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array_codec.go
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/
array_codec.go
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package pgtype
import (
"database/sql/driver"
"encoding/binary"
"fmt"
"reflect"
"github.com/jackc/pgx/v5/internal/anynil"
"github.com/jackc/pgx/v5/internal/pgio"
)
// ArrayGetter is a type that can be converted into a PostgreSQL array.
type ArrayGetter interface {
// Dimensions returns the array dimensions. If array is nil then nil is returned.
Dimensions() []ArrayDimension
// Index returns the element at i.
Index(i int) any
// IndexType returns a non-nil scan target of the type Index will return. This is used by ArrayCodec.PlanEncode.
IndexType() any
}
// ArraySetter is a type can be set from a PostgreSQL array.
type ArraySetter interface {
// SetDimensions prepares the value such that ScanIndex can be called for each element. This will remove any existing
// elements. dimensions may be nil to indicate a NULL array. If unable to exactly preserve dimensions SetDimensions
// may return an error or silently flatten the array dimensions.
SetDimensions(dimensions []ArrayDimension) error
// ScanIndex returns a value usable as a scan target for i. SetDimensions must be called before ScanIndex.
ScanIndex(i int) any
// ScanIndexType returns a non-nil scan target of the type ScanIndex will return. This is used by
// ArrayCodec.PlanScan.
ScanIndexType() any
}
// ArrayCodec is a codec for any array type.
type ArrayCodec struct {
ElementType *Type
}
func (c *ArrayCodec) FormatSupported(format int16) bool {
return c.ElementType.Codec.FormatSupported(format)
}
func (c *ArrayCodec) PreferredFormat() int16 {
return c.ElementType.Codec.PreferredFormat()
}
func (c *ArrayCodec) PlanEncode(m *Map, oid uint32, format int16, value any) EncodePlan {
arrayValuer, ok := value.(ArrayGetter)
if !ok {
return nil
}
elementType := arrayValuer.IndexType()
elementEncodePlan := m.PlanEncode(c.ElementType.OID, format, elementType)
if elementEncodePlan == nil {
return nil
}
switch format {
case BinaryFormatCode:
return &encodePlanArrayCodecBinary{ac: c, m: m, oid: oid}
case TextFormatCode:
return &encodePlanArrayCodecText{ac: c, m: m, oid: oid}
}
return nil
}
type encodePlanArrayCodecText struct {
ac *ArrayCodec
m *Map
oid uint32
}
func (p *encodePlanArrayCodecText) Encode(value any, buf []byte) (newBuf []byte, err error) {
array := value.(ArrayGetter)
dimensions := array.Dimensions()
if dimensions == nil {
return nil, nil
}
elementCount := cardinality(dimensions)
if elementCount == 0 {
return append(buf, '{', '}'), nil
}
buf = encodeTextArrayDimensions(buf, dimensions)
// dimElemCounts is the multiples of elements that each array lies on. For
// example, a single dimension array of length 4 would have a dimElemCounts of
// [4]. A multi-dimensional array of lengths [3,5,2] would have a
// dimElemCounts of [30,10,2]. This is used to simplify when to render a '{'
// or '}'.
dimElemCounts := make([]int, len(dimensions))
dimElemCounts[len(dimensions)-1] = int(dimensions[len(dimensions)-1].Length)
for i := len(dimensions) - 2; i > -1; i-- {
dimElemCounts[i] = int(dimensions[i].Length) * dimElemCounts[i+1]
}
var encodePlan EncodePlan
var lastElemType reflect.Type
inElemBuf := make([]byte, 0, 32)
for i := 0; i < elementCount; i++ {
if i > 0 {
buf = append(buf, ',')
}
for _, dec := range dimElemCounts {
if i%dec == 0 {
buf = append(buf, '{')
}
}
elem := array.Index(i)
var elemBuf []byte
if elem != nil {
elemType := reflect.TypeOf(elem)
if lastElemType != elemType {
lastElemType = elemType
encodePlan = p.m.PlanEncode(p.ac.ElementType.OID, TextFormatCode, elem)
if encodePlan == nil {
return nil, fmt.Errorf("unable to encode %v", array.Index(i))
}
}
elemBuf, err = encodePlan.Encode(elem, inElemBuf)
if err != nil {
return nil, err
}
}
if elemBuf == nil {
buf = append(buf, `NULL`...)
} else {
buf = append(buf, quoteArrayElementIfNeeded(string(elemBuf))...)
}
for _, dec := range dimElemCounts {
if (i+1)%dec == 0 {
buf = append(buf, '}')
}
}
}
return buf, nil
}
type encodePlanArrayCodecBinary struct {
ac *ArrayCodec
m *Map
oid uint32
}
func (p *encodePlanArrayCodecBinary) Encode(value any, buf []byte) (newBuf []byte, err error) {
array := value.(ArrayGetter)
dimensions := array.Dimensions()
if dimensions == nil {
return nil, nil
}
arrayHeader := arrayHeader{
Dimensions: dimensions,
ElementOID: p.ac.ElementType.OID,
}
containsNullIndex := len(buf) + 4
buf = arrayHeader.EncodeBinary(buf)
elementCount := cardinality(dimensions)
var encodePlan EncodePlan
var lastElemType reflect.Type
for i := 0; i < elementCount; i++ {
sp := len(buf)
buf = pgio.AppendInt32(buf, -1)
elem := array.Index(i)
var elemBuf []byte
if elem != nil {
elemType := reflect.TypeOf(elem)
if lastElemType != elemType {
lastElemType = elemType
encodePlan = p.m.PlanEncode(p.ac.ElementType.OID, BinaryFormatCode, elem)
if encodePlan == nil {
return nil, fmt.Errorf("unable to encode %v", array.Index(i))
}
}
elemBuf, err = encodePlan.Encode(elem, buf)
if err != nil {
return nil, err
}
}
if elemBuf == nil {
pgio.SetInt32(buf[containsNullIndex:], 1)
} else {
buf = elemBuf
pgio.SetInt32(buf[sp:], int32(len(buf[sp:])-4))
}
}
return buf, nil
}
func (c *ArrayCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan {
arrayScanner, ok := target.(ArraySetter)
if !ok {
return nil
}
// target / arrayScanner might be a pointer to a nil. If it is create one so we can call ScanIndexType to plan the
// scan of the elements.
if anynil.Is(target) {
arrayScanner = reflect.New(reflect.TypeOf(target).Elem()).Interface().(ArraySetter)
}
elementType := arrayScanner.ScanIndexType()
elementScanPlan := m.PlanScan(c.ElementType.OID, format, elementType)
if _, ok := elementScanPlan.(*scanPlanFail); ok {
return nil
}
return &scanPlanArrayCodec{
arrayCodec: c,
m: m,
oid: oid,
formatCode: format,
}
}
func (c *ArrayCodec) decodeBinary(m *Map, arrayOID uint32, src []byte, array ArraySetter) error {
var arrayHeader arrayHeader
rp, err := arrayHeader.DecodeBinary(m, src)
if err != nil {
return err
}
err = array.SetDimensions(arrayHeader.Dimensions)
if err != nil {
return err
}
elementCount := cardinality(arrayHeader.Dimensions)
if elementCount == 0 {
return nil
}
elementScanPlan := c.ElementType.Codec.PlanScan(m, c.ElementType.OID, BinaryFormatCode, array.ScanIndex(0))
if elementScanPlan == nil {
elementScanPlan = m.PlanScan(c.ElementType.OID, BinaryFormatCode, array.ScanIndex(0))
}
for i := 0; i < elementCount; i++ {
elem := array.ScanIndex(i)
elemLen := int(int32(binary.BigEndian.Uint32(src[rp:])))
rp += 4
var elemSrc []byte
if elemLen >= 0 {
elemSrc = src[rp : rp+elemLen]
rp += elemLen
}
err = elementScanPlan.Scan(elemSrc, elem)
if err != nil {
return fmt.Errorf("failed to scan array element %d: %w", i, err)
}
}
return nil
}
func (c *ArrayCodec) decodeText(m *Map, arrayOID uint32, src []byte, array ArraySetter) error {
uta, err := parseUntypedTextArray(string(src))
if err != nil {
return err
}
err = array.SetDimensions(uta.Dimensions)
if err != nil {
return err
}
if len(uta.Elements) == 0 {
return nil
}
elementScanPlan := c.ElementType.Codec.PlanScan(m, c.ElementType.OID, TextFormatCode, array.ScanIndex(0))
if elementScanPlan == nil {
elementScanPlan = m.PlanScan(c.ElementType.OID, TextFormatCode, array.ScanIndex(0))
}
for i, s := range uta.Elements {
elem := array.ScanIndex(i)
var elemSrc []byte
if s != "NULL" {
elemSrc = []byte(s)
}
err = elementScanPlan.Scan(elemSrc, elem)
if err != nil {
return err
}
}
return nil
}
type scanPlanArrayCodec struct {
arrayCodec *ArrayCodec
m *Map
oid uint32
formatCode int16
elementScanPlan ScanPlan
}
func (spac *scanPlanArrayCodec) Scan(src []byte, dst any) error {
c := spac.arrayCodec
m := spac.m
oid := spac.oid
formatCode := spac.formatCode
array := dst.(ArraySetter)
if src == nil {
return array.SetDimensions(nil)
}
switch formatCode {
case BinaryFormatCode:
return c.decodeBinary(m, oid, src, array)
case TextFormatCode:
return c.decodeText(m, oid, src, array)
default:
return fmt.Errorf("unknown format code %d", formatCode)
}
}
func (c *ArrayCodec) DecodeDatabaseSQLValue(m *Map, oid uint32, format int16, src []byte) (driver.Value, error) {
if src == nil {
return nil, nil
}
switch format {
case TextFormatCode:
return string(src), nil
case BinaryFormatCode:
buf := make([]byte, len(src))
copy(buf, src)
return buf, nil
default:
return nil, fmt.Errorf("unknown format code %d", format)
}
}
func (c *ArrayCodec) DecodeValue(m *Map, oid uint32, format int16, src []byte) (any, error) {
if src == nil {
return nil, nil
}
var slice []any
err := m.PlanScan(oid, format, &slice).Scan(src, &slice)
return slice, err
}
func isRagged(slice reflect.Value) bool {
if slice.Type().Elem().Kind() != reflect.Slice {
return false
}
sliceLen := slice.Len()
innerLen := 0
for i := 0; i < sliceLen; i++ {
if i == 0 {
innerLen = slice.Index(i).Len()
} else {
if slice.Index(i).Len() != innerLen {
return true
}
}
if isRagged(slice.Index(i)) {
return true
}
}
return false
}