Change the share file action icon if the file is already shared with someone

apps/files_sharing/css/sharing.css

@@ -4,5 +4,5 @@
 -moz-border-radius-bottomright:1em; -webkit-border-bottom-right-radius:1em; border-bottom-right-radius:1em; }
 #shared_list { padding:0.5em; list-style-type: none; }
 #public { border-top:1px solid #ddd; padding-top:0.5em; }
-a.unshare { float:right; display:inline; margin:0 .5em; padding:.3em .3em 0 .3em !important; }
-a.unshare:hover { background:#fff; -moz-box-shadow:0 0 10px #fff; -webkit-box-shadow:0 0 10px #fff; box-shadow:0 0 10px #fff; -moz-border-radius:10px; -webkit-border-radius:10px; border-radius:10px; }
+a.unshare { float:right; display:inline; margin:0 .5em; padding:.3em .3em 0 .3em !important; opacity:.5; }
+a.unshare:hover { opacity:1; }

apps/files_sharing/js/share.js

@@ -1,7 +1,25 @@
 $(document).ready(function() {
 	if (typeof FileActions !== 'undefined') {
-		FileActions.register('all', 'Share', OC.imagePath('core', 'actions/share'), function(filename) {
-			if (($('#dropdown').length)) {
+		FileActions.register('all', 'Share', function(filename) {
+			var icon;
+			var file = $('#dir').val()+'/'+filename;
+			$.ajax({
+				type: 'GET',
+				url: OC.linkTo('files_sharing', 'ajax/getitem.php'),
+				dataType: 'json',
+				data: 'source='+file,
+				async: false,
+				success: function(users) {
+					if (users.length > 0) {
+						icon = OC.imagePath('core', 'actions/shared');
+					} else {
+						icon = OC.imagePath('core', 'actions/share');
+					}
+				}
+			});
+			return icon;
+		}, function(filename) {
+			if (($('#dropdown').length > 0)) {
 				$('#dropdown').hide('blind', function() {
 					var dropdownFile = $('#dropdown').data('file') 
 					var file = $('#dir').val()+'/'+filename;