Enhance mouse event handling for middle mouse button #76
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- Set isMiddleMouseDown synchronously in startDrag, endDrag, and cancelDrag methods to prevent race conditions during rapid drag cycles. - Ensure proper state management by synchronously updating isMiddleMouseDown before dispatching asynchronous tasks. - Update MenuBarController to ensure UI mutations occur on the main actor, improving thread safety for UI updates.
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Pull request overview
This PR hardens middle mouse drag handling by eliminating race conditions around the drag state flag and ensures UI updates to the menu bar icon are performed safely on the main actor.
Changes:
- Update
MouseEventGeneratorto setisMiddleMouseDownsynchronously instartDrag,endDrag, andcancelDragwhile keeping event posting on the serialeventQueue, closing race windows that could leave the middle button logically “stuck” or allowupdateDragto continue after a drag ends. - Wrap the completion of the status item icon fade animation in a
Task { @MainActor in ... }to guaranteebutton.alphaValueis mutated on the main actor. - Add a trailing newline to the
Notification.Nameextension for style consistency.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| MiddleDrag/Core/MouseEventGenerator.swift | Adjusts drag state transitions to set isMiddleMouseDown under a lock before/when ending drags, ensuring consistent state and immediate stopping of drag updates while preserving correct sequencing of CGEvents on eventQueue. |
| MiddleDrag/UI/MenuBarController.swift | Ensures the status item button’s alpha reset after the animation is performed on the main actor via Swift concurrency, and adds a trailing newline to the notification name extension. |
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- Updated the MouseEventGenerator to set the isMiddleMouseDown flag and send the mouse-down event synchronously, preventing potential race conditions during drag operations. - Improved comments to clarify the critical nature of synchronous execution for both flag setting and event dispatching.
NullPointerDepressiveDisorder
deleted the
73-still-getting-the-odd-stickiness
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This pull request addresses critical race conditions in the mouse drag event handling logic and improves UI state mutation safety. The most important changes focus on ensuring correct state transitions for mouse events and proper thread usage for UI updates.
Race condition fixes in mouse event handling:
isMiddleMouseDown = trueinstartDrag()before dispatching the async event to prevent a race condition whereendDrag()could be called before the async block runs, which previously could leave the middle mouse button stuck down.isMiddleMouseDown = falsein bothendDrag()andcancelDrag()before dispatching the async event, ensuring that rapid start/end or cancel/start cycles do not cause inconsistent state or missed mouse up events. This also ensures thatupdateDrag()stops processing immediately when the drag ends or is cancelled. [1] [2]UI thread safety improvement:
button.alphaValueafter an animation completion happens on the main actor using Swift concurrency, preventing potential UI glitches or crashes due to thread misuse.Minor codebase maintenance:
Notification.Nameextension for style consistency.