1 files changed, 49 insertions, 0 deletions
diff --git a/toolkit/components/extensions/child/ext-scripting.js b/toolkit/components/extensions/child/ext-scripting.js
new file mode 100644
index 0000000000..cce587227f
--- /dev/null
+++ b/toolkit/components/extensions/child/ext-scripting.js
@@ -0,0 +1,49 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=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/. */
+
+"use strict";
+
+var { ExtensionError } = ExtensionUtils;
+
+this.scripting = class extends ExtensionAPI {
+  getAPI(context) {
+    return {
+      scripting: {
+        executeScript: async details => {
+          let { func, args, ...parentDetails } = details;
+
+          if (details.files) {
+            if (details.args) {
+              throw new ExtensionError(
+                "'args' may not be used with file injections."
+              );
+            }
+          }
+          // `files` and `func` are mutually exclusive but that is checked in
+          // the parent (in `execute()`).
+          if (func) {
+            try {
+              const serializedArgs = args
+                ? JSON.stringify(args).slice(1, -1)
+                : "";
+              // This is a prop that we compute here and pass to the parent.
+              parentDetails.func = `(${func.toString()})(${serializedArgs});`;
+            } catch (e) {
+              throw new ExtensionError("Unserializable arguments.");
+            }
+          } else {
+            parentDetails.func = null;
+          }
+
+          return context.childManager.callParentAsyncFunction(
+            "scripting.executeScriptInternal",
+            [parentDetails]
+          );
+        },
+      },
+    };
+  }
+};