1 files changed, 35 insertions, 0 deletions
diff --git a/toolkit/actors/PurgeSessionHistoryChild.sys.mjs b/toolkit/actors/PurgeSessionHistoryChild.sys.mjs
new file mode 100644
index 0000000000..32de7929a0
--- /dev/null
+++ b/toolkit/actors/PurgeSessionHistoryChild.sys.mjs
@@ -0,0 +1,35 @@
+/* vim: set ts=2 sw=2 sts=2 et tw=80: */
+/* 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 PurgeSessionHistoryChild extends JSWindowActorChild {
+  receiveMessage(message) {
+    if (message.name != "Browser:PurgeSessionHistory") {
+      return;
+    }
+    let sessionHistory = this.docShell.QueryInterface(
+      Ci.nsIWebNavigation
+    ).sessionHistory;
+    if (!sessionHistory) {
+      return;
+    }
+
+    // place the entry at current index at the end of the history list, so it won't get removed
+    if (sessionHistory.index < sessionHistory.count - 1) {
+      let legacy = sessionHistory.legacySHistory;
+      let indexEntry = legacy.getEntryAtIndex(sessionHistory.index);
+      indexEntry.QueryInterface(Ci.nsISHEntry);
+      legacy.addEntry(indexEntry, true);
+    }
+
+    let purge = sessionHistory.count;
+    if (this.document.location.href != "about:blank") {
+      --purge; // Don't remove the page the user's staring at from shistory
+    }
+
+    if (purge > 0) {
+      sessionHistory.legacySHistory.purgeHistory(purge);
+    }
+  }
+}