github.com/mika/distribution@v2.2.2-0.20160108133430-a75790e3d8e0+incompatible/registry/storage/cache/cache.go (about)

     1  // Package cache provides facilities to speed up access to the storage
     2  // backend.
     3  package cache
     4  
     5  import (
     6  	"fmt"
     7  
     8  	"github.com/docker/distribution"
     9  )
    10  
    11  // BlobDescriptorCacheProvider provides repository scoped
    12  // BlobDescriptorService cache instances and a global descriptor cache.
    13  type BlobDescriptorCacheProvider interface {
    14  	distribution.BlobDescriptorService
    15  
    16  	RepositoryScoped(repo string) (distribution.BlobDescriptorService, error)
    17  }
    18  
    19  // ValidateDescriptor provides a helper function to ensure that caches have
    20  // common criteria for admitting descriptors.
    21  func ValidateDescriptor(desc distribution.Descriptor) error {
    22  	if err := desc.Digest.Validate(); err != nil {
    23  		return err
    24  	}
    25  
    26  	if desc.Size < 0 {
    27  		return fmt.Errorf("cache: invalid length in descriptor: %v < 0", desc.Size)
    28  	}
    29  
    30  	if desc.MediaType == "" {
    31  		return fmt.Errorf("cache: empty mediatype on descriptor: %v", desc)
    32  	}
    33  
    34  	return nil
    35  }