aud_midi_core 0.1.1

Runtime contracts for aud_midi: backend interfaces, fake backend, scheduler, port registry, diagnostics

aud_midi_core

Runtime contracts of the aud_midi family: backend interfaces, a fake backend, the software scheduler, the port registry and diagnostics.

Part of the aud_midi family, see aud_midi.

Goals

• MidiBackend, advertiser and BLE transport interfaces
• FakeMidiBackend for tests
• Software scheduler with the send contract
• Port registry and diagnostics bus
• No dart:io, dart:ffi or dart:isolate

State

Implemented; every file is covered 100 % by its own tests on the Dart VM, and the pure-Dart tests also pass in Chrome (dart test -p chrome test/clock test/engine test/fake test/backend test/ble test/error).

• Contracts: MidiBackend with virtual port, Bluetooth and network sub-APIs, MidiBackendHost, MidiServiceAdvertiser, MidiBleTransport, MidiBluetoothSystemPicker (the Bluetooth device picker of the operating system), MidiException with MidiTimeout.
• Native taps: MidiNativeTapBackend next to MidiBackend, found with is, attaches a MidiNativeTap (the addresses of a C function and its user pointer) to an input port; the backend calls it on its own receive thread with UMP words or MIDI 1.0 bytes and a host timestamp in nanoseconds, and with gone when the port disappears. A detach completes after the last call. MidiCompositeBackend routes taps to the backend of the port.
• Clock: MidiSystemClock (Timeline.now on the VM, performance.now() in the browser), MidiClockMapper, and MidiFakeClock with MidiFakeTimers for tests.
• MidiEngine hosts one backend in the current isolate: per input a MIDI 1.0 parser or UMP decoder, JR timestamps as sender time, optional translation, bounded queues with overflow diagnostics; per output translation to the port's protocol, encoding, scheduling by the operating system or the software scheduler (with a lookahead for ports that cannot discard), cancelPending and panic; port registry with re-plug candidates and devices; diagnostics bus; a fixed shutdown order.
• MidiCompositeBackend combines backends, MidiBleBluetoothBackend runs BLE-MIDI over a GATT client.
• FakeMidiBackend with loopback, hotplug, failures, recorded native taps and in-memory virtual ports, BLE and network sessions. The contract tests run against it: they prove the Dart abstraction, not a native binding.

See the plan in aud_midi_pm.

Installation

dart pub add aud_midi_core

Contributing

See doc/guides/develop-guide.md.