Added a garbage collection to the file pool. Apparently something in the kernel or in libsndfile is memory-mapping the files, so that the memory usage stays quite high and there are no disk read. But since ASan does not complain, it seems okay...

sfizz/FilePool.cpp

@@ -28,7 +28,9 @@
 #include "absl/types/span.h"
 #include <chrono>
 #include <memory>
+#include <mutex>
 #include <sndfile.hh>
+#include <thread>
 using namespace std::chrono_literals;
 
 template <class T>
@@ -42,7 +44,7 @@ std::unique_ptr<AudioBuffer<T>> readFromFile(SndfileHandle& sndFile, int numFram
         sndFile.readf(tempReadBuffer->channelWriter(0), numFrames);
         ::readInterleaved<float>(tempReadBuffer->getSpan(0), returnedBuffer->getSpan(0), returnedBuffer->getSpan(1));
     }
-    return returnedBuffer;
+    return std::move(returnedBuffer);
 }
 
 std::optional<sfz::FilePool::FileInformation> sfz::FilePool::getFileInformation(std::string_view filename, uint32_t offset) noexcept
@@ -79,11 +81,20 @@ std::optional<sfz::FilePool::FileInformation> sfz::FilePool::getFileInformation(
     if (preloadedData.contains(filename)) {
         auto alreadyPreloaded = preloadedData[filename];
         if (preloadedSize > alreadyPreloaded->getNumFrames()) {
+            // FIXME: Okay, ideally here you would have a double indirection so that we can update _all_ the preloaded
+            // files in previous regions to account for the new offset
+            //
+            // Before this next command, some old regions and the file pool hold a shared pointer to the same audio buffer.
+            // This audio buffer is OK for the old regions, but too small for the new one.
+            // By resetting the filepool data to a new, longer audiobuffer, we are creating 2 copies of the same audio data.
+            // The filepool and the new regions have the longer copy, and the older regions have the shorter copy.
+            // This is not entirely optimal, but is it better to write a double shared pointer ?
+            // std::shared_ptr<std::shared_ptr<AudioBuffer>>> is a bit ugly...
             alreadyPreloaded.reset(readFromFile<float>(sndFile, preloadedSize).release());
         }
         returnedValue.preloadedData = alreadyPreloaded;
     } else {
-        returnedValue.preloadedData = std::shared_ptr<AudioBuffer<float>>(readFromFile<float>(sndFile, preloadedSize));
+        returnedValue.preloadedData = readFromFile<float>(sndFile, preloadedSize);
         preloadedData[filename] = returnedValue.preloadedData;
     }
 
@@ -99,10 +110,11 @@ void sfz::FilePool::enqueueLoading(Voice* voice, std::string_view sample, int nu
 
 void sfz::FilePool::loadingThread() noexcept
 {
-    FileLoadingInformation fileToLoad {};
     while (!quitThread) {
-        if (!loadingQueue.wait_dequeue_timed(fileToLoad, 10ms))
+        FileLoadingInformation fileToLoad {};
+        if (!loadingQueue.wait_dequeue_timed(fileToLoad, 200ms)) {
             continue;
+        }
 
         if (fileToLoad.voice == nullptr) {
             DBG("Background thread error: voice is null.");
@@ -117,15 +129,34 @@ void sfz::FilePool::loadingThread() noexcept
         }
 
         SndfileHandle sndFile(reinterpret_cast<const char*>(file.c_str()));
-        auto fileLoaded = std::make_unique<AudioBuffer<float>>(sndFile.channels(), fileToLoad.numFrames);
-        fileToLoad.voice->setFileData(readFromFile<float>(sndFile, fileToLoad.numFrames), fileToLoad.ticket);
+        
+        std::lock_guard guard { fileHandleMutex };
+        auto newHandle = fileHandles.emplace_back(readFromFile<float>(sndFile, fileToLoad.numFrames));
+        fileToLoad.voice->setFileData(newHandle, fileToLoad.ticket);
+    }
+}
+
+void sfz::FilePool::garbageThread() noexcept
+{
+    while (!quitThread) {
+        for (auto handle = fileHandles.begin(); handle < fileHandles.end();) {
+            if (handle->use_count() == 1) {
+                handle->reset();
+                std::lock_guard guard { fileHandleMutex };
+                std::iter_swap(handle, fileHandles.end() - 1);
+                fileHandles.pop_back();
+            } else {
+                handle++;
+            }
+        }
+        std::this_thread::sleep_for(200ms);
     }
 }
 
 void sfz::FilePool::clear()
 {
     preloadedData.clear();
-    while(loadingQueue.pop()){
+    while (loadingQueue.pop()) {
         // Pop the queue
     }
 }

sfizz/FilePool.h

@@ -30,6 +30,7 @@
 #include "filesystem.h"
 #include "readerwriterqueue.h"
 #include <absl/container/flat_hash_map.h>
+#include <mutex>
 #include <optional>
 #include <string_view>
 #include <thread>
@@ -39,6 +40,7 @@ class FilePool {
 public:
     FilePool()
         : fileLoadingThread(std::thread(&FilePool::loadingThread, this))
+        , garbageCollectionThread(std::thread(&FilePool::garbageThread, this))
     {
     }
 
@@ -46,6 +48,7 @@ public:
     {
         quitThread = true;
         fileLoadingThread.join();
+        garbageCollectionThread.join();
     }
     void setRootDirectory(const std::filesystem::path& directory) noexcept { rootDirectory = directory; }
     size_t getNumPreloadedSamples() const noexcept { return preloadedData.size(); }
@@ -71,7 +74,11 @@ private:
 
     moodycamel::BlockingReaderWriterQueue<FileLoadingInformation> loadingQueue { config::numVoices };
     void loadingThread() noexcept;
+    void garbageThread() noexcept;
     std::thread fileLoadingThread;
+    std::thread garbageCollectionThread;
+    std::vector<std::shared_ptr<AudioBuffer<float>>> fileHandles;
+    std::mutex fileHandleMutex;
     bool quitThread { false };
     absl::flat_hash_map<std::string_view, std::shared_ptr<AudioBuffer<float>>> preloadedData;
     LEAK_DETECTOR(FilePool);

sfizz/Voice.cpp

@@ -29,6 +29,7 @@
 #include "SIMDHelpers.h"
 #include "SfzHelpers.h"
 #include "absl/algorithm/container.h"
+#include <memory>
 
 sfz::Voice::Voice(const CCValueArray& ccState)
     : ccState(ccState)
@@ -117,7 +118,7 @@ void sfz::Voice::prepareEGEnvelope(int delay, uint8_t velocity) noexcept
         normalizePercents(region->amplitudeEG.getStart(ccState, velocity)));
 }
 
-void sfz::Voice::setFileData(std::unique_ptr<AudioBuffer<float>> file, unsigned ticket) noexcept
+void sfz::Voice::setFileData(std::shared_ptr<AudioBuffer<float>> file, unsigned ticket) noexcept
 {
     if (ticket != this->ticket)
         return;
@@ -473,13 +474,14 @@ sfz::Voice::TriggerType sfz::Voice::getTriggerType() const noexcept
 void sfz::Voice::reset() noexcept
 {
     dataReady.store(false);
+    fileData.reset();
     state = State::idle;
     if (region != nullptr) {
         DBG("Reset voice with sample " << region->sample);
     }
+    region = nullptr;
     sourcePosition = 0;
     floatPositionOffset = 0.0f;
-    region = nullptr;
     noteIsOff = false;
 }
 

sfizz/Voice.h

@@ -32,6 +32,7 @@
 #include "LeakDetector.h"
 #include <absl/types/span.h>
 #include <atomic>
+#include <memory>
 
 namespace sfz {
 class Voice {
@@ -49,7 +50,7 @@ public:
     void startVoice(Region* region, int delay, int channel, int number, uint8_t value, TriggerType triggerType) noexcept;
 
     void expectFileData(unsigned ticket);
-    void setFileData(std::unique_ptr<AudioBuffer<float>> file, unsigned ticket) noexcept;
+    void setFileData(std::shared_ptr<AudioBuffer<float>> file, unsigned ticket) noexcept;
     void registerNoteOff(int delay, int channel, int noteNumber, uint8_t velocity) noexcept;
     void registerCC(int delay, int channel, int ccNumber, uint8_t ccValue) noexcept;
     void registerPitchWheel(int delay, int channel, int pitch) noexcept;
@@ -108,7 +109,7 @@ private:
     int initialDelay { 0 };
 
     std::atomic<bool> dataReady { false };
-    std::unique_ptr<AudioBuffer<float>> fileData { nullptr };
+    std::shared_ptr<AudioBuffer<float>> fileData { nullptr };
     unsigned ticket { 0 };
 
     Buffer<float> tempBuffer1;