// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using ICSharpCode.AvalonEdit.Document;
namespace ICSharpCode.AvalonEdit.Folding
{
/// <summary>
/// Holds information about the start of a fold in an xml string.
/// </summary>
sealed class XmlFoldStart : NewFolding
{
internal int StartLine;
}
/// <summary>
/// Determines folds for an xml string in the editor.
/// </summary>
public class XmlFoldingStrategy : AbstractFoldingStrategy
{
/// <summary>
/// Flag indicating whether attributes should be displayed on folded
/// elements.
/// </summary>
public bool ShowAttributesWhenFolded { get; set; }
/// <summary>
/// Create <see cref="NewFolding"/>s for the specified document.
/// </summary>
public override IEnumerable<NewFolding> CreateNewFoldings(TextDocument document, out int firstErrorOffset)
{
try {
XmlTextReader reader = new XmlTextReader(document.CreateReader());
reader.XmlResolver = null; // don't resolve DTDs
return CreateNewFoldings(document, reader, out firstErrorOffset);
} catch (XmlException) {
firstErrorOffset = 0;
return Enumerable.Empty<NewFolding>();
}
}
/// <summary>
/// Create <see cref="NewFolding"/>s for the specified document.
/// </summary>
public IEnumerable<NewFolding> CreateNewFoldings(TextDocument document, XmlReader reader, out int firstErrorOffset)
{
Stack<XmlFoldStart> stack = new Stack<XmlFoldStart>();
List<NewFolding> foldMarkers = new List<NewFolding>();
try {
while (reader.Read()) {
switch (reader.NodeType) {
case XmlNodeType.Element:
if (!reader.IsEmptyElement) {
XmlFoldStart newFoldStart = CreateElementFoldStart(document, reader);
stack.Push(newFoldStart);
}
break;
case XmlNodeType.EndElement:
XmlFoldStart foldStart = stack.Pop();
CreateElementFold(document, foldMarkers, reader, foldStart);
break;
case XmlNodeType.Comment:
CreateCommentFold(document, foldMarkers, reader);
break;
}
}
firstErrorOffset = -1;
} catch (XmlException ex) {
// ignore errors at invalid positions (prevent ArgumentOutOfRangeException)
if (ex.LineNumber >= 1 && ex.LineNumber <= document.LineCount)
firstErrorOffset = document.GetOffset(ex.LineNumber, ex.LinePosition);
else
firstErrorOffset = 0;
}
foldMarkers.Sort((a,b) => a.StartOffset.CompareTo(b.StartOffset));
return foldMarkers;
}
static int GetOffset(TextDocument document, XmlReader reader)
{
IXmlLineInfo info = reader as IXmlLineInfo;
if (info != null && info.HasLineInfo()) {
return document.GetOffset(info.LineNumber, info.LinePosition);
} else {
throw new ArgumentException("XmlReader does not have positioning information.");
}
}
/// <summary>
/// Creates a comment fold if the comment spans more than one line.
/// </summary>
/// <remarks>The text displayed when the comment is folded is the first
/// line of the comment.</remarks>
static void CreateCommentFold(TextDocument document, List<NewFolding> foldMarkers, XmlReader reader)
{
string comment = reader.Value;
if (comment != null) {
int firstNewLine = comment.IndexOf('\n');
if (firstNewLine >= 0) {
// Take off 4 chars to get the actual comment start (takes
// into account the <!-- chars.
int startOffset = GetOffset(document, reader) - 4;
int endOffset = startOffset + comment.Length + 7;
string foldText = String.Concat("<!--", comment.Substring(0, firstNewLine).TrimEnd('\r') , "-->");
foldMarkers.Add(new NewFolding(startOffset, endOffset) { Name = foldText } );
}
}
}
/// <summary>
/// Creates an XmlFoldStart for the start tag of an element.
/// </summary>
XmlFoldStart CreateElementFoldStart(TextDocument document, XmlReader reader)
{
// Take off 1 from the offset returned
// from the xml since it points to the start
// of the element name and not the beginning
// tag.
//XmlFoldStart newFoldStart = new XmlFoldStart(reader.Prefix, reader.LocalName, reader.LineNumber - 1, reader.LinePosition - 2);
XmlFoldStart newFoldStart = new XmlFoldStart();
IXmlLineInfo lineInfo = (IXmlLineInfo)reader;
newFoldStart.StartLine = lineInfo.LineNumber;
newFoldStart.StartOffset = document.GetOffset(newFoldStart.StartLine, lineInfo.LinePosition - 1);
if (this.ShowAttributesWhenFolded && reader.HasAttributes) {
newFoldStart.Name = String.Concat("<", reader.Name, " ", GetAttributeFoldText(reader), ">");
} else {
newFoldStart.Name = String.Concat("<", reader.Name, ">");
}
return newFoldStart;
}
/// <summary>
/// Create an element fold if the start and end tag are on
/// different lines.
/// </summary>
static void CreateElementFold(TextDocument document, List<NewFolding> foldMarkers, XmlReader reader, XmlFoldStart foldStart)
{
IXmlLineInfo lineInfo = (IXmlLineInfo)reader;
int endLine = lineInfo.LineNumber;
if (endLine > foldStart.StartLine) {
int endCol = lineInfo.LinePosition + reader.Name.Length + 1;
foldStart.EndOffset = document.GetOffset(endLine, endCol);
foldMarkers.Add(foldStart);
}
}
/// <summary>
/// Gets the element's attributes as a string on one line that will
/// be displayed when the element is folded.
/// </summary>
/// <remarks>
/// Currently this puts all attributes from an element on the same
/// line of the start tag. It does not cater for elements where attributes
/// are not on the same line as the start tag.
/// </remarks>
static string GetAttributeFoldText(XmlReader reader)
{
StringBuilder text = new StringBuilder();
for (int i = 0; i < reader.AttributeCount; ++i) {
reader.MoveToAttribute(i);
text.Append(reader.Name);
text.Append("=");
text.Append(reader.QuoteChar.ToString());
text.Append(XmlEncodeAttributeValue(reader.Value, reader.QuoteChar));
text.Append(reader.QuoteChar.ToString());
// Append a space if this is not the
// last attribute.
if (i < reader.AttributeCount - 1) {
text.Append(" ");
}
}
return text.ToString();
}
/// <summary>
/// Xml encode the attribute string since the string returned from
/// the XmlTextReader is the plain unencoded string and .NET
/// does not provide us with an xml encode method.
/// </summary>
static string XmlEncodeAttributeValue(string attributeValue, char quoteChar)
{
StringBuilder encodedValue = new StringBuilder(attributeValue);
encodedValue.Replace("&", "&");
encodedValue.Replace("<", "<");
encodedValue.Replace(">", ">");
if (quoteChar == '"') {
encodedValue.Replace("\"", """);
} else {
encodedValue.Replace("'", "'");
}
return encodedValue.ToString();
}
}
}