77 lines
1.9 KiB
Go
77 lines
1.9 KiB
Go
package k2v
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import (
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"context"
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"errors"
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)
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var StopScroll = errors.New("scroll canceled")
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// ReadIndexResponseHandler is invoked for each batch of index read results.
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//
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// If an error is returned, scrolling is halted and the error is propagated.
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// The sentinel value StopScroll can be returned to end iteration early without propagating an error.
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type ReadIndexResponseHandler func(resp *ReadIndexResponse) error
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type BatchSearchResultHandler func(result *BatchSearchResult) error
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type IndexScroller interface {
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ReadIndex(ctx context.Context, b Bucket, q ReadIndexQuery) (*ReadIndexResponse, error)
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}
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var _ IndexScroller = &Client{}
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type BatchSearchScroller interface {
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ReadBatch(ctx context.Context, b Bucket, q []BatchSearch) ([]*BatchSearchResult, error)
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}
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var _ BatchSearchScroller = &Client{}
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// ScrollIndex calls the ReadIndex API serially, invoking the provided function for each response (batch) until there are no more results.
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func ScrollIndex(ctx context.Context, client IndexScroller, b Bucket, q ReadIndexQuery, fn ReadIndexResponseHandler) error {
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for {
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resp, err := client.ReadIndex(ctx, b, q)
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if err != nil {
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return err
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}
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if err := fn(resp); err != nil {
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if errors.Is(err, StopScroll) {
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return nil
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}
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return err
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}
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if !resp.More || resp.NextStart == nil {
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break
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}
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q.Start = *resp.NextStart
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}
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return nil
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}
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func ScrollBatchSearch(ctx context.Context, client BatchSearchScroller, b Bucket, q []BatchSearch, fn BatchSearchResultHandler) error {
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for {
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results, err := client.ReadBatch(ctx, b, q)
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if err != nil {
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return err
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}
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var nextQ []BatchSearch
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for i := range results {
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if results[i].More && results[i].NextStart != nil {
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batch := q[i]
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batch.Start = *results[i].NextStart
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nextQ = append(nextQ, batch)
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}
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if err := fn(results[i]); err != nil {
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if errors.Is(err, StopScroll) {
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return nil
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}
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return err
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}
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}
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if len(nextQ) == 0 {
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break
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}
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q = nextQ
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}
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return nil
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}
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