Encode dates in binary format

- Also allow NullTime to handle dates

conn.go

@@ -731,7 +731,7 @@ func (c *Conn) sendPreparedQuery(ps *PreparedStatement, arguments ...interface{}
 			wbuf.WriteInt16(TextFormatCode)
 		default:
 			switch oid {
-			case BoolOid, ByteaOid, Int2Oid, Int4Oid, Int8Oid, Float4Oid, Float8Oid, TimestampTzOid, TimestampTzArrayOid, TimestampOid, TimestampArrayOid, BoolArrayOid, Int2ArrayOid, Int4ArrayOid, Int8ArrayOid, Float4ArrayOid, Float8ArrayOid, TextArrayOid, VarcharArrayOid, OidOid, InetOid, CidrOid:
+			case BoolOid, ByteaOid, Int2Oid, Int4Oid, Int8Oid, Float4Oid, Float8Oid, TimestampTzOid, TimestampTzArrayOid, TimestampOid, TimestampArrayOid, DateOid, BoolArrayOid, Int2ArrayOid, Int4ArrayOid, Int8ArrayOid, Float4ArrayOid, Float8ArrayOid, TextArrayOid, VarcharArrayOid, OidOid, InetOid, CidrOid:
 				wbuf.WriteInt16(BinaryFormatCode)
 			default:
 				wbuf.WriteInt16(TextFormatCode)

values.go

@@ -386,9 +386,10 @@ func (n NullBool) Encode(w *WriteBuf, oid Oid) error {
 	return encodeBool(w, n.Bool)
 }
 
-// NullTime represents an bigint that may be null. NullTime implements the
+// NullTime represents an time.Time that may be null. NullTime implements the
 // Scanner and Encoder interfaces so it may be used both as an argument to
-// Query[Row] and a destination for Scan.
+// Query[Row] and a destination for Scan. It corresponds with the PostgreSQL
+// types timestamptz, timestamp, and date.
 //
 // If Valid is false then the value is NULL.
 type NullTime struct {
@@ -398,7 +399,7 @@ type NullTime struct {
 
 func (n *NullTime) Scan(vr *ValueReader) error {
 	oid := vr.Type().DataType
-	if oid != TimestampTzOid && oid != TimestampOid {
+	if oid != TimestampTzOid && oid != TimestampOid && oid != DateOid {
 		return SerializationError(fmt.Sprintf("NullTime.Scan cannot decode OID %d", vr.Type().DataType))
 	}
 
@@ -408,10 +409,13 @@ func (n *NullTime) Scan(vr *ValueReader) error {
 	}
 
 	n.Valid = true
-	if oid == TimestampTzOid {
+	switch oid {
+	case TimestampTzOid:
 		n.Time = decodeTimestampTz(vr)
-	} else {
+	case TimestampOid:
 		n.Time = decodeTimestamp(vr)
+	case DateOid:
+		n.Time = decodeDate(vr)
 	}
 
 	return vr.Err()
@@ -420,7 +424,7 @@ func (n *NullTime) Scan(vr *ValueReader) error {
 func (n NullTime) FormatCode() int16 { return BinaryFormatCode }
 
 func (n NullTime) Encode(w *WriteBuf, oid Oid) error {
-	if oid != TimestampTzOid && oid != TimestampOid {
+	if oid != TimestampTzOid && oid != TimestampOid && oid != DateOid {
 		return SerializationError(fmt.Sprintf("NullTime.Encode cannot encode into OID %d", oid))
 	}
 
@@ -429,10 +433,15 @@ func (n NullTime) Encode(w *WriteBuf, oid Oid) error {
 		return nil
 	}
 
-	if oid == TimestampTzOid {
+	switch oid {
+	case TimestampTzOid:
 		return encodeTimestampTz(w, n.Time)
-	} else {
+	case TimestampOid:
 		return encodeTimestamp(w, n.Time)
+	case DateOid:
+		return encodeDate(w, n.Time)
+	default:
+		panic("unreachable")
 	}
 }
 
@@ -1055,8 +1064,16 @@ func encodeDate(w *WriteBuf, value interface{}) error {
 		return fmt.Errorf("Expected time.Time, received %T", value)
 	}
 
-	s := t.Format("2006-01-02")
-	return encodeText(w, s)
+	tUnix := time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.UTC).Unix()
+	dateEpoch := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC).Unix()
+
+	secSinceDateEpoch := tUnix - dateEpoch
+	daysSinceDateEpoch := secSinceDateEpoch / 86400
+
+	w.WriteInt32(4)
+	w.WriteInt32(int32(daysSinceDateEpoch))
+
+	return nil
 }
 
 const microsecFromUnixEpochToY2K = 946684800 * 1000000

values_test.go

@@ -17,6 +17,12 @@ func TestDateTranscode(t *testing.T) {
 	defer closeConn(t, conn)
 
 	dates := []time.Time{
+		time.Date(1, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(1000, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(1600, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(1700, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(1800, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(1900, 1, 1, 0, 0, 0, 0, time.Local),
 		time.Date(1990, 1, 1, 0, 0, 0, 0, time.Local),
 		time.Date(1999, 12, 31, 0, 0, 0, 0, time.Local),
 		time.Date(2000, 1, 1, 0, 0, 0, 0, time.Local),
@@ -24,6 +30,11 @@ func TestDateTranscode(t *testing.T) {
 		time.Date(2004, 2, 29, 0, 0, 0, 0, time.Local),
 		time.Date(2013, 7, 4, 0, 0, 0, 0, time.Local),
 		time.Date(2013, 12, 25, 0, 0, 0, 0, time.Local),
+		time.Date(2029, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(2081, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(2096, 2, 29, 0, 0, 0, 0, time.Local),
+		time.Date(2550, 1, 1, 0, 0, 0, 0, time.Local),
+		time.Date(9999, 12, 31, 0, 0, 0, 0, time.Local),
 	}
 
 	for _, actualDate := range dates {
@@ -280,6 +291,8 @@ func TestNullX(t *testing.T) {
 		{"select $1::timestamptz", []interface{}{pgx.NullTime{Time: time.Unix(123, 5000), Valid: false}}, []interface{}{&actual.t}, allTypes{t: pgx.NullTime{Time: time.Time{}, Valid: false}}},
 		{"select $1::timestamp", []interface{}{pgx.NullTime{Time: time.Unix(123, 5000), Valid: true}}, []interface{}{&actual.t}, allTypes{t: pgx.NullTime{Time: time.Unix(123, 5000), Valid: true}}},
 		{"select $1::timestamp", []interface{}{pgx.NullTime{Time: time.Unix(123, 5000), Valid: false}}, []interface{}{&actual.t}, allTypes{t: pgx.NullTime{Time: time.Time{}, Valid: false}}},
+		{"select $1::date", []interface{}{pgx.NullTime{Time: time.Date(1990, 1, 1, 0, 0, 0, 0, time.Local), Valid: true}}, []interface{}{&actual.t}, allTypes{t: pgx.NullTime{Time: time.Date(1990, 1, 1, 0, 0, 0, 0, time.Local), Valid: true}}},
+		{"select $1::date", []interface{}{pgx.NullTime{Time: time.Date(1990, 1, 1, 0, 0, 0, 0, time.Local), Valid: false}}, []interface{}{&actual.t}, allTypes{t: pgx.NullTime{Time: time.Time{}, Valid: false}}},
 		{"select 42::int4, $1::float8", []interface{}{pgx.NullFloat64{Float64: 1.23, Valid: true}}, []interface{}{&actual.i32, &actual.f64}, allTypes{i32: pgx.NullInt32{Int32: 42, Valid: true}, f64: pgx.NullFloat64{Float64: 1.23, Valid: true}}},
 	}
 
@@ -473,7 +486,7 @@ func TestNullXMismatch(t *testing.T) {
 		{"select $1::date", []interface{}{pgx.NullFloat32{Float32: 1.23, Valid: true}}, []interface{}{&actual.f32}, "cannot encode into OID 1082"},
 		{"select $1::date", []interface{}{pgx.NullFloat64{Float64: 1.23, Valid: true}}, []interface{}{&actual.f64}, "cannot encode into OID 1082"},
 		{"select $1::date", []interface{}{pgx.NullBool{Bool: true, Valid: true}}, []interface{}{&actual.b}, "cannot encode into OID 1082"},
-		{"select $1::date", []interface{}{pgx.NullTime{Time: time.Unix(123, 5000), Valid: true}}, []interface{}{&actual.t}, "cannot encode into OID 1082"},
+		{"select $1::int4", []interface{}{pgx.NullTime{Time: time.Unix(123, 5000), Valid: true}}, []interface{}{&actual.t}, "cannot encode into OID 23"},
 	}
 
 	for i, tt := range tests {