imagetools inspect: add --format flag

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/moby/buildkit/util/contentutil/multiprovider.go

@@ -0,0 +1,92 @@
+package contentutil
+
+import (
+	"context"
+	"sync"
+
+	"github.com/containerd/containerd/content"
+	"github.com/containerd/containerd/errdefs"
+	digest "github.com/opencontainers/go-digest"
+	ocispecs "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+// NewMultiProvider creates a new mutable provider with a base provider
+func NewMultiProvider(base content.Provider) *MultiProvider {
+	return &MultiProvider{
+		base: base,
+		sub:  map[digest.Digest]content.Provider{},
+	}
+}
+
+// MultiProvider is a provider backed by a mutable map of providers
+type MultiProvider struct {
+	mu   sync.RWMutex
+	base content.Provider
+	sub  map[digest.Digest]content.Provider
+}
+
+func (mp *MultiProvider) SnapshotLabels(descs []ocispecs.Descriptor, index int) map[string]string {
+	if len(descs) < index {
+		return nil
+	}
+	desc := descs[index]
+	type snapshotLabels interface {
+		SnapshotLabels([]ocispecs.Descriptor, int) map[string]string
+	}
+
+	mp.mu.RLock()
+	if p, ok := mp.sub[desc.Digest]; ok {
+		mp.mu.RUnlock()
+		if cd, ok := p.(snapshotLabels); ok {
+			return cd.SnapshotLabels(descs, index)
+		}
+	} else {
+		mp.mu.RUnlock()
+	}
+	if cd, ok := mp.base.(snapshotLabels); ok {
+		return cd.SnapshotLabels(descs, index)
+	}
+	return nil
+}
+
+func (mp *MultiProvider) CheckDescriptor(ctx context.Context, desc ocispecs.Descriptor) error {
+	type checkDescriptor interface {
+		CheckDescriptor(context.Context, ocispecs.Descriptor) error
+	}
+
+	mp.mu.RLock()
+	if p, ok := mp.sub[desc.Digest]; ok {
+		mp.mu.RUnlock()
+		if cd, ok := p.(checkDescriptor); ok {
+			return cd.CheckDescriptor(ctx, desc)
+		}
+	} else {
+		mp.mu.RUnlock()
+	}
+	if cd, ok := mp.base.(checkDescriptor); ok {
+		return cd.CheckDescriptor(ctx, desc)
+	}
+	return nil
+}
+
+// ReaderAt returns a content.ReaderAt
+func (mp *MultiProvider) ReaderAt(ctx context.Context, desc ocispecs.Descriptor) (content.ReaderAt, error) {
+	mp.mu.RLock()
+	if p, ok := mp.sub[desc.Digest]; ok {
+		mp.mu.RUnlock()
+		return p.ReaderAt(ctx, desc)
+	}
+	mp.mu.RUnlock()
+	if mp.base == nil {
+		return nil, errors.Wrapf(errdefs.ErrNotFound, "content %v", desc.Digest)
+	}
+	return mp.base.ReaderAt(ctx, desc)
+}
+
+// Add adds a new child provider for a specific digest
+func (mp *MultiProvider) Add(dgst digest.Digest, p content.Provider) {
+	mp.mu.Lock()
+	defer mp.mu.Unlock()
+	mp.sub[dgst] = p
+}