From 09afa8297a81fbe48dec7ef376db04077ce949c8 Mon Sep 17 00:00:00 2001
From: Tobias Beer <beertobias@gmail.com>
Date: Mon, 9 Feb 2015 23:49:04 +0100
Subject: [PATCH] prevents drag and drop import in same window
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

fixes #592

Introduces and preserves **_origin** field when using drag-and-drop —
bad idea? discard? different field name?

demo http://592.tiddlyspot.com
---
 core/modules/widgets/dropzone.js | 21 ++++++++++++++-------
 core/modules/widgets/link.js     |  2 +-
 core/modules/wiki.js             | 13 ++++++++-----
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/core/modules/widgets/dropzone.js b/core/modules/widgets/dropzone.js
index b0f7510fe..c1441175e 100644
--- a/core/modules/widgets/dropzone.js
+++ b/core/modules/widgets/dropzone.js
@@ -27,14 +27,14 @@ DropZoneWidget.prototype = new Widget();
 Render this widget into the DOM
 */
 DropZoneWidget.prototype.render = function(parent,nextSibling) {
-	var self = this;
+	var domNode;
 	// Remember parent
 	this.parentDomNode = parent;
 	// Compute attributes and execute state
 	this.computeAttributes();
 	this.execute();
 	// Create element
-	var domNode = this.document.createElement("div");
+	domNode = this.document.createElement("div");
 	domNode.className = "tc-dropzone";
 	// Add event handlers
 	$tw.utils.addEventListeners(domNode,[
@@ -119,20 +119,27 @@ DropZoneWidget.prototype.handleDropEvent  = function(event) {
 };
 
 DropZoneWidget.prototype.importData = function(dataTransfer) {
+	var data, dataType, origin, t, tiddlerFields, title;
 	// Try each provided data type in turn
-	for(var t=0; t<this.importDataTypes.length; t++) {
+	for(t=0; t<this.importDataTypes.length; t++) {
 		if(!$tw.browser.isIE || this.importDataTypes[t].IECompatible) {
 			// Get the data
-			var dataType = this.importDataTypes[t];
-				var data = dataTransfer.getData(dataType.type);
+			dataType = this.importDataTypes[t];
+			data = dataTransfer.getData(dataType.type);
 			// Import the tiddlers in the data
 			if(data !== "" && data !== null) {
 				if($tw.log.IMPORT) {
 					console.log("Importing data type '" + dataType.type + "', data: '" + data + "'")
 				}
-				var tiddlerFields = dataType.convertToFields(data);
-				if(!tiddlerFields.title) {
+				tiddlerFields = dataType.convertToFields(data);
+				title = tiddlerFields.title;
+				if(!title) {
 					tiddlerFields.title = this.wiki.generateNewTitle("Untitled");
+				} else {
+					origin = tiddlerFields["_origin"];
+					if(origin && origin === window.location.href && $tw.wiki.getTiddler(title)) {
+						return false;
+					}
 				}
 				this.dispatchEvent({type: "tm-import-tiddlers", param: JSON.stringify([tiddlerFields])});
 				return;
diff --git a/core/modules/widgets/link.js b/core/modules/widgets/link.js
index eac53a050..d57b6b436 100755
--- a/core/modules/widgets/link.js
+++ b/core/modules/widgets/link.js
@@ -153,7 +153,7 @@ LinkWidget.prototype.handleDragStartEvent = function(event) {
 			}
 			// Then the data
 			dataTransfer.clearData();
-			var jsonData = this.wiki.getTiddlerAsJson(this.to),
+			var jsonData = this.wiki.getTiddlerAsJson(this.to,true),
 				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
diff --git a/core/modules/wiki.js b/core/modules/wiki.js
index f1b3c83f8..79141f18f 100755
--- a/core/modules/wiki.js
+++ b/core/modules/wiki.js
@@ -594,17 +594,20 @@ exports.getSubTiddler = function(title,subTiddlerTitle) {
 /*
 Retrieve a tiddler as a JSON string of the fields
 */
-exports.getTiddlerAsJson = function(title) {
-	var tiddler = this.getTiddler(title);
+exports.getTiddlerAsJson = function(title,exporting) {
+	var fields = Object.create(null),
+		tiddler = this.getTiddler(title);
 	if(tiddler) {
-		var fields = Object.create(null);
 		$tw.utils.each(tiddler.fields,function(value,name) {
 			fields[name] = tiddler.getFieldString(name);
 		});
-		return JSON.stringify(fields);
 	} else {
-		return JSON.stringify({title: title});
+		fields["title"] = title;
 	}
+	if(exporting) {
+		fields["_origin"] = window.location.href;
+	}
+	return JSON.stringify(fields);
 };
 
 /*