Expose encoding and decoding functions

CHANGELOG.md

@@ -24,6 +24,8 @@ standard database/sql package such as
 * Add ConnPool.Reset method
 * Add support for database/sql.Scanner and database/sql/driver.Valuer interfaces
 * Rows.Scan errors now include which argument caused error
+* Add Encode() to allow custom Encoders to reuse internal encoding functionality
+* Add Decode() to allow customer Decoders to reuse internal decoding functionality
 
 ## Performance
 

conn.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"crypto/md5"
 	"crypto/tls"
-	"database/sql/driver"
 	"encoding/binary"
 	"encoding/hex"
 	"errors"
@@ -15,7 +14,6 @@ import (
 	"os"
 	"os/user"
 	"path/filepath"
-	"reflect"
 	"regexp"
 	"strconv"
 	"strings"
@@ -849,92 +847,7 @@ func (c *Conn) sendPreparedQuery(ps *PreparedStatement, arguments ...interface{}
 
 	wbuf.WriteInt16(int16(len(arguments)))
 	for i, oid := range ps.ParameterOids {
-	encode:
-		if arguments[i] == nil {
-			wbuf.WriteInt32(-1)
-			continue
-		}
-
-		switch arg := arguments[i].(type) {
-		case Encoder:
-			err = arg.Encode(wbuf, oid)
-		case driver.Valuer:
-			arguments[i], err = arg.Value()
-			if err == nil {
-				goto encode
-			}
-		case string:
-			err = encodeText(wbuf, arguments[i])
-		case []byte:
-			err = encodeBytea(wbuf, arguments[i])
-		default:
-			if v := reflect.ValueOf(arguments[i]); v.Kind() == reflect.Ptr {
-				if v.IsNil() {
-					wbuf.WriteInt32(-1)
-					continue
-				} else {
-					arguments[i] = v.Elem().Interface()
-					goto encode
-				}
-			}
-			switch oid {
-			case BoolOid:
-				err = encodeBool(wbuf, arguments[i])
-			case ByteaOid:
-				err = encodeBytea(wbuf, arguments[i])
-			case Int2Oid:
-				err = encodeInt2(wbuf, arguments[i])
-			case Int4Oid:
-				err = encodeInt4(wbuf, arguments[i])
-			case Int8Oid:
-				err = encodeInt8(wbuf, arguments[i])
-			case Float4Oid:
-				err = encodeFloat4(wbuf, arguments[i])
-			case Float8Oid:
-				err = encodeFloat8(wbuf, arguments[i])
-			case TextOid, VarcharOid:
-				err = encodeText(wbuf, arguments[i])
-			case DateOid:
-				err = encodeDate(wbuf, arguments[i])
-			case TimestampTzOid:
-				err = encodeTimestampTz(wbuf, arguments[i])
-			case TimestampOid:
-				err = encodeTimestamp(wbuf, arguments[i])
-			case InetOid, CidrOid:
-				err = encodeInet(wbuf, arguments[i])
-			case InetArrayOid:
-				err = encodeInetArray(wbuf, arguments[i], InetOid)
-			case CidrArrayOid:
-				err = encodeInetArray(wbuf, arguments[i], CidrOid)
-			case BoolArrayOid:
-				err = encodeBoolArray(wbuf, arguments[i])
-			case Int2ArrayOid:
-				err = encodeInt2Array(wbuf, arguments[i])
-			case Int4ArrayOid:
-				err = encodeInt4Array(wbuf, arguments[i])
-			case Int8ArrayOid:
-				err = encodeInt8Array(wbuf, arguments[i])
-			case Float4ArrayOid:
-				err = encodeFloat4Array(wbuf, arguments[i])
-			case Float8ArrayOid:
-				err = encodeFloat8Array(wbuf, arguments[i])
-			case TextArrayOid:
-				err = encodeTextArray(wbuf, arguments[i], TextOid)
-			case VarcharArrayOid:
-				err = encodeTextArray(wbuf, arguments[i], VarcharOid)
-			case TimestampArrayOid:
-				err = encodeTimestampArray(wbuf, arguments[i], TimestampOid)
-			case TimestampTzArrayOid:
-				err = encodeTimestampArray(wbuf, arguments[i], TimestampTzOid)
-			case OidOid:
-				err = encodeOid(wbuf, arguments[i])
-			case JsonOid, JsonbOid:
-				err = encodeJson(wbuf, arguments[i])
-			default:
-				return SerializationError(fmt.Sprintf("Cannot encode %T into oid %v - %T must implement Encoder or be converted to a string", arg, oid, arg))
-			}
-		}
-		if err != nil {
+		if err := Encode(wbuf, oid, arguments[i]); err != nil {
 			return err
 		}
 	}

query.go

@@ -4,8 +4,6 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
-	"net"
-	"reflect"
 	"time"
 )
 
@@ -297,79 +295,9 @@ func (rows *Rows) Scan(dest ...interface{}) (err error) {
 		} else if vr.Type().DataType == JsonOid || vr.Type().DataType == JsonbOid {
 			decodeJson(vr, &d)
 		} else {
-		decode:
-			switch v := d.(type) {
-			case *bool:
-				*v = decodeBool(vr)
-			case *int64:
-				*v = decodeInt8(vr)
-			case *int16:
-				*v = decodeInt2(vr)
-			case *int32:
-				*v = decodeInt4(vr)
-			case *Oid:
-				*v = decodeOid(vr)
-			case *string:
-				*v = decodeText(vr)
-			case *float32:
-				*v = decodeFloat4(vr)
-			case *float64:
-				*v = decodeFloat8(vr)
-			case *[]bool:
-				*v = decodeBoolArray(vr)
-			case *[]int16:
-				*v = decodeInt2Array(vr)
-			case *[]int32:
-				*v = decodeInt4Array(vr)
-			case *[]int64:
-				*v = decodeInt8Array(vr)
-			case *[]float32:
-				*v = decodeFloat4Array(vr)
-			case *[]float64:
-				*v = decodeFloat8Array(vr)
-			case *[]string:
-				*v = decodeTextArray(vr)
-			case *[]time.Time:
-				*v = decodeTimestampArray(vr)
-			case *time.Time:
-				switch vr.Type().DataType {
-				case DateOid:
-					*v = decodeDate(vr)
-				case TimestampTzOid:
-					*v = decodeTimestampTz(vr)
-				case TimestampOid:
-					*v = decodeTimestamp(vr)
-				default:
-					rows.Fatal(scanArgError{col: i, err: fmt.Errorf("Can't convert OID %v to time.Time", vr.Type().DataType)})
-				}
-			case *net.IPNet:
-				*v = decodeInet(vr)
-			case *[]net.IPNet:
-				*v = decodeInetArray(vr)
-			default:
-				// if d is a pointer to pointer, strip the pointer and try again
-				if v := reflect.ValueOf(d); v.Kind() == reflect.Ptr {
-					if el := v.Elem(); el.Kind() == reflect.Ptr {
-						// -1 is a null value
-						if vr.Len() == -1 {
-							if !el.IsNil() {
-								// if the destination pointer is not nil, nil it out
-								el.Set(reflect.Zero(el.Type()))
-							}
-							continue
-						} else {
-							if el.IsNil() {
-								// allocate destination
-								el.Set(reflect.New(el.Type().Elem()))
-							}
-							d = el.Interface()
-							goto decode
-						}
-					}
-				}
-				rows.Fatal(scanArgError{col: i, err: fmt.Errorf("Scan cannot decode into %T", d)})
+			if err := Decode(vr, d); err != nil {
+				rows.Fatal(scanArgError{col: i, err: err})
 			}
-
 		}
 		if vr.Err() != nil {
 			rows.Fatal(scanArgError{col: i, err: vr.Err()})

query_test.go

@@ -530,7 +530,7 @@ func TestQueryRowErrors(t *testing.T) {
 		{"select $1::badtype", []interface{}{"Jack"}, []interface{}{&actual.i16}, `type "badtype" does not exist`},
 		{"SYNTAX ERROR", []interface{}{}, []interface{}{&actual.i16}, "SQLSTATE 42601"},
 		{"select $1::text", []interface{}{"Jack"}, []interface{}{&actual.i16}, "Cannot decode oid 25 into int16"},
-		{"select $1::point", []interface{}{int(705)}, []interface{}{&actual.s}, "Cannot encode int into oid 600 - int must implement Encoder or be converted to a string"},
+		{"select $1::point", []interface{}{int(705)}, []interface{}{&actual.s}, "cannot encode uint64 into oid 600"},
 		{"select 42::int4", []interface{}{}, []interface{}{&actual.i}, "Scan cannot decode into *int"},
 	}