1 files changed, 57 insertions, 0 deletions
diff --git a/remote/shared/messagehandler/transports/BrowsingContextUtils.sys.mjs b/remote/shared/messagehandler/transports/BrowsingContextUtils.sys.mjs
new file mode 100644
index 0000000000..482f90948a
--- /dev/null
+++ b/remote/shared/messagehandler/transports/BrowsingContextUtils.sys.mjs
@@ -0,0 +1,57 @@
+/* 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/. */
+
+function isExtensionContext(browsingContext) {
+  let principal;
+  if (CanonicalBrowsingContext.isInstance(browsingContext)) {
+    principal = browsingContext.currentWindowGlobal.documentPrincipal;
+  } else {
+    principal = browsingContext.window.document.nodePrincipal;
+  }
+
+  // In practice, note that the principal will never be an expanded principal.
+  // The are only used for content scripts executed in a Sandbox, and do not
+  // have a browsing context on their own.
+  // But we still use this flag because there is no isAddonPrincipal flag.
+  return principal.isAddonOrExpandedAddonPrincipal;
+}
+
+function isParentProcess(browsingContext) {
+  if (CanonicalBrowsingContext.isInstance(browsingContext)) {
+    return browsingContext.currentWindowGlobal.osPid === -1;
+  }
+
+  // If `browsingContext` is not a `CanonicalBrowsingContext`, then we are
+  // necessarily in a content process page.
+  return false;
+}
+
+/**
+ * Check if the given browsing context is valid for the message handler
+ * to use.
+ *
+ * @param {BrowsingContext} browsingContext
+ *     The browsing context to check.
+ * @param {object=} options
+ * @param {string=} options.browserId
+ *    The id of the browser to filter the browsing contexts by (optional).
+ * @returns {boolean}
+ *     True if the browsing context is valid, false otherwise.
+ */
+export function isBrowsingContextCompatible(browsingContext, options = {}) {
+  const { browserId } = options;
+
+  // If a browserId was provided, skip browsing contexts which are not
+  // associated with this browserId.
+  if (browserId !== undefined && browsingContext.browserId !== browserId) {
+    return false;
+  }
+
+  // Skip:
+  // - extension contexts until we support debugging webextensions, see Bug 1755014.
+  // - privileged contexts until we support debugging Chrome context, see Bug 1713440.
+  return (
+    !isExtensionContext(browsingContext) && !isParentProcess(browsingContext)
+  );
+}