Codechange: Pass std::string_view from drivers instead of char *.

src/music/allegro_m.cpp

@@ -26,7 +26,7 @@ static MIDI *_midi = nullptr;
  */
 extern int _allegro_instance_count;
 
-const char *MusicDriver_Allegro::Start(const StringList &)
+std::optional<std::string_view> MusicDriver_Allegro::Start(const StringList &)
 {
 	if (_allegro_instance_count == 0 && install_allegro(SYSTEM_AUTODETECT, &errno, nullptr)) {
 		Debug(driver, 0, "allegro: install_allegro failed '{}'", allegro_error);
@@ -46,7 +46,7 @@ const char *MusicDriver_Allegro::Start(const StringList &)
 		return "No sound card found";
 	}
 
-	return nullptr;
+	return std::nullopt;
 }
 
 void MusicDriver_Allegro::Stop()

src/music/allegro_m.h

@@ -15,7 +15,7 @@
 /** Allegro's music player. */
 class MusicDriver_Allegro : public MusicDriver {
 public:
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -26,7 +26,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "allegro"; }
+	std::string_view GetName() const override { return "allegro"; }
 };
 
 /** Factory for allegro's music player. */

src/music/bemidi.cpp

@@ -18,9 +18,9 @@
 /** Factory for BeOS' midi player. */
 static FMusicDriver_BeMidi iFMusicDriver_BeMidi;
 
-const char *MusicDriver_BeMidi::Start(const StringList &parm)
+std::optional<std::string_view> MusicDriver_BeMidi::Start(const StringList &parm)
 {
-	return nullptr;
+	return std::nullopt;
 }
 
 void MusicDriver_BeMidi::Stop()

src/music/bemidi.h

@@ -18,7 +18,7 @@
 /** The midi player for BeOS. */
 class MusicDriver_BeMidi : public MusicDriver {
 public:
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -29,7 +29,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "bemidi"; }
+	std::string_view GetName() const override { return "bemidi"; }
 
 private:
 	BMidiSynthFile *midi_synth_file = nullptr;

src/music/cocoa_m.cpp

@@ -79,11 +79,11 @@ static void DoSetVolume()
 /**
  * Initialized the MIDI player, including QuickTime initialization.
  */
-const char *MusicDriver_Cocoa::Start(const StringList &)
+std::optional<std::string_view> MusicDriver_Cocoa::Start(const StringList &)
 {
 	if (NewMusicPlayer(&_player) != noErr) return "failed to create music player";
 
-	return nullptr;
+	return std::nullopt;
 }
 
 

src/music/cocoa_m.h

@@ -14,7 +14,7 @@
 
 class MusicDriver_Cocoa : public MusicDriver {
 public:
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -25,7 +25,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "cocoa"; }
+	std::string_view GetName() const override { return "cocoa"; }
 };
 
 class FMusicDriver_Cocoa : public DriverFactoryBase {

src/music/dmusic.cpp

@@ -1072,7 +1072,7 @@ static const char *LoadDefaultDLSFile(const char *user_dls)
 }
 
 
-const char *MusicDriver_DMusic::Start(const StringList &parm)
+std::optional<std::string_view> MusicDriver_DMusic::Start(const StringList &parm)
 {
 	/* Initialize COM */
 	if (FAILED(CoInitializeEx(nullptr, COINIT_MULTITHREADED))) return "COM initialization failed";
@@ -1153,7 +1153,7 @@ const char *MusicDriver_DMusic::Start(const StringList &parm)
 
 	if (!StartNewThread(&_dmusic_thread, "ottd:dmusic", &MidiThreadProc)) return "Can't create MIDI output thread";
 
-	return nullptr;
+	return std::nullopt;
 }
 
 

src/music/dmusic.h

@@ -17,7 +17,7 @@ class MusicDriver_DMusic : public MusicDriver {
 public:
 	virtual ~MusicDriver_DMusic();
 
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -28,7 +28,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "dmusic"; }
+	std::string_view GetName() const override { return "dmusic"; }
 };
 
 /** Factory for the DirectX music player. */

src/music/extmidi.cpp

@@ -35,10 +35,10 @@
 /** Factory for the midi player that uses external players. */
 static FMusicDriver_ExtMidi iFMusicDriver_ExtMidi;
 
-const char *MusicDriver_ExtMidi::Start(const StringList &parm)
+std::optional<std::string_view> MusicDriver_ExtMidi::Start(const StringList &parm)
 {
-	if (strcmp(VideoDriver::GetInstance()->GetName(), "allegro") == 0 ||
-			strcmp(SoundDriver::GetInstance()->GetName(), "allegro") == 0) {
+	if (VideoDriver::GetInstance()->GetName() == "allegro" ||
+			SoundDriver::GetInstance()->GetName() == "allegro") {
 		return "the extmidi driver does not work when Allegro is loaded.";
 	}
 
@@ -62,7 +62,7 @@ const char *MusicDriver_ExtMidi::Start(const StringList &parm)
 
 	this->song.clear();
 	this->pid = -1;
-	return nullptr;
+	return std::nullopt;
 }
 
 void MusicDriver_ExtMidi::Stop()

src/music/extmidi.h

@@ -22,7 +22,7 @@ private:
 	void DoStop();
 
 public:
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -33,7 +33,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "extmidi"; }
+	std::string_view GetName() const override { return "extmidi"; }
 };
 
 class FMusicDriver_ExtMidi : public DriverFactoryBase {

src/music/fluidsynth.cpp

@@ -58,7 +58,7 @@ static void RenderMusicStream(int16_t *buffer, size_t samples)
 	fluid_synth_write_s16(_midi.synth, samples, buffer, 0, 2, buffer, 1, 2);
 }
 
-const char *MusicDriver_FluidSynth::Start(const StringList &param)
+std::optional<std::string_view> MusicDriver_FluidSynth::Start(const StringList &param)
 {
 	std::lock_guard<std::mutex> lock{ _midi.synth_mutex };
 
@@ -110,7 +110,7 @@ const char *MusicDriver_FluidSynth::Start(const StringList &param)
 
 	_midi.player = nullptr;
 
-	return nullptr;
+	return std::nullopt;
 }
 
 void MusicDriver_FluidSynth::Stop()

src/music/fluidsynth.h

@@ -15,7 +15,7 @@
 /** Music driver making use of FluidSynth. */
 class MusicDriver_FluidSynth : public MusicDriver {
 public:
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -26,7 +26,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "fluidsynth"; }
+	std::string_view GetName() const override { return "fluidsynth"; }
 };
 
 /** Factory for the fluidsynth driver. */

src/music/null_m.h

@@ -15,7 +15,7 @@
 /** The music player that does nothing. */
 class MusicDriver_Null : public MusicDriver {
 public:
-	const char *Start(const StringList &) override { return nullptr; }
+	std::optional<std::string_view> Start(const StringList &) override { return std::nullopt; }
 
 	void Stop() override { }
 
@@ -26,7 +26,7 @@ public:
 	bool IsSongPlaying() override { return true; }
 
 	void SetVolume(uint8_t) override { }
-	const char *GetName() const override { return "null"; }
+	std::string_view GetName() const override { return "null"; }
 };
 
 /** Factory for the null music player. */

src/music/win32_m.cpp

@@ -367,7 +367,7 @@ void MusicDriver_Win32::SetVolume(uint8_t vol)
 	_midi.new_volume = vol;
 }
 
-const char *MusicDriver_Win32::Start(const StringList &parm)
+std::optional<std::string_view> MusicDriver_Win32::Start(const StringList &parm)
 {
 	Debug(driver, 2, "Win32-MIDI: Start: initializing");
 
@@ -416,7 +416,7 @@ const char *MusicDriver_Win32::Start(const StringList &parm)
 		if (timeBeginPeriod(_midi.time_period) == MMSYSERR_NOERROR) {
 			/* success */
 			Debug(driver, 2, "Win32-MIDI: Start: timer resolution is {}", _midi.time_period);
-			return nullptr;
+			return std::nullopt;
 		}
 	}
 	midiOutClose(_midi.midi_out);

src/music/win32_m.h

@@ -15,7 +15,7 @@
 /** The Windows music player. */
 class MusicDriver_Win32 : public MusicDriver {
 public:
-	const char *Start(const StringList &param) override;
+	std::optional<std::string_view> Start(const StringList &param) override;
 
 	void Stop() override;
 
@@ -26,7 +26,7 @@ public:
 	bool IsSongPlaying() override;
 
 	void SetVolume(uint8_t vol) override;
-	const char *GetName() const override { return "win32"; }
+	std::string_view GetName() const override { return "win32"; }
 };
 
 /** Factory for Windows' music player. */