Add Codable support to DatabaseDateComponents

GRDB/Core/Support/Foundation/DatabaseDateComponents.swift

@@ -8,7 +8,7 @@ import SQLite3
 #endif
 
 /// DatabaseDateComponents reads and stores DateComponents in the database.
-public struct DatabaseDateComponents: DatabaseValueConvertible, StatementColumnConvertible {
+public struct DatabaseDateComponents: DatabaseValueConvertible, StatementColumnConvertible, Codable {
 
     /// The available formats for reading and storing date components.
     public enum Format: String {
@@ -159,4 +159,30 @@ public struct DatabaseDateComponents: DatabaseValueConvertible, StatementColumnC
 
         return SQLiteDateParser().components(from: string)
     }
+
+    // MARK: - Codable adoption
+
+
+    /// Creates a new instance by decoding from the given decoder.
+    ///
+    /// - parameters:
+    ///     - decoder: The decoder to read data from.
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        let stringValue = try container.decode(String.self)
+        guard let decodedValue = DatabaseDateComponents.fromDatabaseValue(stringValue.databaseValue) else {
+            throw DecodingError.dataCorruptedError(in: container,
+                                                   debugDescription: "Unable to initialise databaseDateComponent")
+        }
+        self = decodedValue
+    }
+
+    /// Encodes this value into the given encoder.
+    ///
+    /// - parameters:
+    ///     - encoder: The encoder to write data to.
+    public func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        try container.encode(String.fromDatabaseValue(databaseValue)!)
+    }
 }

Tests/GRDBTests/FoundationDateComponentsTests.swift

@@ -506,4 +506,27 @@ class FoundationDateComponentsTests : GRDBTestCase {
         let databaseDateComponents = DatabaseDateComponents.fromDatabaseValue("foo".databaseValue)
         XCTAssertTrue(databaseDateComponents == nil)
     }
+
+    func testJSONEncodingOfDatabaseDateComponents() {
+        let year = 2018
+        let month = 12
+        let day = 31
+        let dbDateComponents = DatabaseDateComponents(
+        DateComponents(year: year, month: month, day: day, hour: nil, minute: nil, second: nil, nanosecond: nil),
+        format: .YMD)
+        let encoded = try! JSONEncoder().encode(dbDateComponents)
+        XCTAssertEqual(String(data: encoded, encoding: .utf8)!, "\"\(year)-\(month)-\(day)\"")
+    }
+
+    func testJSONDecodingOfDatabaseDateComponents() {
+        let year = 2018
+        let month = 12
+        let day = 31
+        let dbDateComponents = DatabaseDateComponents(
+        DateComponents(year: year, month: month, day: day, hour: nil, minute: nil, second: nil, nanosecond: nil),
+        format: .YMD)
+        let json = "\"\(year)-\(month)-\(day)\"".data(using: .utf8)!
+        let decodedDatabaseDateComponents = try! JSONDecoder().decode(DatabaseDateComponents.self, from: json)
+        XCTAssertEqual(decodedDatabaseDateComponents.dateComponents, dbDateComponents.dateComponents)
+    }
 }