Utils.swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

@available(*, deprecated, renamed: "SourceEdit")
public typealias IncrementalEdit = SourceEdit

@available(*, deprecated, message: "Use Range<AbsolutePosition> instead")
public typealias ByteSourceRange = Range<AbsolutePosition>

extension Range<AbsolutePosition> {
  @available(*, deprecated, message: "Use lowerBound.utf8Offset instead")
  public var offset: Int { lowerBound.utf8Offset }

  @available(*, deprecated, message: "Construct a Range<AbsolutePosition> instead")
  public init(offset: Int, length: Int) {
    self = AbsolutePosition(utf8Offset: offset)..<AbsolutePosition(utf8Offset: offset + length)
  }

  @available(*, deprecated, message: "Use upperBound.utf8Offset instead")
  public var endOffset: Int {
    return upperBound.utf8Offset
  }

  /// Returns the range for the overlapping region between two ranges.
  ///
  /// If the intersection is empty, this returns a range starting at offset 0 and having length 0.
  public func intersected(_ other: Range<AbsolutePosition>) -> Range<AbsolutePosition> {
    return self.clamped(to: other)
  }
}

extension Range<AbsolutePosition> {
  /// The number of bytes between the range's lower bound and its upper bound
  public var length: SourceLength { return SourceLength(utf8Length: upperBound.utf8Offset - lowerBound.utf8Offset) }

  public init(position: AbsolutePosition, length: SourceLength) {
    self = position..<(position + length)
  }

  // Returns `true` if the intersection between this range and `other` is non-empty or if the two ranges are directly
  /// adjacent to each other.
  public func overlapsOrTouches(_ other: Range<AbsolutePosition>) -> Bool {
    return self.upperBound >= other.lowerBound && self.lowerBound <= other.upperBound
  }

  /// Returns `true` if the intersection between this range and `other` is non-empty or if the two ranges are directly
  /// adjacent to each other.
  @available(*, deprecated, renamed: "overlapsOrTouches(_:)")
  public func intersectsOrTouches(_ other: Range<AbsolutePosition>) -> Bool {
    return self.upperBound >= other.lowerBound && self.lowerBound <= other.upperBound
  }

  /// Returns `true` if the intersection between this range and `other` is non-empty.
  @available(*, deprecated, renamed: "overlaps(_:)")
  public func intersects(_ other: Range<AbsolutePosition>) -> Bool {
    return self.upperBound > other.lowerBound && self.lowerBound < other.upperBound
  }

  /// Returns the range for the overlapping region between two ranges.
  ///
  /// If the intersection is empty, this returns `nil`.
  @available(*, deprecated, message: "Use clamped(to:) instead")
  public func intersecting(_ other: Range<AbsolutePosition>) -> Range<AbsolutePosition>? {
    let lowerBound = Swift.max(self.lowerBound, other.lowerBound)
    let upperBound = Swift.min(self.upperBound, other.upperBound)
    if lowerBound > upperBound {
      return nil
    } else {
      return lowerBound..<upperBound
    }
  }
}

extension RawUnexpectedNodesSyntax {
  /// Construct a ``RawUnexpectedNodesSyntax``with the given `elements`.
  ///
  /// If `isMaximumNestingLevelOverflow` is `true`, the node has the
  /// `isMaximumNestingLevelOverflow` error bit set, indicating that the parser
  /// overflowed its maximum nesting level and thus aborted parsing.
  public init(elements: [RawSyntax], isMaximumNestingLevelOverflow: Bool, arena: __shared SyntaxArena) {
    let raw = RawSyntax.makeLayout(
      kind: .unexpectedNodes,
      uninitializedCount: elements.count,
      isMaximumNestingLevelOverflow: isMaximumNestingLevelOverflow,
      arena: arena
    ) { layout in
      guard var ptr = layout.baseAddress else { return }
      for elem in elements {
        ptr.initialize(to: elem.raw)
        ptr += 1
      }
    }
    self.init(raw: raw)
  }
}

extension TypeSyntaxProtocol {
  /// Check if this syntax matches any of the standard names for `Void`:
  /// * Void
  /// * Swift.Void
  /// * ()
  public var isVoid: Bool {
    if let identifierType = self.as(IdentifierTypeSyntax.self) {
      return identifierType.name.text == "Void"
    }
    if let memberType = self.as(MemberTypeSyntax.self) {
      return memberType.baseType.isSwiftCoreModule && memberType.name.text == "Void"
    }
    if let tupleType = self.as(TupleTypeSyntax.self) {
      return tupleType.elements.isEmpty
    }
    return false
  }

  var isSwiftCoreModule: Bool {
    guard let identifierType = self.as(IdentifierTypeSyntax.self) else {
      return false
    }
    return identifierType.name.text == "Swift"
  }

  /// Check if this syntax could resolve to the type passed. Only supports types where the canonical type
  /// can be named using only IdentifierTypeSyntax and MemberTypeSyntax. A non-exhaustive list of unsupported
  /// types includes:
  /// * array types
  /// * function types
  /// * optional types
  /// * tuple types (including Void!)
  /// The type syntax is allowed to use any level of qualified name for the type, e.g. Swift.Int.self
  /// will match against both "Swift.Int" and "Int".
  ///
  /// - Parameter type: Type to check against. NB: if passing a type alias, the canonical type will be used.
  /// - Returns: true if `self` spells out some suffix of the fully qualified name of `type`, otherwise false
  public func canRepresentBasicType(type: Any.Type) -> Bool {
    let qualifiedTypeName = String(reflecting: type)
    var typeNames = qualifiedTypeName.split(separator: ".")
    var currType: TypeSyntaxProtocol = self

    while !typeNames.isEmpty {
      let typeName = typeNames.popLast()!
      if let identifierType = currType.as(IdentifierTypeSyntax.self) {
        // It doesn't matter whether this is the final element of typeNames, because we don't know
        // surrounding context - the Foo.Bar.Baz type can be referred to as `Baz` inside Foo.Bar
        return identifierType.name.text == typeName
      } else if let memberType = currType.as(MemberTypeSyntax.self) {
        if memberType.name.text != typeName {
          return false
        }
        currType = memberType.baseType
      } else {
        return false
      }
    }

    return false
  }
}