Add ArrayType

array_type.go

@@ -0,0 +1,350 @@
+package pgtype
+
+import (
+	"database/sql/driver"
+	"encoding/binary"
+	"reflect"
+
+	"github.com/jackc/pgio"
+	errors "golang.org/x/xerrors"
+)
+
+// ArrayType represents an array type. While it implements Value, this is only in service of its type conversion duties
+// when registered as a data type in a ConnType. It should not be used directly as a Value. ArrayType is a convenience
+// type for types that do not have an concrete array type.
+type ArrayType struct {
+	elements   []ValueTranscoder
+	dimensions []ArrayDimension
+	status     Status
+
+	typeName   string
+	newElement func() ValueTranscoder
+}
+
+func NewArrayType(typeName string, newElement func() ValueTranscoder) *ArrayType {
+	return &ArrayType{typeName: typeName, newElement: newElement}
+}
+
+func (at *ArrayType) CloneTypeValue() Value {
+	return &ArrayType{
+		elements:   at.elements,
+		dimensions: at.dimensions,
+		status:     at.status,
+
+		typeName:   at.typeName,
+		newElement: at.newElement,
+	}
+}
+
+func (at *ArrayType) TypeName() string {
+	return at.typeName
+}
+
+func (dst *ArrayType) setNil() {
+	dst.elements = nil
+	dst.dimensions = nil
+	dst.status = Null
+}
+
+func (dst *ArrayType) Set(src interface{}) error {
+	// untyped nil and typed nil interfaces are different
+	if src == nil {
+		dst.setNil()
+		return nil
+	}
+
+	sliceVal := reflect.ValueOf(src)
+	if sliceVal.Kind() != reflect.Slice {
+		return errors.Errorf("cannot set non-slice")
+	}
+
+	if sliceVal.IsNil() {
+		dst.setNil()
+		return nil
+	}
+
+	dst.elements = make([]ValueTranscoder, sliceVal.Len())
+	for i := range dst.elements {
+		v := dst.newElement()
+		err := v.Set(sliceVal.Index(i).Interface())
+		if err != nil {
+			return err
+		}
+
+		dst.elements[i] = v
+	}
+	dst.dimensions = []ArrayDimension{{Length: int32(len(dst.elements)), LowerBound: 1}}
+	dst.status = Present
+
+	return nil
+}
+
+func (dst ArrayType) Get() interface{} {
+	switch dst.status {
+	case Present:
+		return dst.elements
+	case Null:
+		return nil
+	default:
+		return dst.status
+	}
+}
+
+func (src *ArrayType) AssignTo(dst interface{}) error {
+	ptrSlice := reflect.ValueOf(dst)
+	if ptrSlice.Kind() != reflect.Ptr {
+		return errors.Errorf("cannot assign to non-pointer")
+	}
+
+	sliceVal := ptrSlice.Elem()
+	sliceType := sliceVal.Type()
+
+	if sliceType.Kind() != reflect.Slice {
+		return errors.Errorf("cannot assign to pointer to non-slice")
+	}
+
+	switch src.status {
+	case Present:
+		slice := reflect.MakeSlice(sliceType, len(src.elements), len(src.elements))
+		elemType := sliceType.Elem()
+
+		for i := range src.elements {
+			ptrElem := reflect.New(elemType)
+			err := src.elements[i].AssignTo(ptrElem.Interface())
+			if err != nil {
+				return err
+			}
+
+			slice.Index(i).Set(ptrElem.Elem())
+		}
+
+		sliceVal.Set(slice)
+		return nil
+	case Null:
+		sliceVal.Set(reflect.Zero(sliceType))
+		return nil
+	}
+
+	return errors.Errorf("cannot decode %#v into %T", src, dst)
+}
+
+func (dst *ArrayType) DecodeText(ci *ConnInfo, src []byte) error {
+	if src == nil {
+		dst.setNil()
+		return nil
+	}
+
+	uta, err := ParseUntypedTextArray(string(src))
+	if err != nil {
+		return err
+	}
+
+	var elements []ValueTranscoder
+
+	if len(uta.Elements) > 0 {
+		elements = make([]ValueTranscoder, len(uta.Elements))
+
+		for i, s := range uta.Elements {
+			elem := dst.newElement()
+			var elemSrc []byte
+			if s != "NULL" {
+				elemSrc = []byte(s)
+			}
+			err = elem.DecodeText(ci, elemSrc)
+			if err != nil {
+				return err
+			}
+
+			elements[i] = elem
+		}
+	}
+
+	dst.elements = elements
+	dst.dimensions = uta.Dimensions
+	dst.status = Present
+
+	return nil
+}
+
+func (dst *ArrayType) DecodeBinary(ci *ConnInfo, src []byte) error {
+	if src == nil {
+		dst.setNil()
+		return nil
+	}
+
+	var arrayHeader ArrayHeader
+	rp, err := arrayHeader.DecodeBinary(ci, src)
+	if err != nil {
+		return err
+	}
+
+	if len(arrayHeader.Dimensions) == 0 {
+		*dst = ArrayType{dimensions: arrayHeader.Dimensions, status: Present}
+		return nil
+	}
+
+	elementCount := arrayHeader.Dimensions[0].Length
+	for _, d := range arrayHeader.Dimensions[1:] {
+		elementCount *= d.Length
+	}
+
+	elements := make([]ValueTranscoder, elementCount)
+
+	for i := range elements {
+		elem := dst.newElement()
+		elemLen := int(int32(binary.BigEndian.Uint32(src[rp:])))
+		rp += 4
+		var elemSrc []byte
+		if elemLen >= 0 {
+			elemSrc = src[rp : rp+elemLen]
+			rp += elemLen
+		}
+		err = elem.DecodeBinary(ci, elemSrc)
+		if err != nil {
+			return err
+		}
+
+		elements[i] = elem
+	}
+
+	dst.elements = elements
+	dst.dimensions = arrayHeader.Dimensions
+	dst.status = Present
+
+	return nil
+}
+
+func (src ArrayType) EncodeText(ci *ConnInfo, buf []byte) ([]byte, error) {
+	switch src.status {
+	case Null:
+		return nil, nil
+	case Undefined:
+		return nil, errUndefined
+	}
+
+	if len(src.dimensions) == 0 {
+		return append(buf, '{', '}'), nil
+	}
+
+	buf = EncodeTextArrayDimensions(buf, src.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(src.dimensions))
+	dimElemCounts[len(src.dimensions)-1] = int(src.dimensions[len(src.dimensions)-1].Length)
+	for i := len(src.dimensions) - 2; i > -1; i-- {
+		dimElemCounts[i] = int(src.dimensions[i].Length) * dimElemCounts[i+1]
+	}
+
+	inElemBuf := make([]byte, 0, 32)
+	for i, elem := range src.elements {
+		if i > 0 {
+			buf = append(buf, ',')
+		}
+
+		for _, dec := range dimElemCounts {
+			if i%dec == 0 {
+				buf = append(buf, '{')
+			}
+		}
+
+		elemBuf, err := elem.EncodeText(ci, 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
+}
+
+func (src ArrayType) EncodeBinary(ci *ConnInfo, buf []byte) ([]byte, error) {
+	switch src.status {
+	case Null:
+		return nil, nil
+	case Undefined:
+		return nil, errUndefined
+	}
+
+	arrayHeader := ArrayHeader{
+		Dimensions: src.dimensions,
+	}
+
+	{
+		value := src.newElement()
+		if dt, ok := ci.DataTypeForValue(value); ok {
+			arrayHeader.ElementOID = int32(dt.OID)
+		} else {
+			return nil, errors.Errorf("unable to find oid for element type %v", value)
+		}
+	}
+
+	for i := range src.elements {
+		if src.elements[i].Get() == nil {
+			arrayHeader.ContainsNull = true
+			break
+		}
+	}
+
+	buf = arrayHeader.EncodeBinary(ci, buf)
+
+	for i := range src.elements {
+		sp := len(buf)
+		buf = pgio.AppendInt32(buf, -1)
+
+		elemBuf, err := src.elements[i].EncodeBinary(ci, buf)
+		if err != nil {
+			return nil, err
+		}
+		if elemBuf != nil {
+			buf = elemBuf
+			pgio.SetInt32(buf[sp:], int32(len(buf[sp:])-4))
+		}
+	}
+
+	return buf, nil
+}
+
+// Scan implements the database/sql Scanner interface.
+func (dst *ArrayType) Scan(src interface{}) error {
+	if src == nil {
+		return dst.DecodeText(nil, nil)
+	}
+
+	switch src := src.(type) {
+	case string:
+		return dst.DecodeText(nil, []byte(src))
+	case []byte:
+		srcCopy := make([]byte, len(src))
+		copy(srcCopy, src)
+		return dst.DecodeText(nil, srcCopy)
+	}
+
+	return errors.Errorf("cannot scan %T", src)
+}
+
+// Value implements the database/sql/driver Valuer interface.
+func (src ArrayType) Value() (driver.Value, error) {
+	buf, err := src.EncodeText(nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	if buf == nil {
+		return nil, nil
+	}
+
+	return string(buf), nil
+}

array_type_test.go

@@ -0,0 +1,62 @@
+package pgtype_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/jackc/pgtype"
+	"github.com/jackc/pgtype/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestArrayTypeValue(t *testing.T) {
+	arrayType := pgtype.NewArrayType("_text", func() pgtype.ValueTranscoder { return &pgtype.Text{} })
+
+	err := arrayType.Set(nil)
+	require.NoError(t, err)
+
+	gotValue := arrayType.Get()
+	require.Nil(t, gotValue)
+
+	slice := []string{"foo", "bar"}
+	err = arrayType.AssignTo(&slice)
+	require.NoError(t, err)
+	require.Nil(t, slice)
+
+	err = arrayType.Set([]string{})
+	require.NoError(t, err)
+
+	gotValue = arrayType.Get()
+	require.Len(t, gotValue, 0)
+
+	err = arrayType.AssignTo(&slice)
+	require.NoError(t, err)
+	require.EqualValues(t, []string{}, slice)
+
+	err = arrayType.Set([]string{"baz", "quz"})
+	require.NoError(t, err)
+
+	gotValue = arrayType.Get()
+	require.Len(t, gotValue, 2)
+
+	err = arrayType.AssignTo(&slice)
+	require.NoError(t, err)
+	require.EqualValues(t, []string{"baz", "quz"}, slice)
+}
+
+func TestArrayTypeTranscode(t *testing.T) {
+	conn := testutil.MustConnectPgx(t)
+	defer testutil.MustCloseContext(t, conn)
+
+	conn.ConnInfo().RegisterDataType(pgtype.DataType{
+		Value: pgtype.NewArrayType("_text", func() pgtype.ValueTranscoder { return &pgtype.Text{} }),
+		Name:  "_text",
+		OID:   pgtype.TextArrayOID,
+	})
+
+	var dstStrings []string
+	err := conn.QueryRow(context.Background(), "select $1::text[]", []string{"red", "green", "blue"}).Scan(&dstStrings)
+	require.NoError(t, err)
+
+	require.EqualValues(t, []string{"red", "green", "blue"}, dstStrings)
+}

pgtype.go

@@ -142,6 +142,15 @@ type TypeValue interface {
 	TypeName() string
 }
 
+// ValueTranscoder is a value that implements the text and binary encoding and decoding interfaces.
+type ValueTranscoder interface {
+	Value
+	TextEncoder
+	BinaryEncoder
+	TextDecoder
+	BinaryDecoder
+}
+
 // ResultFormatPreferrer allows a type to specify its preferred result format instead of it being inferred from
 // whether it is also a BinaryDecoder.
 type ResultFormatPreferrer interface {