1	/*
     2	Copyright 2014 The Perkeep Authors
     3	
     4	Licensed under the Apache License, Version 2.0 (the "License");
     5	you may not use this file except in compliance with the License.
     6	You may obtain a copy of the License at
     7	
     8	     http://www.apache.org/licenses/LICENSE-2.0
     9	
    10	Unless required by applicable law or agreed to in writing, software
    11	distributed under the License is distributed on an "AS IS" BASIS,
    12	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13	See the License for the specific language governing permissions and
    14	limitations under the License.
    15	*/
    16	
    17	package mongo
    18	
    19	import (
    20		"context"
    21		"log"
    22	
    23		"gopkg.in/mgo.v2/bson"
    24		"perkeep.org/pkg/blob"
    25	)
    26	
    27	func (m *mongoStorage) EnumerateBlobs(ctx context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
    28		defer close(dest)
    29	
    30		var b blobDoc
    31		var qry bson.M
    32		if after != "" {
    33			qry = bson.M{"key": bson.M{"$gt": after}}
    34		}
    35		iter := m.c.Find(qry).Limit(limit).Select(bson.M{"key": 1, "size": 1}).Sort("key").Iter()
    36	
    37		for iter.Next(&b) {
    38			br, ok := blob.Parse(b.Key)
    39			if !ok {
    40				continue
    41			}
    42			select {
    43			case dest <- blob.SizedRef{Ref: br, Size: uint32(b.Size)}:
    44			case <-ctx.Done():
    45				// Close the iterator but ignore the error value since we are already cancelling
    46				if err := iter.Close(); err != nil {
    47					log.Printf("Error closing iterator after enumerating: %v", err)
    48				}
    49				return ctx.Err()
    50			}
    51		}
    52	
    53		if err := iter.Close(); err != nil {
    54			return err
    55		}
    56	
    57		return nil
    58	}