366 lines
9.2 KiB
Go
366 lines
9.2 KiB
Go
/*
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* SPDX-FileCopyrightText: 2022 WGH <wgh@torlan.ru>
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* SPDX-License-Identifier: MIT
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*/
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package database
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import (
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"encoding/binary"
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"fmt"
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"reflect"
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"github.com/jackc/pgtype"
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)
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type RecordArray struct {
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Elements []pgtype.Record
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Dimensions []pgtype.ArrayDimension
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Status pgtype.Status
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}
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func (dst *RecordArray) Set(src interface{}) error {
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// untyped nil and typed nil interfaces are different
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if src == nil {
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*dst = RecordArray{Status: pgtype.Null}
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return nil
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}
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if value, ok := src.(interface{ Get() interface{} }); ok {
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value2 := value.Get()
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if value2 != value {
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return dst.Set(value2)
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}
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}
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// Attempt to match to select common types:
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switch value := src.(type) {
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case [][]pgtype.Value:
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if value == nil {
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*dst = RecordArray{Status: pgtype.Null}
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} else if len(value) == 0 {
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*dst = RecordArray{Status: pgtype.Present}
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} else {
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elements := make([]pgtype.Record, len(value))
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for i := range value {
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if err := elements[i].Set(value[i]); err != nil {
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return err
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}
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}
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*dst = RecordArray{
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Elements: elements,
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Dimensions: []pgtype.ArrayDimension{{Length: int32(len(elements)), LowerBound: 1}},
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Status: pgtype.Present,
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}
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}
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case []pgtype.Record:
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if value == nil {
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*dst = RecordArray{Status: pgtype.Null}
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} else if len(value) == 0 {
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*dst = RecordArray{Status: pgtype.Present}
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} else {
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*dst = RecordArray{
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Elements: value,
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Dimensions: []pgtype.ArrayDimension{{Length: int32(len(value)), LowerBound: 1}},
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Status: pgtype.Present,
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}
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}
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default:
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// Fallback to reflection if an optimised match was not found.
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// The reflection is necessary for arrays and multidimensional slices,
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// but it comes with a 20-50% performance penalty for large arrays/slices
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reflectedValue := reflect.ValueOf(src)
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if !reflectedValue.IsValid() || reflectedValue.IsZero() {
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*dst = RecordArray{Status: pgtype.Null}
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return nil
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}
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dimensions, elementsLength, ok := findDimensionsFromValue(reflectedValue, nil, 0)
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if !ok {
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return fmt.Errorf("cannot find dimensions of %v for RecordArray", src)
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}
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if elementsLength == 0 {
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*dst = RecordArray{Status: pgtype.Present}
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return nil
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}
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if len(dimensions) == 0 {
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if originalSrc, ok := underlyingSliceType(src); ok {
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return dst.Set(originalSrc)
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}
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return fmt.Errorf("cannot convert %v to RecordArray", src)
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}
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*dst = RecordArray{
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Elements: make([]pgtype.Record, elementsLength),
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Dimensions: dimensions,
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Status: pgtype.Present,
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}
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elementCount, err := dst.setRecursive(reflectedValue, 0, 0)
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if err != nil {
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// Maybe the target was one dimension too far, try again:
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if len(dst.Dimensions) > 1 {
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dst.Dimensions = dst.Dimensions[:len(dst.Dimensions)-1]
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elementsLength = 0
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for _, dim := range dst.Dimensions {
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if elementsLength == 0 {
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elementsLength = int(dim.Length)
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} else {
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elementsLength *= int(dim.Length)
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}
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}
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dst.Elements = make([]pgtype.Record, elementsLength)
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elementCount, err = dst.setRecursive(reflectedValue, 0, 0)
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if err != nil {
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return err
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}
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} else {
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return err
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}
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}
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if elementCount != len(dst.Elements) {
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return fmt.Errorf("cannot convert %v to RecordArray, expected %d dst.Elements, but got %d instead", src, len(dst.Elements), elementCount)
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}
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}
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return nil
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}
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func (dst *RecordArray) setRecursive(value reflect.Value, index, dimension int) (int, error) {
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switch value.Kind() {
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case reflect.Array:
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fallthrough
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case reflect.Slice:
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if len(dst.Dimensions) == dimension {
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break
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}
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valueLen := value.Len()
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if int32(valueLen) != dst.Dimensions[dimension].Length {
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return 0, fmt.Errorf("multidimensional arrays must have array expressions with matching dimensions")
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}
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for i := 0; i < valueLen; i++ {
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var err error
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index, err = dst.setRecursive(value.Index(i), index, dimension+1)
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if err != nil {
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return 0, err
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}
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}
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return index, nil
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}
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if !value.CanInterface() {
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return 0, fmt.Errorf("cannot convert all values to RecordArray")
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}
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if err := dst.Elements[index].Set(value.Interface()); err != nil {
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return 0, fmt.Errorf("%v in RecordArray", err)
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}
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index++
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return index, nil
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}
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func (dst RecordArray) Get() interface{} {
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switch dst.Status {
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case pgtype.Present:
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return dst
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case pgtype.Null:
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return nil
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default:
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return dst.Status
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}
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}
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func (src *RecordArray) AssignTo(dst interface{}) error {
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switch src.Status {
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case pgtype.Present:
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if len(src.Dimensions) <= 1 {
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// Attempt to match to select common types:
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switch v := dst.(type) {
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case *[][]pgtype.Value:
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*v = make([][]pgtype.Value, len(src.Elements))
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for i := range src.Elements {
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if err := src.Elements[i].AssignTo(&((*v)[i])); err != nil {
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return err
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}
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}
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return nil
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}
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}
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// Try to convert to something AssignTo can use directly.
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if nextDst, retry := pgtype.GetAssignToDstType(dst); retry {
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return src.AssignTo(nextDst)
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}
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// Fallback to reflection if an optimised match was not found.
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// The reflection is necessary for arrays and multidimensional slices,
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// but it comes with a 20-50% performance penalty for large arrays/slices
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value := reflect.ValueOf(dst)
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if value.Kind() == reflect.Ptr {
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value = value.Elem()
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}
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switch value.Kind() {
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case reflect.Array, reflect.Slice:
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default:
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return fmt.Errorf("cannot assign %T to %T", src, dst)
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}
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if len(src.Elements) == 0 {
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if value.Kind() == reflect.Slice {
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value.Set(reflect.MakeSlice(value.Type(), 0, 0))
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return nil
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}
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}
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elementCount, err := src.assignToRecursive(value, 0, 0)
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if err != nil {
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return err
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}
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if elementCount != len(src.Elements) {
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return fmt.Errorf("cannot assign %v, needed to assign %d elements, but only assigned %d", dst, len(src.Elements), elementCount)
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}
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return nil
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case pgtype.Null:
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return pgtype.NullAssignTo(dst)
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}
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return fmt.Errorf("cannot decode %#v into %T", src, dst)
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}
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func (src *RecordArray) assignToRecursive(value reflect.Value, index, dimension int) (int, error) {
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switch kind := value.Kind(); kind {
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case reflect.Array:
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fallthrough
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case reflect.Slice:
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if len(src.Dimensions) == dimension {
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break
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}
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length := int(src.Dimensions[dimension].Length)
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if reflect.Array == kind {
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typ := value.Type()
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if typ.Len() != length {
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return 0, fmt.Errorf("expected size %d array, but %s has size %d array", length, typ, typ.Len())
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}
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value.Set(reflect.New(typ).Elem())
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} else {
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value.Set(reflect.MakeSlice(value.Type(), length, length))
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}
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var err error
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for i := 0; i < length; i++ {
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index, err = src.assignToRecursive(value.Index(i), index, dimension+1)
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if err != nil {
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return 0, err
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}
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}
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return index, nil
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}
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if len(src.Dimensions) != dimension {
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return 0, fmt.Errorf("incorrect dimensions, expected %d, found %d", len(src.Dimensions), dimension)
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}
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if !value.CanAddr() {
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return 0, fmt.Errorf("cannot assign all values from RecordArray")
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}
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addr := value.Addr()
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if !addr.CanInterface() {
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return 0, fmt.Errorf("cannot assign all values from RecordArray")
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}
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if err := src.Elements[index].AssignTo(addr.Interface()); err != nil {
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return 0, err
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}
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index++
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return index, nil
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}
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func (dst *RecordArray) DecodeBinary(ci *pgtype.ConnInfo, src []byte) error {
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if src == nil {
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*dst = RecordArray{Status: pgtype.Null}
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return nil
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}
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var arrayHeader pgtype.ArrayHeader
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rp, err := arrayHeader.DecodeBinary(ci, src)
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if err != nil {
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return err
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}
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if len(arrayHeader.Dimensions) == 0 {
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*dst = RecordArray{Dimensions: arrayHeader.Dimensions, Status: pgtype.Present}
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return nil
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}
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elementCount := arrayHeader.Dimensions[0].Length
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for _, d := range arrayHeader.Dimensions[1:] {
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elementCount *= d.Length
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}
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elements := make([]pgtype.Record, elementCount)
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for i := range elements {
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elemLen := int(int32(binary.BigEndian.Uint32(src[rp:])))
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rp += 4
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var elemSrc []byte
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if elemLen >= 0 {
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elemSrc = src[rp : rp+elemLen]
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rp += elemLen
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}
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err = elements[i].DecodeBinary(ci, elemSrc)
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if err != nil {
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return err
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}
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}
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*dst = RecordArray{Elements: elements, Dimensions: arrayHeader.Dimensions, Status: pgtype.Present}
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return nil
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}
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func underlyingSliceType(val interface{}) (interface{}, bool) {
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refVal := reflect.ValueOf(val)
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switch refVal.Kind() {
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case reflect.Ptr:
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if refVal.IsNil() {
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return nil, false
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}
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convVal := refVal.Elem().Interface()
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return convVal, true
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case reflect.Slice:
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baseSliceType := reflect.SliceOf(refVal.Type().Elem())
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if refVal.Type().ConvertibleTo(baseSliceType) {
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convVal := refVal.Convert(baseSliceType)
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return convVal.Interface(), reflect.TypeOf(convVal.Interface()) != refVal.Type()
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}
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}
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return nil, false
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}
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func findDimensionsFromValue(value reflect.Value, dimensions []pgtype.ArrayDimension, elementsLength int) ([]pgtype.ArrayDimension, int, bool) {
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switch value.Kind() {
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case reflect.Array:
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fallthrough
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case reflect.Slice:
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length := value.Len()
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if 0 == elementsLength {
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elementsLength = length
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} else {
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elementsLength *= length
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}
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dimensions = append(dimensions, pgtype.ArrayDimension{Length: int32(length), LowerBound: 1})
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for i := 0; i < length; i++ {
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if d, l, ok := findDimensionsFromValue(value.Index(i), dimensions, elementsLength); ok {
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return d, l, true
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}
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}
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}
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return dimensions, elementsLength, true
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}
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