Big update. Migration tools in progress

CoreStore/Migrating/MigrationChain.swift

@@ -0,0 +1,129 @@
+//
+//  MigrationChain.swift
+//  CoreStore
+//
+//  Copyright (c) 2015 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import Foundation
+import CoreData
+
+
+// MARK: - MigrationChain
+
+public struct MigrationChain: NilLiteralConvertible, StringLiteralConvertible, DictionaryLiteralConvertible, ArrayLiteralConvertible {
+    
+    // MARK: Public
+    
+    public func contains(version: String) -> Bool {
+        
+        return self.latestVersion == version
+            || find(self.versionTree.keys, version) != nil
+    }
+    
+    
+    // MARK: NilLiteralConvertible
+    
+    public init(nilLiteral: ()) {
+        
+        self.latestVersion = nil
+        self.versionTree = [:]
+    }
+    
+    
+    // MARK: StringLiteralConvertible
+    
+    public init(stringLiteral value: String) {
+        
+        self.latestVersion = value
+        self.versionTree = [:]
+    }
+    
+    // MARK: ExtendedGraphemeClusterLiteralConvertible
+    
+    public init(extendedGraphemeClusterLiteral value: String) {
+        
+        self.latestVersion = value
+        self.versionTree = [:]
+    }
+    
+    
+    // MARK: UnicodeScalarLiteralConvertible
+    
+    public init(unicodeScalarLiteral value: String) {
+        
+        self.latestVersion = value
+        self.versionTree = [:]
+    }
+    
+    
+    // MARK: DictionaryLiteralConvertible
+    
+    public init(dictionaryLiteral elements: (String, String)...) {
+        
+        let versionTree = elements.reduce([String: String]()) { (var versionTree, tuple: (String, String)) -> [String: String] in
+            
+            versionTree[tuple.0] = tuple.1
+            return versionTree
+        }
+        let latestVersions = elements.filter { (tuple: (String, String)) -> Bool in
+            
+            return versionTree[tuple.1] == nil
+        }
+        
+        CoreStore.assert(latestVersions.count == 1, "\(typeName(MigrationChain))'s migration chain could not be resolved due to multiple leaf versions.")
+        
+        self.latestVersion = latestVersions.first?.1
+        self.versionTree = versionTree
+    }
+    
+    
+    // MARK: ArrayLiteralConvertible
+    
+    public init(arrayLiteral elements: String...) {
+        
+        CoreStore.assert(Set(elements).count == elements.count, "\(typeName(MigrationChain))'s migration chain could not be created due to duplicate version strings.")
+        
+        var lastVersion: String?
+        var versionTree = [String: String]()
+        for version in elements {
+            
+            if let lastVersion = lastVersion {
+                
+                versionTree[lastVersion] = version
+            }
+            lastVersion = version
+        }
+        
+        self.versionTree = versionTree
+        self.latestVersion = elements.last
+    }
+    
+    
+    // MARK: Internal
+    
+    internal let latestVersion: String?
+    
+    
+    // MARK: Private
+    
+    private let versionTree: [String: String]
+}