// Repeatedly call bucket.ListObjects until there is nothing further to list,
// returning all objects and collapsed runs encountered.
//
// May modify *req.
func ListAll(
ctx context.Context,
bucket gcs.Bucket,
req *gcs.ListObjectsRequest) (
objects []*gcs.Object,
runs []string,
err error) {
for {
// Grab one set of results.
var listing *gcs.Listing
if listing, err = bucket.ListObjects(ctx, req); err != nil {
return
}
// Accumulate the results.
objects = append(objects, listing.Objects...)
runs = append(runs, listing.CollapsedRuns...)
// Are we done?
if listing.ContinuationToken == "" {
break
}
req.ContinuationToken = listing.ContinuationToken
}
return
}
// List the supplied object name prefix to find out whether it is non-empty.
func objectNamePrefixNonEmpty(
ctx context.Context,
bucket gcs.Bucket,
prefix string) (nonEmpty bool, err error) {
req := &gcs.ListObjectsRequest{
Prefix: prefix,
MaxResults: 1,
}
listing, err := bucket.ListObjects(ctx, req)
if err != nil {
err = fmt.Errorf("ListObjects: %v", err)
return
}
nonEmpty = len(listing.Objects) != 0
return
}
// List objects in the supplied bucket whose name starts with the given prefix.
// Write them into the supplied channel in an undefined order.
func ListPrefix(
ctx context.Context,
bucket gcs.Bucket,
prefix string,
objects chan<- *gcs.Object) (err error) {
req := &gcs.ListObjectsRequest{
Prefix: prefix,
}
// List until we run out.
for {
// Fetch the next batch.
var listing *gcs.Listing
listing, err = bucket.ListObjects(ctx, req)
if err != nil {
err = fmt.Errorf("ListObjects: %v", err)
return
}
// Pass on each object.
for _, o := range listing.Objects {
select {
case objects <- o:
// Cancelled?
case <-ctx.Done():
err = ctx.Err()
return
}
}
// Are we done?
if listing.ContinuationToken == "" {
break
}
req.ContinuationToken = listing.ContinuationToken
}
return
}