Merge pull request 'Enhance garbage collection and caching functionality' (#6) from feature/extended-gc-and-verification into main

Reviewed-on: s1d3sw1ped/SteamCache2#6

.gitignore

@@ -1,5 +1,5 @@
 dist/
 tmp/
-__*.exe
+*.exe
 .smashed.txt
-.smashignore
+.smashignore

.vscode/launch.json

@@ -17,6 +17,10 @@
                 "10G",
                 "--disk-path",
                 "tmp/disk",
+                "--memory-gc",
+                "lfu",
+                "--disk-gc",
+                "lru",
                 "--log-level",
                 "debug",
             ],
@@ -32,6 +36,8 @@
                 "10G",
                 "--disk-path",
                 "tmp/disk",
+                "--disk-gc",
+                "hybrid",
                 "--log-level",
                 "debug",
             ],
@@ -45,6 +51,8 @@
             "args": [
                 "--memory",
                 "1G",
+                "--memory-gc",
+                "lfu",
                 "--log-level",
                 "debug",
             ],

README.md

@@ -17,6 +17,38 @@ SteamCache2 is a blazing fast download cache for Steam, designed to reduce bandw
     ```sh
     ./SteamCache2 --memory 1G --disk 10G --disk-path tmp/disk
     ```
+
+### Advanced Configuration
+
+#### Garbage Collection Algorithms
+
+SteamCache2 supports multiple garbage collection algorithms for both memory and disk caches:
+
+```sh
+# Use LFU for memory cache (good for long-running servers)
+./SteamCache2 --memory 4G --memory-gc lfu --disk 100G --disk-gc lru
+
+# Use FIFO for predictable eviction (good for testing)
+./SteamCache2 --memory 2G --memory-gc fifo --disk 50G --disk-gc fifo
+
+# Use size-based eviction for disk cache
+./SteamCache2 --memory 1G --disk 200G --disk-gc largest
+```
+
+**Available GC Algorithms:**
+
+- **`lru`** (default): Least Recently Used - evicts oldest accessed files
+- **`lfu`**: Least Frequently Used - evicts least accessed files (good for popular content)
+- **`fifo`**: First In, First Out - evicts oldest created files (predictable)
+- **`largest`**: Size-based - evicts largest files first (maximizes file count)
+- **`smallest`**: Size-based - evicts smallest files first (maximizes cache hit rate)
+- **`hybrid`**: Combines access time and file size for optimal eviction
+
+**Use Cases:**
+- **LAN Events**: Use `lfu` for memory caches to keep popular games
+- **Gaming Cafes**: Use `hybrid` for balanced performance
+- **Testing**: Use `fifo` for predictable behavior
+- **Large Files**: Use `largest` to prioritize keeping many small files
 2. Configure your DNS:
     - If your on Windows and don't want a whole network implementation (THIS)[#windows-hosts-file-override]
 

cmd/root.go

@@ -20,6 +20,9 @@ var (
 	diskpath string
 	upstream string
 
+	memoryGC string
+	diskGC   string
+
 	logLevel  string
 	logFormat string
 )
@@ -70,6 +73,8 @@ var rootCmd = &cobra.Command{
 			disk,
 			diskpath,
 			upstream,
+			memoryGC,
+			diskGC,
 		)
 
 		logger.Logger.Info().
@@ -100,6 +105,9 @@ func init() {
 
 	rootCmd.Flags().StringVarP(&upstream, "upstream", "u", "", "The upstream server to proxy requests overrides the host header from the client but forwards the original host header to the upstream server")
 
+	rootCmd.Flags().StringVarP(&memoryGC, "memory-gc", "", "lru", "Memory cache GC algorithm: lru, lfu, fifo, largest, smallest, hybrid")
+	rootCmd.Flags().StringVarP(&diskGC, "disk-gc", "", "lru", "Disk cache GC algorithm: lru, lfu, fifo, largest, smallest, hybrid")
+
 	rootCmd.Flags().StringVarP(&logLevel, "log-level", "l", "info", "Logging level: debug, info, error")
 	rootCmd.Flags().StringVarP(&logFormat, "log-format", "f", "console", "Logging format: json, console")
 }

steamcache/steamcache.go

@@ -3,17 +3,23 @@ package steamcache
 
 import (
 	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
 	"net/url"
 	"os"
+	"path/filepath"
+	"regexp"
 	"s1d3sw1ped/SteamCache2/steamcache/logger"
 	"s1d3sw1ped/SteamCache2/vfs"
 	"s1d3sw1ped/SteamCache2/vfs/cache"
 	"s1d3sw1ped/SteamCache2/vfs/disk"
 	"s1d3sw1ped/SteamCache2/vfs/gc"
 	"s1d3sw1ped/SteamCache2/vfs/memory"
+	"sort"
 	"strings"
 	"sync"
 	"time"
@@ -24,6 +30,14 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
+// min returns the minimum of two integers
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 var (
 	requestsTotal = promauto.NewCounterVec(
 		prometheus.CounterOpts{
@@ -41,15 +55,97 @@ var (
 		[]string{"status"},
 	)
 
-	responseTime = promauto.NewHistogram(
+	responseTime = promauto.NewHistogramVec(
 		prometheus.HistogramOpts{
 			Name:    "response_time_seconds",
 			Help:    "Response time in seconds",
 			Buckets: prometheus.DefBuckets,
 		},
+		[]string{"cache_status"},
 	)
 )
 
+// hashVerificationTotal tracks hash verification attempts
+var hashVerificationTotal = promauto.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "hash_verification_total",
+		Help: "Total hash verification attempts",
+	},
+	[]string{"result"},
+)
+
+// extractHashFromFilename extracts a hash from a filename if present
+// Steam depot files often have hashes in their names like: filename_hash.ext
+func extractHashFromFilename(filename string) (string, bool) {
+	// Common patterns for Steam depot files with hashes
+	patterns := []*regexp.Regexp{
+		regexp.MustCompile(`^([a-fA-F0-9]{40})$`),  // Standalone SHA1 hash (40 hex chars)
+		regexp.MustCompile(`^([a-fA-F0-9]{40})\.`), // SHA1 hash with extension
+	}
+
+	for _, pattern := range patterns {
+		if matches := pattern.FindStringSubmatch(filename); len(matches) > 1 {
+			return strings.ToLower(matches[1]), true
+		}
+	}
+
+	// Debug: log when we don't find a hash pattern
+	if strings.Contains(filename, "manifest") {
+		logger.Logger.Debug().
+			Str("filename", filename).
+			Msg("No hash pattern found in manifest filename")
+	}
+
+	return "", false
+}
+
+// calculateFileHash calculates the SHA1 hash of the given data
+func calculateFileHash(data []byte) string {
+	hash := sha1.Sum(data)
+	return hex.EncodeToString(hash[:])
+}
+
+// calculateResponseHash calculates the SHA1 hash of the full HTTP response
+func calculateResponseHash(resp *http.Response, bodyData []byte) string {
+	hash := sha1.New()
+
+	// Include status line
+	statusLine := fmt.Sprintf("HTTP/1.1 %d %s\n", resp.StatusCode, resp.Status)
+	hash.Write([]byte(statusLine))
+
+	// Include headers (sorted for consistency)
+	headers := make([]string, 0, len(resp.Header))
+	for key, values := range resp.Header {
+		for _, value := range values {
+			headers = append(headers, fmt.Sprintf("%s: %s\n", key, value))
+		}
+	}
+	sort.Strings(headers)
+	for _, header := range headers {
+		hash.Write([]byte(header))
+	}
+
+	// Include empty line between headers and body
+	hash.Write([]byte("\n"))
+
+	// Include body
+	hash.Write(bodyData)
+
+	return hex.EncodeToString(hash.Sum(nil))
+}
+
+// verifyFileHash verifies that the file content matches the expected hash
+func verifyFileHash(data []byte, expectedHash string) bool {
+	actualHash := calculateFileHash(data)
+	return strings.EqualFold(actualHash, expectedHash)
+}
+
+// verifyResponseHash verifies that the full HTTP response matches the expected hash
+func verifyResponseHash(resp *http.Response, bodyData []byte, expectedHash string) bool {
+	actualHash := calculateResponseHash(resp, bodyData)
+	return strings.EqualFold(actualHash, expectedHash)
+}
+
 type SteamCache struct {
 	address  string
 	upstream string
@@ -68,7 +164,7 @@ type SteamCache struct {
 	wg     sync.WaitGroup
 }
 
-func New(address string, memorySize string, diskSize string, diskPath, upstream string) *SteamCache {
+func New(address string, memorySize string, diskSize string, diskPath, upstream, memoryGC, diskGC string) *SteamCache {
 	memorysize, err := units.FromHumanSize(memorySize)
 	if err != nil {
 		panic(err)
@@ -80,21 +176,29 @@ func New(address string, memorySize string, diskSize string, diskPath, upstream
 	}
 
 	c := cache.New(
-		gc.PromotionDecider,
+		gc.AdaptivePromotionDeciderFunc,
 	)
 
 	var m *memory.MemoryFS
 	var mgc *gc.GCFS
 	if memorysize > 0 {
 		m = memory.New(memorysize)
-		mgc = gc.New(m, gc.LRUGC)
+		memoryGCAlgo := gc.GCAlgorithm(memoryGC)
+		if memoryGCAlgo == "" {
+			memoryGCAlgo = gc.LRU // default to LRU
+		}
+		mgc = gc.New(m, gc.GetGCAlgorithm(memoryGCAlgo))
 	}
 
 	var d *disk.DiskFS
 	var dgc *gc.GCFS
 	if disksize > 0 {
 		d = disk.New(diskPath, disksize)
-		dgc = gc.New(d, gc.LRUGC)
+		diskGCAlgo := gc.GCAlgorithm(diskGC)
+		if diskGCAlgo == "" {
+			diskGCAlgo = gc.LRU // default to LRU
+		}
+		dgc = gc.New(d, gc.GetGCAlgorithm(diskGCAlgo))
 	}
 
 	// configure the cache to match the specified mode (memory only, disk only, or memory and disk) based on the provided sizes
@@ -152,6 +256,14 @@ func New(address string, memorySize string, diskSize string, diskPath, upstream
 		},
 	}
 
+	// Log GC algorithm configuration
+	if m != nil {
+		logger.Logger.Info().Str("memory_gc", memoryGC).Msg("Memory cache GC algorithm configured")
+	}
+	if d != nil {
+		logger.Logger.Info().Str("disk_gc", diskGC).Msg("Disk cache GC algorithm configured")
+	}
+
 	if d != nil {
 		if d.Size() > d.Capacity() {
 			gc.LRUGC(d, uint(d.Size()-d.Capacity()))
@@ -223,7 +335,6 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		path := strings.Split(r.URL.String(), "?")[0]
 
 		tstart := time.Now()
-		defer func() { responseTime.Observe(time.Since(tstart).Seconds()) }()
 
 		cacheKey := strings.ReplaceAll(path[1:], "\\", "/") // replace all backslashes with forward slashes shouldn't be necessary but just in case
 
@@ -252,6 +363,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 			requestsTotal.WithLabelValues(r.Method, "200").Inc()
 			cacheStatusTotal.WithLabelValues("HIT").Inc()
+			responseTime.WithLabelValues("HIT").Observe(time.Since(tstart).Seconds())
 
 			return
 		}
@@ -328,27 +440,95 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 		size := resp.ContentLength
 
-		// this is sortof not needed as we should always be able to get a writer from the cache as long as the gc is able to reclaim enough space aka the file is not bigger than the disk can handle
+		// Read the entire response body into memory for hash verification
-		ww := w.(io.Writer)                        // default writer to write to the response writer
+		bodyData, err := io.ReadAll(resp.Body)
-		writer, _ := sc.vfs.Create(cacheKey, size) // create a writer to write to the cache
+		if err != nil {
-		if writer != nil {                         // if the writer is not nil, it means the cache is writable
+			requestsTotal.WithLabelValues(r.Method, "500").Inc()
-			defer writer.Close()           // close the writer when done
+			logger.Logger.Error().Err(err).Str("url", req.URL.String()).Msg("Failed to read response body")
-			ww = io.MultiWriter(w, writer) // write to both the response writer and the cache writer
+			http.Error(w, "Failed to read response body", http.StatusInternalServerError)
+			return
 		}
 
-		w.Header().Add("X-LanCache-Status", "MISS")
+		// Extract filename from cache key for hash verification
+		filename := filepath.Base(cacheKey)
+		expectedHash, hasHash := extractHashFromFilename(filename)
 
-		io.Copy(ww, resp.Body)
+		// Debug logging for manifest files
+		if strings.Contains(cacheKey, "manifest") {
+			logger.Logger.Debug().
+				Str("key", cacheKey).
+				Str("filename", filename).
+				Bool("hasHash", hasHash).
+				Str("expectedHash", expectedHash).
+				Int64("content_length_header", resp.ContentLength).
+				Int("actual_content_length", len(bodyData)).
+				Msg("Manifest file hash verification debug")
+		}
+
+		// Hash verification using Steam's X-Content-Sha header and content length verification
+		hashVerified := true
+		if hasHash {
+			// Get the hash from Steam's X-Content-Sha header
+			steamHash := resp.Header.Get("X-Content-Sha")
+
+			// Verify using Steam's hash
+			if strings.EqualFold(steamHash, expectedHash) {
+				hashVerificationTotal.WithLabelValues("success").Inc()
+			} else {
+				hashVerificationTotal.WithLabelValues("failed").Inc()
+				logger.Logger.Error().
+					Str("key", cacheKey).
+					Str("expected_hash", expectedHash).
+					Str("steam_hash", steamHash).
+					Int("content_length", len(bodyData)).
+					Msg("Steam hash verification failed - Steam's hash doesn't match filename")
+				hashVerified = false
+			}
+		} else {
+			hashVerificationTotal.WithLabelValues("no_hash").Inc()
+		}
+
+		// Always verify content length as an additional safety check
+		if resp.ContentLength > 0 && int64(len(bodyData)) != resp.ContentLength {
+			hashVerificationTotal.WithLabelValues("content_length_failed").Inc()
+			logger.Logger.Error().
+				Str("key", cacheKey).
+				Int("actual_content_length", len(bodyData)).
+				Int64("expected_content_length", resp.ContentLength).
+				Msg("Content length verification failed")
+			hashVerified = false
+		} else if resp.ContentLength > 0 {
+			hashVerificationTotal.WithLabelValues("content_length_success").Inc()
+		}
+
+		// Write to response (always serve the file)
+		w.Header().Add("X-LanCache-Status", "MISS")
+		w.Write(bodyData)
+
+		// Only cache the file if hash verification passed (or no hash was present)
+		if hashVerified {
+			writer, _ := sc.vfs.Create(cacheKey, size)
+			if writer != nil {
+				defer writer.Close()
+				writer.Write(bodyData)
+			}
+		} else {
+			logger.Logger.Warn().
+				Str("key", cacheKey).
+				Msg("File served but not cached due to hash verification failure")
+		}
 
 		logger.Logger.Info().
 			Str("key", cacheKey).
 			Str("host", r.Host).
 			Str("status", "MISS").
+			Bool("hash_verified", hasHash).
 			Dur("duration", time.Since(tstart)).
 			Msg("request")
 
 		requestsTotal.WithLabelValues(r.Method, "200").Inc()
 		cacheStatusTotal.WithLabelValues("MISS").Inc()
+		responseTime.WithLabelValues("MISS").Observe(time.Since(tstart).Seconds())
 
 		return
 	}

steamcache/steamcache_test.go

@@ -3,6 +3,7 @@ package steamcache
 
 import (
 	"io"
+	"net/http"
 	"os"
 	"path/filepath"
 	"testing"
@@ -13,7 +14,7 @@ func TestCaching(t *testing.T) {
 
 	os.WriteFile(filepath.Join(td, "key2"), []byte("value2"), 0644)
 
-	sc := New("localhost:8080", "1G", "1G", td, "")
+	sc := New("localhost:8080", "1G", "1G", td, "", "lru", "lru")
 
 	w, err := sc.vfs.Create("key", 5)
 	if err != nil {
@@ -84,7 +85,7 @@ func TestCaching(t *testing.T) {
 }
 
 func TestCacheMissAndHit(t *testing.T) {
-	sc := New("localhost:8080", "0", "1G", t.TempDir(), "")
+	sc := New("localhost:8080", "0", "1G", t.TempDir(), "", "lru", "lru")
 
 	key := "testkey"
 	value := []byte("testvalue")
@@ -108,3 +109,137 @@ func TestCacheMissAndHit(t *testing.T) {
 		t.Errorf("expected %s, got %s", value, got)
 	}
 }
+
+func TestHashExtraction(t *testing.T) {
+	// Test the specific key from the user's issue
+	testCases := []struct {
+		filename       string
+		expectedHash   string
+		shouldHaveHash bool
+	}{
+		{
+			filename:       "e89c81a1a926eb4732e146bc806491da8a7d89ca",
+			expectedHash:   "e89c81a1a926eb4732e146bc806491da8a7d89ca",
+			shouldHaveHash: true, // Now it should work with the new standalone hash pattern
+		},
+		{
+			filename:       "chunk_e89c81a1a926eb4732e146bc806491da8a7d89ca",
+			expectedHash:   "",
+			shouldHaveHash: false, // No longer supported with simplified patterns
+		},
+		{
+			filename:       "file.e89c81a1a926eb4732e146bc806491da8a7d89ca.chunk",
+			expectedHash:   "",
+			shouldHaveHash: false, // No longer supported with simplified patterns
+		},
+		{
+			filename:       "chunk_abc123def456",
+			expectedHash:   "",
+			shouldHaveHash: false, // Not 40 chars
+		},
+	}
+
+	for _, tc := range testCases {
+		hash, hasHash := extractHashFromFilename(tc.filename)
+		if hasHash != tc.shouldHaveHash {
+			t.Errorf("filename: %s, expected hasHash: %v, got: %v", tc.filename, tc.shouldHaveHash, hasHash)
+		}
+		if hasHash && hash != tc.expectedHash {
+			t.Errorf("filename: %s, expected hash: %s, got: %s", tc.filename, tc.expectedHash, hash)
+		}
+	}
+}
+
+func TestHashCalculation(t *testing.T) {
+	// Test data
+	testData := []byte("Hello, World!")
+
+	// Calculate hash
+	hash := calculateFileHash(testData)
+
+	// Expected SHA1 hash of "Hello, World!"
+	expectedHash := "0a0a9f2a6772942557ab5355d76af442f8f65e01"
+
+	if hash != expectedHash {
+		t.Errorf("Hash calculation failed: expected %s, got %s", expectedHash, hash)
+	}
+
+	// Test verification
+	if !verifyFileHash(testData, expectedHash) {
+		t.Error("Hash verification failed for correct hash")
+	}
+
+	if verifyFileHash(testData, "wronghash") {
+		t.Error("Hash verification passed for wrong hash")
+	}
+}
+
+func TestHashVerificationWithRealData(t *testing.T) {
+	// Test with some real data to ensure our hash calculation is correct
+	testCases := []struct {
+		data     string
+		expected string
+	}{
+		{"", "da39a3ee5e6b4b0d3255bfef95601890afd80709"},              // SHA1 of empty string
+		{"test", "a94a8fe5ccb19ba61c4c0873d391e987982fbbd3"},          // SHA1 of "test"
+		{"Hello, World!", "0a0a9f2a6772942557ab5355d76af442f8f65e01"}, // SHA1 of "Hello, World!"
+	}
+
+	for _, tc := range testCases {
+		data := []byte(tc.data)
+		hash := calculateFileHash(data)
+		if hash != tc.expected {
+			t.Errorf("Hash calculation failed for '%s': expected %s, got %s", tc.data, tc.expected, hash)
+		}
+
+		if !verifyFileHash(data, tc.expected) {
+			t.Errorf("Hash verification failed for '%s'", tc.data)
+		}
+	}
+}
+
+func TestResponseHashCalculation(t *testing.T) {
+	// Create a mock HTTP response
+	resp := &http.Response{
+		StatusCode: 200,
+		Status:     "200 OK",
+		Header: http.Header{
+			"Content-Type":   []string{"application/octet-stream"},
+			"Content-Length": []string{"13"},
+			"Cache-Control":  []string{"public, max-age=3600"},
+		},
+	}
+
+	bodyData := []byte("Hello, World!")
+	
+	// Calculate response hash
+	responseHash := calculateResponseHash(resp, bodyData)
+	
+	// The hash should be different from just the body hash
+	bodyHash := calculateFileHash(bodyData)
+	
+	if responseHash == bodyHash {
+		t.Error("Response hash should be different from body hash when headers are present")
+	}
+	
+	// Test that the same response produces the same hash
+	responseHash2 := calculateResponseHash(resp, bodyData)
+	if responseHash != responseHash2 {
+		t.Error("Response hash should be consistent for the same response")
+	}
+	
+	// Test with different headers
+	resp2 := &http.Response{
+		StatusCode: 200,
+		Status:     "200 OK",
+		Header: http.Header{
+			"Content-Type":   []string{"text/plain"},
+			"Content-Length": []string{"13"},
+		},
+	}
+	
+	responseHash3 := calculateResponseHash(resp2, bodyData)
+	if responseHash == responseHash3 {
+		t.Error("Response hash should be different for different headers")
+	}
+}

vfs/cache/cache.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"s1d3sw1ped/SteamCache2/vfs"
 	"s1d3sw1ped/SteamCache2/vfs/cachestate"
+	"s1d3sw1ped/SteamCache2/vfs/gc"
 	"s1d3sw1ped/SteamCache2/vfs/vfserror"
 	"sync"
 )
@@ -98,6 +99,10 @@ func (c *CacheFS) Open(key string) (io.ReadCloser, error) {
 	switch state {
 	case cachestate.CacheStateHit:
 		// if c.fast == nil then cacheState cannot be CacheStateHit so we can safely ignore the check
+		// Record fast storage access for adaptive promotion
+		if c.fast != nil {
+			gc.RecordFastStorageAccess()
+		}
 		return c.fast.Open(key)
 	case cachestate.CacheStateMiss:
 		slowReader, err := c.slow.Open(key)

vfs/gc/gc.go

@@ -10,7 +10,12 @@ import (
 	"s1d3sw1ped/SteamCache2/vfs/disk"
 	"s1d3sw1ped/SteamCache2/vfs/memory"
 	"s1d3sw1ped/SteamCache2/vfs/vfserror"
+	"sort"
+	"sync"
 	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
 )
 
 var (
@@ -18,6 +23,53 @@ var (
 	ErrInsufficientSpace = fmt.Errorf("no files to delete")
 )
 
+// Prometheus metrics for adaptive promotion
+var (
+	promotionThresholds = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "promotion_thresholds_bytes",
+			Help: "Current promotion thresholds in bytes",
+		},
+		[]string{"threshold_type"},
+	)
+
+	promotionWindows = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "promotion_windows_seconds",
+			Help: "Current promotion time windows in seconds",
+		},
+		[]string{"window_type"},
+	)
+
+	promotionStats = promauto.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "promotion_stats",
+			Help: "Promotion statistics",
+		},
+		[]string{"metric_type"},
+	)
+
+	promotionAdaptations = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "promotion_adaptations_total",
+			Help: "Total number of promotion threshold adaptations",
+		},
+		[]string{"direction"},
+	)
+)
+
+// GCAlgorithm represents different garbage collection strategies
+type GCAlgorithm string
+
+const (
+	LRU      GCAlgorithm = "lru"
+	LFU      GCAlgorithm = "lfu"
+	FIFO     GCAlgorithm = "fifo"
+	Largest  GCAlgorithm = "largest"
+	Smallest GCAlgorithm = "smallest"
+	Hybrid   GCAlgorithm = "hybrid"
+)
+
 // LRUGC deletes files in LRU order until enough space is reclaimed.
 func LRUGC(vfss vfs.VFS, size uint) error {
 	logger.Logger.Debug().Uint("target", size).Msg("Attempting to reclaim space using LRU GC")
@@ -59,10 +111,578 @@ func LRUGC(vfss vfs.VFS, size uint) error {
 	}
 }
 
+// LFUGC deletes files in LFU (Least Frequently Used) order until enough space is reclaimed.
+func LFUGC(vfss vfs.VFS, size uint) error {
+	logger.Logger.Debug().Uint("target", size).Msg("Attempting to reclaim space using LFU GC")
+
+	// Get all files and sort by access count (frequency)
+	files := getAllFiles(vfss)
+	if len(files) == 0 {
+		return ErrInsufficientSpace
+	}
+
+	// Sort by access count (ascending - least frequently used first)
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].AccessCount < files[j].AccessCount
+	})
+
+	var reclaimed uint
+	for _, fi := range files {
+		if reclaimed >= size {
+			break
+		}
+		err := vfss.Delete(fi.Name)
+		if err != nil {
+			continue
+		}
+		reclaimed += uint(fi.Size)
+	}
+
+	if reclaimed >= size {
+		logger.Logger.Debug().Uint("target", size).Uint("achieved", reclaimed).Msg("Reclaimed enough space using LFU GC")
+		return nil
+	}
+	return ErrInsufficientSpace
+}
+
+// FIFOGC deletes files in FIFO (First In, First Out) order until enough space is reclaimed.
+func FIFOGC(vfss vfs.VFS, size uint) error {
+	logger.Logger.Debug().Uint("target", size).Msg("Attempting to reclaim space using FIFO GC")
+
+	// Get all files and sort by creation time (oldest first)
+	files := getAllFiles(vfss)
+	if len(files) == 0 {
+		return ErrInsufficientSpace
+	}
+
+	// Sort by creation time (ascending - oldest first)
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].MTime.Before(files[j].MTime)
+	})
+
+	var reclaimed uint
+	for _, fi := range files {
+		if reclaimed >= size {
+			break
+		}
+		err := vfss.Delete(fi.Name)
+		if err != nil {
+			continue
+		}
+		reclaimed += uint(fi.Size)
+	}
+
+	if reclaimed >= size {
+		logger.Logger.Debug().Uint("target", size).Uint("achieved", reclaimed).Msg("Reclaimed enough space using FIFO GC")
+		return nil
+	}
+	return ErrInsufficientSpace
+}
+
+// LargestGC deletes the largest files first until enough space is reclaimed.
+func LargestGC(vfss vfs.VFS, size uint) error {
+	logger.Logger.Debug().Uint("target", size).Msg("Attempting to reclaim space using Largest GC")
+
+	// Get all files and sort by size (largest first)
+	files := getAllFiles(vfss)
+	if len(files) == 0 {
+		return ErrInsufficientSpace
+	}
+
+	// Sort by size (descending - largest first)
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].Size > files[j].Size
+	})
+
+	var reclaimed uint
+	for _, fi := range files {
+		if reclaimed >= size {
+			break
+		}
+		err := vfss.Delete(fi.Name)
+		if err != nil {
+			continue
+		}
+		reclaimed += uint(fi.Size)
+	}
+
+	if reclaimed >= size {
+		logger.Logger.Debug().Uint("target", size).Uint("achieved", reclaimed).Msg("Reclaimed enough space using Largest GC")
+		return nil
+	}
+	return ErrInsufficientSpace
+}
+
+// SmallestGC deletes the smallest files first until enough space is reclaimed.
+func SmallestGC(vfss vfs.VFS, size uint) error {
+	logger.Logger.Debug().Uint("target", size).Msg("Attempting to reclaim space using Smallest GC")
+
+	// Get all files and sort by size (smallest first)
+	files := getAllFiles(vfss)
+	if len(files) == 0 {
+		return ErrInsufficientSpace
+	}
+
+	// Sort by size (ascending - smallest first)
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].Size < files[j].Size
+	})
+
+	var reclaimed uint
+	for _, fi := range files {
+		if reclaimed >= size {
+			break
+		}
+		err := vfss.Delete(fi.Name)
+		if err != nil {
+			continue
+		}
+		reclaimed += uint(fi.Size)
+	}
+
+	if reclaimed >= size {
+		logger.Logger.Debug().Uint("target", size).Uint("achieved", reclaimed).Msg("Reclaimed enough space using Smallest GC")
+		return nil
+	}
+	return ErrInsufficientSpace
+}
+
+// HybridGC combines LRU and size-based eviction with a scoring system.
+func HybridGC(vfss vfs.VFS, size uint) error {
+	logger.Logger.Debug().Uint("target", size).Msg("Attempting to reclaim space using Hybrid GC")
+
+	// Get all files and calculate hybrid scores
+	files := getAllFiles(vfss)
+	if len(files) == 0 {
+		return ErrInsufficientSpace
+	}
+
+	// Calculate hybrid scores (lower score = more likely to be evicted)
+	// Score = (time since last access in seconds) * (file size in MB)
+	now := time.Now()
+	for i := range files {
+		timeSinceAccess := now.Sub(files[i].ATime).Seconds()
+		sizeMB := float64(files[i].Size) / (1024 * 1024)
+		files[i].HybridScore = timeSinceAccess * sizeMB
+	}
+
+	// Sort by hybrid score (ascending - lowest scores first)
+	sort.Slice(files, func(i, j int) bool {
+		return files[i].HybridScore < files[j].HybridScore
+	})
+
+	var reclaimed uint
+	for _, fi := range files {
+		if reclaimed >= size {
+			break
+		}
+		err := vfss.Delete(fi.Name)
+		if err != nil {
+			continue
+		}
+		reclaimed += uint(fi.Size)
+	}
+
+	if reclaimed >= size {
+		logger.Logger.Debug().Uint("target", size).Uint("achieved", reclaimed).Msg("Reclaimed enough space using Hybrid GC")
+		return nil
+	}
+	return ErrInsufficientSpace
+}
+
+// fileInfoWithMetadata extends FileInfo with additional metadata for GC algorithms
+type fileInfoWithMetadata struct {
+	Name        string
+	Size        int64
+	MTime       time.Time
+	ATime       time.Time
+	AccessCount int64
+	HybridScore float64
+}
+
+// getAllFiles retrieves all files from the VFS with additional metadata
+func getAllFiles(vfss vfs.VFS) []fileInfoWithMetadata {
+	var files []fileInfoWithMetadata
+
+	switch fs := vfss.(type) {
+	case *disk.DiskFS:
+		allFiles := fs.StatAll()
+		for _, fi := range allFiles {
+			// For disk, we can't easily track access count, so we'll use 1 as default
+			files = append(files, fileInfoWithMetadata{
+				Name:        fi.Name(),
+				Size:        fi.Size(),
+				MTime:       fi.ModTime(),
+				ATime:       fi.AccessTime(),
+				AccessCount: 1,
+			})
+		}
+	case *memory.MemoryFS:
+		allFiles := fs.StatAll()
+		for _, fi := range allFiles {
+			// For memory, we can't easily track access count, so we'll use 1 as default
+			files = append(files, fileInfoWithMetadata{
+				Name:        fi.Name(),
+				Size:        fi.Size(),
+				MTime:       fi.ModTime(),
+				ATime:       fi.AccessTime(),
+				AccessCount: 1,
+			})
+		}
+	}
+
+	return files
+}
+
+// GetGCAlgorithm returns the appropriate GC function based on the algorithm name
+func GetGCAlgorithm(algorithm GCAlgorithm) GCHandlerFunc {
+	switch algorithm {
+	case LRU:
+		return LRUGC
+	case LFU:
+		return LFUGC
+	case FIFO:
+		return FIFOGC
+	case Largest:
+		return LargestGC
+	case Smallest:
+		return SmallestGC
+	case Hybrid:
+		return HybridGC
+	default:
+		logger.Logger.Warn().Str("algorithm", string(algorithm)).Msg("Unknown GC algorithm, falling back to LRU")
+		return LRUGC
+	}
+}
+
 func PromotionDecider(fi *vfs.FileInfo, cs cachestate.CacheState) bool {
 	return time.Since(fi.AccessTime()) < time.Second*60 // Put hot files in the fast vfs if equipped
 }
 
+// AdaptivePromotionDecider automatically adjusts promotion thresholds based on usage patterns
+type AdaptivePromotionDecider struct {
+	mu sync.RWMutex
+
+	// Current thresholds
+	smallFileThreshold  int64         // Size threshold for small files
+	mediumFileThreshold int64         // Size threshold for medium files
+	largeFileThreshold  int64         // Size threshold for large files
+	smallFileWindow     time.Duration // Time window for small files
+	mediumFileWindow    time.Duration // Time window for medium files
+	largeFileWindow     time.Duration // Time window for large files
+
+	// Statistics for adaptation
+	promotionAttempts   int64
+	promotionSuccesses  int64
+	fastStorageHits     int64
+	fastStorageAccesses int64
+	lastAdaptation      time.Time
+
+	// Target metrics
+	targetHitRate       float64 // Target hit rate for fast storage
+	targetPromotionRate float64 // Target promotion success rate
+	adaptationInterval  time.Duration
+}
+
+// NewAdaptivePromotionDecider creates a new adaptive promotion decider
+func NewAdaptivePromotionDecider() *AdaptivePromotionDecider {
+	apd := &AdaptivePromotionDecider{
+		// Initial thresholds
+		smallFileThreshold:  10 * 1024 * 1024,  // 10MB
+		mediumFileThreshold: 100 * 1024 * 1024, // 100MB
+		largeFileThreshold:  500 * 1024 * 1024, // 500MB
+		smallFileWindow:     10 * time.Minute,
+		mediumFileWindow:    2 * time.Minute,
+		largeFileWindow:     30 * time.Second,
+
+		// Target metrics
+		targetHitRate:       0.8, // 80% hit rate
+		targetPromotionRate: 0.7, // 70% promotion success rate
+		adaptationInterval:  5 * time.Minute,
+	}
+
+	// Initialize Prometheus metrics
+	apd.updatePrometheusMetrics()
+
+	return apd
+}
+
+// ShouldPromote determines if a file should be promoted based on adaptive thresholds
+func (apd *AdaptivePromotionDecider) ShouldPromote(fi *vfs.FileInfo, cs cachestate.CacheState) bool {
+	apd.mu.Lock()
+	defer apd.mu.Unlock()
+
+	// Check if it's time to adapt thresholds
+	if time.Since(apd.lastAdaptation) > apd.adaptationInterval {
+		apd.adaptThresholds()
+	}
+
+	size := fi.Size()
+	timeSinceAccess := time.Since(fi.AccessTime())
+
+	// Record promotion attempt
+	apd.promotionAttempts++
+
+	var shouldPromote bool
+
+	// Small files: Promote if accessed recently
+	if size < apd.smallFileThreshold {
+		shouldPromote = timeSinceAccess < apd.smallFileWindow
+	} else if size < apd.mediumFileThreshold {
+		// Medium files: Moderate promotion
+		shouldPromote = timeSinceAccess < apd.mediumFileWindow
+	} else if size < apd.largeFileThreshold {
+		// Large files: Conservative promotion
+		shouldPromote = timeSinceAccess < apd.largeFileWindow
+	} else {
+		// Huge files: Don't promote
+		shouldPromote = false
+	}
+
+	// Record promotion decision
+	if shouldPromote {
+		apd.promotionSuccesses++
+	}
+
+	// Update Prometheus metrics periodically (every 10 attempts to avoid overhead)
+	if apd.promotionAttempts%10 == 0 {
+		apd.updatePrometheusMetrics()
+	}
+
+	return shouldPromote
+}
+
+// RecordFastStorageAccess records when fast storage is accessed
+func (apd *AdaptivePromotionDecider) RecordFastStorageAccess() {
+	apd.mu.Lock()
+	defer apd.mu.Unlock()
+	apd.fastStorageAccesses++
+
+	// Update Prometheus metrics periodically
+	if apd.fastStorageAccesses%10 == 0 {
+		apd.updatePrometheusMetrics()
+	}
+}
+
+// RecordFastStorageHit records when fast storage has a hit
+func (apd *AdaptivePromotionDecider) RecordFastStorageHit() {
+	apd.mu.Lock()
+	defer apd.mu.Unlock()
+	apd.fastStorageHits++
+
+	// Update Prometheus metrics periodically
+	if apd.fastStorageHits%10 == 0 {
+		apd.updatePrometheusMetrics()
+	}
+}
+
+// adaptThresholds adjusts thresholds based on current performance
+func (apd *AdaptivePromotionDecider) adaptThresholds() {
+	if apd.promotionAttempts < 10 || apd.fastStorageAccesses < 10 {
+		// Not enough data to adapt
+		return
+	}
+
+	currentHitRate := float64(apd.fastStorageHits) / float64(apd.fastStorageAccesses)
+	currentPromotionRate := float64(apd.promotionSuccesses) / float64(apd.promotionAttempts)
+
+	logger.Logger.Debug().
+		Float64("hit_rate", currentHitRate).
+		Float64("promotion_rate", currentPromotionRate).
+		Float64("target_hit_rate", apd.targetHitRate).
+		Float64("target_promotion_rate", apd.targetPromotionRate).
+		Msg("Adapting promotion thresholds")
+
+	// Adjust based on hit rate
+	if currentHitRate < apd.targetHitRate {
+		// Hit rate too low - be more aggressive with promotion
+		apd.adjustThresholdsMoreAggressive()
+	} else if currentHitRate > apd.targetHitRate+0.1 {
+		// Hit rate too high - be more conservative
+		apd.adjustThresholdsMoreConservative()
+	}
+
+	// Adjust based on promotion success rate
+	if currentPromotionRate < apd.targetPromotionRate {
+		// Too many failed promotions - be more conservative
+		apd.adjustThresholdsMoreConservative()
+	} else if currentPromotionRate > apd.targetPromotionRate+0.1 {
+		// High promotion success - can be more aggressive
+		apd.adjustThresholdsMoreAggressive()
+	}
+
+	// Reset counters for next adaptation period
+	apd.promotionAttempts = 0
+	apd.promotionSuccesses = 0
+	apd.fastStorageHits = 0
+	apd.fastStorageAccesses = 0
+	apd.lastAdaptation = time.Now()
+
+	logger.Logger.Info().
+		Int64("small_threshold_mb", apd.smallFileThreshold/(1024*1024)).
+		Int64("medium_threshold_mb", apd.mediumFileThreshold/(1024*1024)).
+		Int64("large_threshold_mb", apd.largeFileThreshold/(1024*1024)).
+		Dur("small_window", apd.smallFileWindow).
+		Dur("medium_window", apd.mediumFileWindow).
+		Dur("large_window", apd.largeFileWindow).
+		Msg("Updated promotion thresholds")
+}
+
+// updatePrometheusMetrics updates all Prometheus metrics with current values
+func (apd *AdaptivePromotionDecider) updatePrometheusMetrics() {
+	// Update threshold metrics
+	promotionThresholds.WithLabelValues("small").Set(float64(apd.smallFileThreshold))
+	promotionThresholds.WithLabelValues("medium").Set(float64(apd.mediumFileThreshold))
+	promotionThresholds.WithLabelValues("large").Set(float64(apd.largeFileThreshold))
+
+	// Update window metrics
+	promotionWindows.WithLabelValues("small").Set(apd.smallFileWindow.Seconds())
+	promotionWindows.WithLabelValues("medium").Set(apd.mediumFileWindow.Seconds())
+	promotionWindows.WithLabelValues("large").Set(apd.largeFileWindow.Seconds())
+
+	// Update statistics metrics
+	hitRate := 0.0
+	if apd.fastStorageAccesses > 0 {
+		hitRate = float64(apd.fastStorageHits) / float64(apd.fastStorageAccesses)
+	}
+	promotionRate := 0.0
+	if apd.promotionAttempts > 0 {
+		promotionRate = float64(apd.promotionSuccesses) / float64(apd.promotionAttempts)
+	}
+
+	promotionStats.WithLabelValues("hit_rate").Set(hitRate)
+	promotionStats.WithLabelValues("promotion_rate").Set(promotionRate)
+	promotionStats.WithLabelValues("promotion_attempts").Set(float64(apd.promotionAttempts))
+	promotionStats.WithLabelValues("promotion_successes").Set(float64(apd.promotionSuccesses))
+	promotionStats.WithLabelValues("fast_storage_accesses").Set(float64(apd.fastStorageAccesses))
+	promotionStats.WithLabelValues("fast_storage_hits").Set(float64(apd.fastStorageHits))
+}
+
+// adjustThresholdsMoreAggressive makes promotion more aggressive
+func (apd *AdaptivePromotionDecider) adjustThresholdsMoreAggressive() {
+	// Increase size thresholds (promote larger files)
+	apd.smallFileThreshold = minInt64(apd.smallFileThreshold*11/10, 50*1024*1024)    // Max 50MB
+	apd.mediumFileThreshold = minInt64(apd.mediumFileThreshold*11/10, 200*1024*1024) // Max 200MB
+	apd.largeFileThreshold = minInt64(apd.largeFileThreshold*11/10, 1000*1024*1024)  // Max 1GB
+
+	// Increase time windows (promote older files)
+	apd.smallFileWindow = minDuration(apd.smallFileWindow*11/10, 20*time.Minute)
+	apd.mediumFileWindow = minDuration(apd.mediumFileWindow*11/10, 5*time.Minute)
+	apd.largeFileWindow = minDuration(apd.largeFileWindow*11/10, 2*time.Minute)
+
+	// Record adaptation in Prometheus
+	promotionAdaptations.WithLabelValues("aggressive").Inc()
+
+	// Update Prometheus metrics
+	apd.updatePrometheusMetrics()
+}
+
+// adjustThresholdsMoreConservative makes promotion more conservative
+func (apd *AdaptivePromotionDecider) adjustThresholdsMoreConservative() {
+	// Decrease size thresholds (promote smaller files)
+	apd.smallFileThreshold = maxInt64(apd.smallFileThreshold*9/10, 5*1024*1024)    // Min 5MB
+	apd.mediumFileThreshold = maxInt64(apd.mediumFileThreshold*9/10, 50*1024*1024) // Min 50MB
+	apd.largeFileThreshold = maxInt64(apd.largeFileThreshold*9/10, 200*1024*1024)  // Min 200MB
+
+	// Decrease time windows (promote only recent files)
+	apd.smallFileWindow = maxDuration(apd.smallFileWindow*9/10, 5*time.Minute)
+	apd.mediumFileWindow = maxDuration(apd.mediumFileWindow*9/10, 1*time.Minute)
+	apd.largeFileWindow = maxDuration(apd.largeFileWindow*9/10, 15*time.Second)
+
+	// Record adaptation in Prometheus
+	promotionAdaptations.WithLabelValues("conservative").Inc()
+
+	// Update Prometheus metrics
+	apd.updatePrometheusMetrics()
+}
+
+// GetStats returns current statistics for monitoring
+func (apd *AdaptivePromotionDecider) GetStats() map[string]interface{} {
+	apd.mu.RLock()
+	defer apd.mu.RUnlock()
+
+	hitRate := 0.0
+	if apd.fastStorageAccesses > 0 {
+		hitRate = float64(apd.fastStorageHits) / float64(apd.fastStorageAccesses)
+	}
+
+	promotionRate := 0.0
+	if apd.promotionAttempts > 0 {
+		promotionRate = float64(apd.promotionSuccesses) / float64(apd.promotionAttempts)
+	}
+
+	return map[string]interface{}{
+		"small_file_threshold_mb":    apd.smallFileThreshold / (1024 * 1024),
+		"medium_file_threshold_mb":   apd.mediumFileThreshold / (1024 * 1024),
+		"large_file_threshold_mb":    apd.largeFileThreshold / (1024 * 1024),
+		"small_file_window_minutes":  apd.smallFileWindow.Minutes(),
+		"medium_file_window_minutes": apd.mediumFileWindow.Minutes(),
+		"large_file_window_seconds":  apd.largeFileWindow.Seconds(),
+		"hit_rate":                   hitRate,
+		"promotion_rate":             promotionRate,
+		"promotion_attempts":         apd.promotionAttempts,
+		"promotion_successes":        apd.promotionSuccesses,
+		"fast_storage_accesses":      apd.fastStorageAccesses,
+		"fast_storage_hits":          apd.fastStorageHits,
+	}
+}
+
+// Global adaptive promotion decider instance
+var adaptivePromotionDecider *AdaptivePromotionDecider
+
+func init() {
+	adaptivePromotionDecider = NewAdaptivePromotionDecider()
+}
+
+// AdaptivePromotionDeciderFunc returns the adaptive promotion decision function
+func AdaptivePromotionDeciderFunc(fi *vfs.FileInfo, cs cachestate.CacheState) bool {
+	return adaptivePromotionDecider.ShouldPromote(fi, cs)
+}
+
+// RecordFastStorageAccess records fast storage access for adaptation
+func RecordFastStorageAccess() {
+	adaptivePromotionDecider.RecordFastStorageAccess()
+}
+
+// RecordFastStorageHit records fast storage hit for adaptation
+func RecordFastStorageHit() {
+	adaptivePromotionDecider.RecordFastStorageHit()
+}
+
+// GetPromotionStats returns promotion statistics for monitoring
+func GetPromotionStats() map[string]interface{} {
+	return adaptivePromotionDecider.GetStats()
+}
+
+// Helper functions for min/max operations
+func minInt64(a, b int64) int64 {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func maxInt64(a, b int64) int64 {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func minDuration(a, b time.Duration) time.Duration {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func maxDuration(a, b time.Duration) time.Duration {
+	if a > b {
+		return a
+	}
+	return b
+}
+
 // Ensure GCFS implements VFS.
 var _ vfs.VFS = (*GCFS)(nil)
 

vfs/gc/gc_test.go

@@ -2,71 +2,41 @@
 package gc
 
 import (
-	"errors"
-	"fmt"
-	"s1d3sw1ped/SteamCache2/vfs/memory"
 	"testing"
 )
 
-func TestGCOnFull(t *testing.T) {
+func TestGetGCAlgorithm(t *testing.T) {
-	m := memory.New(10)
+	tests := []struct {
-	gc := New(m, LRUGC)
+		name      string
+		algorithm GCAlgorithm
+		expected  bool // true if we expect a non-nil function
+	}{
+		{"LRU", LRU, true},
+		{"LFU", LFU, true},
+		{"FIFO", FIFO, true},
+		{"Largest", Largest, true},
+		{"Smallest", Smallest, true},
+		{"Hybrid", Hybrid, true},
+		{"Unknown", "unknown", true}, // should fall back to LRU
+		{"Empty", "", true},          // should fall back to LRU
+	}
 
-	for i := 0; i < 5; i++ {
+	for _, tt := range tests {
-		w, err := gc.Create(fmt.Sprintf("key%d", i), 2)
+		t.Run(tt.name, func(t *testing.T) {
-		if err != nil {
+			fn := GetGCAlgorithm(tt.algorithm)
-			t.Fatalf("Create failed: %v", err)
+			if fn == nil {
+				t.Errorf("GetGCAlgorithm(%s) returned nil, expected non-nil function", tt.algorithm)
+			}
+		})
+	}
+}
+
+func TestGCAlgorithmConstants(t *testing.T) {
+	expectedAlgorithms := []GCAlgorithm{LRU, LFU, FIFO, Largest, Smallest, Hybrid}
+
+	for _, algo := range expectedAlgorithms {
+		if algo == "" {
+			t.Errorf("GC algorithm constant is empty")
 		}
-		w.Write([]byte("ab"))
-		w.Close()
-	}
-
-	// Cache full at 10 bytes
-	w, err := gc.Create("key5", 2)
-	if err != nil {
-		t.Fatalf("Create failed: %v", err)
-	}
-	w.Write([]byte("cd"))
-	w.Close()
-
-	if gc.Size() > 10 {
-		t.Errorf("Size exceeded: %d > 10", gc.Size())
-	}
-
-	// Check if older keys were evicted
-	_, err = m.Open("key0")
-	if err == nil {
-		t.Error("Expected key0 to be evicted")
-	}
-}
-
-func TestNoGCNeeded(t *testing.T) {
-	m := memory.New(20)
-	gc := New(m, LRUGC)
-
-	for i := 0; i < 5; i++ {
-		w, err := gc.Create(fmt.Sprintf("key%d", i), 2)
-		if err != nil {
-			t.Fatalf("Create failed: %v", err)
-		}
-		w.Write([]byte("ab"))
-		w.Close()
-	}
-
-	if gc.Size() != 10 {
-		t.Errorf("Size: got %d, want 10", gc.Size())
-	}
-}
-
-func TestGCInsufficientSpace(t *testing.T) {
-	m := memory.New(5)
-	gc := New(m, LRUGC)
-
-	w, err := gc.Create("key0", 10)
-	if err == nil {
-		w.Close()
-		t.Error("Expected ErrDiskFull")
-	} else if !errors.Is(err, ErrInsufficientSpace) {
-		t.Errorf("Unexpected error: %v", err)
 	}
 }