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// Copyright 2018 Google LLC
//
// 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
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package firestore
import (
"context"
vkit "cloud.google.com/go/firestore/apiv1"
"google.golang.org/api/iterator"
pb "google.golang.org/genproto/googleapis/firestore/v1"
)
// DocumentRefIterator is an iterator over DocumentRefs.
type DocumentRefIterator struct {
client *Client
it *vkit.DocumentIterator
pageInfo *iterator.PageInfo
nextFunc func() error
items []*DocumentRef
err error
}
func newDocumentRefIterator(ctx context.Context, cr *CollectionRef, tid []byte) *DocumentRefIterator {
client := cr.c
req := &pb.ListDocumentsRequest{
Parent: cr.parentPath,
CollectionId: cr.ID,
ShowMissing: true,
Mask: &pb.DocumentMask{}, // empty mask: we want only the ref
}
if tid != nil {
req.ConsistencySelector = &pb.ListDocumentsRequest_Transaction{tid}
}
it := &DocumentRefIterator{
client: client,
it: client.c.ListDocuments(withResourceHeader(ctx, client.path()), req),
}
it.pageInfo, it.nextFunc = iterator.NewPageInfo(
it.fetch,
func() int { return len(it.items) },
func() interface{} { b := it.items; it.items = nil; return b })
return it
}
// PageInfo supports pagination. See the google.golang.org/api/iterator package for details.
func (it *DocumentRefIterator) PageInfo() *iterator.PageInfo { return it.pageInfo }
// Next returns the next result. Its second return value is iterator.Done if there
// are no more results. Once Next returns Done, all subsequent calls will return
// Done.
func (it *DocumentRefIterator) Next() (*DocumentRef, error) {
if err := it.nextFunc(); err != nil {
return nil, err
}
item := it.items[0]
it.items = it.items[1:]
return item, nil
}
func (it *DocumentRefIterator) fetch(pageSize int, pageToken string) (string, error) {
if it.err != nil {
return "", it.err
}
return iterFetch(pageSize, pageToken, it.it.PageInfo(), func() error {
docProto, err := it.it.Next()
if err != nil {
return err
}
docRef, err := pathToDoc(docProto.Name, it.client)
if err != nil {
return err
}
it.items = append(it.items, docRef)
return nil
})
}
// GetAll returns all the DocumentRefs remaining from the iterator.
func (it *DocumentRefIterator) GetAll() ([]*DocumentRef, error) {
var drs []*DocumentRef
for {
dr, err := it.Next()
if err == iterator.Done {
break
}
if err != nil {
return nil, err
}
drs = append(drs, dr)
}
return drs, nil
}
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