internalize the qerr package

internal/qerr/quic_error.go

@@ -0,0 +1,53 @@
+package qerr
+
+import (
+	"fmt"
+)
+
+// ErrorCode can be used as a normal error without reason.
+type ErrorCode uint16
+
+func (e ErrorCode) Error() string {
+	return e.String()
+}
+
+// A QuicError consists of an error code plus a error reason
+type QuicError struct {
+	ErrorCode    ErrorCode
+	ErrorMessage string
+}
+
+// Error creates a new QuicError instance
+func Error(errorCode ErrorCode, errorMessage string) *QuicError {
+	return &QuicError{
+		ErrorCode:    errorCode,
+		ErrorMessage: errorMessage,
+	}
+}
+
+func (e *QuicError) Error() string {
+	return fmt.Sprintf("%s: %s", e.ErrorCode.String(), e.ErrorMessage)
+}
+
+// Timeout says if this error is a timeout.
+func (e *QuicError) Timeout() bool {
+	switch e.ErrorCode {
+	case NetworkIdleTimeout,
+		HandshakeTimeout,
+		TimeoutsWithOpenStreams:
+		return true
+	}
+	return false
+}
+
+// ToQuicError converts an arbitrary error to a QuicError. It leaves QuicErrors
+// unchanged, and properly handles `ErrorCode`s.
+func ToQuicError(err error) *QuicError {
+	switch e := err.(type) {
+	case *QuicError:
+		return e
+	case ErrorCode:
+		return Error(e, "")
+	}
+	return Error(InternalError, err.Error())
+}