format code cleanup

Author: tanner0101

Sources/PostgreSQL/Message/Messages/PostgreSQLDataRow.swift

@@ -27,6 +27,7 @@ struct PostgreSQLDataRowColumn: Decodable {
     /// The value of the column, in the format indicated by the associated format code. n is the above length.
     var value: Data?
 
+    /// See Decodable.decode
     init(from decoder: Decoder) throws {
         let single = try decoder.singleValueContainer()
         /// The length of the column value, in bytes (this count does not include itself).
@@ -46,4 +47,14 @@ struct PostgreSQLDataRowColumn: Decodable {
         default: fatalError("Illegal data row column value count: \(count)")
         }
     }
+
+
+    func makeString(encoding: String.Encoding = .utf8) throws -> String? {
+        return try value.flatMap { data in
+            guard let string = String(data: data, encoding: encoding) else {
+                throw PostgreSQLError(identifier: "utf8String", reason: "Unexpected non-UTF8 string.")
+            }
+            return string
+        }
+    }
 }

Sources/PostgreSQL/Message/Messages/PostgreSQLRowDescription.swift

@@ -44,7 +44,7 @@ struct PostgreSQLRowDescriptionField: Decodable {
     /// Currently will be zero (text) or one (binary).
     /// In a RowDescription returned from the statement variant of Describe,
     /// the format code is not yet known and will always be zero.
-    var formatCode: Int16
+    var formatCode: PostgreSQLFormatCode
 
     /// See Decodable.decode
     init(from decoder: Decoder) throws {
@@ -55,13 +55,40 @@ struct PostgreSQLRowDescriptionField: Decodable {
         dataType = try single.decode(PostgreSQLDataType.self)
         dataTypeSize = try single.decode(Int16.self)
         dataTypeModifier = try single.decode(Int32.self)
-        formatCode = try single.decode(Int16.self)
+        formatCode = try single.decode(PostgreSQLFormatCode.self)
+    }
+}
+
+/// The format code being used for the field.
+/// Currently will be zero (text) or one (binary).
+/// In a RowDescription returned from the statement variant of Describe,
+/// the format code is not yet known and will always be zero.
+enum PostgreSQLFormatCode: Int16, Decodable {
+    case text = 0
+    case binary = 1
+
+    /// See Decodable.decode
+    init(from decoder: Decoder) throws {
+        let single = try decoder.singleValueContainer()
+        let code = try single.decode(Int16.self)
+        guard let type = PostgreSQLFormatCode.make(code) else {
+            throw PostgreSQLError(
+                identifier: "formatCode",
+                reason: "Unsupported format code: \(code)"
+            )
+        }
+        self = type
+    }
+
+    /// Static make (non-failable)
+    private static func make(_ code: Int16) -> PostgreSQLFormatCode? {
+        return PostgreSQLFormatCode(rawValue: code)
     }
 }
 
 /// The data type's raw object ID.
 /// Use `select * from pg_type where oid in (<idhere>);` to lookup more information.
-enum PostgreSQLDataType: Int32, Decodable, Equatable {
+enum PostgreSQLDataType: Int32, Decodable {
     case bool = 16
     case char = 18
     case name = 19
@@ -79,13 +106,14 @@ enum PostgreSQLDataType: Int32, Decodable, Equatable {
         let objectID = try single.decode(Int32.self)
         guard let type = PostgreSQLDataType.make(objectID) else {
             throw PostgreSQLError(
-                identifier: "unsupportedColumnType",
+                identifier: "dataType",
                 reason: "Unsupported data type: \(objectID)"
             )
         }
         self = type
     }
 
+    /// Static make (non-failable)
     private static func make(_ objectID: Int32) -> PostgreSQLDataType? {
         return PostgreSQLDataType(rawValue: objectID)
     }

Sources/PostgreSQL/PostgreSQLClient.swift

@@ -44,7 +44,7 @@ final class PostgreSQLClient {
                     currentRow = row
                 case .dataRow(let data):
                     guard let row = currentRow else {
-                        fatalError("Unexpected PostgreSQLDataRow without preceeding PostgreSQLRowDescription.")
+                        fatalError("Unexpected PostgreSQLDataRow without preceding PostgreSQLRowDescription.")
                     }
 
                     var parsed: [String: PostgreSQLData] = [:]
@@ -55,36 +55,26 @@ final class PostgreSQLClient {
                         let col = data.columns[i]
                         let data: PostgreSQLData
                         switch field.formatCode {
-                        case 0: // text
-                            func makeString() throws -> String? {
-                                return try col.value.flatMap { data in
-                                    guard let string = String(data: data, encoding: .utf8) else {
-                                        throw PostgreSQLError(identifier: "utf8String", reason: "Unexpected non-UTF8 string.")
-                                    }
-                                    return string
-                                }
-                            }
-
+                        case .text:
                             switch field.dataType {
                             case .bool:
-                                data = try makeString().flatMap { $0 == "t" }.flatMap { .bool($0) } ?? .null
+                                data = try col.makeString().flatMap { $0 == "t" }.flatMap { .bool($0) } ?? .null
                             case .text, .name:
-                                data = try makeString().flatMap { .string($0) } ?? .null
+                                data = try col.makeString().flatMap { .string($0) } ?? .null
                             case .oid, .regproc, .int4:
-                                data = try makeString().flatMap { Int32($0) }.flatMap { .int32($0) } ?? .null
+                                data = try col.makeString().flatMap { Int32($0) }.flatMap { .int32($0) } ?? .null
                             case .int2:
-                                data = try makeString().flatMap { Int16($0) }.flatMap { .int16($0) } ?? .null
+                                data = try col.makeString().flatMap { Int16($0) }.flatMap { .int16($0) } ?? .null
                             case .char:
-                                data = try makeString().flatMap { Character($0) }.flatMap { .character($0) } ?? .null
+                                data = try col.makeString().flatMap { Character($0) }.flatMap { .character($0) } ?? .null
                             case .pg_node_tree:
                                 print("\(field.name): is pg node tree")
                                 data = .null
                             case ._aclitem:
                                 print("\(field.name): is acl item")
                                 data = .null
                             }
-                        case 1: fatalError("Binary format code not supported.")
-                        default: fatalError("Unexpected format code: \(field.formatCode)")
+                        case .binary: fatalError("Binary format code not supported.")
                         }
 
                         parsed[field.name] = data