feat: cache revalidation

internal/filesystem/readdir.go

@@ -0,0 +1,79 @@
+package filesystem
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"os"
+	"strings"
+	"time"
+)
+
+const keyReadDir = "webdav:readdir:"
+
+func (c *CachedClient) ReadDir(path string) ([]os.FileInfo, error) {
+	key := keyReadDir + path
+	ctx := context.Background()
+
+	// Try cache
+	val, err := c.client.Do(ctx, c.client.B().Get().Key(key).Build()).ToString()
+	if err == nil && val != "" {
+		var cached []File
+		if err := json.Unmarshal([]byte(val), &cached); err == nil {
+			c.readDirHits.Add(1)
+			c.hits.Add(1)
+			slog.Debug("cache hit", "key", key)
+			infos := make([]os.FileInfo, len(cached))
+			for i, f := range cached {
+				infos[i] = f
+			}
+			return infos, nil
+		}
+	}
+
+	// Cache miss
+	c.misses.Add(1)
+	slog.Debug("cache miss", "key", key)
+	infos, err := c.impl.ReadDir(path)
+	if err != nil {
+		return nil, err
+	}
+
+	// Serialize and cache
+	cached := make([]File, 0, len(infos))
+	for _, info := range infos {
+		cached = append(cached, ParseToFile(info))
+	}
+
+	bytes, err := json.Marshal(cached)
+	if err == nil {
+		c.client.Do(ctx, c.client.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
+	}
+
+	return infos, nil
+}
+
+func (c *CachedClient) revalidateReadDir(ctx context.Context) {
+	startTime := time.Now()
+	c.scanAndProcess(ctx, keyReadDir+"*", func(key string) error {
+		path := strings.TrimPrefix(key, keyReadDir)
+		infos, err := c.impl.ReadDir(path)
+		if err != nil {
+			c.client.Do(ctx, c.client.B().Del().Key(key).Build())
+			return err
+		}
+
+		// Serialize and cache
+		cached := make([]File, 0, len(infos))
+		for _, info := range infos {
+			cached = append(cached, ParseToFile(info))
+		}
+
+		bytes, err := json.Marshal(cached)
+		if err == nil {
+			c.client.Do(ctx, c.client.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
+		}
+		return nil
+	})
+	slog.Debug("revalidation of readDir complete", "duration", time.Since(startTime))
+}