1 files changed, 79 insertions, 0 deletions
diff --git a/browser/components/pocket/content/panels/js/messages.js b/browser/components/pocket/content/panels/js/messages.js
new file mode 100644
index 0000000000..38d7399ffa
--- /dev/null
+++ b/browser/components/pocket/content/panels/js/messages.js
@@ -0,0 +1,79 @@
+// Documentation of methods used here are at:
+// https://developer.mozilla.org/en-US/Add-ons/Code_snippets/Interaction_between_privileged_and_non-privileged_pages
+
+var pktPanelMessaging = (function() {
+  function panelIdFromURL(url) {
+    var panelId = url.match(/panelId=([\w|\d|\.]*)&?/);
+    if (panelId && panelId.length > 1) {
+      return panelId[1];
+    }
+
+    return 0;
+  }
+
+  function prefixedMessageId(messageId) {
+    return "PKT_" + messageId;
+  }
+
+  function panelPrefixedMessageId(panelId, messageId) {
+    return prefixedMessageId(panelId + "_" + messageId);
+  }
+
+  function addMessageListener(panelId, messageId, callback) {
+    document.addEventListener(
+      panelPrefixedMessageId(panelId, messageId),
+      function(e) {
+        callback(JSON.parse(e.target.getAttribute("payload"))[0]);
+
+        // TODO: Figure out why e.target.parentNode is null
+        // e.target.parentNode.removeChild(e.target);
+      }
+    );
+  }
+
+  function removeMessageListener(panelId, messageId, callback) {
+    document.removeEventListener(
+      panelPrefixedMessageId(panelId, messageId),
+      callback
+    );
+  }
+
+  function sendMessage(panelId, messageId, payload, callback) {
+    // Payload needs to be an object in format:
+    // { panelId: panelId, data: {} }
+    var messagePayload = {
+      panelId,
+      data: payload || {},
+    };
+
+    // Create a callback to listen for a response
+    if (callback) {
+      var messageResponseId = messageId + "Response";
+      var responseListener = function(responsePayload) {
+        callback(responsePayload);
+        removeMessageListener(panelId, messageResponseId, responseListener);
+      };
+
+      addMessageListener(panelId, messageResponseId, responseListener);
+    }
+
+    // Send message
+    var element = document.createElement("PKTMessageFromPanelElement");
+    element.setAttribute("payload", JSON.stringify([messagePayload]));
+    document.documentElement.appendChild(element);
+
+    var evt = document.createEvent("Events");
+    evt.initEvent(prefixedMessageId(messageId), true, false);
+    element.dispatchEvent(evt);
+  }
+
+  /**
+   * Public functions
+   */
+  return {
+    panelIdFromURL,
+    addMessageListener,
+    removeMessageListener,
+    sendMessage,
+  };
+})();