[WIP] Refactor and support encoding to timestamp and decoding to date

CodableFirebase.xcodeproj/project.pbxproj

@@ -7,10 +7,12 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		09D19A4B218D64F900A862A3 /* DecodeStrategy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 09D19A4A218D64F900A862A3 /* DecodeStrategy.swift */; };
+		09D19A4D218D650000A862A3 /* EncodeStrategy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 09D19A4C218D650000A862A3 /* EncodeStrategy.swift */; };
+		09D19A4E218D874000A862A3 /* FirestoreDecoder.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE7DD3821F9D04AE000225C5 /* FirestoreDecoder.swift */; };
+		09D19A4F218D88A800A862A3 /* FirestoreEncoder.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE7DD3811F9D04AE000225C5 /* FirestoreEncoder.swift */; };
 		CE7DD3711F9CFA81000225C5 /* CodableFirebase.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = CE7DD3671F9CFA81000225C5 /* CodableFirebase.framework */; };
 		CE7DD3781F9CFA81000225C5 /* CodableFirebase.h in Headers */ = {isa = PBXBuildFile; fileRef = CE7DD36A1F9CFA81000225C5 /* CodableFirebase.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		CE7DD3831F9D04AE000225C5 /* FirestoreEncoder.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE7DD3811F9D04AE000225C5 /* FirestoreEncoder.swift */; };
-		CE7DD3841F9D04AE000225C5 /* FirestoreDecoder.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE7DD3821F9D04AE000225C5 /* FirestoreDecoder.swift */; };
 		CE7DD3861F9DE4F7000225C5 /* TestCodableFirestore.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE7DD3851F9DE4F7000225C5 /* TestCodableFirestore.swift */; };
 		CEFDBF821FF3B35B00745EBE /* Encoder.swift in Sources */ = {isa = PBXBuildFile; fileRef = CEFDBF811FF3B35B00745EBE /* Encoder.swift */; };
 		CEFDBF861FF3B56200745EBE /* Decoder.swift in Sources */ = {isa = PBXBuildFile; fileRef = CEFDBF851FF3B56200745EBE /* Decoder.swift */; };
@@ -31,6 +33,8 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		09D19A4A218D64F900A862A3 /* DecodeStrategy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DecodeStrategy.swift; sourceTree = "<group>"; };
+		09D19A4C218D650000A862A3 /* EncodeStrategy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EncodeStrategy.swift; sourceTree = "<group>"; };
 		CE7DD3671F9CFA81000225C5 /* CodableFirebase.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = CodableFirebase.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		CE7DD36A1F9CFA81000225C5 /* CodableFirebase.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = CodableFirebase.h; sourceTree = "<group>"; };
 		CE7DD36B1F9CFA81000225C5 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
@@ -92,6 +96,8 @@
 				CE7DD3811F9D04AE000225C5 /* FirestoreEncoder.swift */,
 				CEFDBF891FF3E24200745EBE /* FirebaseDecoder.swift */,
 				CEFDBF8B1FF3E3CB00745EBE /* FirebaseEncoder.swift */,
+				09D19A4A218D64F900A862A3 /* DecodeStrategy.swift */,
+				09D19A4C218D650000A862A3 /* EncodeStrategy.swift */,
 				CEFDBF851FF3B56200745EBE /* Decoder.swift */,
 				CEFDBF811FF3B35B00745EBE /* Encoder.swift */,
 				CE7DD36B1F9CFA81000225C5 /* Info.plist */,
@@ -222,11 +228,13 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				CE7DD3831F9D04AE000225C5 /* FirestoreEncoder.swift in Sources */,
+				09D19A4D218D650000A862A3 /* EncodeStrategy.swift in Sources */,
 				CEFDBF8C1FF3E3CB00745EBE /* FirebaseEncoder.swift in Sources */,
+				09D19A4B218D64F900A862A3 /* DecodeStrategy.swift in Sources */,
+				09D19A4E218D874000A862A3 /* FirestoreDecoder.swift in Sources */,
+				09D19A4F218D88A800A862A3 /* FirestoreEncoder.swift in Sources */,
 				CEFDBF821FF3B35B00745EBE /* Encoder.swift in Sources */,
 				CEFDBF861FF3B56200745EBE /* Decoder.swift in Sources */,
-				CE7DD3841F9D04AE000225C5 /* FirestoreDecoder.swift in Sources */,
 				CEFDBF8A1FF3E24200745EBE /* FirebaseDecoder.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

CodableFirebase/DecodeStrategy.swift

@@ -0,0 +1,77 @@
+//
+//  DecodeStrategy.swift
+//  CodableFirebase
+//
+//  Created by Zitao Xiong on 11/3/18.
+//  Copyright © 2018 ViolentOctopus. All rights reserved.
+//
+
+import Foundation
+
+/// The strategy to use for decoding `Date` values.
+public enum DateDecodingStrategy {
+    /// Defer to `Date` for decoding. This is the default strategy.
+    case deferredToDate
+
+    case deferredToTimestamp
+
+    /// Decode the `Date` as a UNIX timestamp from a JSON number.
+    case secondsSince1970
+
+    /// Decode the `Date` as UNIX millisecond timestamp from a JSON number.
+    case millisecondsSince1970
+
+    /// Decode the `Date` as an ISO-8601-formatted string (in RFC 3339 format).
+    @available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
+    case iso8601
+
+    /// Decode the `Date` as a string parsed by the given formatter.
+    case formatted(DateFormatter)
+
+    /// Decode the `Date` as a custom value decoded by the given closure.
+    case custom((_ decoder: Decoder) throws -> Date)
+}
+
+/// The strategy to use for decoding `Data` values.
+public enum DataDecodingStrategy {
+    /// Defer to `Data` for decoding.
+    case deferredToData
+
+    /// Decode the `Data` from a Base64-encoded string. This is the default strategy.
+    case base64
+
+    /// Decode the `Data` as a custom value decoded by the given closure.
+    case custom((_ decoder: Decoder) throws -> Data)
+}
+
+public enum FirestoreTypeDecodingStrategy {
+    case deferredToPtotocol
+    case custom((_ value: Any) throws -> Any)
+}
+
+
+extension CodingUserInfoKey {
+    public static let dateDecodingStrategy: CodingUserInfoKey = CodingUserInfoKey(rawValue: "dateDecodingStrategy")!
+
+    public static let dataDecodingStrategy: CodingUserInfoKey = CodingUserInfoKey(rawValue: "dataDecodingStrategy")!
+
+    public static let firestoreTypeDecodingStrategy: CodingUserInfoKey = CodingUserInfoKey(rawValue: "firestoreTypeDecodingStrategy")!
+}
+
+extension Dictionary where Key == CodingUserInfoKey, Value == Any {
+    var dateDecodingStrategy: DateDecodingStrategy? {
+        return self[.dateDecodingStrategy] as? DateDecodingStrategy
+    }
+
+    var dataDecodingStrategy: DataDecodingStrategy? {
+        return self[.dataDecodingStrategy] as? DataDecodingStrategy
+    }
+
+    var firestoreTypeDecodingStrategy: FirestoreTypeDecodingStrategy {
+        if let strategy = self[.firestoreTypeDecodingStrategy] as? FirestoreTypeDecodingStrategy {
+            return strategy
+        }
+
+        return FirestoreTypeDecodingStrategy.deferredToPtotocol
+    }
+}

CodableFirebase/Decoder.swift

@@ -9,35 +9,22 @@
 import Foundation
 
 class _FirebaseDecoder : Decoder {
-    /// Options set on the top-level encoder to pass down the decoding hierarchy.
-    struct _Options {
-        let dateDecodingStrategy: FirebaseDecoder.DateDecodingStrategy?
-        let dataDecodingStrategy: FirebaseDecoder.DataDecodingStrategy?
-        let skipFirestoreTypes: Bool
-        let userInfo: [CodingUserInfoKey : Any]
-    }
-
     // MARK: Properties
     /// The decoder's storage.
     fileprivate var storage: _FirebaseDecodingStorage
 
-    fileprivate let options: _Options
-
     /// The path to the current point in encoding.
     fileprivate(set) public var codingPath: [CodingKey]
-
-    /// Contextual user-provided information for use during encoding.
-    public var userInfo: [CodingUserInfoKey : Any] {
-        return options.userInfo
-    }
+
+    let userInfo: [CodingUserInfoKey : Any]
 
     // MARK: - Initialization
     /// Initializes `self` with the given top-level container and options.
-    init(referencing container: Any, at codingPath: [CodingKey] = [], options: _Options) {
+    init(referencing container: Any, at codingPath: [CodingKey] = [], userInfo: [CodingUserInfoKey: Any]) {
         self.storage = _FirebaseDecodingStorage()
         self.storage.push(container: container)
         self.codingPath = codingPath
-        self.options = options
+        self.userInfo = userInfo
     }
 
     // MARK: - Decoder Methods
@@ -410,7 +397,7 @@ fileprivate struct _FirebaseKeyedDecodingContainer<K : CodingKey> : KeyedDecodin
         defer { self.decoder.codingPath.removeLast() }
 
         let value: Any = container[key.stringValue] ?? NSNull()
-        return _FirebaseDecoder(referencing: value, at: self.decoder.codingPath, options: decoder.options)
+        return _FirebaseDecoder(referencing: value, at: self.decoder.codingPath, userInfo: decoder.userInfo)
     }
 
     public func superDecoder() throws -> Decoder {
@@ -771,7 +758,7 @@ fileprivate struct _FirebaseUnkeyedDecodingContainer : UnkeyedDecodingContainer
 
         let value = self.container[self.currentIndex]
         self.currentIndex += 1
-        return _FirebaseDecoder(referencing: value, at: decoder.codingPath, options: decoder.options)
+        return _FirebaseDecoder(referencing: value, at: decoder.codingPath, userInfo: decoder.userInfo)
     }
 }
 
@@ -1109,14 +1096,17 @@ extension _FirebaseDecoder {
     func unbox(_ value: Any, as type: Date.Type) throws -> Date? {
         guard !(value is NSNull) else { return nil }
 
-        guard let options = options.dateDecodingStrategy else {
+        guard let options = userInfo.dateDecodingStrategy else {
             guard let date = value as? Date else {
                 throw DecodingError._typeMismatch(at: codingPath, expectation: type, reality: value)
             }
             return date
         }
 
         switch options {
+        case .deferredToTimestamp:
+            let timestamp = value as! TimestampType
+            return timestamp.dateValue()
         case .deferredToDate:
             self.storage.push(container: value)
             let date = try Date(from: self)
@@ -1162,7 +1152,7 @@ extension _FirebaseDecoder {
     func unbox(_ value: Any, as type: Data.Type) throws -> Data? {
         guard !(value is NSNull) else { return nil }
 
-        guard let options = options.dataDecodingStrategy else {
+        guard let options = userInfo.dataDecodingStrategy else {
             guard let data = value as? Data else {
                 throw DecodingError._typeMismatch(at: codingPath, expectation: type, reality: value)
             }
@@ -1230,9 +1220,17 @@ extension _FirebaseDecoder {
         } else if T.self == Decimal.self || T.self == NSDecimalNumber.self {
             guard let decimal = try self.unbox(value, as: Decimal.self) else { return nil }
             decoded = decimal as! T
-        } else if options.skipFirestoreTypes && (T.self is FirestoreDecodable.Type) {
-            decoded = value as! T
-        } else {
+        }
+        else if userInfo.skipFirestoreTypes && (T.self is FirestoreDecodable.Type) {
+            let strategy = userInfo.firestoreTypeDecodingStrategy
+            switch strategy {
+            case .deferredToPtotocol:
+                decoded = value as! T
+            case .custom(let decodeFunc):
+                decoded = try decodeFunc(value) as! T
+            }
+        }
+        else {
             self.storage.push(container: value)
             decoded = try T(from: self)
             self.storage.popContainer()

CodableFirebase/EncodeStrategy.swift

@@ -0,0 +1,89 @@
+//
+//  EncodeStrategy.swift
+//  CodableFirebase
+//
+//  Created by Zitao Xiong on 11/3/18.
+//  Copyright © 2018 ViolentOctopus. All rights reserved.
+//
+
+import Foundation
+
+/// The strategy to use for encoding `Date` values.
+public enum DateEncodingStrategy {
+    /// Defer to `Date` for choosing an encoding. This is the default strategy.
+    case deferredToDate
+
+    case deferredToTimestamp((Date) -> TimestampType)
+
+    /// Encode the `Date` as a UNIX timestamp (as a JSON number).
+    case secondsSince1970
+
+    /// Encode the `Date` as UNIX millisecond timestamp (as a JSON number).
+    case millisecondsSince1970
+
+    /// Encode the `Date` as an ISO-8601-formatted string (in RFC 3339 format).
+    @available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *)
+    case iso8601
+
+    /// Encode the `Date` as a string formatted by the given formatter.
+    case formatted(DateFormatter)
+
+    /// Encode the `Date` as a custom value encoded by the given closure.
+    ///
+    /// If the closure fails to encode a value into the given encoder, the encoder will encode an empty automatic container in its place.
+    case custom((Date, Encoder) throws -> Void)
+}
+
+/// The strategy to use for encoding `Data` values.
+public enum DataEncodingStrategy {
+    /// Defer to `Data` for choosing an encoding.
+    case deferredToData
+
+    /// Encoded the `Data` as a Base64-encoded string. This is the default strategy.
+    case base64
+
+    /// Encode the `Data` as a custom value encoded by the given closure.
+    ///
+    /// If the closure fails to encode a value into the given encoder, the encoder will encode an empty automatic container in its place.
+    case custom((Data, Encoder) throws -> Void)
+}
+
+public enum FirestoreTypeEncodingStrategy {
+    case deferredToPtotocol
+    case custom((_ value: Any) throws -> Any)
+}
+
+extension CodingUserInfoKey {
+    public static let dateEncodingStrategy: CodingUserInfoKey = CodingUserInfoKey(rawValue: "dateEncodingStrategy")!
+
+    public static let dataEncodingStrategy: CodingUserInfoKey = CodingUserInfoKey(rawValue: "dataEncodingStrategy")!
+
+    public static let skipFirestoreTypes: CodingUserInfoKey = CodingUserInfoKey(rawValue: "skipFirestoreTypes")!
+
+    public static let firestoreTypeEncodingStrategy: CodingUserInfoKey = CodingUserInfoKey(rawValue: "firestoreTypeEncodingStrategy")!
+}
+
+extension Dictionary where Key == CodingUserInfoKey, Value == Any {
+    var dateEncodingStrategy: DateEncodingStrategy? {
+        return self[.dateEncodingStrategy] as? DateEncodingStrategy
+    }
+
+    var dataEncodingStrategy: DataEncodingStrategy? {
+        return self[.dataEncodingStrategy] as? DataEncodingStrategy
+    }
+
+    var skipFirestoreTypes: Bool {
+        if let skip = self[.skipFirestoreTypes] as? Bool {
+            return skip
+        }
+        return false
+    }
+
+    var firestoreTypeEncodingStrategy: FirestoreTypeEncodingStrategy {
+        if let strategy = self[.firestoreTypeEncodingStrategy] as? FirestoreTypeEncodingStrategy {
+            return strategy
+        }
+
+        return FirestoreTypeEncodingStrategy.deferredToPtotocol
+    }
+}