Fixed null reference exception that occurs when attempting to go to the schema definition inside an empty start tag followed by a newline and then spaces.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@3002 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/DisplayBindings/XmlEditor/Project/Src/XmlParser.cs

@@ -446,6 +446,7 @@ namespace ICSharpCode.XmlEditor
 			int elementStartIndex = -1;
 			
 			int currentIndex = index - 1;
+
 			for (int i = 0; i < index; ++i) {
 				
 				char currentChar = xml[currentIndex];
@@ -660,7 +661,10 @@ namespace ICSharpCode.XmlEditor
 					elementEndIndex = xml.IndexOf(' ', elementStartIndex);
 				}
 				if (elementEndIndex >= elementStartIndex) {
-					return xml.Substring(elementStartIndex, elementEndIndex - elementStartIndex);
+					string elementName = xml.Substring(elementStartIndex, elementEndIndex - elementStartIndex).Trim();
+					if (elementName.Length > 1) {
+						return elementName;
+					}
 				}
 			}
 			return null;

src/AddIns/DisplayBindings/XmlEditor/Test/Parser/ActiveElementStartPathTestFixture.cs

@@ -111,5 +111,30 @@ namespace XmlEditor.Tests.Parser
 			elementPath = XmlParser.GetActiveElementStartPath(text, text.Length);
 			Assert.AreEqual(0, elementPath.Elements.Count, "Should have no path.");
 		}
+		
+		/// <summary>
+		/// If the user has entered just the opening tag and then tries to go to the schema definition of the active
+		/// element the XmlParser throws a null exception. The user is also not indenting the xml with tabs but
+		/// spaces. This test fixture tests checks for that bug. Note at the bug does not appear if the xml is indented with
+		/// tabs.
+		/// </summary>
+		[Test]
+		public void EmptyElement()
+		{
+			string xml = "<Page>\r\n" +
+						"    <Grid><\r\n" + // Cursor position is after the opening tag < at the end of this line.
+						"    </Grid>\r\n" +
+						"</Page>";
+			
+			string textToFind = "<Grid><";
+			int index = xml.IndexOf(textToFind) + textToFind.Length;
+
+			// Sanity check that the index position is correct.
+			Assert.AreEqual('\r', xml[index]);
+			Assert.AreEqual('<', xml[index - 1]);
+			
+			XmlElementPath path = XmlParser.GetActiveElementStartPathAtIndex(xml, index);
+			Assert.AreEqual(0, path.Elements.Count, "Should be no elements since there is no element at the index.");
+		}		
 	}
 }