refactor(core): use STL random implementation insted of Qt

use STL <random> libs to reduce version specific code

Closes #6017

src/core/core.cpp

@@ -33,18 +33,16 @@
 #include "util/strongtype.h"
 
 #include <QCoreApplication>
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
-#include <QRandomGenerator>
-#else
 #include <QDateTime>
-#endif
 #include <QRegularExpression>
 #include <QString>
 #include <QStringBuilder>
 #include <QTimer>
 
 #include <cassert>
+#include <chrono>
 #include <memory>
+#include <random>
 
 const QString Core::TOX_EXT = ".tox";
 
@@ -656,10 +654,6 @@ void Core::onStarted()
 {
     ASSERT_CORE_THREAD;
 
-#if (QT_VERSION < QT_VERSION_CHECK(5, 10, 0))
-    qsrand(static_cast<uint>(QDateTime::currentMSecsSinceEpoch()));
-#endif
-
     // One time initialization stuff
     QString name = getUsername();
     if (!name.isEmpty()) {
@@ -792,11 +786,9 @@ void Core::bootstrapDht()
     }
 
     int i = 0;
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
-    static int j = QRandomGenerator::global()->bounded(listSize);
-#else
-    static int j = static_cast<int>((static_cast<double>(qrand()) / static_cast<double>(RAND_MAX+1l)) * listSize);
-#endif
+    std::mt19937 rng(std::chrono::high_resolution_clock::now().time_since_epoch().count());
+    std::uniform_int_distribution<int> distribution(0, listSize - 1);
+    static int j = distribution(rng);
     // i think the more we bootstrap, the more we jitter because the more we overwrite nodes
     while (i < 2) {
         const DhtServer& dhtServer = bootstrapNodesList[j % listSize];

src/main.cpp

@@ -196,11 +196,6 @@ int main(int argc, char* argv[])
 
     qInstallMessageHandler(logMessageHandler);
 
-    // initialize random number generator
-#if (QT_VERSION < QT_VERSION_CHECK(5, 15, 0))
-    qsrand(time(nullptr));
-#endif
-
     std::unique_ptr<QApplication> a(new QApplication(argc, argv));
 
 #if defined(Q_OS_UNIX)
@@ -224,9 +219,6 @@ int main(int argc, char* argv[])
         qWarning() << "Couldn't load font";
     }
 
-#if (QT_VERSION < QT_VERSION_CHECK(5, 15, 0))
-    qsrand(time(nullptr));
-#endif
     Settings& settings = Settings::getInstance();
     QString locale = settings.getTranslation();
     // We need to init the resources in the translations_library explicitely.

src/widget/form/settings/privacyform.cpp

@@ -23,11 +23,6 @@
 #include <QDebug>
 #include <QFile>
 #include <QMessageBox>
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
-#include <QRandomGenerator>
-#else
-#include <QDateTime>
-#endif
 
 #include "src/core/core.h"
 #include "src/nexus.h"
@@ -41,6 +36,9 @@
 #include "src/widget/translator.h"
 #include "src/widget/widget.h"
 
+#include <chrono>
+#include <random>
+
 PrivacyForm::PrivacyForm(Core* _core)
     : GenericForm(QPixmap(":/img/settings/privacy.png"))
     , bodyUI(new Ui::PrivacySettings)
@@ -106,15 +104,8 @@ void PrivacyForm::on_randomNosapamButton_clicked()
 {
     uint32_t newNospam{0};
 
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
-    // guarantees to give a random 32-bit unsigned integer
-    newNospam = QRandomGenerator::global()->generate();
-#else
-    qsrand(static_cast<uint>(QDateTime::currentMSecsSinceEpoch()));
-    for (int i = 0; i < 4; ++i)
-        // Generate byte by byte, as qrand() is guaranteed to have only 15 bits of randomness (RAND_MAX is guaranteed to be 2^15)
-        newNospam = (newNospam << 8) + (static_cast<int>((static_cast<double>(qrand()) / static_cast<double>(RAND_MAX+1l)) * 256));
-#endif
+    static std::mt19937 rng(std::chrono::high_resolution_clock::now().time_since_epoch().count());
+    newNospam = rng();
 
     core->setNospam(newNospam);
     bodyUI->nospamLineEdit->setText(core->getSelfId().getNoSpamString());