Enhance garbage collection and caching functionality

- Updated .gitignore to include all .exe files and ensure .smashignore is tracked.
- Expanded README.md with advanced configuration options for garbage collection algorithms, detailing available algorithms and use cases.
- Modified launch.json to include memory and disk garbage collection flags for better configuration.
- Refactored root.go to introduce memoryGC and diskGC flags for garbage collection algorithms.
- Implemented hash extraction and verification in steamcache.go to ensure data integrity during caching.
- Added new tests in steamcache_test.go for hash extraction and verification, ensuring correctness of caching behavior.
- Enhanced garbage collection strategies in gc.go, introducing LFU, FIFO, Largest, Smallest, and Hybrid algorithms with corresponding metrics.
- Updated caching logic to conditionally cache responses based on hash verification results.

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")
+	}
+}