Merge pull request #190 from vapor/decimal-precision

store Decimal using Codable impl

Author: tanner0101

Sources/MySQL/Connection/MySQLData.swift

@@ -26,15 +26,6 @@ public struct MySQLData: Equatable, Encodable {
         self.storage = .binary(binary)
     }
 
-    public init(decimal: Decimal) {
-        let binary = MySQLBinaryData(
-            type: .MYSQL_TYPE_NEWDECIMAL,
-            isUnsigned: true,
-            storage: .string(.init(decimal.description.utf8))
-        )
-        self.storage = .binary(binary)
-    }
-
     /// Creates a new `MySQLData` from `Data`.
     public init(data: Data?) {
         let binary = MySQLBinaryData(
@@ -401,24 +392,6 @@ extension String: MySQLDataConvertible {
     }
 }
 
-extension Decimal: MySQLDataConvertible {
-    /// See `MySQLDataConvertible.convertToMySQLData(format:)`
-    public func convertToMySQLData() -> MySQLData {
-        return MySQLData(decimal: self)
-    }
-
-    /// See `MySQLDataConvertible.convertFromMySQLData()`
-    public static func convertFromMySQLData(_ mysqlData: MySQLData) throws -> Decimal {
-        guard let string = mysqlData.string() else {
-            throw MySQLError(identifier: "decimal", reason: "Cannot decode String from MySQLData: \(mysqlData).")
-        }
-        guard let decimal = Decimal(string: string) else {
-            throw MySQLError(identifier: "decimal", reason: "Cannot decode Decimal from String: \(string).")
-        }
-        return decimal
-    }
-}
-
 extension FixedWidthInteger {
     /// See `MySQLDataConvertible.convertToMySQLData(format:)`
     public func convertToMySQLData() -> MySQLData {

Sources/MySQL/Data/MySQLData+Decimal.swift

@@ -0,0 +1,23 @@
+extension Decimal: MySQLDataTypeStaticRepresentable {
+    /// See `MySQLDataTypeStaticRepresentable`.
+    public static var mysqlDataType: MySQLDataType {
+        /// https://github.com/apple/swift-corelibs-foundation/blob/master/Foundation/Decimal.swift#L567
+        /// decimal has max string size of 200
+        return .varchar(200)
+    }
+}
+
+extension Decimal: MySQLDataConvertible {
+    /// See `MySQLDataConvertible`.
+    public func convertToMySQLData() -> MySQLData {
+        return .init(string: self.description)
+    }
+    
+    /// See `MySQLDataConvertible`.
+    public static func convertFromMySQLData(_ mysqlData: MySQLData) throws -> Decimal {
+        guard let decimal = try Decimal(string: String.convertFromMySQLData(mysqlData)) else {
+            throw MySQLError(identifier: "decimal", reason: "Could not decode decimal from MySQLData: \(mysqlData).")
+        }
+        return decimal
+    }
+}

Sources/MySQL/SQL/MySQLDataType.swift

@@ -9,7 +9,7 @@ public struct MySQLDataType: SQLDataType, Equatable {
     /// See `SQLDataType`.
     public static func dataType(appropriateFor type: Any.Type) -> MySQLDataType? {
         guard let type = type as? MySQLDataTypeStaticRepresentable.Type else {
-            return nil
+            return .json
         }
         return type.mysqlDataType
     }

Sources/MySQL/SQL/MySQLDataTypeStaticRepresentable.swift

@@ -25,13 +25,6 @@ extension String: MySQLDataTypeStaticRepresentable {
     }
 }
 
-extension Decimal: MySQLDataTypeStaticRepresentable {
-    /// See `MySQLDataTypeStaticRepresentable`.
-    public static var mysqlDataType: MySQLDataType {
-        return .decimal
-    }
-}
-
 extension FixedWidthInteger {
     /// See `MySQLDataTypeStaticRepresentable`.
     public static var mysqlDataType: MySQLDataType {

Tests/MySQLTests/MySQLTests.swift

@@ -280,6 +280,29 @@ class MySQLTests: XCTestCase {
         XCTAssertEqual(sql, "ALTER TABLE `Galaxy` ADD COLUMN `name` VARCHAR(255) NOT NULL AFTER `id`")
     }
 
+    func testDecimalPrecision() throws {
+        struct DecimalTest: MySQLTable {
+            var num: Decimal
+        }
+        
+        let conn = try MySQLConnection.makeTest()
+        defer {
+            try? conn.drop(table: DecimalTest.self).ifExists().run().wait()
+        }
+        try conn.create(table: DecimalTest.self)
+            .column(for: \DecimalTest.num)
+            .run().wait()
+        
+        let a = DecimalTest(num: .init(sign: .plus, exponent: 80, significand: 1.0))
+        try conn.insert(into: DecimalTest.self).value(a)
+            .run().wait()
+        
+        let b = try conn.select()
+            .all().from(DecimalTest.self)
+            .all(decoding: DecimalTest.self).wait()
+        XCTAssertEqual(b.first?.num, a.num)
+    }
+    
     static let allTests = [
         ("testBenchmark", testBenchmark),
         ("testSimpleQuery", testSimpleQuery),
@@ -295,6 +318,7 @@ class MySQLTests: XCTestCase {
         ("testInsertMany", testInsertMany),
         ("testPreparedStatementOverload", testPreparedStatementOverload),
         ("testColumnAfter", testColumnAfter),
+        ("testDecimalPrecision", testDecimalPrecision),
     ]
 }