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windows: Improve foreground task dispatching on Windows (#23283)

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Closes #22653

After some investigation, I found this bug is due to that sometimes
`foreground_task` is not dispatched to the main thread unless there is
user input. The current Windows implementation works as follows: when
the `WindowsDispatcher` receives a `foreground_task`, it adds the task
to a queue and uses `SetEvent(dispatch_event)` to notify the main
thread.

The main thread then listens for notifications using
`MsgWaitForMultipleObjects(&[dispatch_event])`.

Essentially, this is a synchronous method, but it is not robust. For
example, if 100 `foreground_task`s are sent, `dispatch_event` should
theoretically be triggered 100 times, and
`MsgWaitForMultipleObjects(&[dispatch_event])` should receive 100
notifications, causing the main thread to execute all 100 tasks.
However, in practice, some `foreground_task`s may not get a chance to
execute due to certain reasons.

As shown in the attached video, when I don't move the mouse, there are
about 20-30 `foreground_task`s waiting in the queue to be executed. When
I move the mouse, `run_foreground_tasks()` is called, which processes
the tasks in the queue.



https://github.com/user-attachments/assets/83cd09ca-4b17-4a1f-9a2a-5d1569b23483



To address this, this PR adopts an approach similar to `winit`. In
`winit`, an invisible window is created for message passing. In this PR,
we use `PostThreadMessage` to directly send messages to the main thread.

With this implementation, when 100 `foreground_task`s are sent, the
`WindowsDispatcher` uses `PostThreadMessageW(thread_id,
RUNNABLE_DISPATCHED)` to notify the main thread. This approach enqueues
100 `RUNNABLE_DISPATCHED` messages in the main thread's message queue,
ensuring that each `foreground_task` is executed as expected. The main
thread continuously processes these messages, guaranteeing that all 100
tasks are executed.

Release Notes:

- N/A
This commit is contained in:
张小白 2025-01-18 23:43:56 +08:00 • committed by GitHub
parent 5138e6a3c7
commit 728a874b1e
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GPG key ID: B5690EEEBB952194
4 changed files with 110 additions and 66 deletions
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13
crates/gpui/src/platform/windows/events.rs
View file

@ -16,8 +16,9 @@ use windows::Win32::{
use crate::*;
pub(crate) const CURSOR_STYLE_CHANGED: u32 = WM_USER + 1;
pub(crate) const CLOSE_ONE_WINDOW: u32 = WM_USER + 2;
pub(crate) const WM_ZED_CURSOR_STYLE_CHANGED: u32 = WM_USER + 1;
pub(crate) const WM_ZED_CLOSE_ONE_WINDOW: u32 = WM_USER + 2;
pub(crate) const WM_ZED_EVENT_DISPATCHED_ON_MAIN_THREAD: u32 = WM_USER + 3;
const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
@ -89,7 +90,7 @@ pub(crate) fn handle_msg(
WM_SETCURSOR => handle_set_cursor(lparam, state_ptr),
WM_SETTINGCHANGE => handle_system_settings_changed(handle, state_ptr),
WM_DWMCOLORIZATIONCOLORCHANGED => handle_system_theme_changed(state_ptr),
CURSOR_STYLE_CHANGED => handle_cursor_changed(lparam, state_ptr),
WM_ZED_CURSOR_STYLE_CHANGED => handle_cursor_changed(lparam, state_ptr),
_ => None,
};
if let Some(n) = handled {
@ -243,9 +244,9 @@ fn handle_destroy_msg(handle: HWND, state_ptr: Rc<WindowsWindowStatePtr>) -> Opt
callback();
}
unsafe {
PostMessageW(
None,
CLOSE_ONE_WINDOW,
PostThreadMessageW(
state_ptr.main_thread_id_win32,
WM_ZED_CLOSE_ONE_WINDOW,
WPARAM(state_ptr.validation_number),
LPARAM(handle.0 as isize),
)