juce_Thread.h

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 /*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
class JUCE_API  Thread
{
public:
    //==============================================================================
    static constexpr size_t osDefaultStackSize { 0 };
 
    //==============================================================================
    enum class Priority
    {
        highest     = 2,
 
        high        = 1,
 
        normal      = 0,
 
        low         = -1,
 
        background  = -2
    };
 
    //==============================================================================
    struct RealtimeOptions
    {
        [[nodiscard]] RealtimeOptions withPriority (int newPriority) const
        {
            jassert (isPositiveAndNotGreaterThan (newPriority, 10));
            return withMember (*this, &RealtimeOptions::priority, juce::jlimit (0, 10, newPriority));
        }
 
        [[nodiscard]] RealtimeOptions withProcessingTimeMs (double newProcessingTimeMs) const
        {
            jassert (newProcessingTimeMs > 0.0);
            return withMember (*this, &RealtimeOptions::processingTimeMs, newProcessingTimeMs);
        }
 
        [[nodiscard]] RealtimeOptions withMaximumProcessingTimeMs (double newMaximumProcessingTimeMs) const
        {
            jassert (newMaximumProcessingTimeMs > 0.0);
            return withMember (*this, &RealtimeOptions::maximumProcessingTimeMs, newMaximumProcessingTimeMs);
        }
 
        [[nodiscard]] RealtimeOptions withApproximateAudioProcessingTime (int samplesPerFrame, double sampleRate) const
        {
            jassert (samplesPerFrame > 0);
            jassert (sampleRate > 0.0);
 
            const auto approxFrameTimeMs = (samplesPerFrame / sampleRate) * 1000.0;
            return withMaximumProcessingTimeMs (approxFrameTimeMs);
        }
 
        [[nodiscard]] RealtimeOptions withPeriodMs (double newPeriodMs) const
        {
            jassert (newPeriodMs > 0.0);
            return withMember (*this, &RealtimeOptions::periodMs, newPeriodMs);
        }
 
        [[nodiscard]] RealtimeOptions withPeriodHz (double newPeriodHz) const
        {
            jassert (newPeriodHz > 0.0);
            return withPeriodMs (1'000.0 / newPeriodHz);
        }
 
        [[nodiscard]] int getPriority() const
        {
            return priority;
        }
 
        [[nodiscard]] std::optional<double> getProcessingTimeMs() const
        {
            return processingTimeMs;
        }
 
        [[nodiscard]] std::optional<double> getMaximumProcessingTimeMs() const
        {
            return maximumProcessingTimeMs;
        }
 
        [[nodiscard]] std::optional<double> getPeriodMs() const
        {
            return periodMs;
        }
 
    private:
        int priority { 5 };
        std::optional<double> processingTimeMs;
        std::optional<double> maximumProcessingTimeMs;
        std::optional<double> periodMs{};
    };
 
    //==============================================================================
    explicit Thread (const String& threadName, size_t threadStackSize = osDefaultStackSize);
 
    virtual ~Thread();
 
    //==============================================================================
    virtual void run() = 0;
 
    //==============================================================================
    bool startThread();
 
    bool startThread (Priority newPriority);
 
    bool startRealtimeThread (const RealtimeOptions& options);
 
    bool stopThread (int timeOutMilliseconds);
 
    //==============================================================================
    static bool launch (std::function<void()> functionToRun);
 
    //==============================================================================
    static bool launch (Priority priority, std::function<void()> functionToRun);
 
    //==============================================================================
    bool isThreadRunning() const;
 
    void signalThreadShouldExit();
 
    bool threadShouldExit() const;
 
    static bool currentThreadShouldExit();
 
    bool waitForThreadToExit (int timeOutMilliseconds) const;
 
    //==============================================================================
    class JUCE_API Listener
    {
    public:
        virtual ~Listener() = default;
 
        virtual void exitSignalSent() = 0;
    };
 
    void addListener (Listener*);
 
    void removeListener (Listener*);
 
    bool isRealtime() const;
 
    //==============================================================================
    void setAffinityMask (uint32 affinityMask);
 
    static void JUCE_CALLTYPE setCurrentThreadAffinityMask (uint32 affinityMask);
 
    //==============================================================================
    static void JUCE_CALLTYPE sleep (int milliseconds);
 
    static void JUCE_CALLTYPE yield();
 
    //==============================================================================
    bool wait (double timeOutMilliseconds) const;
 
    void notify() const;
 
    //==============================================================================
    using ThreadID = void*;
 
    static ThreadID JUCE_CALLTYPE getCurrentThreadId();
 
    static Thread* JUCE_CALLTYPE getCurrentThread();
 
    ThreadID getThreadId() const noexcept;
 
    const String& getThreadName() const noexcept                    { return threadName; }
 
    static void JUCE_CALLTYPE setCurrentThreadName (const String& newThreadName);
 
   #if JUCE_ANDROID || DOXYGEN
    //==============================================================================
    static void initialiseJUCE (void* jniEnv, void* jContext);
   #endif
 
protected:
    //==============================================================================
    Priority getPriority() const;
 
    bool setPriority (Priority newPriority);
 
private:
    //==============================================================================
    const String threadName;
    std::atomic<void*> threadHandle { nullptr };
    std::atomic<ThreadID> threadId { nullptr };
    std::optional<RealtimeOptions> realtimeOptions = {};
    CriticalSection startStopLock;
    WaitableEvent startSuspensionEvent, defaultEvent;
    size_t threadStackSize;
    uint32 affinityMask = 0;
    bool deleteOnThreadEnd = false;
    std::atomic<bool> shouldExit { false };
    ListenerList<Listener, Array<Listener*, CriticalSection>> listeners;
 
   #if JUCE_ANDROID || JUCE_LINUX || JUCE_BSD
    std::atomic<Priority> priority;
   #endif
 
   #ifndef DOXYGEN
    friend void JUCE_API juce_threadEntryPoint (void*);
   #endif
 
    bool startThreadInternal (Priority);
    bool createNativeThread (Priority);
    void closeThreadHandle();
    void killThread();
    void threadEntryPoint();
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Thread)
};
 
} // namespace juce