Desktop: Handle keyboard shortcuts that are skipped by CEF on Mac (#4322)

* Fix text selection on Mac

* Review

desktop/ui/src/internal.rs

@@ -8,6 +8,8 @@ mod render_process_v8_handler;
 
 mod context_menu_handler;
 mod display_handler;
+#[cfg(target_os = "macos")]
+mod keyboard_handler;
 mod life_span_handler;
 mod load_handler;
 mod request_handler;

desktop/ui/src/internal/browser_process_client.rs

@@ -8,6 +8,8 @@ use crate::ipc::{MessageType, UnpackMessage, UnpackedMessage};
 
 use super::context_menu_handler::ContextMenuHandlerImpl;
 use super::display_handler::DisplayHandlerImpl;
+#[cfg(target_os = "macos")]
+use super::keyboard_handler::KeyboardHandlerImpl;
 use super::life_span_handler::LifeSpanHandlerImpl;
 use super::load_handler::LoadHandlerImpl;
 use super::render_handler::RenderHandlerImpl;
@@ -85,6 +87,11 @@ impl ImplClient for BrowserProcessClientImpl {
 		Some(ContextMenuHandler::new(ContextMenuHandlerImpl::new()))
 	}
 
+	#[cfg(target_os = "macos")]
+	fn keyboard_handler(&self) -> Option<cef::KeyboardHandler> {
+		Some(cef::KeyboardHandler::new(KeyboardHandlerImpl::new()))
+	}
+
 	fn get_raw(&self) -> *mut _cef_client_t {
 		self.object.cast()
 	}

desktop/ui/src/internal/keyboard_handler.rs

@@ -0,0 +1,110 @@
+use cef::rc::{Rc, RcImpl};
+use cef::sys::{_cef_keyboard_handler_t, cef_base_ref_counted_t, cef_event_flags_t, cef_key_event_type_t};
+use cef::{Browser, Frame, ImplBrowser, ImplBrowserHost, ImplFrame, ImplKeyboardHandler, KeyEvent, WrapKeyboardHandler};
+
+const SHIFT: u32 = cef_event_flags_t::EVENTFLAG_SHIFT_DOWN.0;
+const CONTROL: u32 = cef_event_flags_t::EVENTFLAG_CONTROL_DOWN.0;
+const ALT: u32 = cef_event_flags_t::EVENTFLAG_ALT_DOWN.0;
+const COMMAND: u32 = cef_event_flags_t::EVENTFLAG_COMMAND_DOWN.0;
+const MODIFIER_MASK: u32 = SHIFT | CONTROL | ALT | COMMAND;
+const COMMAND_SHIFT: u32 = COMMAND | SHIFT;
+const SHIFT_ALT: u32 = SHIFT | ALT;
+
+const VK_END: i32 = 0x23;
+const VK_HOME: i32 = 0x24;
+const VK_UP: i32 = 0x26;
+const VK_DOWN: i32 = 0x28;
+const VK_A: i32 = 0x41;
+const VK_C: i32 = 0x43;
+const VK_V: i32 = 0x56;
+const VK_X: i32 = 0x58;
+const VK_Z: i32 = 0x5A;
+
+const KVK_HOME: i32 = 0x73;
+const KVK_END: i32 = 0x77;
+const NS_HOME_FUNCTION_KEY: u16 = 0xF729;
+const NS_END_FUNCTION_KEY: u16 = 0xF72B;
+
+pub(crate) struct KeyboardHandlerImpl {
+	object: *mut RcImpl<_cef_keyboard_handler_t, Self>,
+}
+impl KeyboardHandlerImpl {
+	pub(crate) fn new() -> Self {
+		Self { object: std::ptr::null_mut() }
+	}
+}
+
+impl ImplKeyboardHandler for KeyboardHandlerImpl {
+	fn on_key_event(&self, browser: Option<&mut Browser>, event: Option<&KeyEvent>, _os_event: *mut u8) -> std::ffi::c_int {
+		let (Some(browser), Some(event)) = (browser, event) else { return 0 };
+		if event.type_ != cef_key_event_type_t::KEYEVENT_RAWKEYDOWN.into() {
+			return 0;
+		}
+
+		let shortcut = (event.modifiers & MODIFIER_MASK, event.windows_key_code);
+
+		let edit_operation: Option<fn(&Frame)> = match shortcut {
+			(COMMAND, VK_A) => Some(Frame::select_all),
+			(COMMAND, VK_C) => Some(Frame::copy),
+			(COMMAND, VK_V) => Some(Frame::paste),
+			(COMMAND_SHIFT, VK_V) => Some(Frame::paste_and_match_style),
+			(COMMAND, VK_X) => Some(Frame::cut),
+			(COMMAND, VK_Z) => Some(Frame::undo),
+			(COMMAND_SHIFT, VK_Z) => Some(Frame::redo),
+			_ => None,
+		};
+		if let Some(edit_operation) = edit_operation {
+			let Some(frame) = browser.focused_frame() else { return 0 };
+			edit_operation(&frame);
+			return 1;
+		}
+
+		let remap = match shortcut {
+			(SHIFT_ALT, VK_UP) => Some((VK_HOME, KVK_HOME, NS_HOME_FUNCTION_KEY)),
+			(SHIFT_ALT, VK_DOWN) => Some((VK_END, KVK_END, NS_END_FUNCTION_KEY)),
+			_ => None,
+		};
+		if let Some((windows_key_code, native_key_code, character)) = remap {
+			let Some(host) = browser.host() else { return 0 };
+			host.send_key_event(Some(&KeyEvent {
+				type_: cef_key_event_type_t::KEYEVENT_RAWKEYDOWN.into(),
+				modifiers: SHIFT,
+				windows_key_code,
+				native_key_code,
+				character,
+				unmodified_character: character,
+				..Default::default()
+			}));
+			return 1;
+		}
+
+		0
+	}
+
+	fn get_raw(&self) -> *mut _cef_keyboard_handler_t {
+		self.object.cast()
+	}
+}
+
+impl Clone for KeyboardHandlerImpl {
+	fn clone(&self) -> Self {
+		unsafe {
+			let rc_impl = &mut *self.object;
+			rc_impl.interface.add_ref();
+		}
+		Self { object: self.object }
+	}
+}
+impl Rc for KeyboardHandlerImpl {
+	fn as_base(&self) -> &cef_base_ref_counted_t {
+		unsafe {
+			let base = &*self.object;
+			std::mem::transmute(&base.cef_object)
+		}
+	}
+}
+impl WrapKeyboardHandler for KeyboardHandlerImpl {
+	fn wrap_rc(&mut self, object: *mut RcImpl<_cef_keyboard_handler_t, Self>) {
+		self.object = object;
+	}
+}