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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,163 @@ | ||
| extension Pattern { | ||
| struct Parser { | ||
| private var pattern: Substring | ||
| let options: Options | ||
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| init(pattern: some StringProtocol, options: Options) { | ||
| self.pattern = Substring(pattern) | ||
| self.options = options | ||
| } | ||
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| mutating func getNext(_ condition: ((character: Character, isEscaped: Bool)) -> Bool = { _ in true }) throws -> (character: Character, isEscaped: Bool)? { | ||
| if let next = pattern.first { | ||
| let updatedPattern = pattern.dropFirst() | ||
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| if options.allowEscapedCharacters, next == .escape { | ||
| guard let escaped = updatedPattern.first else { throw PatternParsingError.invalidEscapeCharacter } | ||
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| guard condition((escaped, true)) else { return nil } | ||
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| pattern = updatedPattern.dropFirst() | ||
| return (escaped, true) | ||
| } else { | ||
| guard condition((next, false)) else { return nil } | ||
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| pattern = updatedPattern | ||
| return (next, false) | ||
| } | ||
| } | ||
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| return nil | ||
| } | ||
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| mutating func parse() throws -> Pattern { | ||
| do { | ||
| let sections = try self.parseSections() | ||
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| return Pattern(sections: sections, options: options) | ||
| } catch let error as PatternParsingError { | ||
| // add information about where the error was encountered by including the original pattern and our current location | ||
| throw InvalidPatternError( | ||
| pattern: pattern.base, | ||
| location: pattern.startIndex, | ||
| underlyingError: error | ||
| ) | ||
| } | ||
| } | ||
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| private mutating func parseSections(delimeters: some Collection<Character> = EmptyCollection()) throws -> [Section] { | ||
| var sections: [Section] = [] | ||
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| while let next = try getNext() { | ||
| switch next { | ||
| case ("*", false): | ||
| if sections.last == .componentWildcard { | ||
| if options.allowsPathLevelWildcards { | ||
| sections[sections.endIndex - 1] = .pathWildcard | ||
| } else { | ||
| break // ignore repeated wildcards | ||
| } | ||
| } else if sections.last == .pathWildcard { | ||
| break // ignore repeated wildcards | ||
| } else { | ||
| sections.append(.componentWildcard) | ||
| } | ||
| case ("?", false): | ||
| sections.append(.singleCharacter) | ||
| case ("[", false): | ||
| let negated: Bool | ||
| if pattern.first == options.rangeNegationCharacter { | ||
| negated = true | ||
| pattern = pattern.dropFirst() | ||
| } else { | ||
| negated = false | ||
| } | ||
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| var ranges: [CharacterClass] = [] | ||
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| if options.emptyRangeBehavior == .treatClosingBracketAsCharacter, let closing = try getNext({ !$0.isEscaped && $0.character == "]" }) { | ||
| // https://man7.org/linux/man-pages/man7/glob.7.html | ||
| // The string enclosed by the brackets cannot be empty; therefore ']' can be allowed between the brackets, provided that it is the first character. | ||
| ranges.append(.character(closing.character)) | ||
| } | ||
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| while let next = try getNext({ $0.isEscaped || $0.character != "]" }) { | ||
| if !next.isEscaped && next.character == "[" { | ||
| if try getNext({ !$0.isEscaped && $0.character == ":" }) != nil { | ||
| // Named character classes | ||
| guard let endIndex = pattern.firstIndex(of: ":") else { throw PatternParsingError.rangeNotClosed } | ||
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| let name = pattern.prefix(upTo: endIndex) | ||
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| if let name = CharacterClass.Name(rawValue: String(name)) { | ||
| ranges.append(.named(name)) | ||
| pattern = pattern[endIndex...].dropFirst() | ||
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| if try getNext({ !$0.isEscaped && $0.character == "]" }) == nil { | ||
| throw PatternParsingError.rangeNotClosed | ||
| } | ||
| } else { | ||
| throw PatternParsingError.invalidNamedCharacterClass(String(name)) | ||
| } | ||
| } else { | ||
| ranges.append(.character("[")) | ||
| } | ||
| } else if !next.isEscaped && next.character == "-" { | ||
| if !options.allowsRangeSeparatorInCharacterClasses { | ||
| throw PatternParsingError.rangeMissingBounds | ||
| } | ||
|
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| // https://man7.org/linux/man-pages/man7/glob.7.html | ||
| // One may include '-' in its literal meaning by making it the first or last character between the brackets. | ||
| ranges.append(.character("-")) | ||
| } else { | ||
| if try getNext({ !$0.isEscaped && $0.character == "-" }) != nil { | ||
| if pattern.first == "]" { | ||
| if !options.allowsRangeSeparatorInCharacterClasses { | ||
| throw PatternParsingError.rangeNotClosed | ||
| } | ||
|
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| // `-` is the last character in the group, treat it as a character | ||
| // https://man7.org/linux/man-pages/man7/glob.7.html | ||
| // One may include '-' in its literal meaning by making it the first or last character between the brackets. | ||
| ranges.append(.character(next.character)) | ||
| ranges.append(.character("-")) | ||
| } else { | ||
| // this is a range like a-z, find the upper limit of the range | ||
| guard | ||
| let upper = try getNext() | ||
| else { throw PatternParsingError.rangeNotClosed } | ||
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| guard next.character <= upper.character else { throw PatternParsingError.rangeBoundsAreOutOfOrder } | ||
| ranges.append(.range(next.character ... upper.character)) | ||
| } | ||
| } else { | ||
| ranges.append(.character(next.character)) | ||
| } | ||
| } | ||
| } | ||
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| guard try getNext({ !$0.isEscaped && $0.character == "]" }) != nil else { throw PatternParsingError.rangeNotClosed } | ||
|
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| guard !ranges.isEmpty else { | ||
| if options.emptyRangeBehavior == .error { | ||
| throw PatternParsingError.rangeIsEmpty | ||
| } else { | ||
| break | ||
| } | ||
| } | ||
|
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| sections.append(.oneOf(ranges, isNegated: negated)) | ||
| default: | ||
| if case let .constant(value) = sections.last { | ||
| sections[sections.endIndex - 1] = .constant(value + String(next.character)) | ||
| } else { | ||
| sections.append(.constant(String(next.character))) | ||
| } | ||
| } | ||
| } | ||
|
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||
| return sections | ||
| } | ||
| } | ||
| } |
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