| // Copyright 2018 The LUCI Authors. |
| // |
| // 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 cipd |
| |
| import "context" |
| |
| // InstanceEnumerator emits a list of instances, fetching them in batches. |
| // |
| // Returned by ListInstances call. |
| type InstanceEnumerator interface { |
| // Next returns up to 'limit' instances or 0 if there's no more. |
| Next(ctx context.Context, limit int) ([]InstanceInfo, error) |
| } |
| |
| // instanceEnumeratorImpl implements InstanceEnumerator by calling the given |
| // callback that fetches the next page of results. |
| type instanceEnumeratorImpl struct { |
| fetch func(ctx context.Context, limit int, cursor string) (out []InstanceInfo, nextCursor string, err error) |
| |
| cursor string // last fetched cursor or "" at the start of the fetch |
| done bool // true if fetched the last page |
| } |
| |
| func (e *instanceEnumeratorImpl) Next(ctx context.Context, limit int) (out []InstanceInfo, err error) { |
| if e.done { |
| return nil, nil |
| } |
| out, nextCursor, err := e.fetch(ctx, limit, e.cursor) |
| if err != nil { |
| return nil, err |
| } |
| e.cursor = nextCursor |
| e.done = nextCursor == "" |
| return |
| } |