47 lines
867 B
Go
47 lines
867 B
Go
package resource
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import (
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"io"
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"os"
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)
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// An Instance represents the content at some location accessed through some
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// Provider. It's the data at some URL.
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type Instance interface {
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Get() (io.ReadCloser, error)
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Put(io.Reader) error
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Stat() (os.FileInfo, error)
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ReadAt([]byte, int64) (int, error)
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WriteAt([]byte, int64) (int, error)
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Delete() error
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}
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// Creates a io.ReadSeeker to an Instance.
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func ReadSeeker(r Instance) io.ReadSeeker {
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fi, err := r.Stat()
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if err != nil {
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return nil
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}
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return io.NewSectionReader(r, 0, fi.Size())
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}
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// Move instance content, deleting the source if it succeeds.
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func Move(from, to Instance) (err error) {
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rc, err := from.Get()
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if err != nil {
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return
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}
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defer rc.Close()
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err = to.Put(rc)
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if err != nil {
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return
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}
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from.Delete()
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return
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}
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func Exists(i Instance) bool {
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_, err := i.Stat()
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return err == nil
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}
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