Make the StackError an actual Error

This allows it to play nice with error-handling libraries like error-chain or failure.

Author: vorner

src/stack.rs

@@ -5,6 +5,8 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
+use std::error::Error;
+use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::io;
 use std::ops::Deref;
 use std::os::raw::c_void;
@@ -21,6 +23,32 @@ pub enum StackError {
  IoError(io::Error),
 }
 
+impl Display for StackError {
+ fn fmt(&self, fmt: &mut Formatter) -> FmtResult {
+ match *self {
+ StackError::ExceedsMaximumSize(size) => {
+ write!(fmt, "Requested more than max size of {} bytes for a stack", size)
+ },
+ StackError::IoError(ref e) => e.fmt(fmt),
+ }
+ }
+}
+
+impl Error for StackError {
+ fn description(&self) -> &str {
+ match *self {
+ StackError::ExceedsMaximumSize(_) => "exceeds maximum stack size",
+ StackError::IoError(ref e) => e.description(),
+ }
+ }
+ fn cause(&self) -> Option<&Error> {
+ match *self {
+ StackError::ExceedsMaximumSize(_) => None,
+ StackError::IoError(ref e) => Some(e),
+ }
+ }
+}
+
 /// Represents any kind of stack memory.
 ///
 /// `FixedSizeStack` as well as `ProtectedFixedSizeStack`