cri-o/vendor/github.com/containers/image/image/sourced.go
Jonathan Yu 6c9628cdb1
Build and install from GOPATH
* Rename 'vendor/src' -> 'vendor'
  * Ignore vendor/ instead of vendor/src/ for lint
* Rename 'cmd/client' -> 'cmd/ocic' to make it 'go install'able
* Rename 'cmd/server' -> 'cmd/ocid' to make it 'go install'able
* Update Makefile to build and install from GOPATH
* Update tests to locate ocid/ocic in GOPATH/bin
* Search for binaries in GOPATH/bin instead of PATH
* Install tools using `go get -u`, so they are updated on each run

Signed-off-by: Jonathan Yu <jawnsy@redhat.com>
2017-01-17 12:09:09 -08:00

90 lines
3.8 KiB
Go

// Package image consolidates knowledge about various container image formats
// (as opposed to image storage mechanisms, which are handled by types.ImageSource)
// and exposes all of them using an unified interface.
package image
import (
"github.com/containers/image/manifest"
"github.com/containers/image/types"
)
// FromSource returns a types.Image implementation for source.
// The caller must call .Close() on the returned Image.
//
// FromSource “takes ownership” of the input ImageSource and will call src.Close()
// when the image is closed. (This does not prevent callers from using both the
// Image and ImageSource objects simultaneously, but it means that they only need to
// the Image.)
//
// NOTE: If any kind of signature verification should happen, build an UnparsedImage from the value returned by NewImageSource,
// verify that UnparsedImage, and convert it into a real Image via image.FromUnparsedImage instead of calling this function.
func FromSource(src types.ImageSource) (types.Image, error) {
return FromUnparsedImage(UnparsedFromSource(src))
}
// sourcedImage is a general set of utilities for working with container images,
// whatever is their underlying location (i.e. dockerImageSource-independent).
// Note the existence of skopeo/docker.Image: some instances of a `types.Image`
// may not be a `sourcedImage` directly. However, most users of `types.Image`
// do not care, and those who care about `skopeo/docker.Image` know they do.
type sourcedImage struct {
*UnparsedImage
manifestBlob []byte
manifestMIMEType string
// genericManifest contains data corresponding to manifestBlob.
// NOTE: The manifest may have been modified in the process; DO NOT reserialize and store genericManifest
// if you want to preserve the original manifest; use manifestBlob directly.
genericManifest
}
// FromUnparsedImage returns a types.Image implementation for unparsed.
// The caller must call .Close() on the returned Image.
//
// FromSource “takes ownership” of the input UnparsedImage and will call uparsed.Close()
// when the image is closed. (This does not prevent callers from using both the
// UnparsedImage and ImageSource objects simultaneously, but it means that they only need to
// keep a reference to the Image.)
func FromUnparsedImage(unparsed *UnparsedImage) (types.Image, error) {
// Note that the input parameter above is specifically *image.UnparsedImage, not types.UnparsedImage:
// we want to be able to use unparsed.src. We could make that an explicit interface, but, well,
// this is the only UnparsedImage implementation around, anyway.
// Also, we do not explicitly implement types.Image.Close; we let the implementation fall through to
// unparsed.Close.
// NOTE: It is essential for signature verification that all parsing done in this object happens on the same manifest which is returned by unparsed.Manifest().
manifestBlob, manifestMIMEType, err := unparsed.Manifest()
if err != nil {
return nil, err
}
parsedManifest, err := manifestInstanceFromBlob(unparsed.src, manifestBlob, manifestMIMEType)
if err != nil {
return nil, err
}
return &sourcedImage{
UnparsedImage: unparsed,
manifestBlob: manifestBlob,
manifestMIMEType: manifestMIMEType,
genericManifest: parsedManifest,
}, nil
}
// Size returns the size of the image as stored, if it's known, or -1 if it isn't.
func (i *sourcedImage) Size() (int64, error) {
return -1, nil
}
// Manifest overrides the UnparsedImage.Manifest to always use the fields which we have already fetched.
func (i *sourcedImage) Manifest() ([]byte, string, error) {
return i.manifestBlob, i.manifestMIMEType, nil
}
func (i *sourcedImage) Inspect() (*types.ImageInspectInfo, error) {
return inspectManifest(i.genericManifest)
}
func (i *sourcedImage) IsMultiImage() bool {
return i.manifestMIMEType == manifest.DockerV2ListMediaType
}