Async smiley loading for fast start

This can be a ~1s win on startup time with a HDD, now we load and cache the smileys in the background, blocking only if we try to use them while they are still loading

src/persistence/smileypack.cpp

@@ -33,10 +33,12 @@
 #include <QDomElement>
 #include <QBuffer>
 #include <QStringBuilder>
+#include <QtConcurrent/QtConcurrentRun>
 
 SmileyPack::SmileyPack()
 {
-    load(Settings::getInstance().getSmileyPack());
+    loadingMutex.lock();
+    QtConcurrent::run(this, &SmileyPack::load, Settings::getInstance().getSmileyPack());
     connect(&Settings::getInstance(), &Settings::smileyPackChanged, this, &SmileyPack::onSmileyPackChanged);
 }
 
@@ -101,7 +103,10 @@ bool SmileyPack::load(const QString& filename)
     // open emoticons.xml
     QFile xmlFile(filename);
     if (!xmlFile.open(QIODevice::ReadOnly))
+    {
+        loadingMutex.unlock();
         return false; // cannot open file
+    }
 
     /* parse the cfg file
      * sample:
@@ -151,11 +156,14 @@ bool SmileyPack::load(const QString& filename)
     }
 
     // success!
+    loadingMutex.unlock();
     return true;
 }
 
 QString SmileyPack::smileyfied(QString msg)
 {
+    QMutexLocker locker(&loadingMutex);
+
     QRegExp exp("\\S+"); // matches words
 
     int index = msg.indexOf(exp);
@@ -179,6 +187,7 @@ QString SmileyPack::smileyfied(QString msg)
 
 QList<QStringList> SmileyPack::getEmoticons() const
 {
+    QMutexLocker locker(&loadingMutex);
     return emoticons;
 }
 
@@ -189,6 +198,7 @@ QString SmileyPack::getAsRichText(const QString &key)
 
 QIcon SmileyPack::getAsIcon(const QString &key)
 {
+    QMutexLocker locker(&loadingMutex);
     return getCachedSmiley(key);
 }
 
@@ -217,5 +227,6 @@ QIcon SmileyPack::getCachedSmiley(const QString &key)
 
 void SmileyPack::onSmileyPackChanged()
 {
-    load(Settings::getInstance().getSmileyPack());
+    loadingMutex.lock();
+    QtConcurrent::run(this, &SmileyPack::load, Settings::getInstance().getSmileyPack());
 }

src/persistence/smileypack.h

@@ -25,6 +25,7 @@
 #include <QString>
 #include <QStringList>
 #include <QIcon>
+#include <QMutex>
 
 #define SMILEYPACK_SEARCH_PATHS                                                                                             \
     {                                                                                                                       \
@@ -40,7 +41,6 @@ public:
     static QList<QPair<QString, QString> > listSmileyPacks(const QStringList& paths = SMILEYPACK_SEARCH_PATHS);
     static bool isValid(const QString& filename);
 
-    bool load(const QString& filename);
     QString smileyfied(QString msg);
     QList<QStringList> getEmoticons() const;
     QString getAsRichText(const QString& key);
@@ -54,6 +54,7 @@ private:
     SmileyPack(SmileyPack&) = delete;
     SmileyPack& operator=(const SmileyPack&) = delete;
 
+    bool load(const QString& filename); ///< The caller must lock loadingMutex and should run it in a thread
     void cacheSmiley(const QString& name);
     QIcon getCachedSmiley(const QString& key);
 
@@ -61,6 +62,7 @@ private:
     QHash<QString, QIcon> iconCache; // representation of a smiley ie. "happy.png" -> data
     QList<QStringList> emoticons; // {{ ":)", ":-)" }, {":(", ...}, ... }
     QString path; // directory containing the cfg and image files
+    mutable QMutex loadingMutex;
 };
 
 #endif // SMILEYPACK_H