesc event;
            event.aType = EvsEventType::STREAM_STOPPED;
            auto result = mStream_1_1->notify(event);
            if (!result.isOk()) {
                LOG(ERROR) << "Error delivering end of stream event";
            }
        } else {
            // v1.0 client expects a null frame at the end of the stream
            auto result = mStream->deliverFrame({});
            if (!result.isOk()) {
                LOG(ERROR) << "Error delivering end of stream marker";
            }
        }

        // Since we are single threaded, no frame can be delivered while this function is running,
        // so we can go directly to the STOPPED state here on the server.
        // Note, however, that there still might be frames already queued that client will see
        // after returning from the client side of this call.
        mStreamState = STOPPED;

        // Give the underlying hardware camera the heads up that it might be time to stop
        for (auto&& [key, hwCamera] : mHalCamera) {
            auto pHwCamera = hwCamera.promote();
            if (pHwCamera != nullptr) {
                pHwCamera->clientStreamEnding(this);
            }
        }

        // Signal a condition to unblock a capture thread and then join
        {
            std::lock_guard<std::mutex> lock(mFrameDeliveryMutex);
            mSourceCameras.clear();
            mFramesReadySignal.notify_all();
        }

        if (mCaptureThread.joinable()) {
            mCaptureThread.join();
        }

    }

    return Void();
}


Return<int32_t> VirtualCamera::getExtendedInfo(uint32_t opaqueIdentifier)  {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        return 0;
    }

    // Pass straight through to the hardware device
    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera != nullptr) {
        return pHwCamera->getHwCamera()->getExtendedInfo(opaqueIdentifier);
    } else {
        LOG(WARNING) << mHalCamera.begin()->first << " is invalid.";
        return 0;
    }
}


Return<EvsResult> VirtualCamera::setExtendedInfo(uint32_t opaqueIdentifier, int32_t opaqueValue)  {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        return EvsResult::INVALID_ARG;
    }

    // Pass straight through to the hardware device
    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera != nullptr) {
        return pHwCamera->getHwCamera()->setExtendedInfo(opaqueIdentifier, opaqueValue);
    } else {
        LOG(WARNING) << mHalCamera.begin()->first << " is invalid.";
        return EvsResult::INVALID_ARG;
    }
}


// Methods from ::android::hardware::automotive::evs::V1_1::IEvsCamera follow.
Return<void> VirtualCamera::getCameraInfo_1_1(getCameraInfo_1_1_cb info_cb) {
    if (mHalCamera.size() > 1) {
        // Logical camera description is stored in VirtualCamera object.
        info_cb(*mDesc);
        return Void();
    }

    // Straight pass through to hardware layer
    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        // Return an empty list
        info_cb({});
        return Void();
    }

    auto hwCamera_1_1 =
        IEvsCamera_1_1::castFrom(pHwCamera->getHwCamera()).withDefault(nullptr);
    if (hwCamera_1_1 != nullptr) {
        return hwCamera_1_1->getCameraInfo_1_1(info_cb);
    } else {
        // Return an empty list
        info_cb({});
        return Void();
    }
}


Return<void> VirtualCamera::getPhysicalCameraInfo(const hidl_string& deviceId,
                                                  getPhysicalCameraInfo_cb info_cb) {
    auto device = mHalCamera.find(deviceId);
    if (device != mHalCamera.end()) {
        // Straight pass through to hardware layer
        auto pHwCamera = device->second.promote();
        if (pHwCamera != nullptr) {
            auto hwCamera_1_1 =
                IEvsCamera_1_1::castFrom(pHwCamera->getHwCamera()).withDefault(nullptr);
            if (hwCamera_1_1 != nullptr) {
                return hwCamera_1_1->getCameraInfo_1_1(info_cb);
            } else {
                LOG(WARNING) << "Failed to promote HW camera to v1.1.";
            }
        } else {
            LOG(WARNING) << "Camera device " << deviceId << " is not alive.";
        }
    } else {
        LOG(WARNING) << " Requested device " << deviceId
                     << " does not back this device.";
    }

    // Return an empty list
    info_cb({});
    return Void();
}


Return<EvsResult> VirtualCamera::doneWithFrame_1_1(
    const hardware::hidl_vec<BufferDesc_1_1>& buffers) {

    for (auto&& buffer : buffers) {
        if (buffer.buffer.nativeHandle == nullptr) {
            LOG(WARNING) << "Ignoring doneWithFrame called with invalid handle";
        } else {
            // Find this buffer in our "held" list
            auto it = mFramesHeld[buffer.deviceId].begin();
            while (it != mFramesHeld[buffer.deviceId].end()) {
                if (it->bufferId == buffer.bufferId) {
                    // found it!
                    break;
                }
                ++it;
            }
            if (it == mFramesHeld[buffer.deviceId].end()) {
                // We should always find the frame in our "held" list
                LOG(ERROR) << "Ignoring doneWithFrame called with unrecognized frameID "
                           << buffer.bufferId;
            } else {
                // Take this frame out of our "held" list
                mFramesHeld[buffer.deviceId].erase(it);

                // Tell our parent that we're done with this buffer
                auto pHwCamera = mHalCamera[buffer.deviceId].promote();
                if (pHwCamera != nullptr) {
                    pHwCamera->doneWithFrame(buffer);
                } else {
                    LOG(WARNING) << "Possible memory leak; "
                                 << buffer.deviceId << " is not valid.";
                }
            }
        }
    }

    return EvsResult::OK;
}


Return<EvsResult> VirtualCamera::setMaster() {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        return EvsResult::INVALID_ARG;
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera != nullptr) {
        return pHwCamera->setMaster(this);
    } else {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        return EvsResult::INVALID_ARG;
    }
}


Return<EvsResult> VirtualCamera::forceMaster(const sp<IEvsDisplay_1_0>& display) {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        return EvsResult::INVALID_ARG;
    }

    if (display == nullptr) {
        LOG(ERROR) << __FUNCTION__
                   << ": Passed display is invalid";
        return EvsResult::INVALID_ARG;
    }

    DisplayState state = display->getDisplayState();
    if (state == DisplayState::NOT_OPEN ||
        state == DisplayState::DEAD ||
        state >= DisplayState::NUM_STATES) {
        LOG(ERROR) << __FUNCTION__
                   << ": Passed display is in invalid state";
        return EvsResult::INVALID_ARG;
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera != nullptr) {
        return pHwCamera->forceMaster(this);
    } else {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        return EvsResult::INVALID_ARG;
    }
}


Return<EvsResult> VirtualCamera::unsetMaster() {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        return EvsResult::INVALID_ARG;
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera != nullptr) {
        return pHwCamera->unsetMaster(this);
    } else {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        return EvsResult::INVALID_ARG;
    }
}


Return<void> VirtualCamera::getParameterList(getParameterList_cb _hidl_cb) {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;

        // Return an empty list
        _hidl_cb({});
        return Void();
    }

    // Straight pass through to hardware layer
    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";

        // Return an empty list
        _hidl_cb({});
        return Void();
    }

    auto hwCamera_1_1 =
        IEvsCamera_1_1::castFrom(pHwCamera->getHwCamera()).withDefault(nullptr);
    if (hwCamera_1_1 != nullptr) {
        return hwCamera_1_1->getParameterList(_hidl_cb);
    } else {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first
                     << " does not support a parameter programming.";

        // Return an empty list
        _hidl_cb({});
        return Void();
    }
}


Return<void> VirtualCamera::getIntParameterRange(CameraParam id,
                                                 getIntParameterRange_cb _hidl_cb) {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;

        // Return [0, 0, 0]
        _hidl_cb(0, 0, 0);
        return Void();
    }

    // Straight pass through to hardware layer
    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";

        // Return [0, 0, 0]
        _hidl_cb(0, 0, 0);
        return Void();
    }

    auto hwCamera_1_1 =
        IEvsCamera_1_1::castFrom(pHwCamera->getHwCamera()).withDefault(nullptr);
    if (hwCamera_1_1 != nullptr) {
        return hwCamera_1_1->getIntParameterRange(id, _hidl_cb);
    } else {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first
                     << " does not support a parameter programming.";

        // Return [0, 0, 0]
        _hidl_cb(0, 0, 0);
        return Void();
    }
    return Void();
}


Return<void> VirtualCamera::setIntParameter(CameraParam id,
                                            int32_t value,
                                            setIntParameter_cb _hidl_cb) {
    hardware::hidl_vec<int32_t> values;
    EvsResult status = EvsResult::INVALID_ARG;
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        _hidl_cb(status, values);
        return Void();
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        _hidl_cb(status, values);
        return Void();
    }

    status = pHwCamera->setParameter(this, id, value);

    values.resize(1);
    values[0] = value;
    _hidl_cb(status, values);

    return Void();
}


Return<void> VirtualCamera::getIntParameter(CameraParam id,
                                            getIntParameter_cb _hidl_cb) {
    hardware::hidl_vec<int32_t> values;
    EvsResult status = EvsResult::INVALID_ARG;
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        _hidl_cb(status, values);
        return Void();
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        _hidl_cb(status, values);
        return Void();
    }

    int32_t value;
    status = pHwCamera->getParameter(id, value);

    values.resize(1);
    values[0] = value;
    _hidl_cb(status, values);

    return Void();
}


Return<EvsResult> VirtualCamera::setExtendedInfo_1_1(uint32_t opaqueIdentifier,
                                                     const hidl_vec<uint8_t>& opaqueValue) {
    hardware::hidl_vec<int32_t> values;
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        return EvsResult::INVALID_ARG;
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        return EvsResult::INVALID_ARG;
    } else {
        auto hwCamera = IEvsCamera_1_1::castFrom(pHwCamera->getHwCamera()).withDefault(nullptr);
        if (hwCamera != nullptr) {
            return hwCamera->setExtendedInfo_1_1(opaqueIdentifier, opaqueValue);
        } else {
            LOG(ERROR) << "Underlying hardware camera does not implement v1.1 interfaces.";
            return EvsResult::INVALID_ARG;
        }
    }
}


Return<void> VirtualCamera::getExtendedInfo_1_1(uint32_t opaqueIdentifier,
                                                getExtendedInfo_1_1_cb _hidl_cb) {
    hardware::hidl_vec<uint8_t> values;
    EvsResult status = EvsResult::INVALID_ARG;
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        _hidl_cb(status, values);
        return Void();
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        _hidl_cb(status, values);
    } else {
        auto hwCamera = IEvsCamera_1_1::castFrom(pHwCamera->getHwCamera()).withDefault(nullptr);
        if (hwCamera != nullptr) {
            hwCamera->getExtendedInfo_1_1(opaqueIdentifier, _hidl_cb);
        } else {
            LOG(ERROR) << "Underlying hardware camera does not implement v1.1 interfaces.";
            _hidl_cb(status, values);
        }
    }

    return Void();
}


Return<void>
VirtualCamera::importExternalBuffers(const hidl_vec<BufferDesc_1_1>& buffers,
                                     importExternalBuffers_cb _hidl_cb) {
    if (mHalCamera.size() > 1) {
        LOG(WARNING) << "Logical camera device does not support " << __FUNCTION__;
        _hidl_cb(EvsResult::UNDERLYING_SERVICE_ERROR, 0);
        return {};
    }

    auto pHwCamera = mHalCamera.begin()->second.promote();
    if (pHwCamera == nullptr) {
        LOG(WARNING) << "Camera device " << mHalCamera.begin()->first << " is not alive.";
        _hidl_cb(EvsResult::UNDERLYING_SERVICE_ERROR, 0);
        return {};
    }

    int delta = 0;
    if (!pHwCamera->changeFramesInFlight(buffers, &delta)) {
        LOG(ERROR) << "Failed to add extenral capture buffers.";
        _hidl_cb(EvsResult::UNDERLYING_SERVICE_ERROR, 0);
        return {};
    }

    mFramesAllowed += delta;
    _hidl_cb(EvsResult::OK, delta);
    return {};
}


std::string VirtualCamera::toString(const char* indent) const {
    std::string buffer;
    StringAppendF(&buffer, "%sLogical camera device: %s\n"
                           "%sFramesAllowed: %u\n"
                           "%sFrames in use:\n",
                           indent, mHalCamera.size() > 1 ? "T" : "F",
                           indent, mFramesAllowed,
                           indent);

    std::string next_indent(indent);
    next_indent += "\t";
    for (auto&& [id, queue] : mFramesHeld) {
        StringAppendF(&buffer, "%s%s: %d\n",
                               next_indent.c_str(),
                               id.c_str(),
                               static_cast<int>(queue.size()));
    }
    StringAppendF(&buffer, "%sCurrent stream state: %d\n",
                                 indent, mStreamState);

    return buffer;
}


} // namespace implementation
} // namespace V1_1
} // namespace evs
} // namespace automotive
} // namespace android