Split interface, make const.

Analyser/Dynamic/MultiMachine/Implementation/MultiMediaTarget.cpp

@@ -7,6 +7,7 @@
 //
 
 #include "MultiMediaTarget.hpp"
+#include <unordered_set>
 
 using namespace Analyser::Dynamic;
 
@@ -27,3 +28,29 @@ bool MultiMediaTarget::insert_media(const Analyser::Static::Media &media) {
 	}
 	return inserted;
 }
+
+MultiMediaChangeObserver::MultiMediaChangeObserver(const std::vector<std::unique_ptr<::Machine::DynamicMachine>> &machines) {
+	for(const auto &machine: machines) {
+		auto media_change_observer = machine->media_change_observer();
+		if(media_change_observer) targets_.push_back(media_change_observer);
+	}
+}
+
+using ChangeEffect = MachineTypes::MediaChangeObserver::ChangeEffect;
+
+ChangeEffect MultiMediaChangeObserver::effect_for_file_did_change(const std::string &name) const {
+	if(targets_.empty()) {
+		return ChangeEffect::None;
+	}
+
+	std::unordered_set<ChangeEffect> effects;
+	for(const auto &target: targets_) {
+		effects.insert(target->effect_for_file_did_change(name));
+	}
+
+	// No agreement => restart.
+	if(effects.size() > 1) {
+		return ChangeEffect::RestartMachine;
+	}
+	return *effects.begin();
+}

Analyser/Dynamic/MultiMachine/Implementation/MultiMediaTarget.hpp

@@ -33,4 +33,15 @@ private:
 	std::vector<MachineTypes::MediaTarget *> targets_;
 };
 
+struct MultiMediaChangeObserver: public MachineTypes::MediaChangeObserver {
+public:
+	MultiMediaChangeObserver(const std::vector<std::unique_ptr<::Machine::DynamicMachine>> &);
+
+	// Below is the standard MediaTarget::Machine interface; see there for documentation.
+	ChangeEffect effect_for_file_did_change(const std::string &) const final;
+
+private:
+	std::vector<MachineTypes::MediaChangeObserver *> targets_;
+};
+
 }

Analyser/Dynamic/MultiMachine/MultiMachine.cpp

@@ -27,7 +27,8 @@ MultiMachine::MultiMachine(std::vector<std::unique_ptr<DynamicMachine>> &&machin
 	audio_producer_(machines_, machines_mutex_),
 	joystick_machine_(machines_),
 	keyboard_machine_(machines_),
-	media_target_(machines_)
+	media_target_(machines_),
+	media_change_observer_(machines_)
 {
 	timed_machine_.set_delegate(this);
 }
@@ -52,6 +53,7 @@ Provider(MachineTypes::AudioProducer, audio_producer, audio_producer_)
 Provider(MachineTypes::JoystickMachine, joystick_machine, joystick_machine_)
 Provider(MachineTypes::KeyboardMachine, keyboard_machine, keyboard_machine_)
 Provider(MachineTypes::MediaTarget, media_target, media_target_)
+Provider(MachineTypes::MediaChangeObserver, media_change_observer, media_change_observer_)
 
 MachineTypes::MouseMachine *MultiMachine::mouse_machine() {
 	// TODO.

Analyser/Dynamic/MultiMachine/MultiMachine.hpp

@@ -58,6 +58,7 @@ public:
 	MachineTypes::KeyboardMachine *keyboard_machine() final;
 	MachineTypes::MouseMachine *mouse_machine() final;
 	MachineTypes::MediaTarget *media_target() final;
+	MachineTypes::MediaChangeObserver *media_change_observer() final;
 	void *raw_pointer() final;
 
 private:
@@ -73,6 +74,7 @@ private:
 	MultiJoystickMachine joystick_machine_;
 	MultiKeyboardMachine keyboard_machine_;
 	MultiMediaTarget media_target_;
+	MultiMediaChangeObserver media_change_observer_;
 
 	void pick_first();
 	bool has_picked_ = false;

Machines/DynamicMachine.hpp

@@ -31,6 +31,7 @@ struct DynamicMachine {
 	virtual MachineTypes::KeyboardMachine *keyboard_machine() = 0;
 	virtual MachineTypes::MouseMachine *mouse_machine() = 0;
 	virtual MachineTypes::MediaTarget *media_target() = 0;
+	virtual MachineTypes::MediaChangeObserver *media_change_observer() = 0;
 
 	/*!
 		Provides a raw pointer to the underlying machine if and only if this dynamic machine really is
@@ -65,6 +66,7 @@ SpecialisedGet(MachineTypes::JoystickMachine, joystick_machine)
 SpecialisedGet(MachineTypes::KeyboardMachine, keyboard_machine)
 SpecialisedGet(MachineTypes::MouseMachine, mouse_machine)
 SpecialisedGet(MachineTypes::MediaTarget, media_target)
+SpecialisedGet(MachineTypes::MediaChangeObserver, media_change_observer)
 
 #undef SpecialisedGet
 

Machines/MediaTarget.hpp

@@ -30,7 +30,9 @@ struct MediaTarget {
 	// inserted, ejected and ignored. That'll allow the owner to know which media is actually
 	// being consumed, so it knows what to monitor (if available on the host system) and hence
 	// if/when to call effect_for_file_did_change.
+};
 
+struct MediaChangeObserver {
 	enum class ChangeEffect {
 		None,
 		ReinsertMedia,
@@ -58,7 +60,7 @@ struct MediaTarget {
 			might be appropriate depending on whether it is more likely that execution will continue correctly
 			with a simple media swap or whether this implies that previous state should be completely discarded.
 	*/
-	virtual ChangeEffect effect_for_file_did_change([[maybe_unused]] const std::string &file_name) {
+	virtual ChangeEffect effect_for_file_did_change([[maybe_unused]] const std::string &file_name) const {
 		return ChangeEffect::None;
 	}
 };

Machines/Sinclair/ZXSpectrum/ZXSpectrum.cpp

@@ -126,6 +126,7 @@ template<Model model> class ConcreteMachine:
 	public MachineTypes::AudioProducer,
 	public MachineTypes::JoystickMachine,
 	public MachineTypes::MappedKeyboardMachine,
+	public MachineTypes::MediaChangeObserver,
 	public MachineTypes::MediaTarget,
 	public MachineTypes::ScanProducer,
 	public MachineTypes::TimedMachine,
@@ -696,7 +697,7 @@ template<Model model> class ConcreteMachine:
 			return !media.tapes.empty() || (!media.disks.empty() && model == Model::Plus3);
 		}
 
-		ChangeEffect effect_for_file_did_change(const std::string &file_name) override {
+		ChangeEffect effect_for_file_did_change(const std::string &file_name) const override {
 			const auto disk = fdc_->disk();
 			return disk && disk->represents(file_name) && disk->has_written() ?
 				ChangeEffect::None : ChangeEffect::RestartMachine;

Machines/Utility/TypedDynamicMachine.hpp

@@ -40,6 +40,7 @@ public:
 	Provide(MachineTypes::KeyboardMachine, keyboard_machine)
 	Provide(MachineTypes::MouseMachine, mouse_machine)
 	Provide(MachineTypes::MediaTarget, media_target)
+	Provide(MachineTypes::MediaChangeObserver, media_change_observer)
 
 #undef Provide
 

OSBindings/Mac/Clock Signal/Machine/CSMachine.mm

@@ -373,12 +373,12 @@ struct ActivityObserver: public Activity::Observer {
 
 - (CSMachineChangeEffect)effectForFileAtURLDidChange:(nonnull NSURL *)url {
 	@synchronized(self) {
-		const auto mediaTarget = _machine->media_target();
-		if(!mediaTarget) {
+		const auto mediaChangeObserver = _machine->media_change_observer();
+		if(!mediaChangeObserver) {
 			return CSMachineChangeEffectNone;
 		}
-		const auto effect = mediaTarget->effect_for_file_did_change([url fileSystemRepresentation]);
-		using ChangeEffect = MachineTypes::MediaTarget::ChangeEffect;
+		const auto effect = mediaChangeObserver->effect_for_file_did_change([url fileSystemRepresentation]);
+		using ChangeEffect = MachineTypes::MediaChangeObserver::ChangeEffect;
 		switch(effect) {
 			case ChangeEffect::None:
 				return CSMachineChangeEffectNone;