53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
package content
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import (
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"io"
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"os"
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"github.com/opencontainers/go-digest"
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"github.com/pkg/errors"
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)
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// OpenBlob opens the blob for reading identified by dgst.
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//
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// The opened blob may also implement seek. Callers can detect with io.Seeker.
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func OpenBlob(cs *ContentStore, dgst digest.Digest) (io.ReadCloser, error) {
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path, err := cs.GetPath(dgst)
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if err != nil {
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return nil, err
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}
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fp, err := os.Open(path)
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return fp, err
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}
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// WriteBlob writes data with the expected digest into the content store. If
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// expected already exists, the method returns immediately and the reader will
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// not be consumed.
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//
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// This is useful when the digest and size are known beforehand.
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//
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// Copy is buffered, so no need to wrap reader in buffered io.
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func WriteBlob(cs *ContentStore, r io.Reader, size int64, expected digest.Digest) error {
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cw, err := cs.Begin(expected.Hex())
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if err != nil {
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return err
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}
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buf := bufPool.Get().([]byte)
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defer bufPool.Put(buf)
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nn, err := io.CopyBuffer(cw, r, buf)
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if err != nil {
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return err
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}
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if nn != size {
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return errors.Errorf("failed size verification: %v != %v", nn, size)
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}
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if err := cw.Commit(size, expected); err != nil {
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return err
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}
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return nil
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}
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