services/audioflinger/PatchCommandThread.h

/*
**
** Copyright 2022, 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 INCLUDING_FROM_AUDIOFLINGER_H
    #error This header file should only be included from AudioFlinger.h
#endif

class Command;

// Thread to execute create and release patch commands asynchronously. This is needed because
// PatchPanel::createAudioPatch and releaseAudioPatch are executed from audio policy service
// with mutex locked and effect management requires to call back into audio policy service
class PatchCommandThread : public Thread {
public:

    enum {
        CREATE_AUDIO_PATCH,
        RELEASE_AUDIO_PATCH,
    };

    class PatchCommandListener : public virtual RefBase {
    public:
        virtual void onCreateAudioPatch(audio_patch_handle_t handle,
                                        const PatchPanel::Patch& patch) = 0;
        virtual void onReleaseAudioPatch(audio_patch_handle_t handle) = 0;
    };

    PatchCommandThread() : Thread(false /* canCallJava */) {}
    ~PatchCommandThread() override;

    void addListener(const sp<PatchCommandListener>& listener);

    void createAudioPatch(audio_patch_handle_t handle, const PatchPanel::Patch& patch);
    void releaseAudioPatch(audio_patch_handle_t handle);

    // Thread virtuals
    void onFirstRef() override;
    bool threadLoop() override;

    void exit();

    void createAudioPatchCommand(audio_patch_handle_t handle,
            const PatchPanel::Patch& patch);
    void releaseAudioPatchCommand(audio_patch_handle_t handle);

private:
    class CommandData;

    // Command type received from the PatchPanel
    class Command: public RefBase {
    public:
        Command() = default;
        Command(int command, const sp<CommandData>& data)
            : mCommand(command), mData(data) {}

        const int mCommand = -1;
        const sp<CommandData> mData;
    };

    class CommandData: public RefBase {};

    class CreateAudioPatchData : public CommandData {
    public:
        CreateAudioPatchData(audio_patch_handle_t handle, const PatchPanel::Patch& patch)
            :   mHandle(handle), mPatch(patch) {}

        const audio_patch_handle_t mHandle;
        const PatchPanel::Patch mPatch;
    };

    class ReleaseAudioPatchData : public CommandData {
    public:
        ReleaseAudioPatchData(audio_patch_handle_t handle)
            :   mHandle(handle) {}

        audio_patch_handle_t mHandle;
    };

    void sendCommand(const sp<Command>& command);

    std::string mThreadName;
    std::mutex mLock;
    std::condition_variable mWaitWorkCV;
    std::deque<sp<Command>> mCommands GUARDED_BY(mLock); // list of pending commands

    std::mutex mListenerLock;
    std::vector<wp<PatchCommandListener>> mListeners GUARDED_BY(mListenerLock);
};