content: support filters on local.store#Walk()

While Walk() has been taking filter strings, it was not using the parameter.
This change actually makes the filtering work.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

content/adaptor.go

@@ -0,0 +1,52 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package content
+
+import (
+	"strings"
+
+	"github.com/containerd/containerd/filters"
+)
+
+// AdoptInfo returns `filters.Adaptor` that handles `content.Info`.
+func AdaptInfo(info Info) filters.Adaptor {
+	return filters.AdapterFunc(func(fieldpath []string) (string, bool) {
+		if len(fieldpath) == 0 {
+			return "", false
+		}
+
+		switch fieldpath[0] {
+		case "digest":
+			return info.Digest.String(), true
+		case "size":
+			// TODO: support size based filtering
+		case "labels":
+			return checkMap(fieldpath[1:], info.Labels)
+		}
+
+		return "", false
+	})
+}
+
+func checkMap(fieldpath []string, m map[string]string) (string, bool) {
+	if len(m) == 0 {
+		return "", false
+	}
+
+	value, ok := m[strings.Join(fieldpath, ".")]
+	return value, ok
+}

content/local/store.go

@@ -240,9 +240,14 @@ func (s *store) Update(ctx context.Context, info content.Info, fieldpaths ...str
 	return info, nil
 }
 
-func (s *store) Walk(ctx context.Context, fn content.WalkFunc, filters ...string) error {
-	// TODO: Support filters
+func (s *store) Walk(ctx context.Context, fn content.WalkFunc, fs ...string) error {
 	root := filepath.Join(s.root, "blobs")
+
+	filter, err := filters.ParseAll(fs...)
+	if err != nil {
+		return err
+	}
+
 	var alg digest.Algorithm
 	return filepath.Walk(root, func(path string, fi os.FileInfo, err error) error {
 		if err != nil {
@@ -286,7 +291,12 @@ func (s *store) Walk(ctx context.Context, fn content.WalkFunc, filters ...string
 				return err
 			}
 		}
-		return fn(s.info(dgst, fi, labels))
+
+		info := s.info(dgst, fi, labels)
+		if !filter.Match(content.AdaptInfo(info)) {
+			return nil
+		}
+		return fn(info)
 	})
 }
 

metadata/adaptors.go

@@ -90,25 +90,6 @@ func adaptContainer(o interface{}) filters.Adaptor {
 	})
 }
 
-func adaptContentInfo(info content.Info) filters.Adaptor {
-	return filters.AdapterFunc(func(fieldpath []string) (string, bool) {
-		if len(fieldpath) == 0 {
-			return "", false
-		}
-
-		switch fieldpath[0] {
-		case "digest":
-			return info.Digest.String(), true
-		case "size":
-			// TODO: support size based filtering
-		case "labels":
-			return checkMap(fieldpath[1:], info.Labels)
-		}
-
-		return "", false
-	})
-}
-
 func adaptContentStatus(status content.Status) filters.Adaptor {
 	return filters.AdapterFunc(func(fieldpath []string) (string, bool) {
 		if len(fieldpath) == 0 {

metadata/content.go

@@ -181,7 +181,7 @@ func (cs *contentStore) Walk(ctx context.Context, fn content.WalkFunc, fs ...str
 			if err := readInfo(&info, bkt.Bucket(k)); err != nil {
 				return err
 			}
-			if filter.Match(adaptContentInfo(info)) {
+			if filter.Match(content.AdaptInfo(info)) {
 				infos = append(infos, info)
 			}
 			return nil