🎭 Refactor overLink status using window actors

actors/DotLinkStatusChild.sys.mjs

@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const { setTimeout, clearTimeout } = ChromeUtils.importESModule(
+	"resource://gre/modules/Timer.sys.mjs"
+);
+
+const { BrowserUtils } = ChromeUtils.importESModule(
+	"resource://gre/modules/BrowserUtils.sys.mjs"
+);
+
+export class LinkStatusChild extends JSWindowActorChild {
+	/**
+	 * The current mouseover href
+	 */
+	_currentHref = null;
+
+	/**
+	 * The timer before a mouseout event should clear the status
+	 */
+	_clearStatusInt = null;
+
+	/**
+	 * Handles the over link status
+	 * @param {string} href
+	 */
+	handleOverLink(href) {
+		// Prevent duplicate mouseover events from the
+		// same href firing multiple overLink events.
+		if (href && this._currentHref == href) return;
+
+		this.sendAsyncMessage("LinkStatus:OverLink", {
+			href
+		});
+
+		this._currentHref = href;
+	}
+
+	/**
+	 * Handles incoming events to the LinkStatus actor
+	 * @param {Event} event
+	 */
+	handleEvent(event) {
+		clearTimeout(this._clearStatusInt);
+
+		const [href, linkNode] =
+			BrowserUtils.hrefAndLinkNodeForClickEvent(event);
+
+		switch (event.type) {
+			case "mousemove":
+				this.handleOverLink(href);
+				break;
+			case "mouseout":
+				if (linkNode) {
+					// Clearing the overLink right after receiving `mouseout` is a bad idea.
+					//
+					// We rely on `mouseout` for determining if the mouse left the region
+					// of a link (for example tabbing out of the window, but leaving the cursor in the same position).
+					//
+					// Therefore, adding a timer allows us to bypass clearing overLink
+					// straight away, if the user happened to move their mouse between
+					// two links, giving `mousemove` enough time to re-update the href
+					// before `mouseout` can clear it.
+					this._clearStatusInt = setTimeout(() => {
+						this.handleOverLink(null);
+					}, 10);
+				}
+				break;
+		}
+	}
+}

actors/DotLinkStatusParent.sys.mjs

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+export class LinkStatusParent extends JSWindowActorParent {
+	/**
+	 *
+	 * @param {import("third_party/dothq/gecko-types/lib").ReceiveMessageArgument} msg
+	 */
+	receiveMessage(msg) {
+		if (msg.name !== "LinkStatus:OverLink") return;
+
+		const { href } = msg.data;
+
+		const browser = this.manager.browsingContext.top.embedderElement;
+		const win = browser.ownerGlobal;
+
+		if (!win.gDot) return;
+
+		const tab = win.gDot.tabs?.getTabForWebContents(browser);
+
+		if (tab) {
+			win.gDot.status.setTabStatus(tab, "overLink", href);
+		} else {
+			win.gDot.status.setStatus("overLink", href);
+		}
+	}
+}

actors/moz.build

@@ -11,6 +11,8 @@ FINAL_TARGET_FILES.actors += [
     "DotDevToolsChild.sys.mjs",
     "DotGeckoCommandsChild.sys.mjs",
     "DotLinkHandlerParent.sys.mjs",
+    "DotLinkStatusChild.sys.mjs",
+    "DotLinkStatusParent.sys.mjs",
     "DotPromptParent.sys.mjs",
     "DotTooltipListenerChild.sys.mjs",
     "DotUAStylesChild.sys.mjs",

components/DotGlue.sys.mjs

@@ -178,6 +178,22 @@ const JSWINDOWACTORS = {
 		messageManagerGroups: ["browsers"]
 	},
 
+	LinkStatus: {
+		parent: {
+			esModuleURI: "resource:///actors/DotLinkStatusParent.sys.mjs"
+		},
+
+		child: {
+			esModuleURI: "resource:///actors/DotLinkStatusChild.sys.mjs",
+			events: {
+				mousemove: { capture: true, mozSystemGroup: true },
+				mouseout: { capture: true, mozSystemGroup: true }
+			}
+		},
+
+		allFrames: true
+	},
+
 	PageInfo: {
 		child: {
 			esModuleURI: "resource:///actors/PageInfoChild.sys.mjs"

components/XULBrowserWindow.sys.mjs

@@ -21,11 +21,9 @@ export class XULBrowserWindow {
 
 	status = "";
 	defaultStatus = "";
-	overLink = "";
 	startTime = 0;
 	isBusy = false;
 	busyUI = false;
-	hideOverLinkImmediately = false;
 
 	_state = null;
 	_lastLocation = null;
@@ -36,8 +34,6 @@ export class XULBrowserWindow {
 	// with the the HTTPS-Only Mode error page (more details in bug 1656027)
 	_isSecureContext = null;
 
-	_overlinkInt;
-
 	QueryInterface = ChromeUtils.generateQI([
 		"nsIWebProgressListener",
 		"nsIWebProgressListener2",
@@ -81,12 +77,7 @@ export class XULBrowserWindow {
 	 * @param {string} url
 	 */
 	setOverLink(url) {
-		clearTimeout(this._overlinkInt);
-
-		this._overlinkInt = setTimeout(() => {
-			console.log("todo: rewrite to use actor");
-			this.#win.gDot.status.setStatus("overLink", url);
-		}, 100);
+		// noop: Handled by LinkStatus actor
 	}
 
 	/**

third_party/dothq/gecko-types/lib/WindowGlobalParent.d.ts

@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+import { BrowsingContext } from "./BrowsingContext";
 import { FrameLoader } from "./FrameLoader";
 import { JSWindowActorParent } from "./JSWindowActorParent";
 import { WindowGlobalChild } from "./WindowGlobalChild";
@@ -17,6 +18,8 @@ export interface WindowGlobalParentInstance {
 	readonly rootFrameLoader?: FrameLoader;
 	readonly childActor?: WindowGlobalChild;
 
+    readonly browsingContext: BrowsingContext;
+
 	/**
 	 * Checks for any WindowContexts with "beforeunload" listeners in this
 	 * WindowGlobal's subtree. If any exist, a "beforeunload" event is