Mihaela Mihaljevic
4345e6170e
Closes #75, on the validation framework. XSD instance-level features: - nillable elements: an xsi:nil="true" element is accepted (its content model is not checked) only when the element is declared nillable and carries no content; xsi:nil on a non-nillable element, or a nilled element with content, is a located error. - fixed value constraints: a present fixed attribute must equal its fixed value, and a fixed element's text must match. - default/fixed are parsed onto AttributeUse (per use) and collected per element name (nillable set + value constraints), threaded through XSDContext to the ComplexValidator. All findings are located ValidationErrors. Collection and helper methods move to same-file extensions to stay within type-body limits.
59 lines
2.7 KiB
Swift
59 lines
2.7 KiB
Swift
public extension PureXML.Schema {
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/// An error compiling or applying a schema.
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enum SchemaError: Swift.Error, Equatable, Sendable, CustomStringConvertible {
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case notASchema
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public var description: String {
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switch self {
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case .notASchema: "the document is not an xs:schema"
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}
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}
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}
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/// A compiled XSD schema: its global element declarations and named-type
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/// table, parsed from a schema document, used to validate instance documents.
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struct Document: Sendable {
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private let elements: [String: ElementType]
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private let types: [String: ElementType]
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private let constraints: [String: [IdentityConstraint]]
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private let nillableElements: Set<String>
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private let elementConstraints: [String: ValueConstraint]
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/// Compiles a schema document. `schemaLoader` resolves the
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/// `schemaLocation` of `xs:include`, `xs:import`, and `xs:redefine` to
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/// schema source; it returns nil (the default) when external schemas are
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/// not available, which keeps compilation from reaching the filesystem or
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/// network by default.
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public init(_ xsd: String, schemaLoader: @escaping (String) -> String? = { _ in nil }) throws {
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let compiled = try XSDParser.parse(xsd, loader: schemaLoader)
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elements = compiled.elements
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types = compiled.types
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constraints = compiled.constraints
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nillableElements = compiled.nillableElements
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elementConstraints = compiled.elementConstraints
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}
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/// Validates an instance document against the schema, returning one located
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/// ``PureXML/Validation/ValidationError`` per violation. Reports an error
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/// when the root element has no global declaration.
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public func validate(_ xml: String) throws -> [PureXML.Validation.ValidationError] {
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guard case let .document(children) = try PureXML.parse(xml),
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let root = children.compactMap(\.element).first
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else {
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return [.init(reason: "the document has no root element", at: [])]
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}
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guard let declaration = elements[root.name.localName] else {
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return [.init(reason: "no element declaration for '\(root.name.localName)'", at: [])]
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}
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let context = PureXML.Validation.XSDContext(
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types: types,
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constraints: constraints,
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rootDeclaration: declaration,
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nillableElements: nillableElements,
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elementConstraints: elementConstraints,
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)
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return PureXML.Validation.XSD.validator().errors(for: .element(root), in: context)
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}
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}
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}
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