From b267a71f2db3418d81b1aeb674d373a43b9fa6de Mon Sep 17 00:00:00 2001
From: Saq Imtiaz <saq.imtiaz@gmail.com>
Date: Sun, 16 May 2021 15:01:46 +0200
Subject: [PATCH] Dropzone: persistent dragover state fix (#5688)

---
 core/modules/widgets/dropzone.js | 52 ++++++++++++++++++++++++++------
 1 file changed, 42 insertions(+), 10 deletions(-)

diff --git a/core/modules/widgets/dropzone.js b/core/modules/widgets/dropzone.js
index 70bd2bf2e..1200441ff 100644
--- a/core/modules/widgets/dropzone.js
+++ b/core/modules/widgets/dropzone.js
@@ -37,6 +37,7 @@ DropZoneWidget.prototype.render = function(parent,nextSibling) {
 	this.execute();
 	// Create element
 	var domNode = this.document.createElement("div");
+	this.domNode = domNode;
 	domNode.className = this.dropzoneClass || "tc-dropzone";
 	// Add event handlers
 	if(this.dropzoneEnable) {
@@ -47,10 +48,8 @@ DropZoneWidget.prototype.render = function(parent,nextSibling) {
 			{name: "drop", handlerObject: this, handlerMethod: "handleDropEvent"},
 			{name: "paste", handlerObject: this, handlerMethod: "handlePasteEvent"},
 			{name: "dragend", handlerObject: this, handlerMethod: "handleDragEndEvent"}
-		]);		
+		]);
 	}
-	domNode.addEventListener("click",function (event) {
-	},false);
 	// Insert element
 	parent.insertBefore(domNode,nextSibling);
 	this.renderChildren(domNode,null);
@@ -59,12 +58,46 @@ DropZoneWidget.prototype.render = function(parent,nextSibling) {
 	this.currentlyEntered = [];
 };
 
+// Handler for transient event listeners added when the dropzone has an active drag in progress
+DropZoneWidget.prototype.handleEvent = function(event) {
+	if(event.type === "click") {
+		if(this.currentlyEntered.length) {
+			this.resetState();
+		}
+	} else if(event.type === "dragenter") {
+		if(event.target && event.target !== this.domNode && !$tw.utils.domContains(this.domNode,event.target)) {
+			this.resetState();
+		}
+	} else if(event.type === "dragleave") {
+		// Check if drag left the window
+		if(event.relatedTarget === null || (event.relatedTarget && event.relatedTarget.nodeName === "HTML")) {
+			this.resetState();
+		}
+	}
+};
+
+// Reset the state of the dropzone after a drag has ended
+DropZoneWidget.prototype.resetState = function() {
+	$tw.utils.removeClass(this.domNode,"tc-dragover");
+	this.currentlyEntered = [];
+	this.document.body.removeEventListener("click",this,true);
+	this.document.body.removeEventListener("dragenter",this,true);
+	this.document.body.removeEventListener("dragleave",this,true);	
+	this.dragInProgress = false;
+};
+
 DropZoneWidget.prototype.enterDrag = function(event) {
 	if(this.currentlyEntered.indexOf(event.target) === -1) {
 		this.currentlyEntered.push(event.target);
 	}
-	// If we're entering for the first time we need to apply highlighting
-	$tw.utils.addClass(this.domNodes[0],"tc-dragover");
+	if(!this.dragInProgress) {
+		this.dragInProgress = true;
+		// If we're entering for the first time we need to apply highlighting
+		$tw.utils.addClass(this.domNodes[0],"tc-dragover");	
+		this.document.body.addEventListener("click",this,true);
+		this.document.body.addEventListener("dragenter",this,true);
+		this.document.body.addEventListener("dragleave",this,true);
+	}
 };
 
 DropZoneWidget.prototype.leaveDrag = function(event) {
@@ -74,12 +107,11 @@ DropZoneWidget.prototype.leaveDrag = function(event) {
 	}
 	// Remove highlighting if we're leaving externally
 	if(this.currentlyEntered.length === 0) {
-		$tw.utils.removeClass(this.domNodes[0],"tc-dragover");
+		this.resetState();
 	}
 };
 
 DropZoneWidget.prototype.handleDragEnterEvent  = function(event) {
-	// Check for this window being the source of the drag
 	if($tw.dragInProgress) {
 		return false;
 	}
@@ -109,7 +141,7 @@ DropZoneWidget.prototype.handleDragLeaveEvent  = function(event) {
 };
 
 DropZoneWidget.prototype.handleDragEndEvent = function(event) {
-	$tw.utils.removeClass(this.domNodes[0],"tc-dragover");
+	this.resetState();
 };
 
 DropZoneWidget.prototype.filterByContentTypes = function(tiddlerFieldsArray) {
@@ -117,7 +149,7 @@ DropZoneWidget.prototype.filterByContentTypes = function(tiddlerFieldsArray) {
 		filtered = [],
 		types = [];
 	$tw.utils.each(tiddlerFieldsArray,function(tiddlerFields) {
-		types.push(tiddlerFields.type);
+		types.push(tiddlerFields.type || "");
 	});
 	filteredTypes = this.wiki.filterTiddlers(this.contentTypesFilter,this,this.wiki.makeTiddlerIterator(types));
 	$tw.utils.each(tiddlerFieldsArray,function(tiddlerFields) {
@@ -157,7 +189,7 @@ DropZoneWidget.prototype.handleDropEvent  = function(event) {
 	var self = this,
 		dataTransfer = event.dataTransfer;
 	// Remove highlighting
-	$tw.utils.removeClass(this.domNodes[0],"tc-dragover");
+	this.resetState();
 	// Import any files in the drop
 	var numFiles = 0;
 	if(dataTransfer.files) {