Move MIDI parsing up from ALSA driver to platform independent driver.

Aims for more consistent MIDI support across Windows, MacOS, Linux and
to provide a base for adding MIDI drivers for other platforms.
Reworks the MIDIDriverALSAMidi MIDI parsing implementation as a platform
independent version in MIDIDriver::Parser.
Uses MIDIDriver::Parser to provide running status support in MacOS
MIDIDriverCoreMidi.
Collects connected input names at open, ensuring devices indices reported
in events match names in array returned from get_connected_inputs.

Fixes #77035.
Fixes #79811.

With code review changes by: A Thousand Ships (she/her)
<96648715+AThousandShips@users.noreply.github.com>

2 files changed, 62 insertions, 38 deletions

diff --git a/drivers/coremidi/midi_driver_coremidi.cpp b/drivers/coremidi/midi_driver_coremidi.cpp
index 87fc7612f7..f6cc59471e 100644
--- a/drivers/coremidi/midi_driver_coremidi.cpp
+++ b/drivers/coremidi/midi_driver_coremidi.cpp
@@ -37,16 +37,30 @@
 #import <CoreAudio/HostTime.h>
 #import <CoreServices/CoreServices.h>
 
+Mutex MIDIDriverCoreMidi::mutex;
+bool MIDIDriverCoreMidi::core_midi_closed = false;
+
+MIDIDriverCoreMidi::InputConnection::InputConnection(int p_device_index, MIDIEndpointRef p_source) :
+		parser(p_device_index), source(p_source) {}
+
 void MIDIDriverCoreMidi::read(const MIDIPacketList *packet_list, void *read_proc_ref_con, void *src_conn_ref_con) {
-	MIDIPacket *packet = const_cast<MIDIPacket *>(packet_list->packet);
-	int *device_index = static_cast<int *>(src_conn_ref_con);
-	for (UInt32 i = 0; i < packet_list->numPackets; i++) {
-		receive_input_packet(*device_index, packet->timeStamp, packet->data, packet->length);
-		packet = MIDIPacketNext(packet);
+	MutexLock lock(mutex);
+	if (!core_midi_closed) {
+		InputConnection *source = static_cast<InputConnection *>(src_conn_ref_con);
+		const MIDIPacket *packet = packet_list->packet;
+		for (UInt32 packet_index = 0; packet_index < packet_list->numPackets; packet_index++) {
+			for (UInt16 data_index = 0; data_index < packet->length; data_index++) {
+				source->parser.parse_fragment(packet->data[data_index]);
+			}
+			packet = MIDIPacketNext(packet);
+		}
 	}
 }
 
 Error MIDIDriverCoreMidi::open() {
+	ERR_FAIL_COND_V_MSG(client || core_midi_closed, FAILED,
+			"MIDIDriverCoreMidi cannot be reopened.");
+
 	CFStringRef name = CFStringCreateWithCString(nullptr, "Godot", kCFStringEncodingASCII);
 	OSStatus result = MIDIClientCreate(name, nullptr, nullptr, &client);
 	CFRelease(name);
@@ -61,12 +75,27 @@ Error MIDIDriverCoreMidi::open() {
 		return ERR_CANT_OPEN;
 	}
 
-	int sources = MIDIGetNumberOfSources();
-	for (int i = 0; i < sources; i++) {
+	int source_count = MIDIGetNumberOfSources();
+	int connection_index = 0;
+	for (int i = 0; i < source_count; i++) {
 		MIDIEndpointRef source = MIDIGetSource(i);
 		if (source) {
-			MIDIPortConnectSource(port_in, source, static_cast<void *>(&i));
-			connected_sources.insert(i, source);
+			InputConnection *conn = memnew(InputConnection(connection_index, source));
+			const OSStatus res = MIDIPortConnectSource(port_in, source, static_cast<void *>(conn));
+			if (res != noErr) {
+				memdelete(conn);
+			} else {
+				connected_sources.push_back(conn);
+
+				CFStringRef nameRef = nullptr;
+				char name[256];
+				MIDIObjectGetStringProperty(source, kMIDIPropertyDisplayName, &nameRef);
+				CFStringGetCString(nameRef, name, sizeof(name), kCFStringEncodingUTF8);
+				CFRelease(nameRef);
+				connected_input_names.push_back(name);
+
+				connection_index++; // Contiguous index for successfully connected inputs.
+			}
 		}
 	}
 
@@ -74,11 +103,17 @@ Error MIDIDriverCoreMidi::open() {
 }
 
 void MIDIDriverCoreMidi::close() {
-	for (int i = 0; i < connected_sources.size(); i++) {
-		MIDIEndpointRef source = connected_sources[i];
-		MIDIPortDisconnectSource(port_in, source);
+	mutex.lock();
+	core_midi_closed = true;
+	mutex.unlock();
+
+	for (InputConnection *conn : connected_sources) {
+		MIDIPortDisconnectSource(port_in, conn->source);
+		memdelete(conn);
 	}
+
 	connected_sources.clear();
+	connected_input_names.clear();
 
 	if (port_in != 0) {
 		MIDIPortDispose(port_in);
@@ -91,26 +126,6 @@ void MIDIDriverCoreMidi::close() {
 	}
 }
 
-PackedStringArray MIDIDriverCoreMidi::get_connected_inputs() {
-	PackedStringArray list;
-
-	for (int i = 0; i < connected_sources.size(); i++) {
-		MIDIEndpointRef source = connected_sources[i];
-		CFStringRef ref = nullptr;
-		char name[256];
-
-		MIDIObjectGetStringProperty(source, kMIDIPropertyDisplayName, &ref);
-		CFStringGetCString(ref, name, sizeof(name), kCFStringEncodingUTF8);
-		CFRelease(ref);
-
-		list.push_back(name);
-	}
-
-	return list;
-}
-
-MIDIDriverCoreMidi::MIDIDriverCoreMidi() {}
-
 MIDIDriverCoreMidi::~MIDIDriverCoreMidi() {
 	close();
 }
diff --git a/drivers/coremidi/midi_driver_coremidi.h b/drivers/coremidi/midi_driver_coremidi.h
index 38fb515664..02cbc6234c 100644
--- a/drivers/coremidi/midi_driver_coremidi.h
+++ b/drivers/coremidi/midi_driver_coremidi.h
@@ -34,6 +34,7 @@
 #ifdef COREMIDI_ENABLED
 
 #include "core/os/midi_driver.h"
+#include "core/os/mutex.h"
 #include "core/templates/vector.h"
 
 #import <CoreMIDI/CoreMIDI.h>
@@ -43,17 +44,25 @@ class MIDIDriverCoreMidi : public MIDIDriver {
 	MIDIClientRef client = 0;
 	MIDIPortRef port_in;
 
-	Vector<MIDIEndpointRef> connected_sources;
+	struct InputConnection {
+		InputConnection() = default;
+		InputConnection(int p_device_index, MIDIEndpointRef p_source);
+		Parser parser;
+		MIDIEndpointRef source;
+	};
+
+	Vector<InputConnection *> connected_sources;
+
+	static Mutex mutex;
+	static bool core_midi_closed;
 
 	static void read(const MIDIPacketList *packet_list, void *read_proc_ref_con, void *src_conn_ref_con);
 
 public:
-	virtual Error open();
-	virtual void close();
-
-	PackedStringArray get_connected_inputs();
+	virtual Error open() override;
+	virtual void close() override;
 
-	MIDIDriverCoreMidi();
+	MIDIDriverCoreMidi() = default;
 	virtual ~MIDIDriverCoreMidi();
 };