| 1 | namespace CascadeIDE.Services; |
| 2 | |
| 3 | /// <summary>Prefix and camelCase-acronym filtering for completion (e.g. SB → StringBuilder, SByte).</summary> |
| 4 | public static class CSharpCompletionMatcher |
| 5 | { |
| 6 | public enum MatchKind |
| 7 | { |
| 8 | None = 0, |
| 9 | Acronym = 1, |
| 10 | Prefix = 2, |
| 11 | } |
| 12 | |
| 13 | public static MatchKind GetMatchKind(string name, string prefix) |
| 14 | { |
| 15 | if (string.IsNullOrEmpty(prefix)) |
| 16 | return MatchKind.Prefix; |
| 17 | if (name.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)) |
| 18 | return MatchKind.Prefix; |
| 19 | return MatchesCamelCaseAcronym(name, prefix) ? MatchKind.Acronym : MatchKind.None; |
| 20 | } |
| 21 | |
| 22 | public static bool Matches(string name, string prefix) => |
| 23 | GetMatchKind(name, prefix) != MatchKind.None; |
| 24 | |
| 25 | public static int CompareByRelevance(string nameA, string nameB, string prefix) |
| 26 | { |
| 27 | var kindA = GetMatchKind(nameA, prefix); |
| 28 | var kindB = GetMatchKind(nameB, prefix); |
| 29 | if (kindA != kindB) |
| 30 | return kindB.CompareTo(kindA); |
| 31 | |
| 32 | if (prefix.Length > 0) |
| 33 | { |
| 34 | var posA = nameA.StartsWith(prefix, StringComparison.OrdinalIgnoreCase) ? 0 : IndexOfAcronym(nameA, prefix); |
| 35 | var posB = nameB.StartsWith(prefix, StringComparison.OrdinalIgnoreCase) ? 0 : IndexOfAcronym(nameB, prefix); |
| 36 | if (posA != posB) |
| 37 | return posA.CompareTo(posB); |
| 38 | } |
| 39 | |
| 40 | return string.Compare(nameA, nameB, StringComparison.OrdinalIgnoreCase); |
| 41 | } |
| 42 | |
| 43 | private static int IndexOfAcronym(string name, string prefix) |
| 44 | { |
| 45 | var pi = 0; |
| 46 | for (var ni = 0; ni < name.Length && pi < prefix.Length; ni++) |
| 47 | { |
| 48 | if (char.ToUpperInvariant(name[ni]) == char.ToUpperInvariant(prefix[pi])) |
| 49 | pi++; |
| 50 | } |
| 51 | |
| 52 | return pi == prefix.Length ? 0 : int.MaxValue; |
| 53 | } |
| 54 | |
| 55 | private static bool MatchesCamelCaseAcronym(string name, string prefix) |
| 56 | { |
| 57 | if (prefix.Length == 0) |
| 58 | return true; |
| 59 | |
| 60 | var pi = 0; |
| 61 | for (var ni = 0; ni < name.Length && pi < prefix.Length; ni++) |
| 62 | { |
| 63 | if (char.ToUpperInvariant(name[ni]) == char.ToUpperInvariant(prefix[pi])) |
| 64 | pi++; |
| 65 | } |
| 66 | |
| 67 | return pi == prefix.Length; |
| 68 | } |
| 69 | } |
| 70 | |