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

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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>
This commit is contained in:
Ibrahn Sahir
2024-04-10 10:50:28 +01:00
parent 6b281c0c07
commit 607c5ec49f
8 changed files with 335 additions and 319 deletions
Download Patch File Download Diff File Expand all files Collapse all files

177
drivers/alsamidi/midi_driver_alsamidi.cpp
View File

@ -37,137 +37,36 @@
#include <errno.h>
MIDIDriverALSAMidi::MessageCategory MIDIDriverALSAMidi::msg_category(uint8_t msg_part) {
if (msg_part >= 0xf8) {
return MessageCategory::RealTime;
} else if (msg_part >= 0xf0) {
// System Exclusive begin/end are specified as System Common Category messages,
// but we separate them here and give them their own categories as their
// behavior is significantly different.
if (msg_part == 0xf0) {
return MessageCategory::SysExBegin;
} else if (msg_part == 0xf7) {
return MessageCategory::SysExEnd;
}
return MessageCategory::SystemCommon;
} else if (msg_part >= 0x80) {
return MessageCategory::Voice;
}
return MessageCategory::Data;
}
MIDIDriverALSAMidi::InputConnection::InputConnection(int p_device_index,
snd_rawmidi_t *p_rawmidi) :
parser(p_device_index), rawmidi_ptr(p_rawmidi) {}
size_t MIDIDriverALSAMidi::msg_expected_data(uint8_t status_byte) {
if (msg_category(status_byte) == MessageCategory::Voice) {
// Voice messages have a channel number in the status byte, mask it out.
status_byte &= 0xf0;
}
switch (status_byte) {
case 0x80: // Note Off
case 0x90: // Note On
case 0xA0: // Polyphonic Key Pressure (Aftertouch)
case 0xB0: // Control Change (CC)
case 0xE0: // Pitch Bend Change
case 0xF2: // Song Position Pointer
return 2;
case 0xC0: // Program Change
case 0xD0: // Channel Pressure (Aftertouch)
case 0xF1: // MIDI Time Code Quarter Frame
case 0xF3: // Song Select
return 1;
}
return 0;
}
void MIDIDriverALSAMidi::InputConnection::parse_byte(uint8_t byte, MIDIDriverALSAMidi &driver,
uint64_t timestamp, int device_index) {
switch (msg_category(byte)) {
case MessageCategory::RealTime:
// Real-Time messages are single byte messages that can
// occur at any point.
// We pass them straight through.
driver.receive_input_packet(device_index, timestamp, &byte, 1);
break;
case MessageCategory::Data:
// We don't currently forward System Exclusive messages so skip their data.
// Collect any expected data for other message types.
if (!skipping_sys_ex && expected_data > received_data) {
buffer[received_data + 1] = byte;
received_data++;
// Forward a complete message and reset relevant state.
if (received_data == expected_data) {
driver.receive_input_packet(device_index, timestamp, buffer, received_data + 1);
received_data = 0;
if (msg_category(buffer[0]) != MessageCategory::Voice) {
// Voice Category messages can be sent with "running status".
// This means they don't resend the status byte until it changes.
// For other categories, we reset expected data, to require a new status byte.
expected_data = 0;
}
}
}
break;
case MessageCategory::SysExBegin:
buffer[0] = byte;
skipping_sys_ex = true;
break;
case MessageCategory::SysExEnd:
expected_data = 0;
skipping_sys_ex = false;
break;
case MessageCategory::Voice:
case MessageCategory::SystemCommon:
buffer[0] = byte;
received_data = 0;
expected_data = msg_expected_data(byte);
skipping_sys_ex = false;
if (expected_data == 0) {
driver.receive_input_packet(device_index, timestamp, &byte, 1);
}
break;
}
}
int MIDIDriverALSAMidi::InputConnection::read_in(MIDIDriverALSAMidi &driver, uint64_t timestamp, int device_index) {
int ret;
void MIDIDriverALSAMidi::InputConnection::read() {
int read_count;
do {
uint8_t byte = 0;
ret = snd_rawmidi_read(rawmidi_ptr, &byte, 1);
uint8_t buffer[32];
read_count = snd_rawmidi_read(rawmidi_ptr, buffer, sizeof(buffer));
if (ret < 0) {
if (ret != -EAGAIN) {
ERR_PRINT("snd_rawmidi_read error: " + String(snd_strerror(ret)));
if (read_count < 0) {
if (read_count != -EAGAIN) {
ERR_PRINT("snd_rawmidi_read error: " + String(snd_strerror(read_count)));
}
} else {
parse_byte(byte, driver, timestamp, device_index);
for (int i = 0; i < read_count; i++) {
parser.parse_fragment(buffer[i]);
}
}
} while (ret > 0);
return ret;
} while (read_count > 0);
}
void MIDIDriverALSAMidi::thread_func(void *p_udata) {
MIDIDriverALSAMidi *md = static_cast<MIDIDriverALSAMidi *>(p_udata);
uint64_t timestamp = 0;
while (!md->exit_thread.is_set()) {
md->lock();
InputConnection *connections = md->connected_inputs.ptrw();
size_t connection_count = md->connected_inputs.size();
for (size_t i = 0; i < connection_count; i++) {
connections[i].read_in(*md, timestamp, (int)i);
for (InputConnection &conn : md->connected_inputs) {
conn.read();
}
md->unlock();
OS::get_singleton()->delay_usec(1000);
@ -181,15 +80,25 @@ Error MIDIDriverALSAMidi::open() {
return ERR_CANT_OPEN;
}
int i = 0;
for (void **n = hints; *n != nullptr; n++) {
char *name = snd_device_name_get_hint(*n, "NAME");
lock();
int device_index = 0;
for (void **h = hints; *h != nullptr; h++) {
char *name = snd_device_name_get_hint(*h, "NAME");
if (name != nullptr) {
snd_rawmidi_t *midi_in;
int ret = snd_rawmidi_open(&midi_in, nullptr, name, SND_RAWMIDI_NONBLOCK);
if (ret >= 0) {
connected_inputs.insert(i++, InputConnection(midi_in));
// Get display name.
snd_rawmidi_info_t *info;
snd_rawmidi_info_malloc(&info);
snd_rawmidi_info(midi_in, info);
connected_input_names.push_back(snd_rawmidi_info_get_name(info));
snd_rawmidi_info_free(info);
connected_inputs.push_back(InputConnection(device_index, midi_in));
// Only increment device_index for successfully connected devices.
device_index++;
}
}
@ -198,6 +107,7 @@ Error MIDIDriverALSAMidi::open() {
}
}
snd_device_name_free_hint(hints);
unlock();
exit_thread.clear();
thread.start(MIDIDriverALSAMidi::thread_func, this);
@ -211,11 +121,12 @@ void MIDIDriverALSAMidi::close() {
thread.wait_to_finish();
}
for (int i = 0; i < connected_inputs.size(); i++) {
snd_rawmidi_t *midi_in = connected_inputs[i].rawmidi_ptr;
snd_rawmidi_close(midi_in);
for (const InputConnection &conn : connected_inputs) {
snd_rawmidi_close(conn.rawmidi_ptr);
}
connected_inputs.clear();
connected_input_names.clear();
}
void MIDIDriverALSAMidi::lock() const {
@ -226,24 +137,6 @@ void MIDIDriverALSAMidi::unlock() const {
mutex.unlock();
}
PackedStringArray MIDIDriverALSAMidi::get_connected_inputs() {
PackedStringArray list;
lock();
for (int i = 0; i < connected_inputs.size(); i++) {
snd_rawmidi_t *midi_in = connected_inputs[i].rawmidi_ptr;
snd_rawmidi_info_t *info;
snd_rawmidi_info_malloc(&info);
snd_rawmidi_info(midi_in, info);
list.push_back(snd_rawmidi_info_get_name(info));
snd_rawmidi_info_free(info);
}
unlock();
return list;
}
MIDIDriverALSAMidi::MIDIDriverALSAMidi() {
exit_thread.clear();
}