8be340e37b
After some analysis, it was found that Content.Reader was generally redudant to an io.ReaderAt. This change removes `Content.Reader` in favor of a `Content.ReaderAt`. In general, `ReaderAt` can perform better over interfaces with indeterminant latency because it avoids remote state for reads. Where a reader is required, a helper is provided to convert it into an `io.SectionReader`. Signed-off-by: Stephen J Day <stephen.day@docker.com>
50 lines
906 B
Go
50 lines
906 B
Go
package content
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import (
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"context"
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contentapi "github.com/containerd/containerd/api/services/content/v1"
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digest "github.com/opencontainers/go-digest"
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)
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type remoteReaderAt struct {
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ctx context.Context
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digest digest.Digest
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size int64
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client contentapi.ContentClient
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}
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func (ra *remoteReaderAt) Size() int64 {
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return ra.size
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}
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func (ra *remoteReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
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rr := &contentapi.ReadContentRequest{
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Digest: ra.digest,
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Offset: off,
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Size_: int64(len(p)),
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}
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rc, err := ra.client.Read(ra.ctx, rr)
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if err != nil {
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return 0, err
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}
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for len(p) > 0 {
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var resp *contentapi.ReadContentResponse
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// fill our buffer up until we can fill p.
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resp, err = rc.Recv()
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if err != nil {
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return n, err
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}
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copied := copy(p, resp.Data)
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n += copied
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p = p[copied:]
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}
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return n, nil
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}
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func (rr *remoteReaderAt) Close() error {
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return nil
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}
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