Minor improvements to logic around decompression

server/filesystem/errors.go

@@ -17,19 +17,33 @@ const (
 	ErrCodeUnknownArchive ErrorCode = "E_UNKNFMT"
 	ErrCodePathResolution ErrorCode = "E_BADPATH"
 	ErrCodeDenylistFile   ErrorCode = "E_DENYLIST"
+	ErrCodeUnknownError   ErrorCode = "E_UNKNOWN"
 )
 
 type Error struct {
-	code     ErrorCode
-	path     string
+	code ErrorCode
+	// Contains the underlying error leading to this. This value may or may not be
+	// present, it is entirely dependent on how this error was triggered.
+	err error
+	// This contains the value of the final destination that triggered this specific
+	// error event.
 	resolved string
+	// This value is generally only present on errors stemming from a path resolution
+	// error. For everything else you should be setting and reading the resolved path
+	// value which will be far more useful.
+	path string
+}
+
+// Code returns the ErrorCode for this specific error instance.
+func (e *Error) Code() ErrorCode {
+	return e.code
 }
 
 // Returns a human-readable error string to identify the Error by.
 func (e *Error) Error() string {
 	switch e.code {
 	case ErrCodeIsDirectory:
-		return "filesystem: is a directory"
+		return fmt.Sprintf("filesystem: cannot perform action: [%s] is a directory", e.resolved)
 	case ErrCodeDiskSpace:
 		return "filesystem: not enough disk space"
 	case ErrCodeUnknownArchive:
@@ -46,36 +60,17 @@ func (e *Error) Error() string {
 			r = "<empty>"
 		}
 		return fmt.Sprintf("filesystem: server path [%s] resolves to a location outside the server root: %s", e.path, r)
+	case ErrCodeUnknownError:
+		fallthrough
+	default:
+		return fmt.Sprintf("filesystem: an error occurred: %s", e.Cause())
 	}
-	return "filesystem: unhandled error type"
 }
 
-// Returns the ErrorCode for this specific error instance.
-func (e *Error) Code() ErrorCode {
-	return e.code
-}
-
-// Checks if the given error is one of the Filesystem errors.
-func IsFilesystemError(err error) (*Error, bool) {
-	var fserr *Error
-	if errors.As(err, &fserr) {
-		return fserr, true
-	}
-	return nil, false
-}
-
-// Checks if "err" is a filesystem Error type. If so, it will then drop in and check
-// that the error code is the same as the provided ErrorCode passed in "code".
-func IsErrorCode(err error, code ErrorCode) bool {
-	if e, ok := IsFilesystemError(err); ok {
-		return e.code == code
-	}
-	return false
-}
-
-// Returns a new BadPathResolution error.
-func NewBadPathResolution(path string, resolved string) *Error {
-	return &Error{code: ErrCodePathResolution, path: path, resolved: resolved}
+// Cause returns the underlying cause of this filesystem error. In some causes
+// there may not be a cause present, in which case nil will be returned.
+func (e *Error) Cause() error {
+	return e.err
 }
 
 // Generates an error logger instance with some basic information.
@@ -92,10 +87,46 @@ func (fs *Filesystem) handleWalkerError(err error, f os.FileInfo) error {
 	if !IsErrorCode(err, ErrCodePathResolution) {
 		return err
 	}
-
 	if f != nil && f.IsDir() {
 		return filepath.SkipDir
 	}
-
 	return nil
 }
+
+// IsFilesystemError checks if the given error is one of the Filesystem errors.
+func IsFilesystemError(err error) bool {
+	var fserr *Error
+	if err != nil && errors.As(err, &fserr) {
+		return true
+	}
+	return false
+}
+
+// IsErrorCode checks if "err" is a filesystem Error type. If so, it will then
+// drop in and check that the error code is the same as the provided ErrorCode
+// passed in "code".
+func IsErrorCode(err error, code ErrorCode) bool {
+	var fserr *Error
+	if err != nil && errors.As(err, &fserr) {
+		return fserr.code == code
+	}
+	return false
+}
+
+// NewBadPathResolution returns a new BadPathResolution error.
+func NewBadPathResolution(path string, resolved string) *Error {
+	return &Error{code: ErrCodePathResolution, path: path, resolved: resolved}
+}
+
+// WrapError wraps the provided error as a Filesystem error and attaches the
+// provided resolved source to it. If the error is already a Filesystem error
+// no action is taken.
+func WrapError(err error, resolved string) *Error {
+	if err == nil {
+		return nil
+	}
+	if IsFilesystemError(err) {
+		return err.(*Error)
+	}
+	return &Error{code: ErrCodeUnknownError, err: err, resolved: resolved}
+}