all: use range over iterators

Now that we're requiring go 1.23, we can use iterator range.

Signed-off-by: Roger Peppe <[email protected]>
Change-Id: I57880294291d4b269199769cf91eedce29249f62
Reviewed-on: https://review.gerrithub.io/c/cue-labs/oci/+/1209150
TryBot-Result: CUE porcuepine <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>

Author: rogpeppe

ociregistry/iter.go

@@ -14,26 +14,23 @@
 
 package ociregistry
 
-// TODO(go1.23) when we can depend on Go 1.23, this should be:
+// TODO(go1.24) when we can depend on Go 1.24, this should be:
 // type Seq[T any] = iter.Seq2[T, error]
 
 // Seq defines the type of an iterator sequence returned from
 // the iterator functions. In general, a non-nil
 // error means that the item is the last in the sequence.
 type Seq[T any] func(yield func(T, error) bool)
 
-func All[T any](it Seq[T]) (_ []T, _err error) {
+func All[T any](it Seq[T]) ([]T, error) {
 	xs := []T{}
-	// TODO(go1.23) for x, err := range it
-	it(func(x T, err error) bool {
+	for x, err := range it {
 		if err != nil {
-			_err = err
-			return false
+			return nil, err
 		}
 		xs = append(xs, x)
-		return true
-	})
-	return xs, _err
+	}
+	return xs, nil
 }
 
 func SliceSeq[T any](xs []T) Seq[T] {

ociregistry/iter_test.go

@@ -1,5 +1,3 @@
-//go:build go1.23
-
 package ociregistry
 
 import (

ociregistry/ocidebug/debug.go

@@ -262,18 +262,17 @@ func logIterReturn[T any](r *logger, initialMsg string, it ociregistry.Seq[T]) o
 		r.logf("%s {", initialMsg)
 		items := []T{}
 		var _err error
-		it(func(item T, err error) bool {
+		for item, err := range it {
 			if err != nil {
 				yield(*new(T), err)
 				_err = err
-				return false
+				break
 			}
-			ok := yield(item, err)
-			if ok {
-				items = append(items, item)
+			if !yield(item, nil) {
+				break
 			}
-			return ok
-		})
+			items = append(items, item)
+		}
 		if _err != nil {
 			if len(items) > 0 {
 				r.logf("} -> %#v, %v", items, _err)

ociregistry/ocifilter/select.go

@@ -198,17 +198,18 @@ func (r *accessCheckerRegistry) Repositories(ctx context.Context, startAfter str
 		return ociregistry.ErrorSeq[string](err)
 	}
 	return func(yield func(string, error) bool) {
-		// TODO(go1.23): for name, err := range r.r.Repositories(ctx)
-		r.r.Repositories(ctx, startAfter)(func(repo string, err error) bool {
+		for repo, err := range r.r.Repositories(ctx, startAfter) {
 			if err != nil {
 				yield("", err)
-				return false
+				break
 			}
 			if r.check(repo, AccessRead) != nil {
-				return true
+				continue
 			}
-			return yield(repo, nil)
-		})
+			if !yield(repo, nil) {
+				break
+			}
+		}
 	}
 }
 

ociregistry/ocifilter/sub.go

@@ -143,17 +143,15 @@ func (r *subRegistry) Repositories(ctx context.Context, startAfter string) ocire
 	ctx = r.mapScopes(ctx)
 	p := r.prefix + "/"
 	return func(yield func(string, error) bool) {
-		// TODO(go1.23): for name, err := range r.r.Repositories(ctx)
-		r.r.Repositories(ctx, startAfter)(func(repo string, err error) bool {
+		for repo, err := range r.r.Repositories(ctx, startAfter) {
 			if err != nil {
 				yield("", err)
-				return false
+				break
 			}
-			if p, ok := strings.CutPrefix(repo, p); ok {
-				return yield(p, nil)
+			if p, ok := strings.CutPrefix(repo, p); ok && !yield(p, nil) {
+				break
 			}
-			return true
-		})
+		}
 	}
 }
 
@@ -178,13 +176,12 @@ func (r *subRegistry) mapScopes(ctx context.Context) context.Context {
 	// that took an iterator, which could avoid the intermediate
 	// slice allocation.
 	scopes := make([]ociauth.ResourceScope, 0, scope.Len())
-	scope.Iter()(func(rs ociauth.ResourceScope) bool {
+	for rs := range scope.Iter() {
 		if rs.ResourceType == ociauth.TypeRepository {
 			rs.Resource = r.repo(rs.Resource)
 		}
 		scopes = append(scopes, rs)
-		return true
-	})
+	}
 	return ociauth.ContextWithScope(ctx, ociauth.NewScope(scopes...))
 }
 

ociregistry/ociserver/lister.go

@@ -80,7 +80,7 @@ func (r *registry) handleCatalogList(ctx context.Context, resp http.ResponseWrit
 }
 
 // TODO: implement handling of artifactType querystring
-func (r *registry) handleReferrersList(ctx context.Context, resp http.ResponseWriter, req *http.Request, rreq *ocirequest.Request) (_err error) {
+func (r *registry) handleReferrersList(ctx context.Context, resp http.ResponseWriter, req *http.Request, rreq *ocirequest.Request) error {
 	if r.opts.DisableReferrersAPI {
 		return withHTTPCode(http.StatusNotFound, fmt.Errorf("referrers API has been disabled"))
 	}
@@ -91,18 +91,11 @@ func (r *registry) handleReferrersList(ctx context.Context, resp http.ResponseWr
 	}
 
 	// TODO support artifactType filtering
-	it := r.backend.Referrers(ctx, rreq.Repo, ociregistry.Digest(rreq.Digest), "")
-	// TODO(go1.23) for desc, err := range it {
-	it(func(desc ociregistry.Descriptor, err error) bool {
+	for desc, err := range r.backend.Referrers(ctx, rreq.Repo, ociregistry.Digest(rreq.Digest), "") {
 		if err != nil {
-			_err = err
-			return false
+			return err
 		}
 		im.Manifests = append(im.Manifests, desc)
-		return true
-	})
-	if _err != nil {
-		return _err
 	}
 	msg, err := json.Marshal(im)
 	if err != nil {
@@ -115,7 +108,7 @@ func (r *registry) handleReferrersList(ctx context.Context, resp http.ResponseWr
 	return nil
 }
 
-func (r *registry) nextListResults(req *http.Request, rreq *ocirequest.Request, itemsIter ociregistry.Seq[string]) (items []string, link string, _err error) {
+func (r *registry) nextListResults(req *http.Request, rreq *ocirequest.Request, itemsIter ociregistry.Seq[string]) (items []string, link string, _ error) {
 	if r.opts.MaxListPageSize > 0 && rreq.ListN > r.opts.MaxListPageSize {
 		return nil, "", ociregistry.NewError(fmt.Sprintf("query parameter n is too large (n=%d, max=%d)", rreq.ListN, r.opts.MaxListPageSize), ociregistry.ErrUnsupported.Code(), nil)
 	}
@@ -124,24 +117,18 @@ func (r *registry) nextListResults(req *http.Request, rreq *ocirequest.Request,
 		n = maxPageSize
 	}
 	truncated := false
-	// TODO(go1.23) for repo, err := range itemsIter {
-	itemsIter(func(item string, err error) bool {
+	for item, err := range itemsIter {
 		if err != nil {
-			_err = err
-			return false
+			return nil, "", err
 		}
 		if rreq.ListN > 0 && len(items) >= rreq.ListN {
 			truncated = true
-			return false
+			break
 		}
 		// TODO we might want some way to limit on the total number
 		// of items returned in the absence of a ListN limit.
 		items = append(items, item)
 		// TODO sanity check that the items are in lexical order?
-		return true
-	})
-	if _err != nil {
-		return nil, "", _err
 	}
 	if truncated && !r.opts.OmitLinkHeaderFromResponses {
 		link = r.makeNextLink(req, items[len(items)-1])