49 lines
1.2 KiB
Go
49 lines
1.2 KiB
Go
package contentutil
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import (
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"context"
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"sync"
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"github.com/containerd/containerd/content"
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"github.com/containerd/containerd/errdefs"
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digest "github.com/opencontainers/go-digest"
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ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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"github.com/pkg/errors"
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)
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// NewMultiProvider creates a new mutable provider with a base provider
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func NewMultiProvider(base content.Provider) *MultiProvider {
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return &MultiProvider{
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base: base,
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sub: map[digest.Digest]content.Provider{},
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}
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}
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// MultiProvider is a provider backed by a mutable map of providers
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type MultiProvider struct {
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mu sync.RWMutex
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base content.Provider
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sub map[digest.Digest]content.Provider
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}
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// ReaderAt returns a content.ReaderAt
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func (mp *MultiProvider) ReaderAt(ctx context.Context, desc ocispec.Descriptor) (content.ReaderAt, error) {
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mp.mu.RLock()
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if p, ok := mp.sub[desc.Digest]; ok {
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mp.mu.RUnlock()
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return p.ReaderAt(ctx, desc)
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}
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mp.mu.RUnlock()
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if mp.base == nil {
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return nil, errors.Wrapf(errdefs.ErrNotFound, "content %v", desc.Digest)
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}
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return mp.base.ReaderAt(ctx, desc)
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}
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// Add adds a new child provider for a specific digest
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func (mp *MultiProvider) Add(dgst digest.Digest, p content.Provider) {
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mp.mu.Lock()
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defer mp.mu.Unlock()
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mp.sub[dgst] = p
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}
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