Clean up & Reshuffle some API

Moved some apis, added some equality operators and cleaned up some code.

Snappy/Constraint.swift

@@ -27,6 +27,38 @@ import UIKit
 import AppKit
 #endif
 
+public protocol FloatConstantConstraint {
+    func update(float: Float)
+}
+
+public protocol DoubleConstantConstraint {
+    func update(float: Float)
+}
+
+public protocol CGFloatConstantConstraint {
+    func update(float: Float)
+}
+
+public protocol IntConstantConstraint {
+    func update(float: Float)
+}
+
+public protocol UIntConstantConstraint {
+    func update(float: Float)
+}
+
+public protocol CGPointConstantConstraint {
+    func update(float: Float)
+}
+
+public protocol CGSizeConstantConstraint {
+    func update(size: CGSize)
+}
+
+public protocol EdgeInsetsConstantConstraint {
+    func update(insets: EdgeInsets)
+}
+
 /**
  * Constraint is a single item that defines all the properties for a single ConstraintMaker chain
  */
@@ -269,9 +301,14 @@ public class Constraint {
         return self
     }
     
-    // MARK: install
+    // MARK: internal
     
-    public func install() -> Array<LayoutConstraint> {
+    internal func install() -> Array<LayoutConstraint> {
+        if self.installedOnView != nil {
+            NSException(name: "Cannot Install Constraint", reason: "Already installed", userInfo: nil).raise()
+            return []
+        }
+        
         var installOnView: View? = nil
         if self.toItem.view != nil {
             installOnView = Constraint.closestCommonSuperviewFromView(self.fromItem.view, toView: self.toItem.view)
@@ -330,15 +367,13 @@ public class Constraint {
             layoutConstraints.append(layoutConstraint)
         }
         
-        installOnView?.addConstraints(layoutConstraints)
+        installOnView!.addConstraints(layoutConstraints)
         
         self.installedOnView = installOnView
         return layoutConstraints
     }
     
-    // MARK: uninstall
-    
-    public func uninstall() {
+    internal func uninstall() {
         if let view = self.installedOnView {
             #if os(iOS)
             var installedConstraints = view.constraints()
@@ -556,4 +591,12 @@ private extension NSLayoutAttribute {
         
         return CGFloat(0);
     }
+}
+
+internal func ==(left: Constraint, right: Constraint) -> Bool {
+    return (left.fromItem == right.fromItem &&
+            left.toItem == right.toItem &&
+            left.relation == right.relation &&
+            left.multiplier == right.multiplier &&
+            left.priority == right.priority)
 }

Snappy/ConstraintAttributes.swift

@@ -156,12 +156,12 @@ internal struct ConstraintAttributes: RawOptionSetType, BooleanType {
             return attrs
     }
 }
-internal func += (inout left: ConstraintAttributes, right: ConstraintAttributes) {
+internal func +=(inout left: ConstraintAttributes, right: ConstraintAttributes) {
     left = (left | right)
 }
-internal func -= (inout left: ConstraintAttributes, right: ConstraintAttributes) {
+internal func -=(inout left: ConstraintAttributes, right: ConstraintAttributes) {
     left = left & ~right
 }
-internal func == (left: ConstraintAttributes, right: ConstraintAttributes) -> Bool {
+internal func ==(left: ConstraintAttributes, right: ConstraintAttributes) -> Bool {
     return left.rawValue == right.rawValue
 }

Snappy/ConstraintItem.swift

@@ -59,4 +59,21 @@ public class ConstraintItem {
         }
     }
     #endif
+}
+
+
+internal func ==(left: ConstraintItem, right: ConstraintItem) -> Bool {
+    if left.object == nil {
+        return false
+    }
+    if right.object == nil {
+        return false
+    }
+    if left.object !== right.object {
+        return false
+    }
+    if left.attributes != right.attributes {
+        return false
+    }
+    return true
 }

Snappy/ConstraintMaker.swift

@@ -70,11 +70,12 @@ public class ConstraintMaker {
         let maker = ConstraintMaker(view: view)
         block(make: maker)
         
-        var layoutConstraints = LayoutConstraint.layoutConstraintsInstalledOnView(view)
+        var layoutConstraints = view.snp_installedLayoutConstraints
         for constraint in maker.constraints {
             layoutConstraints += constraint.install()
         }
-        LayoutConstraint.setLayoutConstraints(layoutConstraints, installedOnView: view)
+        
+        view.snp_installedLayoutConstraints = layoutConstraints
     }
     
     internal class func remakeConstraints(view: View, block: (make: ConstraintMaker) -> ()) {
@@ -86,7 +87,7 @@ public class ConstraintMaker {
         let maker = ConstraintMaker(view: view)
         block(make: maker)
         
-        var layoutConstraints: Array<LayoutConstraint> = LayoutConstraint.layoutConstraintsInstalledOnView(view)
+        var layoutConstraints: Array<LayoutConstraint> = view.snp_installedLayoutConstraints
         for existingLayoutConstraint in layoutConstraints {
             existingLayoutConstraint.constraint?.uninstall()
         }
@@ -95,13 +96,15 @@ public class ConstraintMaker {
         for constraint in maker.constraints {
             layoutConstraints += constraint.install()
         }
-        LayoutConstraint.setLayoutConstraints(layoutConstraints, installedOnView: view)
+        
+        view.snp_installedLayoutConstraints = layoutConstraints
     }
     
     internal class func removeConstraints(view: View) {
-        for existingLayoutConstraint in LayoutConstraint.layoutConstraintsInstalledOnView(view) {
+        for existingLayoutConstraint in view.snp_installedLayoutConstraints {
             existingLayoutConstraint.constraint?.uninstall()
         }
-        LayoutConstraint.setLayoutConstraints([], installedOnView: view)
+        
+        view.snp_installedLayoutConstraints = []
     }
 }

Snappy/LayoutConstraint.swift

@@ -31,21 +31,5 @@ import AppKit
 * LayoutConstraint is a subclass of NSLayoutConstraint to assist Snappy and also provide better debugging
 */
 public class LayoutConstraint: NSLayoutConstraint {
-    
-    // internal
-    
     internal var constraint: Constraint?
-    
-    internal class func layoutConstraintsInstalledOnView(view: View) -> Array<LayoutConstraint> {
-        var constraints = objc_getAssociatedObject(view, &layoutConstraintsInstalledOnViewKey) as? Array<LayoutConstraint>
-        if constraints != nil {
-            return constraints!
-        }
-        return []
-    }
-    internal class func setLayoutConstraints(layoutConstraints: Array<LayoutConstraint>, installedOnView view: View) {
-        objc_setAssociatedObject(view, &layoutConstraintsInstalledOnViewKey, layoutConstraints, UInt(OBJC_ASSOCIATION_RETAIN_NONATOMIC))
-    }
-}
-
-private var layoutConstraintsInstalledOnViewKey = ""
+}

Snappy/View+Snappy.swift

@@ -30,6 +30,9 @@ public typealias View = NSView
 #endif
 
 public extension View {
+    
+    // normal
+    
     public var snp_left: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Left) }
     public var snp_top: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Top) }
     public var snp_right: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Right) }
@@ -42,8 +45,8 @@ public extension View {
     public var snp_centerY: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.CenterY) }
     public var snp_baseline: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Baseline) }
     
+    #if os(iOS)
     public var snp_firstBaseline: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.FirstBaseline) }
-    
     public var snp_leftMargin: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.LeftMargin) }
     public var snp_rightMargin: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.RightMargin) }
     public var snp_topMargin: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.TopMargin) }
@@ -52,18 +55,27 @@ public extension View {
     public var snp_trailingMargin: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.TrailingMargin) }
     public var snp_centerXWithinMargin: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.CenterXWithinMargins) }
     public var snp_centerYWithinMargin: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.CenterYWithinMargins) }
+    #endif
+    
+    // aggregates
     
     public var snp_edges: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Edges) }
     public var snp_size: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Size) }
     public var snp_center: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Center) }
     
+    #if os(iOS)
     public var snp_margins: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.Margins) }
     public var snp_centerWithinMargins: ConstraintItem { return ConstraintItem(object: self, attributes: ConstraintAttributes.CenterWithinMargins) }
+    #endif
     
     public func snp_makeConstraints(block: (maker: ConstraintMaker) -> ()) {
         ConstraintMaker.makeConstraints(self, block: block)
     }
     
+    public func snp_updateConstraints(block: (maker: ConstraintMaker) -> ()) {
+        ConstraintMaker.updateConstraints(self, block: block)
+    }
+    
     public func snp_remakeConstraints(block: (maker: ConstraintMaker) -> ()) {
         ConstraintMaker.remakeConstraints(self, block: block)
     }
@@ -71,4 +83,21 @@ public extension View {
     public func snp_removeConstraints() {
         ConstraintMaker.removeConstraints(self)
     }
-}
+    
+    // internal
+    
+    internal var snp_installedLayoutConstraints: Array<LayoutConstraint> {
+        get {
+            var constraints = objc_getAssociatedObject(self, &installedLayoutConstraintsKey) as? Array<LayoutConstraint>
+            if constraints != nil {
+                return constraints!
+            }
+            return []
+        }
+        set {
+            objc_setAssociatedObject(self, &installedLayoutConstraintsKey, newValue, UInt(OBJC_ASSOCIATION_RETAIN_NONATOMIC))
+        }
+    }
+}
+
+private var installedLayoutConstraintsKey = ""