LayoutConstraint.swift 2.3 KB

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  1. //
  2. // SnapKit
  3. //
  4. // Copyright (c) 2011-Present SnapKit Team - https://github.com/SnapKit
  5. //
  6. // Permission is hereby granted, free of charge, to any person obtaining a copy
  7. // of this software and associated documentation files (the "Software"), to deal
  8. // in the Software without restriction, including without limitation the rights
  9. // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10. // copies of the Software, and to permit persons to whom the Software is
  11. // furnished to do so, subject to the following conditions:
  12. //
  13. // The above copyright notice and this permission notice shall be included in
  14. // all copies or substantial portions of the Software.
  15. //
  16. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17. // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18. // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19. // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20. // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21. // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22. // THE SOFTWARE.
  23. #if os(iOS) || os(tvOS)
  24. import UIKit
  25. #else
  26. import AppKit
  27. #endif
  28. public class LayoutConstraint : NSLayoutConstraint {
  29. public var label: String? {
  30. get {
  31. return self.identifier
  32. }
  33. set {
  34. self.identifier = newValue
  35. }
  36. }
  37. internal weak var constraint: Constraint? = nil
  38. }
  39. internal func ==(lhs: LayoutConstraint, rhs: LayoutConstraint) -> Bool {
  40. // If firstItem or secondItem on either constraint has a dangling pointer
  41. // this comparison can cause a crash. The solution for this is to ensure
  42. // your layout code hold strong references to things like Views, LayoutGuides
  43. // and LayoutAnchors as SnapKit will not keep strong references to any of these.
  44. guard lhs.firstAttribute == rhs.firstAttribute &&
  45. lhs.secondAttribute == rhs.secondAttribute &&
  46. lhs.relation == rhs.relation &&
  47. lhs.priority == rhs.priority &&
  48. lhs.multiplier == rhs.multiplier &&
  49. lhs.secondItem === rhs.secondItem &&
  50. lhs.firstItem === rhs.firstItem else {
  51. return false
  52. }
  53. return true
  54. }