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package bun
import (
"context"
"database/sql"
"fmt"
"reflect"
"github.com/uptrace/bun/internal"
"github.com/uptrace/bun/schema"
)
type hasManyModel struct {
*sliceTableModel
baseTable *schema.Table
rel *schema.Relation
baseValues map[internal.MapKey][]reflect.Value
structKey []interface{}
}
var _ TableModel = (*hasManyModel)(nil)
func newHasManyModel(j *relationJoin) *hasManyModel {
baseTable := j.BaseModel.Table()
joinModel := j.JoinModel.(*sliceTableModel)
baseValues := baseValues(joinModel, j.Relation.BaseFields)
if len(baseValues) == 0 {
return nil
}
m := hasManyModel{
sliceTableModel: joinModel,
baseTable: baseTable,
rel: j.Relation,
baseValues: baseValues,
}
if !m.sliceOfPtr {
m.strct = reflect.New(m.table.Type).Elem()
}
return &m
}
func (m *hasManyModel) ScanRows(ctx context.Context, rows *sql.Rows) (int, error) {
columns, err := rows.Columns()
if err != nil {
return 0, err
}
m.columns = columns
dest := makeDest(m, len(columns))
var n int
for rows.Next() {
if m.sliceOfPtr {
m.strct = reflect.New(m.table.Type).Elem()
} else {
m.strct.Set(m.table.ZeroValue)
}
m.structInited = false
m.scanIndex = 0
m.structKey = m.structKey[:0]
if err := rows.Scan(dest...); err != nil {
return 0, err
}
if err := m.parkStruct(); err != nil {
return 0, err
}
n++
}
if err := rows.Err(); err != nil {
return 0, err
}
return n, nil
}
func (m *hasManyModel) Scan(src interface{}) error {
column := m.columns[m.scanIndex]
m.scanIndex++
field, err := m.table.Field(column)
if err != nil {
return err
}
if err := field.ScanValue(m.strct, src); err != nil {
return err
}
for _, f := range m.rel.JoinFields {
if f.Name == field.Name {
m.structKey = append(m.structKey, field.Value(m.strct).Interface())
break
}
}
return nil
}
func (m *hasManyModel) parkStruct() error {
baseValues, ok := m.baseValues[internal.NewMapKey(m.structKey)]
if !ok {
return fmt.Errorf(
"bun: has-many relation=%s does not have base %s with id=%q (check join conditions)",
m.rel.Field.GoName, m.baseTable, m.structKey)
}
for i, v := range baseValues {
if !m.sliceOfPtr {
v.Set(reflect.Append(v, m.strct))
continue
}
if i == 0 {
v.Set(reflect.Append(v, m.strct.Addr()))
continue
}
clone := reflect.New(m.strct.Type()).Elem()
clone.Set(m.strct)
v.Set(reflect.Append(v, clone.Addr()))
}
return nil
}
func baseValues(model TableModel, fields []*schema.Field) map[internal.MapKey][]reflect.Value {
fieldIndex := model.Relation().Field.Index
m := make(map[internal.MapKey][]reflect.Value)
key := make([]interface{}, 0, len(fields))
walk(model.rootValue(), model.parentIndex(), func(v reflect.Value) {
key = modelKey(key[:0], v, fields)
mapKey := internal.NewMapKey(key)
m[mapKey] = append(m[mapKey], v.FieldByIndex(fieldIndex))
})
return m
}
func modelKey(key []interface{}, strct reflect.Value, fields []*schema.Field) []interface{} {
for _, f := range fields {
key = append(key, f.Value(strct).Interface())
}
return key
}
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