1 files changed, 148 insertions, 0 deletions
diff --git a/browser/actors/AboutNewTabParent.sys.mjs b/browser/actors/AboutNewTabParent.sys.mjs
new file mode 100644
index 0000000000..27d5f82c0c
--- /dev/null
+++ b/browser/actors/AboutNewTabParent.sys.mjs
@@ -0,0 +1,148 @@
+/* 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/. */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  AboutNewTab: "resource:///modules/AboutNewTab.jsm",
+  ASRouter: "resource://activity-stream/lib/ASRouter.jsm",
+});
+
+// A mapping of loaded new tab pages, where the mapping is:
+//   browser -> { actor, browser, browsingContext, portID, url, loaded }
+let gLoadedTabs = new Map();
+
+export class AboutNewTabParent extends JSWindowActorParent {
+  static get loadedTabs() {
+    return gLoadedTabs;
+  }
+
+  getTabDetails(message) {
+    let browsingContext = message.target.browsingContext;
+    let browser = browsingContext.top.embedderElement;
+    return browser ? gLoadedTabs.get(browser) : null;
+  }
+
+  handleEvent(event) {
+    if (event.type == "SwapDocShells") {
+      let oldBrowser = this.browsingContext.top.embedderElement;
+      let newBrowser = event.detail;
+
+      let tabDetails = gLoadedTabs.get(oldBrowser);
+      if (tabDetails) {
+        tabDetails.browser = newBrowser;
+        gLoadedTabs.delete(oldBrowser);
+        gLoadedTabs.set(newBrowser, tabDetails);
+
+        oldBrowser.removeEventListener("SwapDocShells", this);
+        newBrowser.addEventListener("SwapDocShells", this);
+      }
+    }
+  }
+
+  async receiveMessage(message) {
+    switch (message.name) {
+      case "AboutNewTabVisible":
+        await lazy.ASRouter.waitForInitialized;
+        lazy.ASRouter.sendTriggerMessage({
+          browser: this.browsingContext.top.embedderElement,
+          // triggerId and triggerContext
+          id: "defaultBrowserCheck",
+          context: { source: "newtab" },
+        });
+        break;
+
+      case "Init": {
+        let actor = message.target;
+        let browsingContext = actor.browsingContext;
+        let browser = browsingContext.top.embedderElement;
+        if (!browser) {
+          return;
+        }
+
+        let tabDetails = {
+          actor,
+          browser,
+          browsingContext,
+          portID: message.data.portID,
+          url: message.data.url,
+        };
+        gLoadedTabs.set(browser, tabDetails);
+
+        browser.addEventListener("SwapDocShells", this);
+        browser.addEventListener("EndSwapDocShells", this);
+
+        this.notifyActivityStreamChannel("onNewTabInit", message, tabDetails);
+        break;
+      }
+
+      case "Load":
+        this.notifyActivityStreamChannel("onNewTabLoad", message);
+        break;
+
+      case "Unload": {
+        let tabDetails = this.getTabDetails(message);
+        if (!tabDetails) {
+          // When closing a tab, the embedderElement can already be disconnected, so
+          // an a backup, look up the tab details by browsing context.
+          tabDetails = this.getByBrowsingContext(
+            message.target.browsingContext
+          );
+        }
+
+        if (!tabDetails) {
+          return;
+        }
+
+        tabDetails.browser.removeEventListener("EndSwapDocShells", this);
+
+        gLoadedTabs.delete(tabDetails.browser);
+
+        this.notifyActivityStreamChannel("onNewTabUnload", message, tabDetails);
+        break;
+      }
+
+      case "ActivityStream:ContentToMain":
+        this.notifyActivityStreamChannel("onMessage", message);
+        break;
+    }
+  }
+
+  notifyActivityStreamChannel(name, message, tabDetails) {
+    if (!tabDetails) {
+      tabDetails = this.getTabDetails(message);
+      if (!tabDetails) {
+        return;
+      }
+    }
+
+    let channel = this.getChannel();
+    if (!channel) {
+      return;
+    }
+
+    let messageToSend = {
+      target: message.target,
+      data: message.data || {},
+    };
+
+    channel[name](messageToSend, tabDetails);
+  }
+
+  getByBrowsingContext(expectedBrowsingContext) {
+    for (let tabDetails of AboutNewTabParent.loadedTabs.values()) {
+      if (tabDetails.browsingContext === expectedBrowsingContext) {
+        return tabDetails;
+      }
+    }
+
+    return null;
+  }
+
+  getChannel() {
+    return lazy.AboutNewTab.activityStream?.store?.getMessageChannel();
+  }
+}