reusable voting on hashes

ethcore/src/error.rs

@@ -24,6 +24,7 @@ use client::Error as ClientError;
 use ipc::binary::{BinaryConvertError, BinaryConvertable};
 use types::block_import_error::BlockImportError;
 use snapshot::Error as SnapshotError;
+use engines::VoteError;
 
 pub use types::executed::{ExecutionError, CallError};
 
@@ -238,6 +239,8 @@ pub enum Error {
 	Snappy(::util::snappy::InvalidInput),
 	/// Snapshot error.
 	Snapshot(SnapshotError),
+	/// Consensus vote error.
+	Vote(VoteError),
 }
 
 impl fmt::Display for Error {
@@ -258,6 +261,7 @@ impl fmt::Display for Error {
 			Error::StdIo(ref err) => err.fmt(f),
 			Error::Snappy(ref err) => err.fmt(f),
 			Error::Snapshot(ref err) => err.fmt(f),
+			Error::Vote(ref err) => f.write_str("Bad vote."),
 		}
 	}
 }
@@ -361,6 +365,14 @@ impl From<SnapshotError> for Error {
 	}
 }
 
+impl From<VoteError> for Error {
+	fn from(err: VoteError) -> Error {
+		match err {
+			other => Error::Vote(other),
+		}
+	}
+}
+
 impl<E> From<Box<E>> for Error where Error: From<E> {
 	fn from(err: Box<E>) -> Error {
 		Error::from(*err)