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reuse the existing window procedure
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@amrbashir
amrbashir committed Sep 11, 2023
1 parent 5c61a8c commit 5595e1c
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Showing 2 changed files with 17 additions and 139 deletions.
1 change: 0 additions & 1 deletion Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,6 @@ webview2-com = "0.25"
windows-implement = "0.48"
dunce = "1"
winit = { version = "0.28", features = [ "serde" ], optional = true }
lazy_static = "1"

[target."cfg(target_os = \"windows\")".dependencies.windows]
version = "0.48"
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155 changes: 17 additions & 138 deletions src/webview/webview2/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,14 +27,15 @@ use std::{
sync::{mpsc, Arc},
};

use once_cell::unsync::OnceCell;
use once_cell::{sync::Lazy, unsync::OnceCell};

use windows::{
core::{ComInterface, PCSTR, PCWSTR, PWSTR},
s,
Win32::{
Foundation::*,
Globalization::{self, MAX_LOCALE_NAME},
Graphics::Gdi::RedrawWindow,
Graphics::Gdi::{RedrawWindow, HRGN, RDW_INTERNALPAINT},
System::{
Com::{IStream, StructuredStorage::CreateStreamOnHGlobal},
LibraryLoader::{GetProcAddress, LoadLibraryW},
Expand All @@ -43,7 +44,7 @@ use windows::{
},
UI::{
Shell::{DefSubclassProc, SetWindowSubclass},
WindowsAndMessaging::{self as win32wm},
WindowsAndMessaging::{self as win32wm, PostMessageW, RegisterWindowMessageA},
},
},
};
Expand Down Expand Up @@ -593,9 +594,7 @@ window.addEventListener('mousemove', (e) => window.chrome.webview.postMessage('_
let env = env.clone();
let main_thread_id = std::thread::current().id();

let thread_msg_target = create_event_target_window();
subclass_event_target_window(thread_msg_target);

let hwnd = window.hwnd();
unsafe {
webview
.add_WebResourceRequested(
Expand Down Expand Up @@ -708,7 +707,7 @@ window.addEventListener('mousemove', (e) => window.chrome.webview.postMessage('_
if std::thread::current().id() == main_thread_id {
handler();
} else {
run_on_main_thread(thread_msg_target, handler);
dispatch_handler(hwnd, handler);
}
});

Expand Down Expand Up @@ -834,6 +833,14 @@ window.addEventListener('mousemove', (e) => window.chrome.webview.postMessage('_
win32wm::WM_DESTROY => {
drop(Box::from_raw(dwrefdata as *mut ICoreWebView2Controller));
}

_ if msg == *EXEC_MSG_ID => {
let mut function: Box<Box<dyn FnMut()>> = Box::from_raw(wparam.0 as *mut _);
function();
RedrawWindow(hwnd, None, HRGN::default(), RDW_INTERNALPAINT);
return LRESULT(0);
}

_ => (),
}

Expand Down Expand Up @@ -1167,93 +1174,9 @@ fn url_from_webview(webview: &ICoreWebView2) -> String {
take_pwstr(pwstr)
}

use windows::{
core::s,
Win32::{Graphics::Gdi::*, System::LibraryLoader::GetModuleHandleW, UI::WindowsAndMessaging::*},
};

fn create_event_target_window() -> HWND {
let window = unsafe {
CreateWindowExW(
WS_EX_NOACTIVATE | WS_EX_TRANSPARENT | WS_EX_LAYERED |
// WS_EX_TOOLWINDOW prevents this window from ever showing up in the taskbar, which
// we want to avoid. If you remove this style, this window won't show up in the
// taskbar *initially*, but it can show up at some later point. This can sometimes
// happen on its own after several hours have passed, although this has proven
// difficult to reproduce. Alternatively, it can be manually triggered by killing
// `explorer.exe` and then starting the process back up.
// It is unclear why the bug is triggered by waiting for several hours.
WS_EX_TOOLWINDOW,
PCWSTR::from_raw(THREAD_EVENT_TARGET_WINDOW_CLASS.clone().as_ptr()),
PCWSTR::null(),
WS_OVERLAPPED,
0,
0,
0,
0,
HWND::default(),
HMENU::default(),
GetModuleHandleW(PCWSTR::null()).unwrap_or_default(),
None,
)
};

SetWindowLongPtrW(
window,
GWL_STYLE,
// The window technically has to be visible to receive WM_PAINT messages (which are used
// for delivering events during resizes), but it isn't displayed to the user because of
// the LAYERED style.
(WS_VISIBLE | WS_POPUP).0 as isize,
);
window
}

#[allow(non_snake_case)]
#[cfg(target_pointer_width = "32")]
pub fn SetWindowLongPtrW(window: HWND, index: WINDOW_LONG_PTR_INDEX, value: isize) -> isize {
unsafe { win32wm::SetWindowLongW(window, index, value as _) as _ }
}

#[allow(non_snake_case)]
#[cfg(target_pointer_width = "64")]
pub fn SetWindowLongPtrW(window: HWND, index: WINDOW_LONG_PTR_INDEX, value: isize) -> isize {
unsafe { win32wm::SetWindowLongPtrW(window, index, value) }
}

const THREAD_EVENT_TARGET_SUBCLASS_ID: usize = 1;

fn subclass_event_target_window(window: HWND) {
unsafe {
let subclass_result = SetWindowSubclass(
window,
Some(thread_event_target_callback),
THREAD_EVENT_TARGET_SUBCLASS_ID,
0,
);
assert!(subclass_result.as_bool());
}
}

unsafe extern "system" fn thread_event_target_callback(
window: HWND,
msg: u32,
wparam: WPARAM,
lparam: LPARAM,
_: usize,
_subclass_input_ptr: usize,
) -> LRESULT {
if msg == *EXEC_MSG_ID {
let mut function: Box<Box<dyn FnMut()>> = Box::from_raw(wparam.0 as *mut _);
function();
RedrawWindow(window, None, HRGN::default(), RDW_INTERNALPAINT);
LRESULT(0)
} else {
DefSubclassProc(window, msg, wparam, lparam)
}
}
static EXEC_MSG_ID: Lazy<u32> = Lazy::new(|| unsafe { RegisterWindowMessageA(s!("Wry::ExecMsg")) });

unsafe fn run_on_main_thread<F>(hwnd: HWND, function: F)
unsafe fn dispatch_handler<F>(hwnd: isize, function: F)
where
F: FnMut() + 'static,
{
Expand All @@ -1263,53 +1186,9 @@ where

let raw = Box::into_raw(boxed2);

let res = PostMessageW(hwnd, *EXEC_MSG_ID, WPARAM(raw as _), LPARAM(0));
let res = PostMessageW(HWND(hwnd), *EXEC_MSG_ID, WPARAM(raw as _), LPARAM(0));
assert!(
res.as_bool(),
"PostMessage failed ; is the messages queue full?"
);
}

lazy_static::lazy_static! {
// Message sent when we want to execute a closure in the thread.
// WPARAM contains a Box<Box<dyn FnMut()>> that must be retrieved with `Box::from_raw`,
// and LPARAM is unused.

static ref EXEC_MSG_ID: u32 = {
unsafe {
RegisterWindowMessageA(s!("Wry::ExecMsg"))
}
};

static ref THREAD_EVENT_TARGET_WINDOW_CLASS: Vec<u16> = unsafe {
let class_name= encode_wide("Wry Thread Event Target");

let class = WNDCLASSEXW {
cbSize: std::mem::size_of::<WNDCLASSEXW>() as u32,
style: Default::default(),
lpfnWndProc: Some(call_default_window_proc),
cbClsExtra: 0,
cbWndExtra: 0,
hInstance: GetModuleHandleW(PCWSTR::null()).unwrap_or_default(),
hIcon: HICON::default(),
hCursor: HCURSOR::default(), // must be null in order for cursor state to work properly
hbrBackground: HBRUSH::default(),
lpszMenuName: PCWSTR::null(),
lpszClassName: PCWSTR::from_raw(class_name.as_ptr()),
hIconSm: HICON::default(),
};

RegisterClassExW(&class);

class_name
};
}

unsafe extern "system" fn call_default_window_proc(
hwnd: HWND,
msg: u32,
wparam: WPARAM,
lparam: LPARAM,
) -> LRESULT {
DefWindowProcW(hwnd, msg, wparam, lparam)
}

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