/// <summary>
/// Parses the specified line, searching for the start of a region.
/// </summary>
/// <param name="line">The line.</param>
/// <param name="text">The text.</param>
/// <param name="currentRegion">The current region.</param>
/// <param name="regionStart">The region start.</param>
/// <returns></returns>
private static bool ParseRegionStart(ITextSnapshotLine line, string text, ref PartialRegion currentRegion, ref int regionStart)
{
var regionStartMatch = RegionRegex.RegionStart.Match(text);
if (!regionStartMatch.Success)
{
return(false);
}
regionStart = regionStartMatch.Groups[1].Success
? regionStartMatch.Groups[1].Length
: 0;
var currentLevel = currentRegion != null
? currentRegion.Level
: 1;
currentRegion = new PartialRegion
{
Level = currentLevel + 1,
StartLine = line.LineNumber,
StartOffset = regionStart,
PartialParent = currentRegion
};
return(true);
}
/// <summary>
/// Parses the current snapshot of <see cref="_buffer"/>.
/// </summary>
private void Parse()
{
var snapshot = _buffer.CurrentSnapshot;
var regions = new List <Region>();
PartialRegion currentRegion = null;
foreach (var line in snapshot.Lines)
{
var regionStart = -1;
var text = line.GetText();
if (!ParseRegionStart(line, text, ref currentRegion, ref regionStart))
{
ParseRegionEnd(regions, line, text, ref currentRegion, ref regionStart);
}
}
var oldSpans = new List <Span>(_regions
.Select(r => AsSnapshotSpan(r, _snapshot)
.TranslateTo(snapshot, SpanTrackingMode.EdgeExclusive)
.Span));
var newSpans = new List <Span>(regions
.Select(r => AsSnapshotSpan(r, snapshot).Span));
var oldSpanCollection = new NormalizedSpanCollection(oldSpans);
var newSpanCollection = new NormalizedSpanCollection(newSpans);
var removed = NormalizedSpanCollection.Difference(oldSpanCollection, newSpanCollection);
var changeStart = int.MaxValue;
var changeEnd = -1;
if (removed.Count > 0)
{
changeStart = removed[0].Start;
changeEnd = removed[removed.Count - 1].End;
}
if (newSpans.Count > 0)
{
changeStart = Math.Min(changeStart, newSpans[0].Start);
changeEnd = Math.Max(changeEnd, newSpans[newSpans.Count - 1].End);
}
_snapshot = snapshot;
_regions.Clear();
_regions.AddRange(regions);
if (changeStart <= changeEnd)
{
TagsChanged?.Invoke(this, new SnapshotSpanEventArgs(new SnapshotSpan(_snapshot, Span.FromBounds(changeStart, changeEnd))));
}
}
/// <summary>
/// Parses the specified line, searching for the end of a region.
/// </summary>
/// <param name="regions">The regions.</param>
/// <param name="line">The line.</param>
/// <param name="text">The text.</param>
/// <param name="currentRegion">The current region.</param>
/// <param name="regionStart">The region start.</param>
private static void ParseRegionEnd(List <Region> regions, ITextSnapshotLine line, string text, ref PartialRegion currentRegion, ref int regionStart)
{
var regionEndMatch = RegionRegex.RegionEnd.Match(text);
if (!regionEndMatch.Success)
{
return;
}
regionStart = regionEndMatch.Groups[1].Success
? regionEndMatch.Groups[1].Length
: 0;
if (currentRegion == null)
{
return;
}
regions.Add(new Region
{
Level = currentRegion.Level,
StartLine = currentRegion.StartLine,
StartOffset = currentRegion.StartOffset,
EndLine = line.LineNumber
});
currentRegion = currentRegion.PartialParent;
}
