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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Globalization;
using Microsoft.CodeAnalysis.PatternMatching;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.Completion
{
/// <summary>
/// This type is not thread safe due to the restriction of underlying PatternMatcher.
/// Must be disposed after use.
/// </summary>
internal sealed class PatternMatchHelper : IDisposable
{
private readonly object _gate = new();
private readonly Dictionary<(CultureInfo, bool includeMatchedSpans), PatternMatcher> _patternMatcherMap = new();
private static readonly CultureInfo EnUSCultureInfo = new("en-US");
public string Pattern { get; }
public PatternMatchHelper(string pattern)
{
Pattern = pattern;
}
public ImmutableArray<TextSpan> GetHighlightedSpans(string text, CultureInfo culture)
{
var match = GetMatch(text, includeMatchSpans: true, culture: culture);
return match == null ? ImmutableArray<TextSpan>.Empty : match.Value.MatchedSpans;
}
public PatternMatch? GetMatch(string text, bool includeMatchSpans, CultureInfo culture)
{
var patternMatcher = GetPatternMatcher(culture, includeMatchSpans);
var match = patternMatcher.GetFirstMatch(text);
// We still have making checks for language having different to English capitalization,
// for example, for Turkish with dotted and dotless i capitalization totally diferent from English.
// Now we escaping from the second check for English languages.
// Maybe we can escape as well for more similar languages in case if we meet performance issues.
if (culture.ThreeLetterWindowsLanguageName.Equals(EnUSCultureInfo.ThreeLetterWindowsLanguageName))
{
return match;
}
// Keywords in .NET are always in En-US.
// Identifiers can be in user language.
// Try to get matches for both and return the best of them.
patternMatcher = GetPatternMatcher(EnUSCultureInfo, includeMatchSpans);
var enUSCultureMatch = patternMatcher.GetFirstMatch(text);
if (match == null)
{
return enUSCultureMatch;
}
if (enUSCultureMatch == null)
{
return match;
}
return match.Value.CompareTo(enUSCultureMatch.Value) < 0 ? match.Value : enUSCultureMatch.Value;
}
private PatternMatcher GetPatternMatcher(CultureInfo culture, bool includeMatchedSpans)
{
lock (_gate)
{
var key = (culture, includeMatchedSpans);
if (!_patternMatcherMap.TryGetValue(key, out var patternMatcher))
{
patternMatcher = PatternMatcher.CreatePatternMatcher(
Pattern, culture, includeMatchedSpans,
allowFuzzyMatching: false);
_patternMatcherMap.Add(key, patternMatcher);
}
return patternMatcher;
}
}
public MatchResult GetMatchResult(
CompletionItem item,
bool includeMatchSpans,
CultureInfo culture)
{
var match = GetMatch(item.FilterText, includeMatchSpans, culture);
string? matchedAdditionalFilterText = null;
if (item.HasAdditionalFilterTexts)
{
foreach (var additionalFilterText in item.AdditionalFilterTexts)
{
var additionalMatch = GetMatch(additionalFilterText, includeMatchSpans, culture);
if (additionalMatch.HasValue && additionalMatch.Value.CompareTo(match, ignoreCase: false) < 0)
{
match = additionalMatch;
matchedAdditionalFilterText = additionalFilterText;
}
}
}
return new MatchResult(
item,
shouldBeConsideredMatchingFilterText: match is not null,
match,
index: -1,
matchedAdditionalFilterText);
}
/// <summary>
/// Returns true if the completion item matches the pattern so far. Returns 'true'
/// if and only if the completion item matches and should be included in the filtered completion
/// results, or false if it should not be.
/// </summary>
public bool MatchesPattern(CompletionItem item, CultureInfo culture)
=> GetMatchResult(item, includeMatchSpans: false, culture).ShouldBeConsideredMatchingFilterText;
public bool TryCreateMatchResult(
CompletionItem item,
CompletionTriggerKind initialTriggerKind,
CompletionFilterReason filterReason,
int recentItemIndex,
bool includeMatchSpans,
int currentIndex,
out MatchResult matchResult)
{
// Get the match of the given completion item for the pattern provided so far.
// A completion item is checked against the pattern by see if it's
// CompletionItem.FilterText matches the item. That way, the pattern it checked
// against terms like "IList" and not IList<>.
// Note that the check on filter text length is purely for efficiency, we should
// get the same result with or without it.
var patternMatch = Pattern.Length > 0
? GetMatch(item.FilterText, includeMatchSpans, CultureInfo.CurrentCulture)
: null;
string? matchedAdditionalFilterText = null;
var shouldBeConsideredMatchingFilterText = ShouldBeConsideredMatchingFilterText(
item.FilterText,
item.Rules.MatchPriority,
initialTriggerKind,
filterReason,
recentItemIndex,
patternMatch);
if (Pattern.Length > 0 && item.HasAdditionalFilterTexts)
{
foreach (var additionalFilterText in item.AdditionalFilterTexts)
{
var additionalMatch = GetMatch(additionalFilterText, includeMatchSpans, CultureInfo.CurrentCulture);
var additionalFlag = ShouldBeConsideredMatchingFilterText(
additionalFilterText,
item.Rules.MatchPriority,
initialTriggerKind,
filterReason,
recentItemIndex,
additionalMatch);
if (!shouldBeConsideredMatchingFilterText ||
additionalFlag && additionalMatch.HasValue && additionalMatch.Value.CompareTo(patternMatch, ignoreCase: false) < 0)
{
matchedAdditionalFilterText = additionalFilterText;
shouldBeConsideredMatchingFilterText = additionalFlag;
patternMatch = additionalMatch;
}
}
}
if (shouldBeConsideredMatchingFilterText || KeepAllItemsInTheList(initialTriggerKind, Pattern))
{
matchResult = new MatchResult(
item, shouldBeConsideredMatchingFilterText,
patternMatch, currentIndex, matchedAdditionalFilterText, recentItemIndex);
return true;
}
matchResult = default;
return false;
bool ShouldBeConsideredMatchingFilterText(
string filterText,
int matchPriority,
CompletionTriggerKind initialTriggerKind,
CompletionFilterReason filterReason,
int recentItemIndex,
PatternMatch? patternMatch)
{
// For the deletion we bake in the core logic for how matching should work.
// This way deletion feels the same across all languages that opt into deletion
// as a completion trigger.
// Specifically, to avoid being too aggressive when matching an item during
// completion, we require that the current filter text be a prefix of the
// item in the list.
if (filterReason == CompletionFilterReason.Deletion &&
initialTriggerKind == CompletionTriggerKind.Deletion)
{
return filterText.GetCaseInsensitivePrefixLength(Pattern) > 0;
}
// If the user hasn't typed anything, and this item was preselected, or was in the
// MRU list, then we definitely want to include it.
if (Pattern.Length == 0)
{
if (recentItemIndex >= 0 || matchPriority > MatchPriority.Default)
return true;
}
// Otherwise, the item matches filter text if a pattern match is returned.
return patternMatch != null;
}
// If the item didn't match the filter text, we still keep it in the list
// if one of two things is true:
// 1. The user has typed nothing or only typed a single character. In this case they might
// have just typed the character to get completion. Filtering out items
// here is not desirable.
//
// 2. They brought up completion with ctrl-j or through deletion. In these
// cases we just always keep all the items in the list.
static bool KeepAllItemsInTheList(CompletionTriggerKind initialTriggerKind, string filterText)
{
return filterText.Length <= 1 ||
initialTriggerKind == CompletionTriggerKind.Invoke ||
initialTriggerKind == CompletionTriggerKind.Deletion;
}
}
public void Dispose()
{
lock (_gate)
{
foreach (var matcher in _patternMatcherMap.Values)
matcher.Dispose();
_patternMatcherMap.Clear();
}
}
}
}
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