1 files changed, 187 insertions, 0 deletions
diff --git a/mobile/android/modules/geckoview/GeckoViewSessionStore.sys.mjs b/mobile/android/modules/geckoview/GeckoViewSessionStore.sys.mjs
new file mode 100644
index 0000000000..584429295e
--- /dev/null
+++ b/mobile/android/modules/geckoview/GeckoViewSessionStore.sys.mjs
@@ -0,0 +1,187 @@
+/* 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 { GeckoViewUtils } from "resource://gre/modules/GeckoViewUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  SessionHistory: "resource://gre/modules/sessionstore/SessionHistory.sys.mjs",
+});
+
+const { debug, warn } = GeckoViewUtils.initLogging("SessionStore");
+const kNoIndex = Number.MAX_SAFE_INTEGER;
+const kLastIndex = Number.MAX_SAFE_INTEGER - 1;
+
+class SHistoryListener {
+  constructor(browsingContext) {
+    this.QueryInterface = ChromeUtils.generateQI([
+      "nsISHistoryListener",
+      "nsISupportsWeakReference",
+    ]);
+
+    this._browserId = browsingContext.browserId;
+    this._fromIndex = kNoIndex;
+  }
+
+  unregister(permanentKey) {
+    const bc = BrowsingContext.getCurrentTopByBrowserId(this._browserId);
+    bc?.sessionHistory?.removeSHistoryListener(this);
+    GeckoViewSessionStore._browserSHistoryListener?.delete(permanentKey);
+  }
+
+  collect(
+    permanentKey, // eslint-disable-line no-shadow
+    browsingContext, // eslint-disable-line no-shadow
+    { collectFull = true, writeToCache = false }
+  ) {
+    // Don't bother doing anything if we haven't seen any navigations.
+    if (!collectFull && this._fromIndex === kNoIndex) {
+      return null;
+    }
+
+    const fromIndex = collectFull ? -1 : this._fromIndex;
+    this._fromIndex = kNoIndex;
+
+    const historychange = lazy.SessionHistory.collectFromParent(
+      browsingContext.currentURI?.spec,
+      true, // Bug 1704574
+      browsingContext.sessionHistory,
+      fromIndex
+    );
+
+    if (writeToCache) {
+      const win =
+        browsingContext.embedderElement?.ownerGlobal ||
+        browsingContext.currentWindowGlobal?.browsingContext?.window;
+
+      GeckoViewSessionStore.onTabStateUpdate(permanentKey, win, {
+        data: { historychange },
+      });
+    }
+
+    return historychange;
+  }
+
+  collectFrom(index) {
+    if (this._fromIndex <= index) {
+      // If we already know that we need to update history from index N we
+      // can ignore any changes that happened with an element with index
+      // larger than N.
+      //
+      // Note: initially we use kNoIndex which is MAX_SAFE_INTEGER which
+      // means we don't ignore anything here, and in case of navigation in
+      // the history back and forth cases we use kLastIndex which ignores
+      // only the subsequent navigations, but not any new elements added.
+      return;
+    }
+
+    const bc = BrowsingContext.getCurrentTopByBrowserId(this._browserId);
+    if (bc?.embedderElement?.frameLoader) {
+      this._fromIndex = index;
+
+      // Queue a tab state update on the |browser.sessionstore.interval|
+      // timer. We'll call this.collect() when we receive the update.
+      bc.embedderElement.frameLoader.requestSHistoryUpdate();
+    }
+  }
+
+  OnHistoryNewEntry(newURI, oldIndex) {
+    // We use oldIndex - 1 to collect the current entry as well. This makes
+    // sure to collect any changes that were made to the entry while the
+    // document was active.
+    this.collectFrom(oldIndex == -1 ? oldIndex : oldIndex - 1);
+  }
+  OnHistoryGotoIndex() {
+    this.collectFrom(kLastIndex);
+  }
+  OnHistoryPurge() {
+    this.collectFrom(-1);
+  }
+  OnHistoryReload() {
+    this.collectFrom(-1);
+    return true;
+  }
+  OnHistoryReplaceEntry() {
+    this.collectFrom(-1);
+  }
+}
+
+export var GeckoViewSessionStore = {
+  // For each <browser> element, records the SHistoryListener.
+  _browserSHistoryListener: new WeakMap(),
+
+  observe(aSubject, aTopic, aData) {
+    debug`observe ${aTopic}`;
+
+    switch (aTopic) {
+      case "browsing-context-did-set-embedder": {
+        if (
+          aSubject &&
+          aSubject === aSubject.top &&
+          aSubject.isContent &&
+          aSubject.embedderElement &&
+          aSubject.embedderElement.permanentKey
+        ) {
+          const permanentKey = aSubject.embedderElement.permanentKey;
+          this._browserSHistoryListener
+            .get(permanentKey)
+            ?.unregister(permanentKey);
+
+          this.getOrCreateSHistoryListener(permanentKey, aSubject, true);
+        }
+        break;
+      }
+      case "browsing-context-discarded":
+        const permanentKey = aSubject?.embedderElement?.permanentKey;
+        if (permanentKey) {
+          this._browserSHistoryListener
+            .get(permanentKey)
+            ?.unregister(permanentKey);
+        }
+        break;
+    }
+  },
+
+  onTabStateUpdate(permanentKey, win, data) {
+    win.WindowEventDispatcher.sendRequest({
+      type: "GeckoView:StateUpdated",
+      data: data.data,
+    });
+  },
+
+  getOrCreateSHistoryListener(
+    permanentKey,
+    browsingContext,
+    collectImmediately = false
+  ) {
+    if (!permanentKey || browsingContext !== browsingContext.top) {
+      return null;
+    }
+
+    const sessionHistory = browsingContext.sessionHistory;
+    if (!sessionHistory) {
+      return null;
+    }
+
+    let listener = this._browserSHistoryListener.get(permanentKey);
+    if (listener) {
+      return listener;
+    }
+
+    listener = new SHistoryListener(browsingContext);
+    sessionHistory.addSHistoryListener(listener);
+    this._browserSHistoryListener.set(permanentKey, listener);
+
+    if (
+      collectImmediately &&
+      (!(browsingContext.currentURI?.spec === "about:blank") ||
+        sessionHistory.count !== 0)
+    ) {
+      listener.collect(permanentKey, browsingContext, { writeToCache: true });
+    }
+
+    return listener;
+  },
+};