From 47be26deedf788f1c769be575397a6d5de6af999 Mon Sep 17 00:00:00 2001
From: Anthony Nicholls <anthony@juce.com>
Date: Mon, 27 Nov 2023 14:08:26 +0000
Subject: [PATCH] Timer: Replace DeletedAtShutdown with SharedResourcePointer

---
 modules/juce_events/timers/juce_Timer.cpp | 99 +++++++++--------------
 modules/juce_events/timers/juce_Timer.h   |  2 +-
 2 files changed, 37 insertions(+), 64 deletions(-)

diff --git a/modules/juce_events/timers/juce_Timer.cpp b/modules/juce_events/timers/juce_Timer.cpp
index 79cec02508..7475fb0857 100644
--- a/modules/juce_events/timers/juce_Timer.cpp
+++ b/modules/juce_events/timers/juce_Timer.cpp
@@ -24,7 +24,6 @@ namespace juce
 {
 
 class Timer::TimerThread final : private Thread,
-                                 private DeletedAtShutdown,
                                  private AsyncUpdater
 {
 public:
@@ -42,10 +41,6 @@ public:
         signalThreadShouldExit();
         callbackArrived.signal();
         stopThread (4000);
-        jassert (instance == this || instance == nullptr);
-
-        if (instance == this)
-            instance = nullptr;
     }
 
     void run() override
@@ -137,54 +132,10 @@ public:
         callTimers();
     }
 
-    static void add (Timer* tim) noexcept
-    {
-        if (instance == nullptr)
-            instance = new TimerThread();
-
-        instance->addTimer (tim);
-    }
-
-    static void remove (Timer* tim) noexcept
-    {
-        if (instance != nullptr)
-            instance->removeTimer (tim);
-    }
-
-    static void resetCounter (Timer* tim) noexcept
-    {
-        if (instance != nullptr)
-            instance->resetTimerCounter (tim);
-    }
-
-    static TimerThread* instance;
-    static LockType lock;
-
-private:
-    struct TimerCountdown
-    {
-        Timer* timer;
-        int countdownMs;
-    };
-
-    std::vector<TimerCountdown> timers;
-
-    WaitableEvent callbackArrived;
-
-    struct CallTimersMessage final : public MessageManager::MessageBase
-    {
-        CallTimersMessage() {}
-
-        void messageCallback() override
-        {
-            if (instance != nullptr)
-                instance->callTimers();
-        }
-    };
-
-    //==============================================================================
     void addTimer (Timer* t)
     {
+        const LockType::ScopedLockType sl (lock);
+
         // Trying to add a timer that's already here - shouldn't get to this point,
         // so if you get this assertion, let me know!
         jassert (std::none_of (timers.begin(), timers.end(),
@@ -200,6 +151,8 @@ private:
 
     void removeTimer (Timer* t)
     {
+        const LockType::ScopedLockType sl (lock);
+
         auto pos = t->positionInQueue;
         auto lastIndex = timers.size() - 1;
 
@@ -217,6 +170,8 @@ private:
 
     void resetTimerCounter (Timer* t) noexcept
     {
+        const LockType::ScopedLockType sl (lock);
+
         auto pos = t->positionInQueue;
 
         jassert (pos < timers.size());
@@ -238,6 +193,31 @@ private:
         }
     }
 
+private:
+    LockType lock;
+
+    struct TimerCountdown
+    {
+        Timer* timer;
+        int countdownMs;
+    };
+
+    std::vector<TimerCountdown> timers;
+
+    WaitableEvent callbackArrived;
+
+    struct CallTimersMessage final : public MessageManager::MessageBase
+    {
+        CallTimersMessage() = default;
+
+        void messageCallback() override
+        {
+            if (auto instance = SharedResourcePointer<TimerThread>::getSharedObjectWithoutCreating())
+                (*instance)->callTimers();
+        }
+    };
+
+    //==============================================================================
     void shuffleTimerBackInQueue (size_t pos)
     {
         auto numTimers = timers.size();
@@ -309,9 +289,6 @@ private:
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TimerThread)
 };
 
-Timer::TimerThread* Timer::TimerThread::instance = nullptr;
-Timer::TimerThread::LockType Timer::TimerThread::lock;
-
 //==============================================================================
 Timer::Timer() noexcept {}
 Timer::Timer (const Timer&) noexcept {}
@@ -335,15 +312,13 @@ void Timer::startTimer (int interval) noexcept
     // running, then you're not going to get any timer callbacks!
     JUCE_ASSERT_MESSAGE_MANAGER_EXISTS
 
-    const TimerThread::LockType::ScopedLockType sl (TimerThread::lock);
-
     bool wasStopped = (timerPeriodMs == 0);
     timerPeriodMs = jmax (1, interval);
 
     if (wasStopped)
-        TimerThread::add (this);
+        timerThread->addTimer (this);
     else
-        TimerThread::resetCounter (this);
+        timerThread->resetTimerCounter (this);
 }
 
 void Timer::startTimerHz (int timerFrequencyHz) noexcept
@@ -356,19 +331,17 @@ void Timer::startTimerHz (int timerFrequencyHz) noexcept
 
 void Timer::stopTimer() noexcept
 {
-    const TimerThread::LockType::ScopedLockType sl (TimerThread::lock);
-
     if (timerPeriodMs > 0)
     {
-        TimerThread::remove (this);
+        timerThread->removeTimer (this);
         timerPeriodMs = 0;
     }
 }
 
 void JUCE_CALLTYPE Timer::callPendingTimersSynchronously()
 {
-    if (TimerThread::instance != nullptr)
-        TimerThread::instance->callTimersSynchronously();
+    if (auto instance = SharedResourcePointer<TimerThread>::getSharedObjectWithoutCreating())
+        (*instance)->callTimersSynchronously();
 }
 
 struct LambdaInvoker final : private Timer
diff --git a/modules/juce_events/timers/juce_Timer.h b/modules/juce_events/timers/juce_Timer.h
index 4d0c1acd07..24761624d9 100644
--- a/modules/juce_events/timers/juce_Timer.h
+++ b/modules/juce_events/timers/juce_Timer.h
@@ -127,9 +127,9 @@ public:
 
 private:
     class TimerThread;
-    friend class TimerThread;
     size_t positionInQueue = (size_t) -1;
     int timerPeriodMs = 0;
+    SharedResourcePointer<TimerThread> timerThread;
 
     Timer& operator= (const Timer&) = delete;
 };