Replace Set.Values with a non-allocating Set.All

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

copy/single.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"iter"
 	"maps"
 	"reflect"
 	"slices"
@@ -417,7 +418,7 @@ func (ic *imageCopier) compareImageDestinationManifestEqual(ctx context.Context,
 		}
 	}
 
-	algos, err := algorithmsByNames(compressionAlgos.Values())
+	algos, err := algorithmsByNames(compressionAlgos.All())
 	if err != nil {
 		return nil, err
 	}
@@ -552,7 +553,7 @@ func (ic *imageCopier) copyLayers(ctx context.Context) ([]compressiontypes.Algor
 	if srcInfosUpdated || layerDigestsDiffer(srcInfos, destInfos) {
 		ic.manifestUpdates.LayerInfos = destInfos
 	}
-	algos, err := algorithmsByNames(compressionAlgos.Values())
+	algos, err := algorithmsByNames(compressionAlgos.All())
 	if err != nil {
 		return nil, err
 	}
@@ -988,10 +989,10 @@ func computeDiffID(stream io.Reader, decompressor compressiontypes.DecompressorF
 	return digest.Canonical.FromReader(stream)
 }
 
-// algorithmsByNames returns slice of Algorithms from slice of Algorithm Names
-func algorithmsByNames(names []string) ([]compressiontypes.Algorithm, error) {
+// algorithmsByNames returns slice of Algorithms from a sequence of Algorithm Names
+func algorithmsByNames(names iter.Seq[string]) ([]compressiontypes.Algorithm, error) {
 	result := []compressiontypes.Algorithm{}
-	for _, name := range names {
+	for name := range names {
 		algo, err := compression.AlgorithmByName(name)
 		if err != nil {
 			return nil, err

internal/set/set.go

@@ -1,6 +1,10 @@
 package set
 
-import "golang.org/x/exp/maps"
+import (
+	"iter"
+
+	"golang.org/x/exp/maps"
+)
 
 // FIXME:
 // - Docstrings
@@ -47,6 +51,12 @@ func (s *Set[E]) Empty() bool {
 	return len(s.m) == 0
 }
 
-func (s *Set[E]) Values() []E {
-	return maps.Keys(s.m)
+func (s *Set[E]) All() iter.Seq[E] {
+	return func(yield func(E) bool) {
+		for _, v := range maps.Keys(s.m) {
+			if !yield(v) {
+				return
+			}
+		}
+	}
 }

internal/set/set_test.go

@@ -1,6 +1,7 @@
 package set
 
 import (
+	"slices"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -26,7 +27,7 @@ func TestAdd(t *testing.T) {
 	s.Add(2) // Adding an already-present element
 	assert.True(t, s.Contains(2))
 	// should not contain duplicate value of `2`
-	assert.ElementsMatch(t, []int{1, 2}, s.Values())
+	assert.ElementsMatch(t, []int{1, 2}, slices.Collect(s.All()))
 	// Unrelated elements are unaffected
 	assert.True(t, s.Contains(1))
 	assert.False(t, s.Contains(3))
@@ -36,7 +37,7 @@ func TestAddSlice(t *testing.T) {
 	s := NewWithValues(1)
 	s.Add(2)
 	s.AddSlice([]int{3, 4})
-	assert.ElementsMatch(t, []int{1, 2, 3, 4}, s.Values())
+	assert.ElementsMatch(t, []int{1, 2, 3, 4}, slices.Collect(s.All()))
 }
 
 func TestDelete(t *testing.T) {
@@ -66,12 +67,20 @@ func TestEmpty(t *testing.T) {
 	assert.True(t, s.Empty())
 }
 
-func TestValues(t *testing.T) {
+func TestAll(t *testing.T) {
 	s := New[int]()
-	assert.Empty(t, s.Values())
+	assert.Empty(t, slices.Collect(s.All()))
 	s.Add(1)
 	s.Add(2)
 	// ignore duplicate
 	s.Add(2)
-	assert.ElementsMatch(t, []int{1, 2}, s.Values())
+	assert.ElementsMatch(t, []int{1, 2}, slices.Collect(s.All()))
+	// Break / return inside the range body (yield function returning false) works
+	var partial []int
+	for v := range s.All() {
+		partial = append(partial, v)
+		break
+	}
+	assert.Len(t, partial, 1)
+	assert.True(t, partial[0] == 1 || partial[0] == 2)
 }

oci/layout/oci_delete.go

@@ -123,7 +123,7 @@ func (ref ociReference) getBlobsToDelete(blobsUsedByDescriptorToDelete map[diges
 //
 // So, NOTE: the blobPath() call below hard-codes "" even in calls where OCISharedBlobDirPath is set
 func (ref ociReference) deleteBlobs(blobsToDelete *set.Set[digest.Digest]) error {
-	for _, digest := range blobsToDelete.Values() {
+	for digest := range blobsToDelete.All() {
 		blobPath, err := ref.blobPath(digest, "") //Only delete in the local directory, see comment above
 		if err != nil {
 			return err

pkg/blobinfocache/memory/memory.go

@@ -240,7 +240,7 @@ func (mem *cache) candidateLocations(transport types.ImageTransport, scope types
 		if uncompressedDigest = mem.uncompressedDigestLocked(primaryDigest); uncompressedDigest != "" {
 			otherDigests := mem.digestsByUncompressed[uncompressedDigest] // nil if not present in the map
 			if otherDigests != nil {
-				for _, d := range otherDigests.Values() {
+				for d := range otherDigests.All() {
 					if d != primaryDigest && d != uncompressedDigest {
 						res = mem.appendReplacementCandidates(res, transport, scope, d, v2Options)
 					}

pkg/docker/config/config.go

@@ -124,7 +124,7 @@ func GetAllCredentials(sys *types.SystemContext) (map[string]types.DockerAuthCon
 	// Now use `GetCredentials` to the specific auth configs for each
 	// previously listed registry.
 	allCreds := make(map[string]types.DockerAuthConfig)
-	for _, key := range allKeys.Values() {
+	for key := range allKeys.All() {
 		creds, err := GetCredentials(sys, key)
 		if err != nil {
 			// Note: we rely on the logging in `GetCredentials`.