Mihaela Mihaljevic
5c306482e5
Replace the notImplemented stub with a real parser built on a pull-based, streaming event core that never requires the whole document in memory. - Parsing.EventReader: pulls characters through a source closure with a bounded lookahead buffer and emits one Parsing.Event at a time, holding only an open-element stack. Drives chunked/streamed input. - Parsing.Parser: builds a Model.Node tree iteratively over the event core (explicit stack, no recursion). - Reader: streaming character cursor (closure-backed, bounded buffer) replacing the previous whole-string Array. - EntityDecoder: the five predefined entities and decimal/hex char references. - Handles elements, attributes, text, comments, CDATA, processing instructions, and an XML declaration in the prolog. Rejects <!DOCTYPE> by default (no DTD/XXE/entity-expansion exposure). - Top-level API: parse(_:), parse(pulling:), events(_:), events(pulling:). - 21 tests including event-stream and chunked-source coverage.
55 lines
2.3 KiB
Swift
55 lines
2.3 KiB
Swift
extension PureXML.Parsing {
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/// Decodes XML references inside text and attribute values: the five
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/// predefined entities and decimal/hex character references. General entity
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/// declarations from a DTD are deliberately not supported (DTD processing is
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/// off by default), so any other `&name;` is rejected rather than expanded.
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enum EntityDecoder {
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static func decode(_ raw: String, at mark: Mark) throws -> String {
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guard raw.contains("&") else { return raw }
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var result = ""
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var iterator = raw.startIndex
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while iterator < raw.endIndex {
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let character = raw[iterator]
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guard character == "&" else {
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result.append(character)
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iterator = raw.index(after: iterator)
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continue
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}
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guard let semicolon = raw[iterator...].firstIndex(of: ";") else {
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throw PureXML.Parsing.ParseError.invalidReference(String(raw[iterator...]), mark)
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}
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let body = String(raw[raw.index(after: iterator) ..< semicolon])
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try result.append(resolve(body, at: mark))
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iterator = raw.index(after: semicolon)
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}
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return result
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}
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private static func resolve(_ body: String, at mark: Mark) throws -> Character {
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switch body {
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case "amp": return "&"
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case "lt": return "<"
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case "gt": return ">"
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case "quot": return "\""
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case "apos": return "'"
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default:
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break
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}
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guard body.hasPrefix("#") else {
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throw PureXML.Parsing.ParseError.invalidReference("&\(body);", mark)
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}
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let digits = String(body.dropFirst())
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let scalarValue: UInt32? = if digits.hasPrefix("x") || digits.hasPrefix("X") {
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UInt32(digits.dropFirst(), radix: 16)
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} else {
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UInt32(digits, radix: 10)
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}
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guard let value = scalarValue, let scalar = Unicode.Scalar(value) else {
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throw PureXML.Parsing.ParseError.invalidReference("&\(body);", mark)
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}
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return Character(scalar)
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}
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}
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}
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