Mihaela Mihaljevic
9168f990d6
Parse the XML declaration's pseudo-attributes instead of skipping the <?xml?> processing instruction: - version, encoding, and standalone are surfaced on a new XMLDeclaration, returned from parseWithDocumentType and via PureXML.xmlDeclaration(_:). - The pseudo-attributes are validated: fixed order (version, encoding, standalone), known names only, and standalone must be yes or no. A malformed declaration is rejected. - The declared version is now readable, a prerequisite for XML 1.1. parseWithDocumentType returns a ParsedDocument struct (node, documentType, declaration) rather than a 2-tuple; the member names are unchanged so existing call sites are unaffected. Closes #95
75 lines
2.6 KiB
Swift
75 lines
2.6 KiB
Swift
extension PureXML.Parsing.XMLDeclaration {
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/// A name/value pair from an XML declaration.
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struct PseudoAttribute: Equatable {
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let name: String
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let value: String
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}
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/// Scans the `name="value"` pseudo-attributes of an XML declaration's text.
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/// Each value must be quoted; anything malformed (a missing `=`, an unquoted
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/// value, trailing junk) makes the whole scan fail so the declaration is
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/// rejected rather than partly read.
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struct PseudoAttributeScanner {
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private let chars: [Character]
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private var index = 0
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init(_ text: String) {
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chars = Array(text)
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}
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mutating func scan() -> [PseudoAttribute]? {
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var pairs: [PseudoAttribute] = []
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skipSpace()
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while index < chars.count {
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guard let name = scanName(), !name.isEmpty else { return nil }
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skipSpace()
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guard consume("=") else { return nil }
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skipSpace()
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guard let value = scanQuoted() else { return nil }
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pairs.append(PseudoAttribute(name: name, value: value))
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skipSpace()
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}
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return pairs
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}
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private mutating func scanName() -> String? {
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var name = ""
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while index < chars.count, isNameCharacter(chars[index]) {
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name.append(chars[index])
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index += 1
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}
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return name.isEmpty ? nil : name
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}
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private mutating func scanQuoted() -> String? {
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guard index < chars.count, chars[index] == "\"" || chars[index] == "'" else { return nil }
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let quote = chars[index]
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index += 1
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var value = ""
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while index < chars.count, chars[index] != quote {
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value.append(chars[index])
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index += 1
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}
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guard index < chars.count else { return nil }
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index += 1
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return value
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}
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private mutating func consume(_ character: Character) -> Bool {
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guard index < chars.count, chars[index] == character else { return false }
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index += 1
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return true
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}
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private mutating func skipSpace() {
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while index < chars.count, chars[index] == " " || chars[index] == "\t" || chars[index] == "\n" || chars[index] == "\r" {
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index += 1
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}
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}
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private func isNameCharacter(_ character: Character) -> Bool {
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character.isLetter || character.isNumber || character == "-" || character == "_" || character == "."
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}
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}
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}
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