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mongox-go-driver/mongox/database/streamloader.go

79 lines
1.4 KiB

package database
import (
"context"
"fmt"
"github.com/mainnika/mongox-go-driver/v2/mongox"
"github.com/mainnika/mongox-go-driver/v2/mongox/base"
)
// StreamLoader is a controller for a database cursor
type StreamLoader struct {
cur *mongox.Cursor
ctx context.Context
target interface{}
}
// DecodeNext loads next documents to a target or returns an error
func (l *StreamLoader) DecodeNext() error {
hasNext := l.cur.Next(l.ctx)
if l.cur.Err() != nil {
return l.cur.Err()
}
if !hasNext {
return mongox.ErrNoDocuments
}
base.Reset(l.target)
err := l.cur.Decode(l.target)
if err != nil {
return fmt.Errorf("can't decode desult: %w", err)
}
return nil
}
// Decode function decodes the current cursor document into the target
func (l *StreamLoader) Decode() error {
base.Reset(l.target)
err := l.cur.Decode(l.target)
if err != nil {
return fmt.Errorf("can't decode desult: %w", err)
}
return nil
}
// Next loads next documents but doesn't perform decoding
func (l *StreamLoader) Next() error {
hasNext := l.cur.Next(l.ctx)
if l.cur.Err() != nil {
return l.cur.Err()
}
if !hasNext {
return mongox.ErrNoDocuments
}
return nil
}
func (l *StreamLoader) Cursor() *mongox.Cursor {
return l.cur
}
// Close cursor
func (l *StreamLoader) Close() error {
return l.cur.Close(l.ctx)
}
func (l *StreamLoader) Err() error {
return l.cur.Err()
}