From 27581c0ff4e191313af8257a402c7ac65b9a642c Mon Sep 17 00:00:00 2001
From: Age <Age@AgeManning.com>
Date: Wed, 19 Sep 2018 16:25:39 +1000
Subject: [PATCH] Implement generalised error ParameterError

---
 .../state/transition/attestation_parent_hashes.rs  | 14 +++++++-------
 lighthouse/state/transition/mod.rs                 |  7 +------
 lighthouse/utils/errors.rs                         | 11 ++++++++---
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/lighthouse/state/transition/attestation_parent_hashes.rs b/lighthouse/state/transition/attestation_parent_hashes.rs
index 624d8c4437..f635972b2c 100644
--- a/lighthouse/state/transition/attestation_parent_hashes.rs
+++ b/lighthouse/state/transition/attestation_parent_hashes.rs
@@ -1,5 +1,5 @@
 use super::Hash256;
-use super::TransitionError;
+use super::ParameterError;
 
 /// This function is used to select the hashes used in
 /// the signing of an AttestationRecord.
@@ -18,22 +18,22 @@ pub fn attestation_parent_hashes(
     attestation_slot: &u64,
     current_hashes: &Vec<Hash256>,
     oblique_hashes: &Vec<Hash256>)
-    -> Result<Vec<Hash256>, TransitionError>
+    -> Result<Vec<Hash256>, ParameterError>
 {
     // This cast places a limit on cycle_length. If you change it, check math
     // for overflow.
     let cycle_length: u64 = *cycle_length as u64;
 
     if current_hashes.len() as u64 != (cycle_length * 2) {
-        return Err(TransitionError::InvalidInput(String::from(
+        return Err(ParameterError::InvalidInput(String::from(
                     "current_hashes.len() must equal cycle_length * 2")));
     }
     if attestation_slot >= block_slot {
-        return Err(TransitionError::InvalidInput(String::from(
+        return Err(ParameterError::InvalidInput(String::from(
                     "attestation_slot must be less than block_slot")));
     }
     if oblique_hashes.len() as u64 > cycle_length {
-        return Err(TransitionError::InvalidInput(String::from(
+        return Err(ParameterError::InvalidInput(String::from(
                     "oblique_hashes.len() must be <= cycle_length * 2")));
     }
 
@@ -44,7 +44,7 @@ pub fn attestation_parent_hashes(
     let attestation_distance = block_slot - attestation_slot;
 
     if attestation_distance > cycle_length {
-        return Err(TransitionError::InvalidInput(String::from(
+        return Err(ParameterError::InvalidInput(String::from(
                     "attestation_slot must be withing one cycle of block_slot")));
     }
 
@@ -63,7 +63,7 @@ pub fn attestation_parent_hashes(
      */
     let end = start.checked_add(cycle_length)
         .and_then(|x| x.checked_sub(oblique_hashes.len() as u64))
-        .ok_or(TransitionError::IntWrapping)?;
+        .ok_or(ParameterError::IntWrapping)?;
 
 
     let mut hashes = Vec::new();
diff --git a/lighthouse/state/transition/mod.rs b/lighthouse/state/transition/mod.rs
index dd8967e652..f3da910276 100644
--- a/lighthouse/state/transition/mod.rs
+++ b/lighthouse/state/transition/mod.rs
@@ -1,4 +1,5 @@
 use super::super::utils::types::Hash256;
+use super::super::utils::errors::ParameterError;
 
 mod attestation_parent_hashes;
 mod shuffling;
@@ -6,12 +7,6 @@ mod shuffling;
 pub use self::attestation_parent_hashes::attestation_parent_hashes;
 pub use self::shuffling::shuffle;
 
-#[derive(Debug)]
-pub enum TransitionError {
-    IntWrapping,
-    OutOfBounds,
-    InvalidInput(String),
-}
 
 
 
diff --git a/lighthouse/utils/errors.rs b/lighthouse/utils/errors.rs
index 4f12cfbdd6..2a25b29b8e 100644
--- a/lighthouse/utils/errors.rs
+++ b/lighthouse/utils/errors.rs
@@ -1,7 +1,7 @@
-// Collection of custom errors 
+// Collection of custom errors
 
 #[derive(Debug,PartialEq)]
-pub enum AttestationValidationError { 
+pub enum AttestationValidationError {
     SlotTooHigh,
     SlotTooLow(String),
     IncorrectBitField,
@@ -9,4 +9,9 @@ pub enum AttestationValidationError {
     AggregateSignatureFail
 }
 
-
+#[derive(Debug,PartialEq)]
+pub enum ParameterError {
+    IntWrapping,
+    OutOfBounds,
+    InvalidInput(String),
+}