dotcloud/docker

//go:build !windows

package distribution // import "github.com/docker/docker/distribution"

import (
    "context"
    "sort"

    "github.com/containerd/log"
    "github.com/containerd/platforms"
    "github.com/docker/distribution"
    "github.com/docker/distribution/manifest/manifestlist"
    ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)

func (ld *layerDescriptor) open(ctx context.Context) (distribution.ReadSeekCloser, error) {
    blobs := ld.repo.Blobs(ctx)
    return blobs.Open(ctx, ld.digest)
}

func filterManifests(manifests []manifestlist.ManifestDescriptor, p ocispec.Platform) []manifestlist.ManifestDescriptor {
    p = platforms.Normalize(withDefault(p))
    m := platforms.Only(p)
    var matches []manifestlist.ManifestDescriptor
    for _, desc := range manifests {
        descP := toOCIPlatform(desc.Platform)
        if descP == nil || m.Match(*descP) {
            matches = append(matches, desc)
            if descP != nil {
                log.G(context.TODO()).Debugf("found match for %s with media type %s, digest %s", platforms.Format(p), desc.MediaType, desc.Digest.String())
            }
        }
    }

    sort.SliceStable(matches, func(i, j int) bool {
        p1 := toOCIPlatform(matches[i].Platform)
        if p1 == nil {
            return false
        }
        p2 := toOCIPlatform(matches[j].Platform)
        if p2 == nil {
            return true
        }
        return m.Less(*p1, *p2)
    })

    return matches
}

// checkImageCompatibility is a Windows-specific function. No-op on Linux
func checkImageCompatibility(imageOS, imageOSVersion string) error {
    return nil
}

func withDefault(p ocispec.Platform) ocispec.Platform {
    def := maximumSpec()
    if p.OS == "" {
        p.OS = def.OS
    }
    if p.Architecture == "" {
        p.Architecture = def.Architecture
        p.Variant = def.Variant
    }
    return p
}

func formatPlatform(platform ocispec.Platform) string {
    if platform.OS == "" {
        platform = platforms.DefaultSpec()
    }
    return platforms.Format(platform)
}