From 8f1114960a20ba3d84dd1633ad1976db9461a41c Mon Sep 17 00:00:00 2001
From: Jermolene <jeremy@jermolene.com>
Date: Thu, 23 Mar 2017 14:23:33 +0000
Subject: [PATCH] Refactor draggable stuff for easier reuse
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

And in the process, make the button widget draggable.

Unfortunately, Firefox has a bug that prevents buttons from being
dragged (see https://bugzilla.mozilla.org/show_bug.cgi?id=568313 and
https://bugzilla.mozilla.org/show_bug.cgi?id=646823). So we have to use
the “tag” attribute to make it use a different element.
---
 core/modules/utils/dom/datatransfer.js |  82 ------------
 core/modules/utils/dom/dragndrop.js    | 172 +++++++++++++++++++++++++
 core/modules/widgets/button.js         |  13 +-
 core/modules/widgets/draggable.js      |  86 +------------
 core/modules/widgets/link.js           |  63 +--------
 core/ui/TagTemplate.tid                |   4 +-
 6 files changed, 198 insertions(+), 222 deletions(-)
 delete mode 100644 core/modules/utils/dom/datatransfer.js
 create mode 100644 core/modules/utils/dom/dragndrop.js

diff --git a/core/modules/utils/dom/datatransfer.js b/core/modules/utils/dom/datatransfer.js
deleted file mode 100644
index de8dac46a..000000000
--- a/core/modules/utils/dom/datatransfer.js
+++ /dev/null
@@ -1,82 +0,0 @@
-/*\
-title: $:/core/modules/utils/dom/datatransfer.js
-type: application/javascript
-module-type: utils
-
-Browser data transfer utilities, used with the clipboard and drag and drop
-
-\*/
-(function(){
-
-/*jslint node: true, browser: true */
-/*global $tw: false */
-"use strict";
-
-exports.importDataTransfer = function(dataTransfer,fallbackTitle,callback) {
-	// Try each provided data type in turn
-	for(var t=0; t<importDataTypes.length; t++) {
-		if(!$tw.browser.isIE || importDataTypes[t].IECompatible) {
-			// Get the data
-			var dataType = importDataTypes[t];
-				var data = dataTransfer.getData(dataType.type);
-			// Import the tiddlers in the data
-			if(data !== "" && data !== null) {
-				if($tw.log.IMPORT) {
-					console.log("Importing data type '" + dataType.type + "', data: '" + data + "'")
-				}
-				var tiddlerFields = dataType.toTiddlerFieldsArray(data,fallbackTitle);
-				callback(tiddlerFields);
-				return;
-			}
-		}
-	}
-};
-
-var importDataTypes = [
-	{type: "text/vnd.tiddler", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		return parseJSONTiddlers(data,fallbackTitle);
-	}},
-	{type: "URL", IECompatible: true, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		// Check for tiddler data URI
-		var match = decodeURIComponent(data).match(/^data\:text\/vnd\.tiddler,(.*)/i);
-		if(match) {
-			return parseJSONTiddlers(match[1],fallbackTitle);
-		} else {
-			return [{text: data}]; // As URL string
-		}
-	}},
-	{type: "text/x-moz-url", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		// Check for tiddler data URI
-		var match = decodeURIComponent(data).match(/^data\:text\/vnd\.tiddler,(.*)/i);
-		if(match) {
-			return parseJSONTiddlers(match[1],fallbackTitle);
-		} else {
-			return [{text: data}]; // As URL string
-		}
-	}},
-	{type: "text/html", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		return [{text: data}];
-	}},
-	{type: "text/plain", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		return [{text: data}];
-	}},
-	{type: "Text", IECompatible: true, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		return [{text: data}];
-	}},
-	{type: "text/uri-list", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
-		return [{text: data}];
-	}}
-];
-
-function parseJSONTiddlers(json,fallbackTitle) {
-	var data = JSON.parse(json);
-	if(!$tw.utils.isArray(data)) {
-		data = [data];
-	}
-	data.forEach(function(fields) {
-		fields.title = fields.title || fallbackTitle;
-	});
-	return data;
-};
-
-})();
diff --git a/core/modules/utils/dom/dragndrop.js b/core/modules/utils/dom/dragndrop.js
new file mode 100644
index 000000000..3594d4414
--- /dev/null
+++ b/core/modules/utils/dom/dragndrop.js
@@ -0,0 +1,172 @@
+/*\
+title: $:/core/modules/utils/dom/dragndrop.js
+type: application/javascript
+module-type: utils
+
+Browser data transfer utilities, used with the clipboard and drag and drop
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+/*
+Options:
+
+domNode: dom node to make draggable
+dragTiddlerFn: optional function to retrieve the title of tiddler to drag
+dragFilterFn: optional function to retreive the filter defining a list of tiddlers to drag
+widget: widget to use as the contect for the filter
+*/
+exports.makeDraggable = function(options) {
+	var dragImage,
+		domNode = options.domNode;
+	// Make the dom node draggable
+	domNode.setAttribute("draggable","true");
+	// Add event handlers
+	$tw.utils.addEventListeners(domNode,[
+		{name: "dragstart", handlerFunction: function(event) {
+			// Collect the tiddlers being dragged
+			var dragTiddler = options.dragTiddlerFn && options.dragTiddlerFn(),
+				dragFilter = options.dragFilterFn && options.dragFilterFn(),
+				titles = dragTiddler ? [dragTiddler] : [];
+			if(dragFilter) {
+				titles.push.apply(titles,options.widget.wiki.filterTiddlers(dragFilter,options.widget));
+			}
+			var titleString = $tw.utils.stringifyList(titles);
+			// Check that we've something to drag
+			if(titles.length > 0 && event.target === domNode) {
+				// Mark the drag in progress
+				$tw.dragInProgress = domNode;
+				// Set the dragging class on the element being dragged
+				$tw.utils.addClass(event.target,"tc-dragging");
+				// Create the drag image elements
+				dragImage = options.widget.document.createElement("div");
+				dragImage.className = "tc-tiddler-dragger";
+				var inner = options.widget.document.createElement("div");
+				inner.className = "tc-tiddler-dragger-inner";
+				inner.appendChild(options.widget.document.createTextNode(
+					titles.length === 1 ? 
+						titles[0] :
+						titles.length + " tiddlers"
+				));
+				dragImage.appendChild(inner);
+				options.widget.document.body.appendChild(dragImage);
+				// Set the data transfer properties
+				var dataTransfer = event.dataTransfer;
+				// Set up the image
+				dataTransfer.effectAllowed = "copy";
+				if(dataTransfer.setDragImage) {
+					dataTransfer.setDragImage(dragImage.firstChild,-16,-16);
+				}
+				// Set up the data transfer
+				dataTransfer.clearData();
+				var jsonData = [];
+				if(titles.length > 1) {
+					titles.forEach(function(title) {
+						jsonData.push(options.widget.wiki.getTiddlerAsJson(title));
+					});
+					jsonData = "[" + jsonData.join(",") + "]";
+				} else {
+					jsonData = options.widget.wiki.getTiddlerAsJson(titles[0]);
+				}
+				// IE doesn't like these content types
+				if(!$tw.browser.isIE) {
+					dataTransfer.setData("text/vnd.tiddler",jsonData);
+					dataTransfer.setData("text/plain",titleString);
+					dataTransfer.setData("text/x-moz-url","data:text/vnd.tiddler," + encodeURIComponent(jsonData));
+				}
+				dataTransfer.setData("URL","data:text/vnd.tiddler," + encodeURIComponent(jsonData));
+				dataTransfer.setData("Text",titleString);
+				event.stopPropagation();
+			} else {
+				event.preventDefault();
+			}
+			return false;
+		}},
+		{name: "dragend", handlerFunction: function(event) {
+			if(event.target === domNode) {
+				$tw.dragInProgress = null;
+				// Remove the dragging class on the element being dragged
+				$tw.utils.removeClass(event.target,"tc-dragging");
+				// Delete the drag image element
+				if(dragImage) {
+					dragImage.parentNode.removeChild(dragImage);
+					dragImage = null;
+				}
+			}
+			return false;
+		}}
+	]);
+};
+
+exports.importDataTransfer = function(dataTransfer,fallbackTitle,callback) {
+	// Try each provided data type in turn
+	for(var t=0; t<importDataTypes.length; t++) {
+		if(!$tw.browser.isIE || importDataTypes[t].IECompatible) {
+			// Get the data
+			var dataType = importDataTypes[t];
+				var data = dataTransfer.getData(dataType.type);
+			// Import the tiddlers in the data
+			if(data !== "" && data !== null) {
+				if($tw.log.IMPORT) {
+					console.log("Importing data type '" + dataType.type + "', data: '" + data + "'")
+				}
+				var tiddlerFields = dataType.toTiddlerFieldsArray(data,fallbackTitle);
+				callback(tiddlerFields);
+				return;
+			}
+		}
+	}
+};
+
+var importDataTypes = [
+	{type: "text/vnd.tiddler", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		return parseJSONTiddlers(data,fallbackTitle);
+	}},
+	{type: "URL", IECompatible: true, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		// Check for tiddler data URI
+		var match = decodeURIComponent(data).match(/^data\:text\/vnd\.tiddler,(.*)/i);
+		if(match) {
+			return parseJSONTiddlers(match[1],fallbackTitle);
+		} else {
+			return [{text: data}]; // As URL string
+		}
+	}},
+	{type: "text/x-moz-url", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		// Check for tiddler data URI
+		var match = decodeURIComponent(data).match(/^data\:text\/vnd\.tiddler,(.*)/i);
+		if(match) {
+			return parseJSONTiddlers(match[1],fallbackTitle);
+		} else {
+			return [{text: data}]; // As URL string
+		}
+	}},
+	{type: "text/html", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		return [{text: data}];
+	}},
+	{type: "text/plain", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		return [{text: data}];
+	}},
+	{type: "Text", IECompatible: true, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		return [{text: data}];
+	}},
+	{type: "text/uri-list", IECompatible: false, toTiddlerFieldsArray: function(data,fallbackTitle) {
+		return [{text: data}];
+	}}
+];
+
+function parseJSONTiddlers(json,fallbackTitle) {
+	var data = JSON.parse(json);
+	if(!$tw.utils.isArray(data)) {
+		data = [data];
+	}
+	data.forEach(function(fields) {
+		fields.title = fields.title || fallbackTitle;
+	});
+	return data;
+};
+
+})();
diff --git a/core/modules/widgets/button.js b/core/modules/widgets/button.js
index 07c0c5ac1..4bb2b2638 100644
--- a/core/modules/widgets/button.js
+++ b/core/modules/widgets/button.js
@@ -95,6 +95,15 @@ ButtonWidget.prototype.render = function(parent,nextSibling) {
 		}
 		return handled;
 	},false);
+	// Make it draggable if required
+	if(this.dragTiddler || this.dragFilter) {
+		$tw.utils.makeDraggable({
+			domNode: domNode,
+			dragTiddlerFn: function() {return self.dragTiddler;},
+			dragFilterFn: function() {return self.dragFilter;},
+			widget: this
+		});
+	}
 	// Insert element
 	parent.insertBefore(domNode,nextSibling);
 	this.renderChildren(domNode,null);
@@ -172,6 +181,8 @@ ButtonWidget.prototype.execute = function() {
 	this.selectedClass = this.getAttribute("selectedClass");
 	this.defaultSetValue = this.getAttribute("default","");
 	this.buttonTag = this.getAttribute("tag");
+	this.dragTiddler = this.getAttribute("dragTiddler");
+	this.dragFilter = this.getAttribute("dragFilter");
 	// Make child widgets
 	this.makeChildWidgets();
 };
@@ -181,7 +192,7 @@ Selectively refreshes the widget if needed. Returns true if the widget or any of
 */
 ButtonWidget.prototype.refresh = function(changedTiddlers) {
 	var changedAttributes = this.computeAttributes();
-	if(changedAttributes.to || changedAttributes.message || changedAttributes.param || changedAttributes.set || changedAttributes.setTo || changedAttributes.popup || changedAttributes.hover || changedAttributes["class"] || changedAttributes.selectedClass || changedAttributes.style || (this.set && changedTiddlers[this.set]) || (this.popup && changedTiddlers[this.popup])) {
+	if(changedAttributes.to || changedAttributes.message || changedAttributes.param || changedAttributes.set || changedAttributes.setTo || changedAttributes.popup || changedAttributes.hover || changedAttributes["class"] || changedAttributes.selectedClass || changedAttributes.style || changedAttributes.dragFilter || changedAttributes.dragTiddler || (this.set && changedTiddlers[this.set]) || (this.popup && changedTiddlers[this.popup])) {
 		this.refreshSelf();
 		return true;
 	}
diff --git a/core/modules/widgets/draggable.js b/core/modules/widgets/draggable.js
index f623903e9..8ee6e957b 100644
--- a/core/modules/widgets/draggable.js
+++ b/core/modules/widgets/draggable.js
@@ -47,96 +47,24 @@ DraggableWidget.prototype.render = function(parent,nextSibling) {
 		classes.push(this.draggableClasses);
 	}
 	domNode.setAttribute("class",classes.join(" "));
-	domNode.setAttribute("draggable","true");
 	// Add event handlers
-	$tw.utils.addEventListeners(domNode,[
-		{name: "dragstart", handlerObject: this, handlerMethod: "handleDragStartEvent"},
-		{name: "dragend", handlerObject: this, handlerMethod: "handleDragEndEvent"}
-	]);
+	$tw.utils.makeDraggable({
+		domNode: domNode,
+		dragTiddlerFn: function() {return self.getAttribute("tiddler");},
+		dragFilterFn: function() {return self.getAttribute("filter");},
+		widget: this
+	});
 	// Insert the link into the DOM and render any children
 	parent.insertBefore(domNode,nextSibling);
 	this.renderChildren(domNode,null);
 	this.domNodes.push(domNode);
 };
 
-DraggableWidget.prototype.handleDragStartEvent = function(event) {
-	var self = this;
-	// Collect the tiddlers
-	var titles = [];
-	if(this.draggableTiddler) {
-		titles.push(this.draggableTiddler);
-	}
-	if(this.draggableFilter) {
-		titles.push.apply(titles,this.wiki.filterTiddlers(this.draggableFilter,this));
-	}
-	var titleString = $tw.utils.stringifyList(titles);
-	if(titles.length > 0 && event.target === this.domNodes[0]) {
-		$tw.dragInProgress = this.domNodes[0];
-		// Set the dragging class on the element being dragged
-		$tw.utils.addClass(event.target,"tc-dragging");
-		// Create the drag image elements
-		this.dragImage = this.document.createElement("div");
-		this.dragImage.className = "tc-tiddler-dragger";
-		var inner = this.document.createElement("div");
-		inner.className = "tc-tiddler-dragger-inner";
-		inner.appendChild(this.document.createTextNode(
-			titles.length === 1 ? 
-				titles[0] :
-				titles.length + " tiddlers"
-		));
-		this.dragImage.appendChild(inner);
-		this.document.body.appendChild(this.dragImage);
-		// Set the data transfer properties
-		var dataTransfer = event.dataTransfer;
-		// Set up the image
-		dataTransfer.effectAllowed = "copy";
-		if(dataTransfer.setDragImage) {
-			dataTransfer.setDragImage(this.dragImage.firstChild,-16,-16);
-		}
-		// Set up the data transfer
-		dataTransfer.clearData();
-		var jsonData = [];
-		if(titles.length > 1) {
-			titles.forEach(function(title) {
-				jsonData.push(self.wiki.getTiddlerAsJson(title));
-			});
-			jsonData = "[" + jsonData.join(",") + "]";
-		} else {
-			jsonData = this.wiki.getTiddlerAsJson(titles[0]);
-		}
-		// IE doesn't like these content types
-		if(!$tw.browser.isIE) {
-			dataTransfer.setData("text/vnd.tiddler",jsonData);
-			dataTransfer.setData("text/plain",titleString);
-			dataTransfer.setData("text/x-moz-url","data:text/vnd.tiddler," + encodeURIComponent(jsonData));
-		}
-		dataTransfer.setData("URL","data:text/vnd.tiddler," + encodeURIComponent(jsonData));
-		dataTransfer.setData("Text",titleString);
-		event.stopPropagation();
-	} else {
-		event.preventDefault();
-	}
-};
-
-DraggableWidget.prototype.handleDragEndEvent = function(event) {
-	if(event.target === this.domNodes[0]) {
-		$tw.dragInProgress = null;
-		// Remove the dragging class on the element being dragged
-		$tw.utils.removeClass(event.target,"tc-dragging");
-		// Delete the drag image element
-		if(this.dragImage) {
-			this.dragImage.parentNode.removeChild(this.dragImage);
-		}
-	}
-};
-
 /*
 Compute the internal state of the widget
 */
 DraggableWidget.prototype.execute = function() {
 	// Pick up our attributes
-	this.draggableTiddler = this.getAttribute("tiddler");
-	this.draggableFilter = this.getAttribute("filter");
 	this.draggableTag = this.getAttribute("tag","div");
 	this.draggableClasses = this.getAttribute("class");
 	// Make the child widgets
@@ -148,7 +76,7 @@ Selectively refreshes the widget if needed. Returns true if the widget or any of
 */
 DraggableWidget.prototype.refresh = function(changedTiddlers) {
 	var changedAttributes = this.computeAttributes();
-	if(changedAttributes.tiddler || changedTiddlers.tag || changedTiddlers["class"]) {
+	if(changedTiddlers.tag || changedTiddlers["class"]) {
 		this.refreshSelf();
 		return true;
 	}
diff --git a/core/modules/widgets/link.js b/core/modules/widgets/link.js
index 04c8edfbe..4d8b5cfc0 100755
--- a/core/modules/widgets/link.js
+++ b/core/modules/widgets/link.js
@@ -111,11 +111,13 @@ LinkWidget.prototype.renderLink = function(parent,nextSibling) {
 	$tw.utils.addEventListeners(domNode,[
 		{name: "click", handlerObject: this, handlerMethod: "handleClickEvent"},
 	]);
+	// Make the link draggable if required
 	if(this.draggable === "yes") {
-		$tw.utils.addEventListeners(domNode,[
-			{name: "dragstart", handlerObject: this, handlerMethod: "handleDragStartEvent"},
-			{name: "dragend", handlerObject: this, handlerMethod: "handleDragEndEvent"}
-		]);
+		$tw.utils.makeDraggable({
+			domNode: domNode,
+			dragTiddlerFn: function() {return self.to;},
+			widget: this
+		});
 	}
 	// Insert the link into the DOM and render any children
 	parent.insertBefore(domNode,nextSibling);
@@ -142,59 +144,6 @@ LinkWidget.prototype.handleClickEvent = function(event) {
 	return false;
 };
 
-LinkWidget.prototype.handleDragStartEvent = function(event) {
-	if(event.target === this.domNodes[0]) {
-		if(this.to) {
-			$tw.dragInProgress = this.domNodes[0];
-			// Set the dragging class on the element being dragged
-			$tw.utils.addClass(event.target,"tc-tiddlylink-dragging");
-			// Create the drag image elements
-			this.dragImage = this.document.createElement("div");
-			this.dragImage.className = "tc-tiddler-dragger";
-			var inner = this.document.createElement("div");
-			inner.className = "tc-tiddler-dragger-inner";
-			inner.appendChild(this.document.createTextNode(this.to));
-			this.dragImage.appendChild(inner);
-			this.document.body.appendChild(this.dragImage);
-			// Set the data transfer properties
-			var dataTransfer = event.dataTransfer;
-			// First the image
-			dataTransfer.effectAllowed = "copy";
-			if(dataTransfer.setDragImage) {
-				dataTransfer.setDragImage(this.dragImage.firstChild,-16,-16);
-			}
-			// Then the data
-			dataTransfer.clearData();
-			var jsonData = this.wiki.getTiddlerAsJson(this.to),
-				textData = this.wiki.getTiddlerText(this.to,""),
-				title = (new RegExp("^" + $tw.config.textPrimitives.wikiLink + "$","mg")).exec(this.to) ? this.to : "[[" + this.to + "]]";
-			// IE doesn't like these content types
-			if(!$tw.browser.isIE) {
-				dataTransfer.setData("text/vnd.tiddler",jsonData);
-				dataTransfer.setData("text/plain",title);
-				dataTransfer.setData("text/x-moz-url","data:text/vnd.tiddler," + encodeURIComponent(jsonData));
-			}
-			dataTransfer.setData("URL","data:text/vnd.tiddler," + encodeURIComponent(jsonData));
-			dataTransfer.setData("Text",title);
-			event.stopPropagation();
-		} else {
-			event.preventDefault();
-		}
-	}
-};
-
-LinkWidget.prototype.handleDragEndEvent = function(event) {
-	if(event.target === this.domNodes[0]) {
-		$tw.dragInProgress = null;
-		// Remove the dragging class on the element being dragged
-		$tw.utils.removeClass(event.target,"tc-tiddlylink-dragging");
-		// Delete the drag image element
-		if(this.dragImage) {
-			this.dragImage.parentNode.removeChild(this.dragImage);
-		}
-	}
-};
-
 /*
 Compute the internal state of the widget
 */
diff --git a/core/ui/TagTemplate.tid b/core/ui/TagTemplate.tid
index f1a5a582a..243062be7 100644
--- a/core/ui/TagTemplate.tid
+++ b/core/ui/TagTemplate.tid
@@ -2,9 +2,7 @@ title: $:/core/ui/TagTemplate
 
 <span class="tc-tag-list-item">
 <$set name="transclusion" value=<<currentTiddler>>>
-<$draggable tag="span" filter="[all[current]tagging[]]">
-<$macrocall $name="tag-pill-body" tag=<<currentTiddler>> icon={{!!icon}} colour={{!!color}} palette={{$:/palette}} element-tag="""$button""" element-attributes="""popup=<<qualify "$:/state/popup/tag">>"""/>
-</$draggable>
+<$macrocall $name="tag-pill-body" tag=<<currentTiddler>> icon={{!!icon}} colour={{!!color}} palette={{$:/palette}} element-tag="""$button""" element-attributes="""popup=<<qualify "$:/state/popup/tag">> dragFilter='[all[current]tagging[]]' tag='span'"""/>
 <$reveal state=<<qualify "$:/state/popup/tag">> type="popup" position="below" animate="yes" class="tc-drop-down">
 <$transclude tiddler="$:/core/ui/ListItemTemplate"/>
 <$list filter="[all[shadows+tiddlers]tag[$:/tags/TagDropdown]!has[draft.of]]" variable="listItem">