swarm: localstore hasser (#19230)

swarm/shed/db.go

@@ -123,6 +123,17 @@ func (db *DB) Get(key []byte) (value []byte, err error) {
 	return value, nil
 }
 
+// Has wraps LevelDB Has method to increment metrics counter.
+func (db *DB) Has(key []byte) (yes bool, err error) {
+	yes, err = db.ldb.Has(key, nil)
+	if err != nil {
+		metrics.GetOrRegisterCounter("DB.hasFail", nil).Inc(1)
+		return false, err
+	}
+	metrics.GetOrRegisterCounter("DB.has", nil).Inc(1)
+	return yes, nil
+}
+
 // Delete wraps LevelDB Delete method to increment metrics counter.
 func (db *DB) Delete(key []byte) (err error) {
 	err = db.ldb.Delete(key, nil)

swarm/shed/index.go

@@ -145,6 +145,17 @@ func (f Index) Get(keyFields Item) (out Item, err error) {
 	return out.Merge(keyFields), nil
 }
 
+// Has accepts key fields represented as Item to check
+// if there this Item's encoded key is stored in
+// the index.
+func (f Index) Has(keyFields Item) (bool, error) {
+	key, err := f.encodeKeyFunc(keyFields)
+	if err != nil {
+		return false, err
+	}
+	return f.db.Has(key)
+}
+
 // Put accepts Item to encode information from it
 // and save it to the database.
 func (f Index) Put(i Item) (err error) {

swarm/shed/index_test.go

@@ -49,7 +49,7 @@ var retrievalIndexFuncs = IndexFuncs{
 	},
 }
 
-// TestIndex validates put, get and delete functions of the Index implementation.
+// TestIndex validates put, get, has and delete functions of the Index implementation.
 func TestIndex(t *testing.T) {
 	db, cleanupFunc := newTestDB(t)
 	defer cleanupFunc()
@@ -177,6 +177,41 @@ func TestIndex(t *testing.T) {
 		checkItem(t, got, want)
 	})
 
+	t.Run("has", func(t *testing.T) {
+		want := Item{
+			Address:        []byte("has-hash"),
+			Data:           []byte("DATA"),
+			StoreTimestamp: time.Now().UTC().UnixNano(),
+		}
+
+		dontWant := Item{
+			Address:        []byte("do-not-has-hash"),
+			Data:           []byte("DATA"),
+			StoreTimestamp: time.Now().UTC().UnixNano(),
+		}
+
+		err := index.Put(want)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		has, err := index.Has(want)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !has {
+			t.Error("item is not found")
+		}
+
+		has, err = index.Has(dontWant)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if has {
+			t.Error("unwanted item is found")
+		}
+	})
+
 	t.Run("delete", func(t *testing.T) {
 		want := Item{
 			Address:        []byte("delete-hash"),