[CoreMidi] Add missing CoreMIDI bindings and MidiEventList support. by rolfbjarne · Pull Request #24738 · dotnet/macios

rolfbjarne · 2026-02-18T19:27:38Z

Bind the following missing CoreMIDI APIs:

MIDIDeviceCreate/MIDIDeviceDispose
MIDIExternalDeviceCreate
MIDISetupAddDevice/MIDISetupRemoveDevice
MIDISetupAddExternalDevice/MIDISetupRemoveExternalDevice
MIDIEntityAddOrRemoveEndpoints
MIDIDeviceRemoveEntity
MIDIEndPointGetRefCons/MIDIEndPointSetRefCons
MIDIDriverEnableMonitoring
MIDIGetDriverDeviceList/MIDIGetDriverIORunLoop
MIDISendSysex/MIDISendUMPSysex
MIDIDestinationCreateWithProtocol
MIDISourceCreateWithProtocol
MIDIInputPortCreateWithProtocol
MIDIEventPacketSysexBytesForGroup
MIDI 2.0 structs (MIDI2DeviceManufacturer, MIDI2DeviceRevisionLevel,
MIDICIProfileID, MIDISysexSendRequest, MIDISysexSendRequestUMP)
MidiDriver abstract class for implementing custom MIDI drivers

Add MidiEventList and MidiEventPacket classes for MIDI 2.0 Universal MIDI
Packet (UMP) support (MIDIEventList/MIDIEventPacket structs).

Add comprehensive tests including a Happy Birthday melody test.

There's a sample project in progress here: dotnet/macios-samples#10.

Fixes #4452
Fixes #12489

Copilot

Pull request overview

This PR adds comprehensive CoreMIDI bindings for missing APIs and implements MIDI 2.0 Universal MIDI Packet (UMP) support, addressing issues #4452 and #12489. The changes enable developers to work with MIDI devices at a lower level, including custom driver implementation, and provide full support for the modern MIDI 2.0 protocol.

Changes:

Added MidiEventList and MidiEventPacket classes for MIDI 2.0 UMP support, enabling Universal MIDI Packet handling
Implemented missing CoreMIDI device/entity management APIs (Create, Dispose, AddOrRemoveEndpoints, etc.) and sysex sending functionality
Introduced experimental MidiDriver abstract class for implementing custom MIDI drivers with full lifecycle management

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
tests/xtro-sharpie/api-annotations-dotnet/*.ignore	Removed API ignore entries for newly bound CoreMIDI APIs across all platforms
tests/cecil-tests/Documentation.cs	Added FunctionPointerType handling to return empty doc IDs for unmanaged function pointers
tests/cecil-tests/Documentation.KnownFailures.txt	Removed known failures for newly documented CoreMIDI types and fixed function pointer doc IDs
tests/monotouch-test/CoreMidi/MidiEventPacketTest.cs	Comprehensive unit tests for MidiEventPacket struct including bounds checking and data manipulation
tests/monotouch-test/CoreMidi/MidiEventListTest.cs	Unit tests for MidiEventList covering construction, adding packets, iteration, and edge cases
tests/monotouch-test/CoreMidi/MidiEndpointTest.cs	Added tests for GetRefCons/SetRefCons endpoint reference management APIs
tests/monotouch-test/CoreMidi/MidiDeviceTest.cs	Tests for external device creation and MidiSetup add/remove operations
tests/monotouch-test/CoreMidi/MidiComprehensiveTest.cs	Extensive integration tests including a complete "Happy Birthday" melody demonstration
src/frameworks.sources	Registered new CoreMidi and CoreFoundation source files in the build system
src/coremidi.cs	Added MidiDriverProperty enum for driver-specific properties
src/CoreMidi/MidiThruConnectionParams.cs	Moved enum definitions outside TVOS conditional to fix tvOS build issues
src/CoreMidi/MidiStructs.cs	Implemented MIDI 2.0 structs (Midi2DeviceManufacturer, Midi2DeviceRevisionLevel, MidiCIProfileId variants, MidiSysexSendRequest)
src/CoreMidi/MidiServices.cs	Added device/entity creation, external device support, sysex async sending, and protocol-aware port/endpoint creation methods
src/CoreMidi/MidiEventPacket.cs	Implemented MidiEventPacket struct with 64-word capacity, indexer, and GetSysexBytes method
src/CoreMidi/MidiEventList.cs	Implemented MidiEventList as IDisposable wrapper with Add, Send, Receive, and iteration support
src/CoreMidi/MidiDriverInterface.cs	Created experimental MidiDriver abstract class with COM-style interface for custom driver implementation
src/CoreMidi/MidiBluetoothDriver.cs	Removed TVOS conditional and added XML documentation for Bluetooth driver methods
src/CoreFoundation/CFUuidBytes.cs	Added CFUuidBytes struct for CoreMIDI driver interface QueryInterface method
docs/preview-apis.md	Documented MidiDriver as experimental (APL0004) until .NET 12

Bind the following missing CoreMIDI APIs: - MIDIDeviceCreate/MIDIDeviceDispose - MIDIExternalDeviceCreate - MIDISetupAddDevice/MIDISetupRemoveDevice - MIDISetupAddExternalDevice/MIDISetupRemoveExternalDevice - MIDIEntityAddOrRemoveEndpoints - MIDIDeviceRemoveEntity - MIDIEndPointGetRefCons/MIDIEndPointSetRefCons - MIDIDriverEnableMonitoring - MIDIGetDriverDeviceList/MIDIGetDriverIORunLoop - MIDISendSysex/MIDISendUMPSysex - MIDIDestinationCreateWithProtocol - MIDISourceCreateWithProtocol - MIDIInputPortCreateWithProtocol - MIDIClientCreateWithBlock - MIDIEventPacketSysexBytesForGroup - MIDI 2.0 structs (MIDI2DeviceManufacturer, MIDI2DeviceRevisionLevel, MIDICIProfileID, MIDISysexSendRequest, MIDISysexSendRequestUMP) - MidiDriver abstract class for implementing custom MIDI drivers Add MidiEventList and MidiEventPacket classes for MIDI 2.0 Universal MIDI Packet (UMP) support (MIDIEventList/MIDIEventPacket structs). Add comprehensive tests including a Happy Birthday melody test. There's a sample project in progress here: dotnet/macios-samples#10. Fixes #4452 Fixes #12489

…sage. Add a binding for the native MIDIEventListForEachEvent function, which parses each Universal MIDI Packet (UMP) in a MidiEventList and invokes a callback with the parsed message. This adds: * A faithful managed MidiUniversalMessage struct (and its variant structs) mirroring the native MIDIUniversalMessage union. * A MidiEventList.ForEachEvent method + MidiUniversalMessageVisitor delegate. * Thorough tests, including parsing a MIDI 1.0 note on, a MIDI 2.0 note on, and the Happy Birthday melody. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Explicit struct layout (with overlapping union fields) makes a struct non-blittable, which forces the runtime to generate marshaling code and prevents passing the struct by value through a 'delegate* unmanaged' function pointer without overhead. Rewrite MidiUniversalMessage and its variant structs to use sequential blittable layout with opaque storage fields, exposing the native unions through unsafe accessor properties that reinterpret the storage. Also replace fixed buffers / array fields with named byte fields. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

rolfbjarne

🤖 Code Review — CoreMIDI bindings

Verdict: ⚠️ Needs Changes (minor) — No bugs, breaking changes, or memory-safety issues found. The COM-style driver ref-counting, blittable union emulation (MidiUniversalMessage/MidiEventPacket avoid explicit layout/arrays to stay blittable for delegate* unmanaged), and the sysex async lifetime management (disposing the CancellationTokenRegistration before freeing native memory) are all sound. A few correctness/polish items inline.

Positive callouts

No API-breaking changes; removals handled via [ObsoletedOSPlatform] with actionable "Call 'X' instead." messages.
MidiDriver COM ref-counting (AddRef/Release under lock, weak GCHandle, finalizer releasing the managed ref) is coherent; experimental surface gated behind APL0004 and documented in docs/preview-apis.md.
.ignore entries for the now-bound MIDIEventListForEachEvent/Init/Add and the tvOS enums are correctly removed.
Thorough XML docs replacing "To be added." stubs; Happy Birthday test present. 🎂

Severity counts: 0 ❌ · 1 ⚠️ · 4 💡

Reviewed against origin/main (HEAD 01b1410). CI status not evaluated in this review.

@struct

* Fix ArgumentOutOfRangeException constructor misuse (string was passed as paramName instead of message) in MidiEventPacket and MidiEventList. * Add MIT license header and #nullable enable to CFUuidBytes.cs. * Fix CreateInputPort <returns> doc and local alias (MidiPort, not MidiEndpoint). * Remove redundant native @struct comment block in MidiStructs.cs. * Use Assert.That/Is.EqualTo with correct argument order in MidiEndpointTest. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…ilot # Conflicts: # src/CoreMidi/MidiServices.cs # tests/cecil-tests/Documentation.KnownFailures.txt

* Fix XML doc typos in MidiEventList.cs ("lis" -> "list", "packates" -> "packets"). * Make the static strongReferences field in MidiDriverInterface.cs readonly. * Dispose MidiEventList instances in MidiEventListTest.cs using `using` statements. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

🟡 Changes recommended

Several correctness and API-quality issues were identified (null-handling, unsafe interop, malformed doc IDs, and PR-scope mismatch) that should be resolved before merging.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Files reviewed: 24/24 changed files
Comments generated: 10
Review effort level: Lite

vs-mobiletools-engineering-service2 · 2026-09-07T18:01:40Z

✅ API diff for current PR / commit

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

✅ API diff vs stable

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

Pipeline on Agent
Hash: 18b055dc42ca66ec739400cf53cc57f9773c96ae [PR build]

vs-mobiletools-engineering-service2 · 2026-09-07T20:04:17Z

🔥 [CI Build #18b055d] Test results 🔥

Test results

❌ Tests failed on VSTS: test results

0 tests crashed, 2 tests failed, 262 tests passed.

Failures

❌ cecil tests

1 tests failed, 0 tests passed.

Failed tests

Cecil-based tests: Failed (Execution failed with exit code 1)
- Cecil.Tests.ApiAvailabilityTest.AttributeConsistency(builds/down...: Multiple failures or warnings in test:

[FAIL] 17.0 <= 17.0 (Min) on 'CoreMidi.MidiEventPacket.GetSysexBytes(System.Byte, ou...
* Cecil.Tests.ApiAvailabilityTest.AttributeConsistency(builds/down...: Multiple failures or warnings in test:
[FAIL] 14.0 <= 14.0 (Min) on 'CoreMidi.MidiEventPacket.GetSysexBytes(System.Byte, ou...
* Cecil.Tests.Documentation.VerifyEveryVisibleMemberIsDocumented: Found 1 undocumented APIs (not known failures) and 2 APIs that were marked as known failures but are now documented. If this is ...

Html Report (VSDrops) Download

❌ dotnettests tests (macOS)

1 tests failed, 0 tests passed.

Failed tests

DotNet tests: Failed (Execution failed with exit code 1)
- Xamarin.Tests.AppSizeTest.CoreCLR_Interpreter_TrimmableStatic(Ma...: App size changed significantly (+30,036 bytes (29.3 KB = 0.0 MB) different > tolerance of +-10,240 bytes (10.0 KB = 0.0 MB)). Ex...
- Xamarin.Tests.AppSizeTest.CoreCLR_Interpreter(MacOSX,"osx-arm64;...: App size changed significantly (+30,036 bytes (29.3 KB = 0.0 MB) different > tolerance of +-10,240 bytes (10.0 KB = 0.0 MB)). Ex...
- Xamarin.Tests.AppSizeTest.CoreCLR_R2R(MacOSX,"osx-arm64;osx-x64"...: App size changed significantly (+122,196 bytes (119.3 KB = 0.1 MB) different > tolerance of +-10,240 bytes (10.0 KB = 0.0 MB)). ...

Html Report (VSDrops) Download

Successes

✅ assembly-processing: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 5 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ introspection: All 7 tests passed. Html Report (VSDrops) Download
✅ linker (iOS): All 31 tests passed. Html Report (VSDrops) Download
✅ linker (MacCatalyst): All 31 tests passed. Html Report (VSDrops) Download
✅ linker (macOS): All 21 tests passed. Html Report (VSDrops) Download
✅ linker (tvOS): All 31 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 25 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 25 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 20 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 25 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ sharpie: All 1 tests passed. Html Report (VSDrops) Download
✅ windows: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

macOS tests

✅ Tests on macOS Sonoma (14): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Sequoia (15): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Tahoe (26): All 5 tests passed. Html Report (VSDrops) Download

Linux Build Verification

✅ Linux build succeeded

Pipeline on Agent
Hash: 18b055dc42ca66ec739400cf53cc57f9773c96ae [PR build]

vs-mobiletools-engineering-service2 · 2026-09-07T20:04:37Z

⚠️ AppSizeTest expected files changed ⚠️

The AppSizeTest detected changes in the expected app size files.

To update the expected files, add a comment with the following command:

/apply-gist https://gist.github.com/vs-mobiletools-engineering-service2/2f7c02969f90c7ad58ebbeb4d3050163

Updated files

MacOSX-CoreCLR-Interpreter-size.txt
MacOSX-CoreCLR-Interpreter-TrimmableStatic-size.txt
MacOSX-CoreCLR-R2R-size.txt

Pipeline on Agent
Hash: 18b055dc42ca66ec739400cf53cc57f9773c96ae [PR build]

rolfbjarne requested a review from Copilot February 18, 2026 19:27

rolfbjarne added the copilot label Feb 18, 2026

Copilot started reviewing on behalf of rolfbjarne February 18, 2026 19:28 View session

rolfbjarne mentioned this pull request Feb 18, 2026

[CoreMidi] Implement some of the missing CoreMIDI APIs. #22459

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rolfbjarne and others added 3 commits June 25, 2026 08:28

rolfbjarne force-pushed the dev/rolf/coremidi-copilot branch from 9db33b7 to 01b1410 Compare June 25, 2026 06:59

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rolfbjarne commented Jun 25, 2026

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Comment thread src/CoreMidi/MidiEventPacket.cs Outdated

Comment thread src/CoreFoundation/CFUuidBytes.cs

Comment thread src/CoreMidi/MidiServices.cs Outdated

Comment thread src/CoreMidi/MidiStructs.cs Outdated

Comment thread tests/monotouch-test/CoreMidi/MidiEndpointTest.cs Outdated

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rolfbjarne and others added 2 commits September 7, 2026 18:08

Merge remote-tracking branch 'origin/main' into dev/rolf/coremidi-cop…

d89d77e

…ilot # Conflicts: # src/CoreMidi/MidiServices.cs # tests/cecil-tests/Documentation.KnownFailures.txt

rolfbjarne requested a lite review from Copilot September 7, 2026 17:22

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Pull request overview

Reviewed changes

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🟡 Changes recommended

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vs-mobiletools-engineering-service2 commented Sep 7, 2026

✅ API diff for current PR / commit

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vs-mobiletools-engineering-service2 commented Sep 7, 2026

🔥 [CI Build #18b055d] Test results 🔥

Test results

Failures

❌ cecil tests

Failed tests

❌ dotnettests tests (macOS)

Failed tests

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macOS tests

Linux Build Verification

rolfbjarne commented Feb 18, 2026 •

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