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|
//go:build !remote
package libimage
import (
"context"
ociv1 "github.com/opencontainers/image-spec/specs-go/v1"
)
// toOCI returns the image as OCI v1 image.
func (i *Image) toOCI(ctx context.Context) (*ociv1.Image, error) {
if i.cached.ociv1Image != nil {
return i.cached.ociv1Image, nil
}
ref, err := i.StorageReference()
if err != nil {
return nil, err
}
img, err := ref.NewImage(ctx, i.runtime.systemContextCopy())
if err != nil {
return nil, err
}
defer img.Close()
return img.OCIConfig(ctx)
}
// historiesMatch returns the number of entries in the histories which have the
// same contents
func historiesMatch(a, b []ociv1.History) int {
i := 0
for i < len(a) && i < len(b) {
if a[i].Created != nil && b[i].Created == nil {
return i
}
if a[i].Created == nil && b[i].Created != nil {
return i
}
if a[i].Created != nil && b[i].Created != nil {
if !a[i].Created.Equal(*(b[i].Created)) {
return i
}
}
if a[i].CreatedBy != b[i].CreatedBy {
return i
}
if a[i].Author != b[i].Author {
return i
}
if a[i].Comment != b[i].Comment {
return i
}
if a[i].EmptyLayer != b[i].EmptyLayer {
return i
}
i++
}
return i
}
// areParentAndChild checks diff ID and history in the two images and return
// true if the second should be considered to be directly based on the first
func areParentAndChild(parent, child *ociv1.Image) bool {
// the child and candidate parent should share all of the
// candidate parent's diff IDs, which together would have
// controlled which layers were used
// Both, child and parent, may be nil when the storage is left in an
// incoherent state. Issue #7444 describes such a case when a build
// has been killed.
if child == nil || parent == nil {
return false
}
if len(parent.RootFS.DiffIDs) > len(child.RootFS.DiffIDs) {
return false
}
childUsesCandidateDiffs := true
for i := range parent.RootFS.DiffIDs {
if child.RootFS.DiffIDs[i] != parent.RootFS.DiffIDs[i] {
childUsesCandidateDiffs = false
break
}
}
if !childUsesCandidateDiffs {
return false
}
// the child should have the same history as the parent, plus
// one more entry
if len(parent.History)+1 != len(child.History) {
return false
}
if historiesMatch(parent.History, child.History) != len(parent.History) {
return false
}
return true
}
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