forked from TrueCloudLab/restic
59 lines
1.2 KiB
Go
59 lines
1.2 KiB
Go
package restic
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import (
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"context"
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"github.com/restic/restic/internal/debug"
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"golang.org/x/sync/errgroup"
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)
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func ParallelList(ctx context.Context, r Lister, t FileType, parallelism uint, fn func(context.Context, ID, int64) error) error {
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type FileIDInfo struct {
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ID
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Size int64
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}
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// track spawned goroutines using wg, create a new context which is
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// cancelled as soon as an error occurs.
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wg, ctx := errgroup.WithContext(ctx)
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ch := make(chan FileIDInfo)
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// send list of index files through ch, which is closed afterwards
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wg.Go(func() error {
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defer close(ch)
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return r.List(ctx, t, func(fi FileInfo) error {
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id, err := ParseID(fi.Name)
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if err != nil {
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debug.Log("unable to parse %v as an ID", fi.Name)
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return nil
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}
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select {
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case <-ctx.Done():
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return nil
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case ch <- FileIDInfo{id, fi.Size}:
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}
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return nil
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})
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})
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// a worker receives an index ID from ch, loads the index, and sends it to indexCh
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worker := func() error {
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for fi := range ch {
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debug.Log("worker got file %v", fi.ID.Str())
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err := fn(ctx, fi.ID, fi.Size)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// run workers on ch
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for i := uint(0); i < parallelism; i++ {
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wg.Go(worker)
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}
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return wg.Wait()
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}
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