Unify codestile

1 files changed, 544 insertions, 546 deletions

diff --git a/program/js/treelist.js b/program/js/treelist.js
index fec2d7f21..5913f44b4 100644
--- a/program/js/treelist.js
+++ b/program/js/treelist.js
@@ -23,552 +23,550 @@
  */
 function rcube_treelist_widget(node, p)
 {
-	// apply some defaults to p
-	p = $.extend({
-		id_prefix: '',
-		autoexpand: 1000,
-		selectable: false,
-		check_droptarget: function(node){ return !node.virtual }
-	}, p || {});
-
-	var container = $(node);
-	var data = p.data || [];
-	var indexbyid = {};
-	var selection = null;
-	var drag_active = false;
-	var box_coords = {};
-	var item_coords = [];
-	var autoexpand_timer;
-	var autoexpand_item;
-	var body_scroll_top = 0;
-	var list_scroll_top = 0;
-	var me = this;
-
-
-	/////// export public members and methods
-
-	this.container = container;
-	this.expand = expand;
-	this.collapse = collapse;
-	this.select = select;
-	this.render = render;
-	this.drag_start = drag_start;
-	this.drag_end = drag_end;
-	this.intersects = intersects;
-	this.update = update_node;
-	this.insert = insert;
-	this.remove = remove;
-	this.get_item = get_item;
-	this.get_selection = get_selection;
-
-
-	/////// startup code (constructor)
-
-	// abort if node not found
-	if (!container.length)
-		return;
-
-	if (p.data) {
-		index_data({ children:data });
-	}
-	// load data from DOM
-	else {
-		update_data();
-	}
-
-	// register click handlers on list
-	container.on('click', 'div.treetoggle', function(e){
-		toggle(dom2id($(this).parent()));
-	});
-
-	container.on('click', 'li', function(e){
-		var node = p.selectable ? indexbyid[dom2id($(this))] : null;
-		if (node && !node.virtual) {
-			select(node.id);
-			e.stopPropagation();
-		}
-	});
-
-
-	/////// private methods
-
-	/**
-	 * Collaps a the node with the given ID
-	 */
-	function collapse(id, recursive, set)
-	{
-		var node;
-		if (node = indexbyid[id]) {
-			node.collapsed = typeof set == 'undefined' || set;
-			update_dom(node);
-
-			// Work around a bug in IE6 and IE7, see #1485309
-			if (window.bw && (bw.ie6 || bw.ie7) && node.collapsed) {
-				id2dom(node.id).next().children('ul:visible').hide().show();
-			}
-
-			if (recursive && node.children) {
-				for (var i=0; i < node.children.length; i++) {
-					collapse(node.children[i].id, recursive, set);
-				}
-			}
-
-			me.triggerEvent(node.collapsed ? 'collapse' : 'expand', node);
-		}
-	}
-
-	/**
-	 * Expand a the node with the given ID
-	 */
-	function expand(id, recursive)
-	{
-		collapse(id, recursive, false);
-	}
-
-	/**
-	 * Toggle collapsed state of a list node
-	 */
-	function toggle(id, recursive)
-	{
-		var node;
-		if (node = indexbyid[id]) {
-			collapse(id, recursive, !node.collapsed);
-		}
-	}
-
-	/**
-	 * Select a tree node by it's ID
-	 */
-	function select(id)
-	{
-		if (selection) {
-			id2dom(selection).removeClass('selected');
-			selection = null;
-		}
-
-		var li = id2dom(id);
-		if (li.length) {
-			li.addClass('selected');
-			selection = id;
-			// TODO: expand all parent nodes if collapsed
-			scroll_to_node(li);
-		}
-
-		me.triggerEvent('select', indexbyid[id]);
-	}
-
-	/**
-	 * Getter for the currently selected node ID
-	 */
-	function get_selection()
-	{
-		return selection;
-	}
-
-	/**
-	 * Return the DOM element of the list item with the given ID
-	 */
-	function get_item(id)
-	{
-		return id2dom(id).get(0);
-	}
-
-	/**
-	 * Insert the given node
-	 */
-	function insert(node, parent_id, sort)
-	{
-		var li, parent_li,
-			parent_node = parent_id ? indexbyid[parent_id] : null;
-
-		// insert as child of an existing node
-		if (parent_node) {
-			if (!parent_node.children)
-				parent_node.children = [];
-
-			parent_node.children.push(node);
-			parent_li = id2dom(parent_id);
-
-			// re-render the entire subtree
-			if (parent_node.children.length == 1) {
-				render_node(parent_node, parent_li.parent(), parent_li);
-				li = id2dom(node.id);
-			}
-			else {
-				// append new node to parent's child list
-				li = render_node(node, parent_li.children('ul').first());
-			}
-		}
-		// insert at top level
-		else {
-			data.push(node);
-			li = render_node(node, container);
-		}
-
-		indexbyid[node.id] = node;
-
-		if (sort) {
-			resort_node(li, typeof sort == 'string' ? '[class~="' + sort + '"]' : '');
-		}
-	}
-
-	/**
-	 * Update properties of an existing node
-	 */
-	function update_node(id, updates, sort)
-	{
-		var li, node = indexbyid[id];
-		if (node) {
-			li = id2dom(id);
-
-			if (updates.id || updates.html || updates.children || updates.classes) {
-				$.extend(node, updates);
-				render_node(node, li.parent(), li);
-			}
-
-			if (node.id != id) {
-				delete indexbyid[id];
-				indexbyid[node.id] = node;
-			}
-
-			if (sort) {
-				resort_node(li, typeof sort == 'string' ? '[class~="' + sort + '"]' : '');
-			}
-		}
-	}
-
-	/**
-	 * Helper method to sort the list of the given item
-	 */
-	function resort_node(li, filter)
-	{
-		var first, sibling,
-			myid = li.get(0).id,
-			sortname = li.children().first().text().toUpperCase();
-
-		li.parent().children('li' + filter).each(function(i, elem) {
-			if (i == 0)
-				first = elem;
-			if (elem.id == myid) {
-				// skip
-			}
-			else if (elem.id != myid && sortname >= $(elem).children().first().text().toUpperCase()) {
-				sibling = elem;
-			}
-			else {
-				return false;
-			}
-		});
-
-		if (sibling) {
-			li.insertAfter(sibling);
-		}
-		else if (first.id != myid) {
-			li.insertBefore(first);
-		}
-
-		// reload data from dom
-		update_data();
-	}
-
-	/**
-	 * Remove the item with the given ID
-	 */
-	function remove(id)
-	{
-		var node, li;
-		if (node = indexbyid[id]) {
-			li = id2dom(id);
-			li.remove();
-
-			node.deleted = true;
-			delete indexbyid[id];
-
-			return true;
-		}
-
-		return false;
-	}
-
-	/**
-	 * (Re-)read tree data from DOM
-	 */
-	function update_data()
-	{
-		data = walk_list(container);
-	}
-
-	/**
-	 * Apply the 'collapsed' status of the data node to the corresponding DOM element(s)
-	 */
-	function update_dom(node)
-	{
-		var li = id2dom(node.id);
-		li.children('ul').first()[(node.collapsed ? 'hide' : 'show')]();
-		li.children('div.treetoggle').removeClass('collapsed expanded').addClass(node.collapsed ? 'collapsed' : 'expanded');
-		me.triggerEvent('toggle', node);
-	}
-
-	/**
-	 * Render the tree list from the internal data structure
-	 */
-	function render()
-	{
-		if (me.triggerEvent('renderBefore', data) === false)
-			return;
-
-		// remove all child nodes
-		container.html('');
-
-		// render child nodes
-		for (var i=0; i < data.length; i++) {
-			render_node(data[i], container);
-		}
-
-		me.triggerEvent('renderAfter', container);
-	}
-
-	/**
-	 * Render a specific node into the DOM list
-	 */
-	function render_node(node, parent, replace)
-	{
-		if (node.deleted)
-			return;
-
-		var li = $('<li>')
-			.attr('id', p.id_prefix + (p.id_encode ? p.id_encode(node.id) : node.id))
-			.addClass((node.classes || []).join(' '));
-
-		if (replace)
-			replace.replaceWith(li);
-		else
-			li.appendTo(parent);
-
-		if (typeof node.html == 'string') {
-			li.html(node.html);
-		}
-		else if (typeof node.html == 'object') {
-			li.append(node.html);
-		}
-
-		if (node.virtual)
-			li.addClass('virtual');
-		if (node.id == selection)
-			li.addClass('selected');
-
-		// add child list and toggle icon
-		if (node.children && node.children.length) {
-			$('<div class="treetoggle '+(node.collapsed ? 'collapsed' : 'expanded') + '">&nbsp;</div>').appendTo(li);
-			var ul = $('<ul>').appendTo(li).attr('class', node.childlistclass);
-			if (node.collapsed)
-				ul.hide();
-
-			for (var i=0; i < node.children.length; i++) {
-				render_node(node.children[i], ul);
-			}
-		}
-
-		return li;
-	}
-
-	/**
-	 * Recursively walk the DOM tree and build an internal data structure
-	 * representing the skeleton of this tree list.
-	 */
-	function walk_list(ul)
-	{
-		var result = [];
-		ul.children('li').each(function(i,e){
-			var li = $(e), sublist = li.children('ul');
-			var node = {
-				id: dom2id(li),
-				classes: li.attr('class').split(' '),
-				virtual: li.hasClass('virtual'),
-				html: li.children().first().get(0).outerHTML,
-				children: walk_list(sublist)
-			}
-
-			if (sublist.length) {
-				node.childlistclass = sublist.attr('class');
-			}
-			if (node.children.length) {
-				node.collapsed = sublist.css('display') == 'none';
-			}
-			if (li.hasClass('selected')) {
-				selection = node.id;
-			}
-
-			result.push(node);
-			indexbyid[node.id] = node;
-		})
-
-		return result;
-	}
-
-	/**
-	 * Recursively walk the data tree and index nodes by their ID
-	 */
-	function index_data(node)
-	{
-		if (node.id) {
-			indexbyid[node.id] = node;
-		}
-		for (var c=0; node.children && c < node.children.length; c++) {
-			index_data(node.children[c]);
-		}
-	}
-
-	/**
-	 * Get the (stripped) node ID from the given DOM element
-	 */
-	function dom2id(li)
-	{
-		var domid = li.attr('id').replace(new RegExp('^' + (p.id_prefix) || '%'), '');
-		return p.id_decode ? p.id_decode(domid) : domid;
-	}
-
-	/**
-	 * Get the <li> element for the given node ID
-	 */
-	function id2dom(id)
-	{
-		var domid = p.id_encode ? p.id_encode(id) : id;
-		return $('#' + p.id_prefix + domid);
-	}
-
-	/**
-	 * Scroll the parent container to make the given list item visible
-	 */
-	function scroll_to_node(li)
-	{
-		var scroller = container.parent(),
-			current_offset = scroller.scrollTop(),
-			rel_offset = li.offset().top - scroller.offset().top;
-
-		if (rel_offset < 0 || rel_offset + li.height() > scroller.height())
-			scroller.scrollTop(rel_offset + current_offset);
-	}
-
-	///// drag & drop support
-
-	/**
-	 * When dragging starts, compute absolute bounding boxes of the list and it's items
-	 * for faster comparisons while mouse is moving
-	 */
-	function drag_start()
-	{
-		var li, item, height,
-			pos = container.offset();
-
-		body_scroll_top = bw.ie ? 0 : window.pageYOffset;
-		list_scroll_top = container.parent().scrollTop();
-
-		drag_active = true;
-		box_coords = {
-			x1: pos.left,
-			y1: pos.top,
-			x2: pos.left + container.width(),
-			y2: pos.top + container.height()
-		};
-
-		item_coords = [];
-		for (var id in indexbyid) {
-			li = id2dom(id);
-			item = li.children().first().get(0);
-			if (height = item.offsetHeight) {
-				pos = $(item).offset();
-				item_coords[id] = {
-					x1: pos.left,
-					y1: pos.top,
-					x2: pos.left + item.offsetWidth,
-					y2: pos.top + height,
-					on: id == autoexpand_item
-				};
-			}
-		}
-	}
-
-	/**
-	 * Signal that dragging has stopped
-	 */
-	function drag_end()
-	{
-		drag_active = false;
-
-		if (autoexpand_timer) {
-			clearTimeout(autoexpand_timer);
-			autoexpand_timer = null;
-			autoexpand_item = null;
-		}
-
-		$('li.droptarget', container).removeClass('droptarget');
-	}
-
-	/**
-	 * Determine if the given mouse coords intersect the list and one if its items
-	 */
-	function intersects(mouse, highlight)
-	{
-		// offsets to compensate for scrolling while dragging a message
-		var boffset = bw.ie ? -document.documentElement.scrollTop : body_scroll_top,
-			moffset = list_scroll_top - container.parent().scrollTop(),
-			result = null;
-
-		mouse.top = mouse.y + -moffset - boffset;
-
-		// no intersection with list bounding box
-		if (mouse.x < box_coords.x1 || mouse.x >= box_coords.x2 || mouse.top < box_coords.y1 || mouse.top >= box_coords.y2) {
-		  // TODO: optimize performance for this operation
-		  $('li.droptarget', container).removeClass('droptarget');
-			return result;
-		}
-
-		// check intersection with visible list items
-		var pos, node;
-		for (var id in item_coords) {
-			pos = item_coords[id];
-			if (mouse.x >= pos.x1 && mouse.x < pos.x2 && mouse.top >= pos.y1 && mouse.top < pos.y2) {
-				node = indexbyid[id];
-
-				// if the folder is collapsed, expand it after the configured time
-				if (node.children && node.children.length && node.collapsed && p.autoexpand && autoexpand_item != id) {
-					if (autoexpand_timer)
-						clearTimeout(autoexpand_timer);
-
-					autoexpand_item = id;
-					autoexpand_timer = setTimeout(function() {
-						expand(autoexpand_item);
-						drag_start();  // re-calculate item coords
-						autoexpand_item = null;
-					}, p.autoexpand);
-				}
-				else if (autoexpand_timer && autoexpand_item != id) {
-					clearTimeout(autoexpand_timer);
-					autoexpand_item = null;
-					autoexpand_timer = null;
-				}
-
-				// check if this item is accepted as drop target
-				if (p.check_droptarget(node)) {
-					if (highlight) {
-						id2dom(id).addClass('droptarget');
-						pos.on = true;
-					}
-					result = id;
-				}
-				else {
-					result = null;
-				}
-			}
-			else if (pos.on) {
-				id2dom(id).removeClass('droptarget');
-				pos.on = false;
-			}
-		}
-
-		return result;
-	}
+  // apply some defaults to p
+  p = $.extend({
+    id_prefix: '',
+    autoexpand: 1000,
+    selectable: false,
+    check_droptarget: function(node){ return !node.virtual }
+  }, p || {});
+
+  var container = $(node),
+    data = p.data || [],
+    indexbyid = {},
+    selection = null,
+    drag_active = false,
+    box_coords = {},
+    item_coords = [],
+    autoexpand_timer,
+    autoexpand_item,
+    body_scroll_top = 0,
+    list_scroll_top = 0,
+    me = this;
+
+
+  /////// export public members and methods
+
+  this.container = container;
+  this.expand = expand;
+  this.collapse = collapse;
+  this.select = select;
+  this.render = render;
+  this.drag_start = drag_start;
+  this.drag_end = drag_end;
+  this.intersects = intersects;
+  this.update = update_node;
+  this.insert = insert;
+  this.remove = remove;
+  this.get_item = get_item;
+  this.get_selection = get_selection;
+
+  /////// startup code (constructor)
+
+  // abort if node not found
+  if (!container.length)
+    return;
+
+  if (p.data)
+    index_data({ children:data });
+  // load data from DOM
+  else
+    update_data();
+
+  // register click handlers on list
+  container.on('click', 'div.treetoggle', function(e){
+    toggle(dom2id($(this).parent()));
+  });
+
+  container.on('click', 'li', function(e){
+    var node = p.selectable ? indexbyid[dom2id($(this))] : null;
+    if (node && !node.virtual) {
+      select(node.id);
+      e.stopPropagation();
+    }
+  });
+
+
+  /////// private methods
+
+  /**
+   * Collaps a the node with the given ID
+   */
+  function collapse(id, recursive, set)
+  {
+    var node;
+
+    if (node = indexbyid[id]) {
+      node.collapsed = typeof set == 'undefined' || set;
+      update_dom(node);
+
+      // Work around a bug in IE6 and IE7, see #1485309
+      if (window.bw && (bw.ie6 || bw.ie7) && node.collapsed) {
+        id2dom(node.id).next().children('ul:visible').hide().show();
+      }
+
+      if (recursive && node.children) {
+        for (var i=0; i < node.children.length; i++) {
+          collapse(node.children[i].id, recursive, set);
+        }
+      }
+
+      me.triggerEvent(node.collapsed ? 'collapse' : 'expand', node);
+    }
+  }
+
+  /**
+   * Expand a the node with the given ID
+   */
+  function expand(id, recursive)
+  {
+    collapse(id, recursive, false);
+  }
+
+  /**
+   * Toggle collapsed state of a list node
+   */
+  function toggle(id, recursive)
+  {
+    var node;
+    if (node = indexbyid[id]) {
+      collapse(id, recursive, !node.collapsed);
+    }
+  }
+
+  /**
+   * Select a tree node by it's ID
+   */
+  function select(id)
+  {
+    if (selection) {
+      id2dom(selection).removeClass('selected');
+      selection = null;
+    }
+
+    var li = id2dom(id);
+    if (li.length) {
+      li.addClass('selected');
+      selection = id;
+      // TODO: expand all parent nodes if collapsed
+      scroll_to_node(li);
+    }
+
+    me.triggerEvent('select', indexbyid[id]);
+  }
+
+  /**
+   * Getter for the currently selected node ID
+   */
+  function get_selection()
+  {
+    return selection;
+  }
+
+  /**
+   * Return the DOM element of the list item with the given ID
+   */
+  function get_item(id)
+  {
+    return id2dom(id).get(0);
+  }
+
+  /**
+   * Insert the given node
+   */
+  function insert(node, parent_id, sort)
+  {
+    var li, parent_li,
+      parent_node = parent_id ? indexbyid[parent_id] : null;
+
+    // insert as child of an existing node
+    if (parent_node) {
+      if (!parent_node.children)
+        parent_node.children = [];
+
+      parent_node.children.push(node);
+      parent_li = id2dom(parent_id);
+
+      // re-render the entire subtree
+      if (parent_node.children.length == 1) {
+        render_node(parent_node, parent_li.parent(), parent_li);
+        li = id2dom(node.id);
+      }
+      else {
+        // append new node to parent's child list
+        li = render_node(node, parent_li.children('ul').first());
+      }
+    }
+    // insert at top level
+    else {
+      data.push(node);
+      li = render_node(node, container);
+    }
+
+    indexbyid[node.id] = node;
+
+    if (sort) {
+      resort_node(li, typeof sort == 'string' ? '[class~="' + sort + '"]' : '');
+    }
+  }
+
+  /**
+   * Update properties of an existing node
+   */
+  function update_node(id, updates, sort)
+  {
+    var li, node = indexbyid[id];
+
+    if (node) {
+      li = id2dom(id);
+
+      if (updates.id || updates.html || updates.children || updates.classes) {
+        $.extend(node, updates);
+        render_node(node, li.parent(), li);
+      }
+
+      if (node.id != id) {
+        delete indexbyid[id];
+        indexbyid[node.id] = node;
+      }
+
+      if (sort) {
+        resort_node(li, typeof sort == 'string' ? '[class~="' + sort + '"]' : '');
+      }
+    }
+  }
+
+  /**
+   * Helper method to sort the list of the given item
+   */
+  function resort_node(li, filter)
+  {
+    var first, sibling,
+      myid = li.get(0).id,
+      sortname = li.children().first().text().toUpperCase();
+
+    li.parent().children('li' + filter).each(function(i, elem) {
+      if (i == 0)
+        first = elem;
+      if (elem.id == myid) {
+        // skip
+      }
+      else if (elem.id != myid && sortname >= $(elem).children().first().text().toUpperCase()) {
+        sibling = elem;
+      }
+      else {
+        return false;
+      }
+    });
+
+    if (sibling) {
+      li.insertAfter(sibling);
+    }
+    else if (first.id != myid) {
+      li.insertBefore(first);
+    }
+
+    // reload data from dom
+    update_data();
+  }
+
+  /**
+   * Remove the item with the given ID
+   */
+  function remove(id)
+  {
+    var node, li;
+
+    if (node = indexbyid[id]) {
+      li = id2dom(id);
+      li.remove();
+
+      node.deleted = true;
+      delete indexbyid[id];
+
+      return true;
+    }
+
+    return false;
+  }
+
+  /**
+   * (Re-)read tree data from DOM
+   */
+  function update_data()
+  {
+    data = walk_list(container);
+  }
+
+  /**
+   * Apply the 'collapsed' status of the data node to the corresponding DOM element(s)
+   */
+  function update_dom(node)
+  {
+    var li = id2dom(node.id);
+    li.children('ul').first()[(node.collapsed ? 'hide' : 'show')]();
+    li.children('div.treetoggle').removeClass('collapsed expanded').addClass(node.collapsed ? 'collapsed' : 'expanded');
+    me.triggerEvent('toggle', node);
+  }
+
+  /**
+   * Render the tree list from the internal data structure
+   */
+  function render()
+  {
+    if (me.triggerEvent('renderBefore', data) === false)
+      return;
+
+    // remove all child nodes
+    container.html('');
+
+    // render child nodes
+    for (var i=0; i < data.length; i++) {
+      render_node(data[i], container);
+    }
+
+    me.triggerEvent('renderAfter', container);
+  }
+
+  /**
+   * Render a specific node into the DOM list
+   */
+  function render_node(node, parent, replace)
+  {
+    if (node.deleted)
+      return;
+
+    var li = $('<li>')
+      .attr('id', p.id_prefix + (p.id_encode ? p.id_encode(node.id) : node.id))
+      .addClass((node.classes || []).join(' '));
+
+    if (replace)
+      replace.replaceWith(li);
+    else
+      li.appendTo(parent);
+
+    if (typeof node.html == 'string')
+      li.html(node.html);
+    else if (typeof node.html == 'object')
+      li.append(node.html);
+
+    if (node.virtual)
+      li.addClass('virtual');
+    if (node.id == selection)
+      li.addClass('selected');
+
+    // add child list and toggle icon
+    if (node.children && node.children.length) {
+      $('<div class="treetoggle '+(node.collapsed ? 'collapsed' : 'expanded') + '">&nbsp;</div>').appendTo(li);
+      var ul = $('<ul>').appendTo(li).attr('class', node.childlistclass);
+      if (node.collapsed)
+        ul.hide();
+
+      for (var i=0; i < node.children.length; i++) {
+        render_node(node.children[i], ul);
+      }
+    }
+
+    return li;
+  }
+
+  /**
+   * Recursively walk the DOM tree and build an internal data structure
+   * representing the skeleton of this tree list.
+   */
+  function walk_list(ul)
+  {
+    var result = [];
+    ul.children('li').each(function(i,e){
+      var li = $(e), sublist = li.children('ul');
+      var node = {
+        id: dom2id(li),
+        classes: li.attr('class').split(' '),
+        virtual: li.hasClass('virtual'),
+        html: li.children().first().get(0).outerHTML,
+        children: walk_list(sublist)
+      }
+
+      if (sublist.length) {
+        node.childlistclass = sublist.attr('class');
+      }
+      if (node.children.length) {
+        node.collapsed = sublist.css('display') == 'none';
+      }
+      if (li.hasClass('selected')) {
+        selection = node.id;
+      }
+
+      result.push(node);
+      indexbyid[node.id] = node;
+    })
+
+    return result;
+  }
+
+  /**
+   * Recursively walk the data tree and index nodes by their ID
+   */
+  function index_data(node)
+  {
+    if (node.id) {
+      indexbyid[node.id] = node;
+    }
+    for (var c=0; node.children && c < node.children.length; c++) {
+      index_data(node.children[c]);
+    }
+  }
+
+  /**
+   * Get the (stripped) node ID from the given DOM element
+   */
+  function dom2id(li)
+  {
+    var domid = li.attr('id').replace(new RegExp('^' + (p.id_prefix) || '%'), '');
+    return p.id_decode ? p.id_decode(domid) : domid;
+  }
+
+  /**
+   * Get the <li> element for the given node ID
+   */
+  function id2dom(id)
+  {
+    var domid = p.id_encode ? p.id_encode(id) : id;
+    return $('#' + p.id_prefix + domid);
+  }
+
+  /**
+   * Scroll the parent container to make the given list item visible
+   */
+  function scroll_to_node(li)
+  {
+    var scroller = container.parent(),
+      current_offset = scroller.scrollTop(),
+      rel_offset = li.offset().top - scroller.offset().top;
+
+    if (rel_offset < 0 || rel_offset + li.height() > scroller.height())
+      scroller.scrollTop(rel_offset + current_offset);
+  }
+
+  ///// drag & drop support
+
+  /**
+   * When dragging starts, compute absolute bounding boxes of the list and it's items
+   * for faster comparisons while mouse is moving
+   */
+  function drag_start()
+  {
+    var li, item, height,
+      pos = container.offset();
+
+    body_scroll_top = bw.ie ? 0 : window.pageYOffset;
+    list_scroll_top = container.parent().scrollTop();
+
+    drag_active = true;
+    box_coords = {
+      x1: pos.left,
+      y1: pos.top,
+      x2: pos.left + container.width(),
+      y2: pos.top + container.height()
+    };
+
+    item_coords = [];
+    for (var id in indexbyid) {
+      li = id2dom(id);
+      item = li.children().first().get(0);
+      if (height = item.offsetHeight) {
+        pos = $(item).offset();
+        item_coords[id] = {
+          x1: pos.left,
+          y1: pos.top,
+          x2: pos.left + item.offsetWidth,
+          y2: pos.top + height,
+          on: id == autoexpand_item
+        };
+      }
+    }
+  }
+
+  /**
+   * Signal that dragging has stopped
+   */
+  function drag_end()
+  {
+    drag_active = false;
+
+    if (autoexpand_timer) {
+      clearTimeout(autoexpand_timer);
+      autoexpand_timer = null;
+      autoexpand_item = null;
+    }
+
+    $('li.droptarget', container).removeClass('droptarget');
+  }
+
+  /**
+   * Determine if the given mouse coords intersect the list and one if its items
+   */
+  function intersects(mouse, highlight)
+  {
+    // offsets to compensate for scrolling while dragging a message
+    var boffset = bw.ie ? -document.documentElement.scrollTop : body_scroll_top,
+      moffset = list_scroll_top - container.parent().scrollTop(),
+      result = null;
+
+    mouse.top = mouse.y + -moffset - boffset;
+
+    // no intersection with list bounding box
+    if (mouse.x < box_coords.x1 || mouse.x >= box_coords.x2 || mouse.top < box_coords.y1 || mouse.top >= box_coords.y2) {
+      // TODO: optimize performance for this operation
+      $('li.droptarget', container).removeClass('droptarget');
+      return result;
+    }
+
+    // check intersection with visible list items
+    var pos, node;
+    for (var id in item_coords) {
+      pos = item_coords[id];
+      if (mouse.x >= pos.x1 && mouse.x < pos.x2 && mouse.top >= pos.y1 && mouse.top < pos.y2) {
+        node = indexbyid[id];
+
+        // if the folder is collapsed, expand it after the configured time
+        if (node.children && node.children.length && node.collapsed && p.autoexpand && autoexpand_item != id) {
+          if (autoexpand_timer)
+            clearTimeout(autoexpand_timer);
+
+          autoexpand_item = id;
+          autoexpand_timer = setTimeout(function() {
+            expand(autoexpand_item);
+            drag_start();  // re-calculate item coords
+            autoexpand_item = null;
+          }, p.autoexpand);
+        }
+        else if (autoexpand_timer && autoexpand_item != id) {
+          clearTimeout(autoexpand_timer);
+          autoexpand_item = null;
+          autoexpand_timer = null;
+        }
+
+        // check if this item is accepted as drop target
+        if (p.check_droptarget(node)) {
+          if (highlight) {
+            id2dom(id).addClass('droptarget');
+            pos.on = true;
+          }
+          result = id;
+        }
+        else {
+          result = null;
+        }
+      }
+      else if (pos.on) {
+        id2dom(id).removeClass('droptarget');
+        pos.on = false;
+      }
+    }
+
+    return result;
+  }
 }
 
 // use event processing functions from Roundcube's rcube_event_engine