32ac467992
Move the Walk types into registry/storage/driver, and add a Walk method to each storage driver. Although this is yet another API to implement, there is a fall back implementation that relies on List and Stat. For some filesystems this is very slow. Also, this WalkDir Method conforms better do a traditional WalkDir (a la filepath). This change is in preparation for refactoring. Signed-off-by: Sargun Dhillon <sargun@sargun.me>
53 lines
1.6 KiB
Go
53 lines
1.6 KiB
Go
package driver
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import (
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"context"
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"errors"
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"sort"
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)
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// ErrSkipDir is used as a return value from onFileFunc to indicate that
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// the directory named in the call is to be skipped. It is not returned
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// as an error by any function.
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var ErrSkipDir = errors.New("skip this directory")
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// WalkFn is called once per file by Walk
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type WalkFn func(fileInfo FileInfo) error
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// WalkFallback traverses a filesystem defined within driver, starting
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// from the given path, calling f on each file. It uses the List method and Stat to drive itself.
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// If the returned error from the WalkFn is ErrSkipDir and fileInfo refers
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// to a directory, the directory will not be entered and Walk
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// will continue the traversal. If fileInfo refers to a normal file, processing stops
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func WalkFallback(ctx context.Context, driver StorageDriver, from string, f WalkFn) error {
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children, err := driver.List(ctx, from)
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if err != nil {
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return err
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}
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sort.Stable(sort.StringSlice(children))
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for _, child := range children {
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// TODO(stevvooe): Calling driver.Stat for every entry is quite
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// expensive when running against backends with a slow Stat
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// implementation, such as s3. This is very likely a serious
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// performance bottleneck.
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fileInfo, err := driver.Stat(ctx, child)
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if err != nil {
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return err
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}
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err = f(fileInfo)
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if err == nil && fileInfo.IsDir() {
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if err := WalkFallback(ctx, driver, child, f); err != nil {
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return err
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}
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} else if err == ErrSkipDir {
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// Stop iteration if it's a file, otherwise noop if it's a directory
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if !fileInfo.IsDir() {
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return nil
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}
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} else 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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