Move "char" to pgtype

pgtype_test.go

@@ -74,12 +74,15 @@ func (f forceBinaryEncoder) EncodeBinary(w io.Writer) error {
 func forceEncoder(e interface{}, formatCode int16) interface{} {
 	switch formatCode {
 	case pgx.TextFormatCode:
-		return forceTextEncoder{e: e.(pgtype.TextEncoder)}
+		if e, ok := e.(pgtype.TextEncoder); ok {
+			return forceTextEncoder{e: e}
+		}
 	case pgx.BinaryFormatCode:
-		return forceBinaryEncoder{e: e.(pgtype.BinaryEncoder)}
+		if e, ok := e.(pgtype.BinaryEncoder); ok {
-	default:
+			return forceBinaryEncoder{e: e.(pgtype.BinaryEncoder)}
-		panic("bad encoder")
+		}
 	}
+	return nil
 }
 
 func testSuccessfulTranscode(t testing.TB, pgTypeName string, values []interface{}) {
@@ -105,9 +108,14 @@ func testSuccessfulTranscodeEqFunc(t testing.TB, pgTypeName string, values []int
 		{name: "BinaryFormat", formatCode: pgx.BinaryFormatCode},
 	}
 
-	for _, fc := range formats {
+	for i, v := range values {
-		ps.FieldDescriptions[0].FormatCode = fc.formatCode
+		for _, fc := range formats {
-		for i, v := range values {
+			ps.FieldDescriptions[0].FormatCode = fc.formatCode
+			vEncoder := forceEncoder(v, fc.formatCode)
+			if vEncoder == nil {
+				t.Logf("%v does not implement %v", fc.name)
+				continue
+			}
 			// Derefence value if it is a pointer
 			derefV := v
 			refVal := reflect.ValueOf(v)

qchar.go

@@ -0,0 +1,144 @@
+package pgtype
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+
+	"github.com/jackc/pgx/pgio"
+)
+
+// QChar is for PostgreSQL's special 8-bit-only "char" type more akin to the C
+// language's char type, or Go's byte type. (Note that the name in PostgreSQL
+// itself is "char", in double-quotes, and not char.) It gets used a lot in
+// PostgreSQL's system tables to hold a single ASCII character value (eg
+// pg_class.relkind). It is named Qchar for quoted char to disambiguate from SQL
+// standard type char.
+//
+// Not all possible values of QChar are representable in the text format.
+// Therefore, QChar does not implement TextEncoder and TextDecoder.
+type QChar struct {
+	Int    int8
+	Status Status
+}
+
+func (dst *QChar) ConvertFrom(src interface{}) error {
+	switch value := src.(type) {
+	case QChar:
+		*dst = value
+	case int8:
+		*dst = QChar{Int: value, Status: Present}
+	case uint8:
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case int16:
+		if value < math.MinInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case uint16:
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case int32:
+		if value < math.MinInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case uint32:
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case int64:
+		if value < math.MinInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case uint64:
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case int:
+		if value < math.MinInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case uint:
+		if value > math.MaxInt8 {
+			return fmt.Errorf("%d is greater than maximum value for QChar", value)
+		}
+		*dst = QChar{Int: int8(value), Status: Present}
+	case string:
+		num, err := strconv.ParseInt(value, 10, 8)
+		if err != nil {
+			return err
+		}
+		*dst = QChar{Int: int8(num), Status: Present}
+	default:
+		if originalSrc, ok := underlyingNumberType(src); ok {
+			return dst.ConvertFrom(originalSrc)
+		}
+		return fmt.Errorf("cannot convert %v to QChar", value)
+	}
+
+	return nil
+}
+
+func (src *QChar) AssignTo(dst interface{}) error {
+	return int64AssignTo(int64(src.Int), src.Status, dst)
+}
+
+func (dst *QChar) DecodeBinary(r io.Reader) error {
+	size, err := pgio.ReadInt32(r)
+	if err != nil {
+		return err
+	}
+
+	if size == -1 {
+		*dst = QChar{Status: Null}
+		return nil
+	}
+
+	if size != 1 {
+		return fmt.Errorf(`invalid length for "char": %v`, size)
+	}
+
+	byt, err := pgio.ReadByte(r)
+	if err != nil {
+		return err
+	}
+
+	*dst = QChar{Int: int8(byt), Status: Present}
+	return nil
+}
+
+func (src QChar) EncodeBinary(w io.Writer) error {
+	if done, err := encodeNotPresent(w, src.Status); done {
+		return err
+	}
+
+	_, err := pgio.WriteInt32(w, 1)
+	if err != nil {
+		return nil
+	}
+
+	return pgio.WriteByte(w, byte(src.Int))
+}

qchar_test.go

@@ -0,0 +1,140 @@
+package pgtype_test
+
+import (
+	"math"
+	"reflect"
+	"testing"
+
+	"github.com/jackc/pgx/pgtype"
+)
+
+func TestQCharTranscode(t *testing.T) {
+	testSuccessfulTranscode(t, `"char"`, []interface{}{
+		pgtype.QChar{Int: math.MinInt8, Status: pgtype.Present},
+		pgtype.QChar{Int: -1, Status: pgtype.Present},
+		pgtype.QChar{Int: 0, Status: pgtype.Present},
+		pgtype.QChar{Int: 1, Status: pgtype.Present},
+		pgtype.QChar{Int: math.MaxInt8, Status: pgtype.Present},
+		pgtype.QChar{Int: 0, Status: pgtype.Null},
+	})
+}
+
+func TestQCharConvertFrom(t *testing.T) {
+	successfulTests := []struct {
+		source interface{}
+		result pgtype.QChar
+	}{
+		{source: int8(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: int16(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: int32(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: int64(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: int8(-1), result: pgtype.QChar{Int: -1, Status: pgtype.Present}},
+		{source: int16(-1), result: pgtype.QChar{Int: -1, Status: pgtype.Present}},
+		{source: int32(-1), result: pgtype.QChar{Int: -1, Status: pgtype.Present}},
+		{source: int64(-1), result: pgtype.QChar{Int: -1, Status: pgtype.Present}},
+		{source: uint8(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: uint16(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: uint32(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: uint64(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: "1", result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+		{source: _int8(1), result: pgtype.QChar{Int: 1, Status: pgtype.Present}},
+	}
+
+	for i, tt := range successfulTests {
+		var r pgtype.QChar
+		err := r.ConvertFrom(tt.source)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if r != tt.result {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.source, tt.result, r)
+		}
+	}
+}
+
+func TestQCharAssignTo(t *testing.T) {
+	var i8 int8
+	var i16 int16
+	var i32 int32
+	var i64 int64
+	var i int
+	var ui8 uint8
+	var ui16 uint16
+	var ui32 uint32
+	var ui64 uint64
+	var ui uint
+	var pi8 *int8
+	var _i8 _int8
+	var _pi8 *_int8
+
+	simpleTests := []struct {
+		src      pgtype.QChar
+		dst      interface{}
+		expected interface{}
+	}{
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &i8, expected: int8(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &i16, expected: int16(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &i32, expected: int32(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &i64, expected: int64(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &i, expected: int(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &ui8, expected: uint8(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &ui16, expected: uint16(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &ui32, expected: uint32(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &ui64, expected: uint64(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &ui, expected: uint(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &_i8, expected: _int8(42)},
+		{src: pgtype.QChar{Int: 0, Status: pgtype.Null}, dst: &pi8, expected: ((*int8)(nil))},
+		{src: pgtype.QChar{Int: 0, Status: pgtype.Null}, dst: &_pi8, expected: ((*_int8)(nil))},
+	}
+
+	for i, tt := range simpleTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if dst := reflect.ValueOf(tt.dst).Elem().Interface(); dst != tt.expected {
+			t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+		}
+	}
+
+	pointerAllocTests := []struct {
+		src      pgtype.QChar
+		dst      interface{}
+		expected interface{}
+	}{
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &pi8, expected: int8(42)},
+		{src: pgtype.QChar{Int: 42, Status: pgtype.Present}, dst: &_pi8, expected: _int8(42)},
+	}
+
+	for i, tt := range pointerAllocTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if dst := reflect.ValueOf(tt.dst).Elem().Elem().Interface(); dst != tt.expected {
+			t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+		}
+	}
+
+	errorTests := []struct {
+		src pgtype.QChar
+		dst interface{}
+	}{
+		{src: pgtype.QChar{Int: -1, Status: pgtype.Present}, dst: &ui8},
+		{src: pgtype.QChar{Int: -1, Status: pgtype.Present}, dst: &ui16},
+		{src: pgtype.QChar{Int: -1, Status: pgtype.Present}, dst: &ui32},
+		{src: pgtype.QChar{Int: -1, Status: pgtype.Present}, dst: &ui64},
+		{src: pgtype.QChar{Int: -1, Status: pgtype.Present}, dst: &ui},
+		{src: pgtype.QChar{Int: 0, Status: pgtype.Null}, dst: &i16},
+	}
+
+	for i, tt := range errorTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err == nil {
+			t.Errorf("%d: expected error but none was returned (%v -> %v)", i, tt.src, tt.dst)
+		}
+	}
+}