Fixed lag in notifications by added a byte stream cache

NotificationAudio.cpp

@@ -14,7 +14,13 @@ NotificationAudio::NotificationAudio(QObject *parent):
 }
 
 NotificationAudio::~NotificationAudio(){
+    // stop the audio
     stop();
+
+    // clean cache
+    foreach(auto pair, m_cache){
+        delete pair.second;
+    }
 }
 
 void NotificationAudio::status(QString message){
@@ -36,20 +42,49 @@ void NotificationAudio::setDevice(const QAudioDeviceInfo &device, unsigned chann
 }
 
 void NotificationAudio::play(const QString &filePath){
+    if(m_cache.contains(filePath)){
+        auto pair = m_cache.value(filePath);
+        auto format = pair.first;
+        auto bytes = pair.second;
+
+        qDebug() << "notification: playing" << filePath << "with format" << format << "from cache";
+        playBytes(format, bytes);
+        return;
+    }
+
     if(m_file->isOpen()){
         m_file->close();
     }
     m_file->setFileName(filePath);
     if(m_file->open(BWFFile::ReadOnly)){
-        auto format = m_file->format();
-        auto channels = format.channelCount();
-        auto bytes = m_file->readAll();
-        auto buffer = new QBuffer(new QByteArray(bytes));
-        if(buffer->open(QIODevice::ReadOnly)){
-            m_stream->setDeviceFormat(m_device, format, channels, m_msBuffer);
-            m_stream->restart(buffer);
+        QAudioFormat format = m_file->format();
+        QByteArray *bytes = new QByteArray(m_file->readAll());
+
+        qDebug() << "notification: playing" << filePath << "with format" << format << "from disk";
+        playBytes(format, bytes);
+
+        // cache the buffer
+        m_cache.insert(filePath, {format, bytes});
     }
+}
+
+void NotificationAudio::playBytes(const QAudioFormat &format, QByteArray *bytes){
+    if(bytes == nullptr){
+        return;
     }
+
+    if(m_buffer.isOpen()){
+        m_buffer.close();
+    }
+
+    m_buffer.setBuffer(bytes);
+
+    if(!m_buffer.open(QIODevice::ReadOnly)){
+        return;
+    }
+
+    m_stream->setDeviceFormat(m_device, format, format.channelCount(), m_msBuffer);
+    m_stream->restart(&m_buffer);
 }
 
 void NotificationAudio::stop(){

NotificationAudio.h

@@ -7,7 +7,11 @@
 #include <QAudioFormat>
 #include <QAudioOutput>
 #include <QFile>
+#include <QPair>
 #include <QPointer>
+#include <QByteArray>
+#include <QCache>
+#include <QScopedPointer>
 
 #include "AudioDevice.hpp"
 #include "AudioDecoder.h"
@@ -32,10 +36,15 @@ public slots:
     void stop();
 
 private:
+    void playBytes(const QAudioFormat &format, QByteArray *bytes);
+
+private:
+    QMap<QString, QPair<QAudioFormat, QByteArray*>> m_cache;
     QPointer<SoundOutput> m_stream;
     QPointer<AudioDecoder> m_decoder;
     QPointer<BWFFile> m_file;
     QAudioDeviceInfo m_device;
+    QBuffer m_buffer;
     unsigned m_channels;
     unsigned m_msBuffer;
 };