From 5e6e4615264214cf86cd74d63938c503fd36b74d Mon Sep 17 00:00:00 2001
From: Chris Xiong <chirs241097@gmail.com>
Date: Fri, 25 Dec 2020 01:09:18 +0800
Subject: Proper event-based playback interruption.

Also fixed random pauses after seeking.
This should address everything left over by 64fd118e.
---
 core/qmpmidiplay.cpp                  | 27 +++++++++++++++++----------
 core/qmpmidiplay.hpp                  |  5 +++++
 visualization/renderer/CMakeLists.txt |  1 +
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/core/qmpmidiplay.cpp b/core/qmpmidiplay.cpp
index aeb39be..7e35b95 100644
--- a/core/qmpmidiplay.cpp
+++ b/core/qmpmidiplay.cpp
@@ -242,21 +242,21 @@ void CMidiPlayer::playEvents()
             double correction = (getTick() - ttick) * dpt - (b - ttime).count();
             if (correction > 0)
                 correction = 0;
-            if (ns_sleep + correction > 2e8)
+            if (ns_sleep + correction > 2.5e8)
             {
                 high_resolution_clock::time_point t = high_resolution_clock::now();
                 uint64_t tts = uint64_t(ns_sleep + correction);
-                while (tts > 2e8 && !tcstop && midiReaders)
+                std::unique_lock<std::mutex> lock(intmtx);
+                std::cv_status intr = intcv.wait_for(lock, std::chrono::nanoseconds(uint64_t(ns_sleep + correction - 5e7)));
+                if (intr == std::cv_status::no_timeout)
                 {
-#ifdef _WIN32
-                    w32usleep(2e5);
-#else
-                    std::this_thread::sleep_for(std::chrono::nanoseconds(uint64_t(2e8)));
-#endif
-                    tts -= uint64_t((high_resolution_clock::now() - t).count());
-                    t = high_resolution_clock::now();
+                    if (tcstop)
+                    {
+                        break;
+                    }
                 }
-                if (tts > 0 && !tcstop && midiReaders)
+                tts -= uint64_t((high_resolution_clock::now() - t).count());
+                if (tts > 0 && intr == std::cv_status::timeout && !tcstop && midiReaders)
                 {
 #ifdef _WIN32
                     w32usleep(tts / 1000);
@@ -442,6 +442,7 @@ void CMidiPlayer::playerDeinit()
 {
     tceptr = 0;
     tcstop = true;
+    interrupt();
     tcpaused = 0;
     delete midiFile;
     midiFile = nullptr;
@@ -470,6 +471,7 @@ void CMidiPlayer::setTCeptr(uint32_t ep, uint32_t st)
     if (ep == ecnt)
         tcstop = true;
     else tceptr = ep;
+    this->interrupt();
     for (int i = 0; i < 16; ++i)
     {
         qmpMidiOutDevice *dest = mididev[mappedoutput[i]].dev;
@@ -560,6 +562,11 @@ void CMidiPlayer::setTCpaused(uint32_t ps)
 {
     tcpaused = ps;
 }
+
+void CMidiPlayer::interrupt()
+{
+    intcv.notify_one();
+}
 uint32_t CMidiPlayer::isFinished()
 {
     return finished;
diff --git a/core/qmpmidiplay.hpp b/core/qmpmidiplay.hpp
index b6a40d9..a4245ae 100644
--- a/core/qmpmidiplay.hpp
+++ b/core/qmpmidiplay.hpp
@@ -3,7 +3,9 @@
 #define QMPMIDIPLAY_H
 #include <cstring>
 #include <cstdlib>
+#include <condition_variable>
 #include <chrono>
+#include <mutex>
 #include <unordered_map>
 #include <tuple>
 #include <utility>
@@ -70,6 +72,8 @@ private:
     //raw tempo, timesig num., timesig den., division, keysig
     //thread control
     uint32_t tceptr, tcpaused, ct;
+    std::mutex intmtx;
+    std::condition_variable intcv;
     bool tcstop;
     uint32_t finished, resumed;
     uint32_t pbr[16], pbv[16];
@@ -121,6 +125,7 @@ public:
     void setTCeptr(uint32_t ep, uint32_t st);
     uint32_t getTCpaused();
     void setTCpaused(uint32_t ps);
+    void interrupt();
     uint32_t isFinished();
     bool stopFlag();
     void setResumed();
diff --git a/visualization/renderer/CMakeLists.txt b/visualization/renderer/CMakeLists.txt
index bbd3daf..106d453 100644
--- a/visualization/renderer/CMakeLists.txt
+++ b/visualization/renderer/CMakeLists.txt
@@ -21,6 +21,7 @@ target_link_libraries(qmpvisrender
     Qt5::Core
     qmpcore
     ${CMAKE_DL_LIBS}
+    ${CMAKE_THREAD_LIBS_INIT}
 )
 
 if(WIN32)
-- 
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