Fixing design flaw external event attachment mechanism

jsPDF.API.events was {} where new events would attach using [eventname] = handler

Now it is obvious that only last of several handlers fighting for same event would win.

Switching for less pretty, but working array of pairs model

jsPDF.API.events = [[e,h], [e,h]...]

Instead of jsPDF.API.events[e] = h
one would jsPDF.API.events.push([e,h])

Author: Daniel Dotsenko

jspdf.js

@@ -1261,31 +1261,39 @@ function jsPDF(/** String */ orientation, /** String */ unit, /** String */ form
 	// this is intentional as we allow plugins to override 
 	// built-ins
 	for (var plugin in jsPDF.API){
-		if (plugin !== 'events' && jsPDF.API.hasOwnProperty(plugin)){
-			API[plugin] = jsPDF.API[plugin]
-		}
-	}
-
-	// jsPDF.API.events is a JS Object with events catalog likely
-	// added by plugins to the jsPDF instantiator.
-	// These are always added to the new instance and some ran
-	// during instantiation.
-	var events_from_plugins = jsPDF.API.events
-	for (var e in events_from_plugins){
-		if (events_from_plugins.hasOwnProperty(e)) {
-			// subscribe takes 3 args: 'topic', function, runonce_flag
-			// if undefined, runonce is false.
-			// users can attach callback directly, 
-			// or they can attach an array with [callback, runonce_flag]
-			// that's what the "apply" magic is for below.
-			events.subscribe.apply(
-				events
-				, [e].concat(
-					typeof events_from_plugins[e] === 'function' ?
-				  	[ events_from_plugins[e] ] :
-				  	events_from_plugins[e]
-				) // it's the topic / event channel name String
-			)
+		if (jsPDF.API.hasOwnProperty(plugin)){
+			if (plugin === 'events' && jsPDF.API.events.length) {
+				(function(events, newEvents){
+
+					// jsPDF.API.events is a JS Array of Arrays 
+					// where each Array is a pair of event name, handler
+					// Events were added by plugins to the jsPDF instantiator.
+					// These are always added to the new instance and some ran
+					// during instantiation.
+
+					var eventname, handler_and_args
+
+					for (var i = newEvents.length - 1; i !== -1; i--){
+						// subscribe takes 3 args: 'topic', function, runonce_flag
+						// if undefined, runonce is false.
+						// users can attach callback directly, 
+						// or they can attach an array with [callback, runonce_flag]
+						// that's what the "apply" magic is for below.
+						eventname = newEvents[i][0]
+						handler_and_args = newEvents[i][1]
+						events.subscribe.apply(
+							events
+							, [eventname].concat(
+								typeof handler_and_args === 'function' ?
+							  	[ handler_and_args ] :
+							  	handler_and_args
+							)
+						)
+					}
+				})(events, jsPDF.API.events)
+			} else {
+				API[plugin] = jsPDF.API[plugin]
+			}
 		}
 	}
 
@@ -1328,7 +1336,7 @@ Examples:
 	var pdfdoc = new jsPDF()
 	pdfdoc.mymethod() // <- !!!!!!	
 */
-jsPDF.API = {'events':{}}
+jsPDF.API = {'events':[]}
 
 return jsPDF
 })()

jspdf.plugin.standard_fonts_metrics.js

@@ -333,63 +333,63 @@ char codes to StandardEncoding character codes. The encoding table is to be used
 somewhere around "pdfEscape" call.
 */
 
-API.events['addFonts'] = function(fontManagementObjects) {
-	// fontManagementObjects is {
-	//	'fonts':font_ID-keyed hash of font objects
-	//	, 'dictionary': lookup object, linking ["FontFamily"]['Style'] to font ID
-	//}
-	var font
-	, fontID
-	, metrics
-	, unicode_section
-	, encoding = 'Unicode'
-	, encodingBlock
-
-	for (fontID in fontManagementObjects.fonts){
-		if (fontManagementObjects.fonts.hasOwnProperty(fontID)) {
-			font = fontManagementObjects.fonts[fontID]
-
-			// // we only ship 'Unicode' mappings and metrics. No need for loop.
-			// // still, leaving this for the future.
-
-			// for (encoding in fontMetrics){
-			// 	if (fontMetrics.hasOwnProperty(encoding)) {
-
-					metrics = fontMetrics[encoding][font.PostScriptName]
-					if (metrics) {
-						if (font.metadata[encoding]) {
-							unicode_section = font.metadata[encoding]
-						} else {
-							unicode_section = font.metadata[encoding] = {}
+API.events.push([ 
+	'addFonts'
+	,function(fontManagementObjects) {
+		// fontManagementObjects is {
+		//	'fonts':font_ID-keyed hash of font objects
+		//	, 'dictionary': lookup object, linking ["FontFamily"]['Style'] to font ID
+		//}
+		var font
+		, fontID
+		, metrics
+		, unicode_section
+		, encoding = 'Unicode'
+		, encodingBlock
+
+		for (fontID in fontManagementObjects.fonts){
+			if (fontManagementObjects.fonts.hasOwnProperty(fontID)) {
+				font = fontManagementObjects.fonts[fontID]
+
+				// // we only ship 'Unicode' mappings and metrics. No need for loop.
+				// // still, leaving this for the future.
+
+				// for (encoding in fontMetrics){
+				// 	if (fontMetrics.hasOwnProperty(encoding)) {
+
+						metrics = fontMetrics[encoding][font.PostScriptName]
+						if (metrics) {
+							if (font.metadata[encoding]) {
+								unicode_section = font.metadata[encoding]
+							} else {
+								unicode_section = font.metadata[encoding] = {}
+							}
+
+							unicode_section.widths = metrics.widths
+							unicode_section.kerning = metrics.kerning
 						}
-
-						unicode_section.widths = metrics.widths
-						unicode_section.kerning = metrics.kerning
-					}
-			// 	}
-			// }
-			// for (encoding in encodings){
-			// 	if (encodings.hasOwnProperty(encoding)) {
-					encodingBlock = encodings[encoding][font.PostScriptName]
-					if (encodingBlock) {
-						if (font.metadata[encoding]) {
-							unicode_section = font.metadata[encoding]
-						} else {
-							unicode_section = font.metadata[encoding] = {}
-						}
-
-						unicode_section.encoding = encodingBlock
-						if (encodingBlock.codePages && encodingBlock.codePages.length) {
-							font.encoding = encodingBlock.codePages[0]
+				// 	}
+				// }
+				// for (encoding in encodings){
+				// 	if (encodings.hasOwnProperty(encoding)) {
+						encodingBlock = encodings[encoding][font.PostScriptName]
+						if (encodingBlock) {
+							if (font.metadata[encoding]) {
+								unicode_section = font.metadata[encoding]
+							} else {
+								unicode_section = font.metadata[encoding] = {}
+							}
+
+							unicode_section.encoding = encodingBlock
+							if (encodingBlock.codePages && encodingBlock.codePages.length) {
+								font.encoding = encodingBlock.codePages[0]
+							}
 						}
-					}
-			// 	}
-			// }
+				// 	}
+				// }
+			}
 		}
 	}
-
-
-
-}
+]) // end of adding event handler
 
 })(jsPDF.API);