Introduction of gsl::not_null<T*>()

CMakeLists.txt

@@ -111,6 +111,7 @@ set(BUILD_COLORS "auto" CACHE STRING "Try to use colors auto/always/no")
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")
 include(CMakeDependentOption)
 include(CheckSymbolExists)
+include(CheckIncludeFileCXX)
 include(ExternalProject)
 include(GNUInstallDirs)
 include(DefaultOption)
@@ -2778,6 +2779,18 @@ if(MODPLUG)
   target_link_libraries(mixxx-lib PRIVATE Modplug::Modplug)
 endif()
 
+find_package(Microsoft.GSL CONFIG)
+if(Microsoft.GSL_FOUND)
+  target_link_libraries(mixxx-lib PRIVATE Microsoft.GSL::GSL)
+else()
+  # check if the headers have been installed without cmake config (< 3.1.0)
+  check_include_file_cxx(gsl/gsl HAVE_GSL_GSL)
+  if(NOT HAVE_GSL_GSL)
+    message(FATAL_ERROR "ms-gsl deveopment headers (libmsgsl-dev) not found")
+  endif()
+endif()
+
+
 # QtKeychain
 option(QTKEYCHAIN "Secure credentials storage support for Live Broadcasting profiles" ON)
 if(QTKEYCHAIN)

packaging/debian/control.in

@@ -59,6 +59,7 @@ Build-Depends: debhelper (>= 11),
                libudev-dev,
 # Note: libdjinterop is available within the Mixxx PPA
                libdjinterop-dev,
+               libmsgsl-dev,
 # for running mixxx-test
                xvfb
 Rules-Requires-Root: no

src/engine/controls/cuecontrol.cpp

@@ -70,11 +70,9 @@ inline int hotcueNumberToHotcueIndex(int hotcueNumber) {
     }
 }
 
-void appendCueHint(HintVector* pHintList, const mixxx::audio::FramePos& frame, Hint::Type type) {
-    VERIFY_OR_DEBUG_ASSERT(pHintList) {
-        return;
-    }
-
+void appendCueHint(gsl::not_null<HintVector*> pHintList,
+        const mixxx::audio::FramePos& frame,
+        Hint::Type type) {
     if (frame.isValid()) {
         const Hint cueHint = {
                 /*.frame =*/static_cast<SINT>(frame.toLowerFrameBoundary().value()),
@@ -1178,7 +1176,7 @@ void CueControl::hotcueEndPositionChanged(
     }
 }
 
-void CueControl::hintReader(HintVector* pHintList) {
+void CueControl::hintReader(gsl::not_null<HintVector*> pHintList) {
     appendCueHint(pHintList, m_pCuePoint->get(), Hint::Type::MainCue);
 
     // this is called from the engine thread

src/engine/controls/cuecontrol.h

@@ -194,7 +194,7 @@ class CueControl : public EngineControl {
             UserSettingsPointer pConfig);
     ~CueControl() override;
 
-    void hintReader(HintVector* pHintList) override;
+    void hintReader(gsl::not_null<HintVector*> pHintList) override;
     bool updateIndicatorsAndModifyPlay(bool newPlay, bool oldPlay, bool playPossible);
     void updateIndicators();
     bool isTrackAtIntroCue();

src/engine/controls/enginecontrol.cpp

@@ -36,7 +36,7 @@ void EngineControl::trackBeatsUpdated(mixxx::BeatsPointer pBeats) {
     Q_UNUSED(pBeats);
 }
 
-void EngineControl::hintReader(HintVector*) {
+void EngineControl::hintReader(gsl::not_null<HintVector*>) {
 }
 
 void EngineControl::setEngineMaster(EngineMaster* pEngineMaster) {

src/engine/controls/enginecontrol.h

@@ -4,6 +4,7 @@
 
 #include <QList>
 #include <QObject>
+#include <gsl/pointers>
 
 #include "audio/frame.h"
 #include "control/controlvalue.h"
@@ -53,7 +54,7 @@ class EngineControl : public QObject {
     // hintReader allows the EngineControl to provide hints to the reader to
     // indicate that the given portion of a song is a potential imminent seek
     // target.
-    virtual void hintReader(HintVector* pHintList);
+    virtual void hintReader(gsl::not_null<HintVector*> pHintList);
 
     virtual void setEngineMaster(EngineMaster* pEngineMaster);
     void setEngineBuffer(EngineBuffer* pEngineBuffer);

src/engine/controls/loopingcontrol.cpp

@@ -474,7 +474,7 @@ mixxx::audio::FramePos LoopingControl::nextTrigger(bool reverse,
     return mixxx::audio::kInvalidFramePos;
 }
 
-void LoopingControl::hintReader(HintVector* pHintList) {
+void LoopingControl::hintReader(gsl::not_null<HintVector*> pHintList) {
     LoopInfo loopInfo = m_loopInfo.getValue();
     Hint loop_hint;
     // If the loop is enabled, then this is high priority because we will loop

src/engine/controls/loopingcontrol.h

@@ -41,7 +41,7 @@ class LoopingControl : public EngineControl {
 
     // hintReader will add to hintList hints both the loop in and loop out
     // sample, if set.
-    void hintReader(HintVector* pHintList) override;
+    void hintReader(gsl::not_null<HintVector*> pHintList) override;
     mixxx::audio::FramePos getSyncPositionInsideLoop(
             mixxx::audio::FramePos requestedPlayPosition,
             mixxx::audio::FramePos syncedPlayPosition);

src/engine/readaheadmanager.cpp

@@ -188,7 +188,7 @@ void ReadAheadManager::notifySeek(double seekPosition) {
     // }
 }
 
-void ReadAheadManager::hintReader(double dRate, HintVector* pHintList) {
+void ReadAheadManager::hintReader(double dRate, gsl::not_null<HintVector*> pHintList) {
     bool in_reverse = dRate < 0;
     Hint current_position;
 

src/engine/readaheadmanager.h

@@ -2,6 +2,7 @@
 
 #include <QList>
 #include <QPair>
+#include <gsl/pointers>
 #include <list>
 
 #include "audio/frame.h"
@@ -53,7 +54,7 @@ class ReadAheadManager {
 
     /// hintReader allows the ReadAheadManager to provide hints to the reader to
     /// indicate that the given portion of a song is about to be read.
-    virtual void hintReader(double dRate, HintVector* hintList);
+    virtual void hintReader(double dRate, gsl::not_null<HintVector*> pHintList);
 
     virtual double getFilePlaypositionFromLog(
             double currentFilePlayposition,

tools/debian_buildenv.sh

@@ -60,6 +60,7 @@ case "$1" in
             libmad0-dev \
             libmodplug-dev \
             libmp3lame-dev \
+            libmsgsl-dev \
             libopus-dev \
             libopusfile-dev \
             libportmidi-dev \