public static void GetClassifications(SyntaxNode root, int start, int length, bool clipToRange, List <ClassifiedRange> list, CancellationToken cancellationToken)
{
var end = start + length;
// don't let classification ranges escape the requested bounds.
Action <ClassifiedRange> limiter = range =>
{
// only if the classification range overlaps window
if (range.End > start && range.Start < end)
{
// adjust range it if starts before or ends after the window
if (clipToRange && (range.Start < start || range.End > end))
{
var clipStart = Math.Max(range.Start, start);
var clipEnd = Math.Min(range.End, end);
range = new ClassifiedRange(range.Kind, clipStart, clipEnd - clipStart);
}
// merge ranges if this range is adjacent to the last range and the same kind
if (list.Count > 0)
{
var last = list[list.Count - 1];
if (last.Kind == range.Kind &&
last.End == range.Start)
{
list[list.Count - 1] = new ClassifiedRange(last.Kind, last.Start, last.Length + range.Length);
return;
}
}
list.Add(range);
}
};
// produce classification ranges for all tokens that coincide with the window
root.WalkTokens(start, end, token =>
{
cancellationToken.ThrowIfCancellationRequested();
GetTriviaClassifications(token, limiter);
if (token.IsLiteral && token.Prefix.Length > 0)
{
// special case for literals with prefix
limiter(new ClassifiedRange(ClassificationKind.Keyword, token.TextStart, token.Prefix.Length));
limiter(new ClassifiedRange(ClassificationKind.Literal, token.TextStart + token.Prefix.Length, token.Text.Length - token.Prefix.Length));
}
else
{
var kind = GetKind(token);
limiter(new ClassifiedRange(kind, token.TextStart, token.Width));
}
});
}
/// <summary>
/// Add the two classification ranges together.
/// If any overlap, classifications from <see cref="P:classifications2"/> take precedence.
/// </summary>
protected static IReadOnlyList <ClassifiedRange> Add(
IReadOnlyList <ClassifiedRange> classifications1,
IReadOnlyList <ClassifiedRange> classifications2)
{
if (classifications2.Count == 0)
{
return(classifications1);
}
if (classifications1.Count == 0)
{
return(classifications2);
}
var list = new List <ClassifiedRange>(classifications1.Count + classifications2.Count);
int index1 = 0;
int index2 = 0;
ClassifiedRange class1 = null;
ClassifiedRange class2 = null;
while (true)
{
if (class1 == null && index1 < classifications1.Count)
{
class1 = classifications1[index1];
}
if (class2 == null && index2 < classifications2.Count)
{
class2 = classifications2[index2];
}
if (class1 == null && class2 == null)
{
// we are done
break;
}
else if (class1 != null && class2 == null)
{
// no more class2, just add class1
list.Add(class1);
class1 = null;
index1++;
}
else if (class2 != null && class1 == null)
{
// no more class1, just add class2
list.Add(class2);
class2 = null;
index2++;
}
else if (class1.End < class2.Start)
{
// class1 is entirely before class2, so add class1 and advance it
list.Add(class1);
class1 = null;
index1++;
}
else if (class2.End < class1.Start)
{
// class2 is entirely before classs1, so add class2 and advance it
list.Add(class2);
class2 = null;
index2++;
}
else if (class1.Start >= class2.Start && class1.End <= class2.End)
{
// class1 is entirely within class2
// drop class1 because class2 takes precedence
class1 = null;
index1++;
}
else if (class1.Start < class2.Start)
{
// class1 starts before class2
var len = class2.Start - class1.Start;
// add the first part off class1
list.Add(new ClassifiedRange(class1.Kind, class1.Start, len));
if (class1.Length > len)
{
// adjust class1 for next time around
class1 = new ClassifiedRange(class1.Kind, class1.Start + len, class1.Length - len);
}
else
{
// advance class1 if no more
class1 = null;
index1++;
}
}
else if (class2.Start < class1.Start)
{
// class2 starts before class1
var len = class1.Start - class2.Start;
// add the first part of class2
list.Add(new ClassifiedRange(class2.Kind, class2.Start, len));
if (class2.Length > len)
{
class2 = new ClassifiedRange(class2.Kind, class2.Start + len, class2.Length - len);
}
else
{
// advance class2 if no more
class2 = null;
index2++;
}
}
else if (class1.End <= class2.End)
{
// both start at same position, class1 ends first
// just drop class1, since class2 takes precedence
class1 = null;
index1++;
}
else
{
// both start at same position, class2 ends first
var len = class2.Length;
// add class2 since it takes precedence
list.Add(class2);
class2 = null;
index2++;
// adjust remainder of class1
class1 = new ClassifiedRange(class1.Kind, class1.Start + len, class1.Length - len);
}
}
return(list);
}
