dotcloud/docker

package containerd

import (
    "github.com/containerd/platforms"
    ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)

type allPlatformsWithPreferenceMatcher struct {
    preferred platforms.MatchComparer
}

// matchAllWithPreference will return a platform matcher that matches all
// platforms but will order platforms matching the preferred matcher first.
func matchAllWithPreference(preferred platforms.MatchComparer) platforms.MatchComparer {
    return allPlatformsWithPreferenceMatcher{
        preferred: preferred,
    }
}

func (c allPlatformsWithPreferenceMatcher) Match(_ ocispec.Platform) bool {
    return true
}

func (c allPlatformsWithPreferenceMatcher) Less(p1, p2 ocispec.Platform) bool {
    return c.preferred.Less(p1, p2)
}

// platformMatcherWithRequestedPlatform is a platform matcher that also
// contains the platform that was requested by the user in the context
// in which the matcher was created.
type platformMatcherWithRequestedPlatform struct {
    Requested *ocispec.Platform

    platforms.MatchComparer
}

type matchComparerProvider func(ocispec.Platform) platforms.MatchComparer

func (i *ImageService) matchRequestedOrDefault(
    fpm matchComparerProvider, // function to create a platform matcher if platform is not nil
    platform *ocispec.Platform, // input platform, nil if not specified
) platformMatcherWithRequestedPlatform {
    var inner platforms.MatchComparer
    if platform == nil {
        inner = matchAllWithPreference(i.hostPlatformMatcher())
    } else {
        inner = fpm(*platform)
    }

    return platformMatcherWithRequestedPlatform{
        Requested:     platform,
        MatchComparer: inner,
    }
}

func (i *ImageService) hostPlatformMatcher() platforms.MatchComparer {
    // Allow to override the host platform for testing purposes.
    if i.defaultPlatformOverride != nil {
        return i.defaultPlatformOverride
    }
    return platforms.Default()
}