notes plugin now operates entirely through window.postMessage, adding support for file protocol

plugin/notes/notes.js

@@ -1,6 +1,13 @@
 /**
  * Handles opening of and synchronization with the reveal.js
  * notes window.
+ *
+ * Handshake process:
+ * 1. This window posts 'connect' to notes window
+ *    - Includes URL of presentation to show
+ * 2. Notes window responds with 'connected' when it is available
+ * 3. This window proceeds to send the current presentation state
+ *    to the notes window
  */
 var RevealNotes = (function() {
 
@@ -9,41 +16,46 @@ var RevealNotes = (function() {
 		jsFileLocation = jsFileLocation.replace(/notes\.js(\?.*)?$/, '');   // the js folder path
 		var notesPopup = window.open( jsFileLocation + 'notes.html', 'reveal.js - Notes', 'width=1120,height=850' );
 
-		// Fires when slide is changed
-		Reveal.addEventListener( 'slidechanged', post );
+		/**
+		 * Connect to the notes window through a postmessage handshake.
+		 * Using postmessage enables us to work in situations where the
+		 * origins differ, such as a presentation being opened from the
+		 * file system.
+		 */
+		function connect() {
+			// Keep trying to connect until we get a 'connected' message back
+			var connectInterval = setInterval( function() {
+				notesPopup.postMessage( JSON.stringify( {
+					namespace: 'reveal-notes',
+					type: 'connect',
+					url: window.location.protocol + '//' + window.location.host + window.location.pathname,
+					state: Reveal.getState()
+				} ), '*' );
+			}, 500 );
 
-		// Fires when a fragment is shown
-		Reveal.addEventListener( 'fragmentshown', post );
-
-		// Fires when a fragment is hidden
-		Reveal.addEventListener( 'fragmenthidden', post );
+			window.addEventListener( 'message', function( event ) {
+				var data = JSON.parse( event.data );
+				if( data && data.namespace === 'reveal-notes' && data.type === 'connected' ) {
+					clearInterval( connectInterval );
+					onConnected();
+				}
+			} );
+		}
 
 		/**
 		 * Posts the current slide data to the notes window
 		 */
 		function post() {
-			var slideElement = Reveal.getCurrentSlide(),
-				slideIndices = Reveal.getIndices(),
-				notesElement = slideElement.querySelector( 'aside.notes' ),
-				nextindexh,
-				nextindexv;
 
-			if( slideElement.nextElementSibling && slideElement.parentNode.nodeName == 'SECTION' ) {
-				nextindexh = slideIndices.h;
-				nextindexv = slideIndices.v + 1;
-			} else {
-				nextindexh = slideIndices.h + 1;
-				nextindexv = 0;
-			}
+			var slideElement = Reveal.getCurrentSlide(),
+				notesElement = slideElement.querySelector( 'aside.notes' );
 
 			var messageData = {
-				notes : '',
-				indexh : slideIndices.h,
-				indexv : slideIndices.v,
-				indexf : slideIndices.f,
-				nextindexh : nextindexh,
-				nextindexv : nextindexv,
-				markdown : false
+				namespace: 'reveal-notes',
+				type: 'state',
+				notes: '',
+				markdown: false,
+				state: Reveal.getState()
 			};
 
 			// Look for notes defined in a slide attribute
@@ -58,12 +70,30 @@ var RevealNotes = (function() {
 			}
 
 			notesPopup.postMessage( JSON.stringify( messageData ), '*' );
+
 		}
 
-		// Navigate to the current slide when the notes are loaded
-		notesPopup.addEventListener( 'load', function( event ) {
+		/**
+		 * Called once we have established a connection to the notes
+		 * window.
+		 */
+		function onConnected() {
+
+			// Monitor events that trigger a change in state
+			Reveal.addEventListener( 'slidechanged', post );
+			Reveal.addEventListener( 'fragmentshown', post );
+			Reveal.addEventListener( 'fragmenthidden', post );
+			Reveal.addEventListener( 'overviewhidden', post );
+			Reveal.addEventListener( 'overviewshown', post );
+			Reveal.addEventListener( 'paused', post );
+			Reveal.addEventListener( 'resumed', post );
+
+			// Post the initial state
 			post();
-		}, false );
+
+		}
+
+		connect();
 	}
 
 	// If the there's a 'notes' query set, open directly