services/oboeservice/AAudioEndpointManager.h

/*
 * 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.
 */

#ifndef AAUDIO_AAUDIO_ENDPOINT_MANAGER_H
#define AAUDIO_AAUDIO_ENDPOINT_MANAGER_H

#include <map>
#include <mutex>
#include <sys/types.h>

#include <android-base/thread_annotations.h>
#include <utils/Singleton.h>

#include "binding/AAudioServiceMessage.h"
#include "AAudioServiceEndpoint.h"
#include "AAudioServiceEndpointCapture.h"
#include "AAudioServiceEndpointMMAP.h"
#include "AAudioServiceEndpointPlay.h"

namespace aaudio {

class AAudioEndpointManager : public android::Singleton<AAudioEndpointManager> {
public:
    AAudioEndpointManager();
    ~AAudioEndpointManager() = default;

    /**
     * Returns information about the state of the this class.
     *
     * Will attempt to get the object lock, but will proceed
     * even if it cannot.
     *
     * Each line of information ends with a newline.
     *
     * @return a string with useful information
     */
    std::string dump() const;

    /**
     * Find a service endpoint for the given deviceId, sessionId and direction.
     * If an endpoint does not already exist then try to create one.
     *
     * @param audioService
     * @param request
     * @param sharingMode
     * @return endpoint or null
     */
    android::sp<AAudioServiceEndpoint> openEndpoint(
            android::AAudioService &audioService,
            const aaudio::AAudioStreamRequest &request)
            EXCLUDES(mExclusiveLock, mSharedLock);

    void closeEndpoint(const android::sp<AAudioServiceEndpoint>& serviceEndpoint)
            EXCLUDES(mExclusiveLock, mSharedLock);;

private:
    android::sp<AAudioServiceEndpoint> openExclusiveEndpoint(
            android::AAudioService &aaudioService,
            const aaudio::AAudioStreamRequest &request,
            sp<AAudioServiceEndpoint> &endpointToSteal)
            EXCLUDES(mExclusiveLock);

    android::sp<AAudioServiceEndpoint> openSharedEndpoint(
            android::AAudioService &aaudioService,
            const aaudio::AAudioStreamRequest &request)
            EXCLUDES(mSharedLock);

    android::sp<AAudioServiceEndpoint> findExclusiveEndpoint_l(
            const AAudioStreamConfiguration& configuration)
            REQUIRES(mExclusiveLock);

    android::sp<AAudioServiceEndpointShared> findSharedEndpoint_l(
            const AAudioStreamConfiguration& configuration)
            REQUIRES(mSharedLock)
            EXCLUDES(mExclusiveLock);

    void closeExclusiveEndpoint(const android::sp<AAudioServiceEndpoint>& serviceEndpoint);
    void closeSharedEndpoint(const android::sp<AAudioServiceEndpoint>& serviceEndpoint);

    // Use separate locks because opening a Shared endpoint requires opening an Exclusive one.
    // That could cause a recursive lock.
    // Lock mSharedLock before mExclusiveLock.
    // it is OK to only lock mExclusiveLock.
    mutable std::mutex                                     mSharedLock;
    std::vector<android::sp<AAudioServiceEndpointShared>>  mSharedStreams
            GUARDED_BY(mSharedLock);

    mutable std::mutex                                     mExclusiveLock;
    std::vector<android::sp<AAudioServiceEndpointMMAP>>    mExclusiveStreams
            GUARDED_BY(mExclusiveLock);

    // Counts related to an exclusive endpoint.
    int32_t mExclusiveSearchCount GUARDED_BY(mExclusiveLock) = 0; // # SEARCHED
    int32_t mExclusiveFoundCount  GUARDED_BY(mExclusiveLock) = 0; // # FOUND
    int32_t mExclusiveOpenCount   GUARDED_BY(mExclusiveLock) = 0; // # OPENED
    int32_t mExclusiveCloseCount  GUARDED_BY(mExclusiveLock) = 0; // # CLOSED
    int32_t mExclusiveStolenCount GUARDED_BY(mExclusiveLock) = 0; // # STOLEN

    // Same as above but for SHARED endpoints.
    int32_t mSharedSearchCount    GUARDED_BY(mSharedLock) = 0;
    int32_t mSharedFoundCount     GUARDED_BY(mSharedLock) = 0;
    int32_t mSharedOpenCount      GUARDED_BY(mSharedLock) = 0;
    int32_t mSharedCloseCount     GUARDED_BY(mSharedLock) = 0;

    // For easily disabling the stealing of exclusive streams.
    static constexpr bool kStealingEnabled = true;
};
} /* namespace aaudio */

#endif //AAUDIO_AAUDIO_ENDPOINT_MANAGER_H