/
document_result.go
56 lines (49 loc) · 1.43 KB
/
document_result.go
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// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package mongo
import (
"context"
"errors"
"github.com/mongodb/mongo-go-driver/bson"
)
// ErrNoDocuments is returned by Decode when an operation that returns a
// DocumentResult doesn't return any documents.
var ErrNoDocuments = errors.New("mongo: no documents in result")
// DocumentResult represents a single document returned from an operation. If
// the operation returned an error, the Err method of DocumentResult will
// return that error.
type DocumentResult struct {
err error
cur Cursor
rdr bson.Reader
}
// Decode will attempt to decode the first document into v. If there was an
// error from the operation that created this DocumentResult then the error
// will be returned. If there were no returned documents, ErrNoDocuments is
// returned.
func (dr *DocumentResult) Decode(v interface{}) error {
switch {
case dr.err != nil:
return dr.err
case dr.rdr != nil:
if v == nil {
return nil
}
return bson.Unmarshal(dr.rdr, v)
case dr.cur != nil:
if !dr.cur.Next(context.TODO()) {
if err := dr.cur.Err(); err != nil {
return err
}
return ErrNoDocuments
}
if v == nil {
return nil
}
return dr.cur.Decode(v)
}
return ErrNoDocuments
}