media/libaaudio/src/binding/AAudioBinderClient.cpp

/*
 * Copyright (C) 2017 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 "AAudio"
//#define LOG_NDEBUG 0
#include <utils/Log.h>

#include <binder/IServiceManager.h>
#include <utils/Mutex.h>
#include <utils/RefBase.h>

#include <aaudio/AAudio.h>

#include "AudioEndpointParcelable.h"
#include "binding/AAudioStreamRequest.h"
#include "binding/AAudioStreamConfiguration.h"
#include "binding/IAAudioService.h"
#include "binding/AAudioServiceMessage.h"

#include "AAudioBinderClient.h"
#include "AAudioServiceInterface.h"

using android::String16;
using android::IServiceManager;
using android::defaultServiceManager;
using android::interface_cast;
using android::IAAudioService;
using android::Mutex;
using android::sp;

using namespace aaudio;

static android::Mutex gServiceLock;
static sp<IAAudioService>  gAAudioService;

// TODO Share code with other service clients.
// Helper function to get access to the "AAudioService" service.
// This code was modeled after frameworks/av/media/libaudioclient/AudioSystem.cpp
static const sp<IAAudioService> getAAudioService() {
    sp<IBinder> binder;
    Mutex::Autolock _l(gServiceLock);
    if (gAAudioService == 0) {
        sp<IServiceManager> sm = defaultServiceManager();
        // Try several times to get the service.
        int retries = 4;
        do {
            binder = sm->getService(String16(AAUDIO_SERVICE_NAME)); // This will wait a while.
            if (binder != 0) {
                break;
            }
        } while (retries-- > 0);

        if (binder != 0) {
            // TODO Add linkToDeath() like in frameworks/av/media/libaudioclient/AudioSystem.cpp
            // TODO Create a DeathRecipient that disconnects all active streams.
            gAAudioService = interface_cast<IAAudioService>(binder);
        } else {
            ALOGE("AudioStreamInternal could not get %s", AAUDIO_SERVICE_NAME);
        }
    }
    return gAAudioService;
}


AAudioBinderClient::AAudioBinderClient()
        : AAudioServiceInterface() {}

AAudioBinderClient::~AAudioBinderClient() {}

/**
* @param request info needed to create the stream
* @param configuration contains information about the created stream
* @return handle to the stream or a negative error
*/
aaudio_handle_t AAudioBinderClient::openStream(const AAudioStreamRequest &request,
                                               AAudioStreamConfiguration &configurationOutput) {

    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->openStream(request, configurationOutput);
}

aaudio_result_t AAudioBinderClient::closeStream(aaudio_handle_t streamHandle) {

    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->closeStream(streamHandle);
}

/* Get an immutable description of the in-memory queues
* used to communicate with the underlying HAL or Service.
*/
aaudio_result_t AAudioBinderClient::getStreamDescription(aaudio_handle_t streamHandle,
                                                         AudioEndpointParcelable &parcelable) {

    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->getStreamDescription(streamHandle, parcelable);
}

/**
* Start the flow of data.
*/
aaudio_result_t AAudioBinderClient::startStream(aaudio_handle_t streamHandle) {
    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->startStream(streamHandle);
}

/**
* Stop the flow of data such that start() can resume without loss of data.
*/
aaudio_result_t AAudioBinderClient::pauseStream(aaudio_handle_t streamHandle) {
    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->startStream(streamHandle);
}

/**
*  Discard any data held by the underlying HAL or Service.
*/
aaudio_result_t AAudioBinderClient::flushStream(aaudio_handle_t streamHandle) {
    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->startStream(streamHandle);
}

/**
* Manage the specified thread as a low latency audio thread.
*/
aaudio_result_t AAudioBinderClient::registerAudioThread(aaudio_handle_t streamHandle,
                                                        pid_t clientProcessId,
                                                        pid_t clientThreadId,
                                                        int64_t periodNanoseconds) {
    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->registerAudioThread(streamHandle,
                                        clientProcessId,
                                        clientThreadId,
                                        periodNanoseconds);
}

aaudio_result_t AAudioBinderClient::unregisterAudioThread(aaudio_handle_t streamHandle,
                                                          pid_t clientProcessId,
                                                          pid_t clientThreadId) {
    const sp<IAAudioService> &service = getAAudioService();
    if (service == 0) return AAUDIO_ERROR_NO_SERVICE;
    return service->unregisterAudioThread(streamHandle,
                                          clientProcessId,
                                          clientThreadId);
}