76 lines
1.4 KiB
Go
76 lines
1.4 KiB
Go
package content
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import (
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"context"
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"io"
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contentapi "github.com/docker/containerd/api/services/content"
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"github.com/docker/containerd/content"
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digest "github.com/opencontainers/go-digest"
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)
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func NewProviderFromClient(client contentapi.ContentClient) content.Provider {
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return &remoteProvider{
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client: client,
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}
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}
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type remoteProvider struct {
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client contentapi.ContentClient
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}
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func (rp *remoteProvider) Reader(ctx context.Context, dgst digest.Digest) (io.ReadCloser, error) {
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client, err := rp.client.Read(ctx, &contentapi.ReadRequest{Digest: dgst})
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if err != nil {
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return nil, err
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}
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return &remoteReader{
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client: client,
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}, nil
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}
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type remoteReader struct {
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client contentapi.Content_ReadClient
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extra []byte
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}
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func (rr *remoteReader) Read(p []byte) (n int, err error) {
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n += copy(p, rr.extra)
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if n >= len(p) {
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if n <= len(rr.extra) {
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rr.extra = rr.extra[n:]
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} else {
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rr.extra = rr.extra[:0]
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}
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return
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}
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p = p[n:]
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for len(p) > 0 {
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var resp *contentapi.ReadResponse
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// fill our buffer up until we can fill p.
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resp, err = rr.client.Recv()
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if err != nil {
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return
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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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if copied < len(p) {
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continue
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}
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rr.extra = append(rr.extra, resp.Data[copied:]...)
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}
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return
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}
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// TODO(stevvooe): Implemente io.ReaderAt.
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func (rr *remoteReader) Close() error {
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return rr.client.CloseSend()
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}
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