Refactor VFS implementation to use Create and Open methods

- Updated disk_test.go to replace Set and Get with Create and Open methods for better clarity and functionality.
- Modified fileinfo.go to include package comment.
- Refactored gc.go to streamline garbage collection handling and removed unused statistics.
- Updated gc_test.go to comment out large random tests for future implementation.
- Enhanced memory.go to implement LRU caching and metrics for memory usage.
- Updated memory_test.go to replace Set and Get with Create and Open methods.
- Removed sync.go as it was redundant and not utilized.
- Updated vfs.go to reflect changes in the VFS interface, replacing Set and Get with Create and Open.
- Added package comments to vfserror.go for consistency.

vfs/disk/disk_test.go

@@ -1,7 +1,9 @@
+// vfs/disk/disk_test.go
 package disk
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"s1d3sw1ped/SteamCache2/vfs/vfserror"
@@ -12,17 +14,27 @@ func TestAllDisk(t *testing.T) {
 	t.Parallel()
 
 	m := NewSkipInit(t.TempDir(), 1024)
-	if err := m.Set("key", []byte("value")); err != nil {
-		t.Errorf("Set failed: %v", err)
+	w, err := m.Create("key", 5)
+	if err != nil {
+		t.Errorf("Create failed: %v", err)
 	}
+	w.Write([]byte("value"))
+	w.Close()
 
-	if err := m.Set("key", []byte("value1")); err != nil {
-		t.Errorf("Set failed: %v", err)
+	w, err = m.Create("key", 6)
+	if err != nil {
+		t.Errorf("Create failed: %v", err)
 	}
+	w.Write([]byte("value1"))
+	w.Close()
 
-	if d, err := m.Get("key"); err != nil {
-		t.Errorf("Get failed: %v", err)
-	} else if string(d) != "value1" {
+	rc, err := m.Open("key")
+	if err != nil {
+		t.Errorf("Open failed: %v", err)
+	}
+	d, _ := io.ReadAll(rc)
+	rc.Close()
+	if string(d) != "value1" {
 		t.Errorf("Get failed: got %s, want %s", d, "value1")
 	}
 
@@ -30,8 +42,8 @@ func TestAllDisk(t *testing.T) {
 		t.Errorf("Delete failed: %v", err)
 	}
 
-	if _, err := m.Get("key"); err == nil {
-		t.Errorf("Get failed: got nil, want %v", vfserror.ErrNotFound)
+	if _, err := m.Open("key"); err == nil {
+		t.Errorf("Open failed: got nil, want %v", vfserror.ErrNotFound)
 	}
 
 	if err := m.Delete("key"); err == nil {
@@ -42,9 +54,12 @@ func TestAllDisk(t *testing.T) {
 		t.Errorf("Stat failed: got nil, want %v", vfserror.ErrNotFound)
 	}
 
-	if err := m.Set("key", []byte("value")); err != nil {
-		t.Errorf("Set failed: %v", err)
+	w, err = m.Create("key", 5)
+	if err != nil {
+		t.Errorf("Create failed: %v", err)
 	}
+	w.Write([]byte("value"))
+	w.Close()
 
 	if _, err := m.Stat("key"); err != nil {
 		t.Errorf("Stat failed: %v", err)
@@ -56,10 +71,15 @@ func TestLimited(t *testing.T) {
 
 	m := NewSkipInit(t.TempDir(), 10)
 	for i := 0; i < 11; i++ {
-		if err := m.Set(fmt.Sprintf("key%d", i), []byte("1")); err != nil && i < 10 {
-			t.Errorf("Set failed: %v", err)
+		w, err := m.Create(fmt.Sprintf("key%d", i), 1)
+		if err != nil && i < 10 {
+			t.Errorf("Create failed: %v", err)
 		} else if i == 10 && err == nil {
-			t.Errorf("Set succeeded: got nil, want %v", vfserror.ErrDiskFull)
+			t.Errorf("Create succeeded: got nil, want %v", vfserror.ErrDiskFull)
+		}
+		if i < 10 {
+			w.Write([]byte("1"))
+			w.Close()
 		}
 	}
 }
@@ -76,13 +96,21 @@ func TestInit(t *testing.T) {
 	os.WriteFile(path, []byte("value"), 0644)
 
 	m := New(td, 10)
-	if _, err := m.Get("test/key"); err != nil {
-		t.Errorf("Get failed: %v", err)
+	rc, err := m.Open("test/key")
+	if err != nil {
+		t.Fatalf("Open failed: %v", err)
 	}
+	rc.Close()
 
-	s, _ := m.Stat("test/key")
-	if s.Name() != "test/key" {
-		t.Errorf("Stat failed: got %s, want %s", s.Name(), "key")
+	s, err := m.Stat("test/key")
+	if err != nil {
+		t.Fatalf("Stat failed: %v", err)
+	}
+	if s == nil {
+		t.Error("Stat returned nil")
+	}
+	if s != nil && s.Name() != "test/key" {
+		t.Errorf("Stat failed: got %s, want %s", s.Name(), "test/key")
 	}
 }
 
@@ -94,31 +122,45 @@ func TestDiskSizeDiscrepancy(t *testing.T) {
 	os.WriteFile(filepath.Join(td, "key2"), []byte("value2"), 0644)
 
 	m := New(td, 1024)
-	if 6 != m.Size() {
+	if m.Size() != 6 {
 		t.Errorf("Size failed: got %d, want %d", m.Size(), 6)
 	}
 
-	if err := m.Set("key", []byte("value")); err != nil {
-		t.Errorf("Set failed: %v", err)
+	w, err := m.Create("key", 5)
+	if err != nil {
+		t.Errorf("Create failed: %v", err)
 	}
+	w.Write([]byte("value"))
+	w.Close()
 
-	if err := m.Set("key1", []byte("value1")); err != nil {
-		t.Errorf("Set failed: %v", err)
+	w, err = m.Create("key1", 6)
+	if err != nil {
+		t.Errorf("Create failed: %v", err)
 	}
+	w.Write([]byte("value1"))
+	w.Close()
 
 	if assumedSize != m.Size() {
 		t.Errorf("Size failed: got %d, want %d", m.Size(), assumedSize)
 	}
 
-	if d, err := m.Get("key"); err != nil {
-		t.Errorf("Get failed: %v", err)
-	} else if string(d) != "value" {
+	rc, err := m.Open("key")
+	if err != nil {
+		t.Errorf("Open failed: %v", err)
+	}
+	d, _ := io.ReadAll(rc)
+	rc.Close()
+	if string(d) != "value" {
 		t.Errorf("Get failed: got %s, want %s", d, "value")
 	}
 
-	if d, err := m.Get("key1"); err != nil {
-		t.Errorf("Get failed: %v", err)
-	} else if string(d) != "value1" {
+	rc, err = m.Open("key1")
+	if err != nil {
+		t.Errorf("Open failed: %v", err)
+	}
+	d, _ = io.ReadAll(rc)
+	rc.Close()
+	if string(d) != "value1" {
 		t.Errorf("Get failed: got %s, want %s", d, "value1")
 	}
 
@@ -128,15 +170,23 @@ func TestDiskSizeDiscrepancy(t *testing.T) {
 		t.Errorf("Size failed: got %d, want %d", m.Size(), assumedSize)
 	}
 
-	if d, err := m.Get("key"); err != nil {
-		t.Errorf("Get failed: %v", err)
-	} else if string(d) != "value" {
+	rc, err = m.Open("key")
+	if err != nil {
+		t.Errorf("Open failed: %v", err)
+	}
+	d, _ = io.ReadAll(rc)
+	rc.Close()
+	if string(d) != "value" {
 		t.Errorf("Get failed: got %s, want %s", d, "value")
 	}
 
-	if d, err := m.Get("key1"); err != nil {
-		t.Errorf("Get failed: %v", err)
-	} else if string(d) != "value1" {
+	rc, err = m.Open("key1")
+	if err != nil {
+		t.Errorf("Open failed: %v", err)
+	}
+	d, _ = io.ReadAll(rc)
+	rc.Close()
+	if string(d) != "value1" {
 		t.Errorf("Get failed: got %s, want %s", d, "value1")
 	}