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[QRM] Prevent recursive scan if destination contains circular dependency.

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This commit is contained in:
go-jet 2021-12-07 17:16:10 +01:00
parent 7f54036b1a
commit 02123005c1
4 changed files with 389 additions and 17 deletions
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54
qrm/qrm.go
View file

@ -87,7 +87,7 @@ func ScanOneRowToDest(rows *sql.Rows, destPtr interface{}) error {
tempSlicePtrValue := reflect.New(reflect.SliceOf(destinationPtrType))
tempSliceValue := tempSlicePtrValue.Elem()
_, err = mapRowToSlice(scanContext, "", tempSlicePtrValue, nil)
_, err = mapRowToSlice(scanContext, "", newTypeStack(), tempSlicePtrValue, nil)
if err != nil {
return fmt.Errorf("failed to map a row, %w", err)
@ -141,7 +141,7 @@ func queryToSlice(ctx context.Context, db DB, query string, args []interface{},
scanContext.rowNum++
_, err = mapRowToSlice(scanContext, "", slicePtrValue, nil)
_, err = mapRowToSlice(scanContext, "", newTypeStack(), slicePtrValue, nil)
if err != nil {
return
@ -164,7 +164,12 @@ func queryToSlice(ctx context.Context, db DB, query string, args []interface{},
return
}
func mapRowToSlice(scanContext *scanContext, groupKey string, slicePtrValue reflect.Value, field *reflect.StructField) (updated bool, err error) {
func mapRowToSlice(
scanContext *scanContext,
groupKey string,
typesVisited *typeStack,
slicePtrValue reflect.Value,
field *reflect.StructField) (updated bool, err error) {
sliceElemType := getSliceElemType(slicePtrValue)
@ -184,12 +189,12 @@ func mapRowToSlice(scanContext *scanContext, groupKey string, slicePtrValue refl
if ok {
structPtrValue := getSliceElemPtrAt(slicePtrValue, index)
return mapRowToStruct(scanContext, groupKey, structPtrValue, field, true)
return mapRowToStruct(scanContext, groupKey, typesVisited, structPtrValue, field, true)
}
destinationStructPtr := newElemPtrValueForSlice(slicePtrValue)
updated, err = mapRowToStruct(scanContext, groupKey, destinationStructPtr, field)
updated, err = mapRowToStruct(scanContext, groupKey, typesVisited, destinationStructPtr, field)
if err != nil {
return
@ -228,10 +233,25 @@ func mapRowToBaseTypeSlice(scanContext *scanContext, slicePtrValue reflect.Value
return
}
func mapRowToStruct(scanContext *scanContext, groupKey string, structPtrValue reflect.Value, parentField *reflect.StructField, onlySlices ...bool) (updated bool, err error) {
func mapRowToStruct(
scanContext *scanContext,
groupKey string,
typesVisited *typeStack, // to prevent circular dependency scan
structPtrValue reflect.Value,
parentField *reflect.StructField,
onlySlices ...bool, // small optimization, not to assign to already assigned struct fields
) (updated bool, err error) {
mapOnlySlices := len(onlySlices) > 0
structType := structPtrValue.Type().Elem()
if typesVisited.contains(&structType) {
return false, nil
}
typesVisited.push(&structType)
defer typesVisited.pop()
typeInf := scanContext.getTypeInfo(structType, parentField)
structValue := structPtrValue.Elem()
@ -248,7 +268,7 @@ func mapRowToStruct(scanContext *scanContext, groupKey string, structPtrValue re
if fieldMap.complexType {
var changed bool
changed, err = mapRowToDestinationValue(scanContext, groupKey, fieldValue, &field)
changed, err = mapRowToDestinationValue(scanContext, groupKey, typesVisited, fieldValue, &field)
if err != nil {
return
@ -295,7 +315,12 @@ func mapRowToStruct(scanContext *scanContext, groupKey string, structPtrValue re
return
}
func mapRowToDestinationValue(scanContext *scanContext, groupKey string, dest reflect.Value, structField *reflect.StructField) (updated bool, err error) {
func mapRowToDestinationValue(
scanContext *scanContext,
groupKey string,
typesVisited *typeStack,
dest reflect.Value,
structField *reflect.StructField) (updated bool, err error) {
var destPtrValue reflect.Value
@ -309,7 +334,7 @@ func mapRowToDestinationValue(scanContext *scanContext, groupKey string, dest re
}
}
updated, err = mapRowToDestinationPtr(scanContext, groupKey, destPtrValue, structField)
updated, err = mapRowToDestinationPtr(scanContext, groupKey, typesVisited, destPtrValue, structField)
if err != nil {
return
@ -322,16 +347,21 @@ func mapRowToDestinationValue(scanContext *scanContext, groupKey string, dest re
return
}
func mapRowToDestinationPtr(scanContext *scanContext, groupKey string, destPtrValue reflect.Value, structField *reflect.StructField) (updated bool, err error) {
func mapRowToDestinationPtr(
scanContext *scanContext,
groupKey string,
typesVisited *typeStack,
destPtrValue reflect.Value,
structField *reflect.StructField) (updated bool, err error) {
utils.ValueMustBe(destPtrValue, reflect.Ptr, "jet: internal error. Destination is not pointer.")
destValueKind := destPtrValue.Elem().Kind()
if destValueKind == reflect.Struct {
return mapRowToStruct(scanContext, groupKey, destPtrValue, structField)
return mapRowToStruct(scanContext, groupKey, typesVisited, destPtrValue, structField)
} else if destValueKind == reflect.Slice {
return mapRowToSlice(scanContext, groupKey, destPtrValue, structField)
return mapRowToSlice(scanContext, groupKey, typesVisited, destPtrValue, structField)
} else {
panic("jet: unsupported dest type: " + structField.Name + " " + structField.Type.String())
}

21
qrm/scan_context.go
View file

@ -132,7 +132,7 @@ func (s *scanContext) getGroupKey(structType reflect.Type, structField *reflect.
return s.constructGroupKey(groupKeyInfo)
}
groupKeyInfo := s.getGroupKeyInfo(structType, structField)
groupKeyInfo := s.getGroupKeyInfo(structType, structField, newTypeStack())
s.groupKeyInfoCache[mapKey] = groupKeyInfo
@ -144,7 +144,7 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
return fmt.Sprintf("|ROW:%d|", s.rowNum)
}
groupKeys := []string{}
var groupKeys []string
for _, index := range groupKeyInfo.indexes {
cellValue := s.rowElem(index)
@ -153,7 +153,7 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
groupKeys = append(groupKeys, subKey)
}
subTypesGroupKeys := []string{}
var subTypesGroupKeys []string
for _, subType := range groupKeyInfo.subTypes {
subTypesGroupKeys = append(subTypesGroupKeys, s.constructGroupKey(subType))
}
@ -161,9 +161,20 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
return groupKeyInfo.typeName + "(" + strings.Join(groupKeys, ",") + strings.Join(subTypesGroupKeys, ",") + ")"
}
func (s *scanContext) getGroupKeyInfo(structType reflect.Type, parentField *reflect.StructField) groupKeyInfo {
func (s *scanContext) getGroupKeyInfo(
structType reflect.Type,
parentField *reflect.StructField,
typeVisited *typeStack) groupKeyInfo {
ret := groupKeyInfo{typeName: structType.Name()}
if typeVisited.contains(&structType) {
return ret
}
typeVisited.push(&structType)
defer typeVisited.pop()
typeName := getTypeName(structType, parentField)
primaryKeyOverwrites := parentFieldPrimaryKeyOverwrite(parentField)
@ -176,7 +187,7 @@ func (s *scanContext) getGroupKeyInfo(structType reflect.Type, parentField *refl
continue
}
subType := s.getGroupKeyInfo(fieldType, &field)
subType := s.getGroupKeyInfo(fieldType, &field, typeVisited)
if len(subType.indexes) != 0 || len(subType.subTypes) != 0 {
ret.subTypes = append(ret.subTypes, subType)

40
qrm/type_stack.go Normal file
View file

@ -0,0 +1,40 @@
package qrm
import "reflect"
type typeStack []*reflect.Type
func newTypeStack() *typeStack {
stack := make(typeStack, 0, 20)
return &stack
}
func (s *typeStack) isEmpty() bool {
return len(*s) == 0
}
func (s *typeStack) push(t *reflect.Type) {
*s = append(*s, t)
}
func (s *typeStack) pop() bool {
if s.isEmpty() {
return false
}
*s = (*s)[:len(*s)-1]
return true
}
func (s *typeStack) contains(t *reflect.Type) bool {
if s.isEmpty() {
return false
}
for _, typ := range *s {
if *typ == *t {
return true
}
}
return false
}