Initial commit.

internal/storage/storage.go

@@ -0,0 +1,110 @@
+package storage
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// EnsureDir creates a directory with specified permissions if it doesn't exist
+func EnsureDir(path string, perm os.FileMode) error {
+	if err := os.MkdirAll(path, perm); err != nil {
+		return fmt.Errorf("creating directory %s: %w", path, err)
+	}
+	return nil
+}
+
+// FileExists checks if a file exists
+func FileExists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
+// WriteFile writes content to a file with specified permissions
+func WriteFile(path string, content []byte, perm os.FileMode) error {
+	if err := os.WriteFile(path, content, perm); err != nil {
+		return fmt.Errorf("writing file %s: %w", path, err)
+	}
+	return nil
+}
+
+// ReadFile reads content from a file
+func ReadFile(path string) ([]byte, error) {
+	content, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("reading file %s: %w", path, err)
+	}
+	return content, nil
+}
+
+// Lock represents a file lock
+type Lock struct {
+	file *os.File
+	path string
+}
+
+// AcquireLock acquires an exclusive lock on a file
+func AcquireLock(lockPath string) (*Lock, error) {
+	// Ensure lock directory exists
+	if err := EnsureDir(filepath.Dir(lockPath), 0755); err != nil {
+		return nil, err
+	}
+
+	// Open or create lock file
+	file, err := os.OpenFile(lockPath, os.O_CREATE|os.O_RDWR, 0644)
+	if err != nil {
+		return nil, fmt.Errorf("opening lock file %s: %w", lockPath, err)
+	}
+
+	// Acquire exclusive lock with flock
+	if err := syscall.Flock(int(file.Fd()), syscall.LOCK_EX); err != nil {
+		file.Close()
+		return nil, fmt.Errorf("acquiring lock on %s: %w", lockPath, err)
+	}
+
+	return &Lock{
+		file: file,
+		path: lockPath,
+	}, nil
+}
+
+// Release releases the file lock
+func (l *Lock) Release() error {
+	if l.file == nil {
+		return nil
+	}
+
+	// Release flock
+	if err := syscall.Flock(int(l.file.Fd()), syscall.LOCK_UN); err != nil {
+		l.file.Close()
+		return fmt.Errorf("releasing lock on %s: %w", l.path, err)
+	}
+
+	// Close file
+	if err := l.file.Close(); err != nil {
+		return fmt.Errorf("closing lock file %s: %w", l.path, err)
+	}
+
+	l.file = nil
+	return nil
+}
+
+// WithLock executes a function while holding a lock
+func WithLock(lockPath string, fn func() error) error {
+	lock, err := AcquireLock(lockPath)
+	if err != nil {
+		return err
+	}
+	defer lock.Release()
+
+	return fn()
+}
+
+// EnsureFilePermissions ensures a file has the correct permissions
+func EnsureFilePermissions(path string, perm os.FileMode) error {
+	if err := os.Chmod(path, perm); err != nil {
+		return fmt.Errorf("setting permissions on %s: %w", path, err)
+	}
+	return nil
+}