perf: use new built-in methods introduced before go 1.22 (#726)

Changes:
* chore: use built-in slices
* perf: use built-in map clone
* chore: use built-in map copy
* perf: use slices.Sort instead of sort.Strings

Resolves: #713

---------

Signed-off-by: Shiwei Zhang <shizh@microsoft.com>

content/oci/oci.go

@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"os"
 	"path"
 	"path/filepath"
@@ -333,7 +334,7 @@ func (s *Store) Tags(ctx context.Context, last string, fn func(tags []string) er
 	s.sync.RLock()
 	defer s.sync.RUnlock()
 
-	return listTags(ctx, s.tagResolver, last, fn)
+	return listTags(s.tagResolver, last, fn)
 }
 
 // ensureOCILayoutFile ensures the `oci-layout` file.
@@ -418,9 +419,7 @@ func (s *Store) saveIndex() error {
 	for ref, desc := range refMap {
 		if ref != desc.Digest.String() {
 			annotations := make(map[string]string, len(desc.Annotations)+1)
-			for k, v := range desc.Annotations {
-				annotations[k] = v
-			}
+			maps.Copy(annotations, desc.Annotations)
 			annotations[ocispec.AnnotationRefName] = ref
 			desc.Annotations = annotations
 			manifests = append(manifests, desc)

content/oci/readonlyoci.go

@@ -22,7 +22,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"sort"
+	"slices"
 
 	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
@@ -125,7 +125,7 @@ func (s *ReadOnlyStore) Predecessors(ctx context.Context, node ocispec.Descripto
 //
 // See also `Tags()` in the package `registry`.
 func (s *ReadOnlyStore) Tags(ctx context.Context, last string, fn func(tags []string) error) error {
-	return listTags(ctx, s.tagResolver, last, fn)
+	return listTags(s.tagResolver, last, fn)
 }
 
 // validateOCILayoutFile validates the `oci-layout` file.
@@ -216,7 +216,7 @@ func resolveBlob(fsys fs.FS, dgst string) (ocispec.Descriptor, error) {
 // list.
 //
 // See also `Tags()` in the package `registry`.
-func listTags(ctx context.Context, tagResolver *resolver.Memory, last string, fn func(tags []string) error) error {
+func listTags(tagResolver *resolver.Memory, last string, fn func(tags []string) error) error {
 	var tags []string
 
 	tagMap := tagResolver.Map()
@@ -229,7 +229,7 @@ func listTags(ctx context.Context, tagResolver *resolver.Memory, last string, fn
 		}
 		tags = append(tags, tag)
 	}
-	sort.Strings(tags)
+	slices.Sort(tags)
 
 	return fn(tags)
 }

internal/resolver/memory.go

@@ -17,6 +17,7 @@ package resolver
 
 import (
 	"context"
+	"maps"
 	"sync"
 
 	"github.com/opencontainers/go-digest"
@@ -90,11 +91,7 @@ func (m *Memory) Map() map[string]ocispec.Descriptor {
 	m.lock.RLock()
 	defer m.lock.RUnlock()
 
-	res := make(map[string]ocispec.Descriptor, len(m.index))
-	for key, value := range m.index {
-		res[key] = value
-	}
-	return res
+	return maps.Clone(m.index)
 }
 
 // TagSet returns the set of tags of the descriptor.
@@ -103,9 +100,5 @@ func (m *Memory) TagSet(desc ocispec.Descriptor) set.Set[string] {
 	defer m.lock.RUnlock()
 
 	tagSet := m.tags[desc.Digest]
-	res := make(set.Set[string], len(tagSet))
-	for tag := range tagSet {
-		res.Add(tag)
-	}
-	return res
+	return maps.Clone(tagSet)
 }

pack.go

@@ -21,6 +21,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"maps"
 	"regexp"
 	"time"
 
@@ -420,9 +421,8 @@ func ensureAnnotationCreated(annotations map[string]string, annotationCreatedKey
 
 	// copy the original annotation map
 	copied := make(map[string]string, len(annotations)+1)
-	for k, v := range annotations {
-		copied[k] = v
-	}
+	maps.Copy(copied, annotations)
+
 	// set creation time in RFC 3339 format
 	// reference: https://github.com/opencontainers/image-spec/blob/v1.1.0-rc2/annotations.md#pre-defined-annotation-keys
 	now := time.Now().UTC()

registry/remote/auth/scope.go

@@ -17,10 +17,9 @@ package auth
 
 import (
 	"context"
-	"sort"
+	"slices"
 	"strings"
 
-	"oras.land/oras-go/v2/internal/slices"
 	"oras.land/oras-go/v2/registry"
 )
 
@@ -276,14 +275,14 @@ func CleanScopes(scopes []string) []string {
 				}
 				actions = append(actions, action)
 			}
-			sort.Strings(actions)
+			slices.Sort(actions)
 			scope := resourceType + ":" + resourceName + ":" + strings.Join(actions, ",")
 			result = append(result, scope)
 		}
 	}
 
 	// sort and return
-	sort.Strings(result)
+	slices.Sort(result)
 	return result
 }
 
@@ -302,7 +301,7 @@ func cleanActions(actions []string) []string {
 	}
 
 	// slow path
-	sort.Strings(actions)
+	slices.Sort(actions)
 	n := 0
 	for i := 0; i < len(actions); i++ {
 		if actions[i] == "*" {

registry/remote/repository.go

@@ -24,6 +24,7 @@ import (
 	"io"
 	"mime"
 	"net/http"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -37,7 +38,6 @@ import (
 	"oras.land/oras-go/v2/internal/cas"
 	"oras.land/oras-go/v2/internal/httputil"
 	"oras.land/oras-go/v2/internal/ioutil"
-	"oras.land/oras-go/v2/internal/slices"
 	"oras.land/oras-go/v2/internal/spec"
 	"oras.land/oras-go/v2/internal/syncutil"
 	"oras.land/oras-go/v2/registry"