mirror of https://github.com/go-gorm/gorm.git
72 lines
1.9 KiB
Go
72 lines
1.9 KiB
Go
package gorm
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import (
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"errors"
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"fmt"
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"reflect"
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)
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func Preload(scope *Scope) {
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// Get Fields
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var fields map[string]*Field
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if scope.IndirectValue().Kind() == reflect.Slice {
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elem := reflect.New(scope.IndirectValue().Type().Elem()).Elem()
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fields = scope.New(elem.Addr().Interface()).Fields()
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} else {
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fields = scope.Fields()
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}
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if scope.Search.Preload != nil {
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for key := range scope.Search.Preload {
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for _, field := range fields {
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if field.Name == key && field.Relationship != nil {
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results := makeSlice(field.Field)
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relation := field.Relationship
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primaryName := scope.PrimaryKeyField().Name
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switch relation.Kind {
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case "has_one":
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sql := fmt.Sprintf("%v IN (?)", scope.Quote(relation.ForeignKey))
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scope.NewDB().Find(results, sql, scope.getColumnAsArray(primaryName))
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case "has_many":
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sql := fmt.Sprintf("%v IN (?)", scope.Quote(relation.ForeignKey))
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scope.NewDB().Find(results, sql, scope.getColumnAsArray(primaryName))
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case "belongs_to":
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scope.NewDB().Find(results, scope.getColumnAsArray(relation.ForeignKey))
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case "many_to_many":
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scope.Err(errors.New("not supported relation"))
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default:
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scope.Err(errors.New("not supported relation"))
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}
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break
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}
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}
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}
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}
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}
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func makeSlice(value reflect.Value) interface{} {
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typ := value.Type()
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if value.Kind() == reflect.Slice {
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typ = typ.Elem()
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}
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sliceType := reflect.SliceOf(typ)
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slice := reflect.New(sliceType)
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slice.Elem().Set(reflect.MakeSlice(sliceType, 0, 0))
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return slice.Interface()
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}
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func (scope *Scope) getColumnAsArray(column string) (primaryKeys []interface{}) {
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values := scope.IndirectValue()
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switch values.Kind() {
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case reflect.Slice:
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for i := 0; i < values.Len(); i++ {
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value := values.Index(i)
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primaryKeys = append(primaryKeys, value.FieldByName(column).Interface())
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}
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case reflect.Struct:
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return []interface{}{values.FieldByName(column).Interface()}
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}
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return
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}
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