Initial Commit

internal/store/cached/cached.go

@@ -0,0 +1,72 @@
+/*
+ * distrohop - A utility for correlating and identifying equivalent software
+ * packages across different Linux distributions
+ *
+ * Copyright (C) 2025 Elara Ivy <elara@elara.ws>
+ *
+ * This file is part of distrohop.
+ *
+ * distrohop is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * distrohop is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with distrohop.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package cached
+
+import (
+	"strings"
+	"time"
+
+	"github.com/patrickmn/go-cache"
+	"go.elara.ws/distrohop/internal/store"
+)
+
+var _ store.ReadOnly = (*Store)(nil)
+
+// cacheRecord represents a single item stored in the cache
+type cacheRecord struct {
+	results []store.TagResult
+	latency time.Duration
+}
+
+// Store represents a cached store that caches search results from [go.elara.ws/distrohop/internal/store.ReadOnly] instances.
+// It implements [go.elara.ws/distrohop/internal/store.ReadOnly].
+type Store struct {
+	store.ReadOnly
+	cache *cache.Cache
+}
+
+// New creates a new cached store with the provided cache settings and underlying store.
+func New(s store.ReadOnly, exp, cleanup time.Duration) Store {
+	return Store{
+		ReadOnly: s,
+		cache:    cache.New(exp, cleanup),
+	}
+}
+
+// Search retrieves cached search results for the given tags. If the search doesn't exist
+// in the cache, it queries the underlying store and adds the results to the cache.
+func (cs Store) Search(tags []string) ([]store.TagResult, time.Duration, error) {
+	cacheKey := strings.Join(tags, "\x1F")
+	if results, ok := cs.cache.Get(cacheKey); ok {
+		record := results.(cacheRecord)
+		return record.results, record.latency, nil
+	}
+	res, latency, err := cs.ReadOnly.Search(tags)
+	if err != nil {
+		return nil, 0, err
+	}
+	if len(res) != 0 {
+		cs.cache.Set(cacheKey, cacheRecord{res, latency}, cache.DefaultExpiration)
+	}
+	return res, latency, nil
+}