Remove (almost all) panickers from trie module (#1776)

* memorydb ub patch and other cleanup

* fix denote invocations

* move trie traits into trie module

* replace "denote" with shim

* triedb returns results and no longer panics

* fix warnings

* get ethcore compiling

* warn on trie errors in ethcore

* remove unsafety from node decoder

* restore broken denote behavior for this branch

* fix overlayrecent fallout

* fix triedb tests

* remove unwrap in state

* alter Trie::get to return Result<Option<_>>

* fix refcell error in require

* fix test warnings

* fix json tests

* whitespace

[ci:skip]

* Avoid unneeded match/indentation

* whitespace

* prettify map_or_else

* remove test warning

util/src/trie/fatdbmut.rs

@@ -17,7 +17,7 @@
 use hash::H256;
 use sha3::Hashable;
 use hashdb::HashDB;
-use super::{TrieDBMut, TrieMut, TrieError};
+use super::{TrieDBMut, TrieMut};
 
 /// A mutable `Trie` implementation which hashes keys and uses a generic `HashDB` backing database.
 /// Additionaly it stores inserted hash-key mappings for later retrieval.
@@ -38,7 +38,7 @@ impl<'db> FatDBMut<'db> {
 	/// Create a new trie with the backing database `db` and `root`.
 	///
 	/// Returns an error if root does not exist.
-	pub fn from_existing(db: &'db mut HashDB, root: &'db mut H256) -> Result<Self, TrieError> {
+	pub fn from_existing(db: &'db mut HashDB, root: &'db mut H256) -> super::Result<Self> {
 		Ok(FatDBMut { raw: try!(TrieDBMut::from_existing(db, root)) })
 	}
 
@@ -62,23 +62,26 @@ impl<'db> TrieMut for FatDBMut<'db> {
 		self.raw.is_empty()
 	}
 
-	fn contains(&self, key: &[u8]) -> bool {
+	fn contains(&self, key: &[u8]) -> super::Result<bool> {
 		self.raw.contains(&key.sha3())
 	}
 
-	fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Option<&'a [u8]> where 'a: 'key {
+	fn get<'a, 'key>(&'a self, key: &'key [u8]) -> super::Result<Option<&'a [u8]>>
+		where 'a: 'key
+	{
 		self.raw.get(&key.sha3())
 	}
 
-	fn insert(&mut self, key: &[u8], value: &[u8]) {
+	fn insert(&mut self, key: &[u8], value: &[u8]) -> super::Result<()> {
 		let hash = key.sha3();
-		self.raw.insert(&hash, value);
+		try!(self.raw.insert(&hash, value));
 		let db = self.raw.db_mut();
 		db.insert_aux(hash.to_vec(), key.to_vec());
+		Ok(())
 	}
 
-	fn remove(&mut self, key: &[u8]) {
-		self.raw.remove(&key.sha3());
+	fn remove(&mut self, key: &[u8]) -> super::Result<()> {
+		self.raw.remove(&key.sha3())
 	}
 }
 
@@ -92,8 +95,8 @@ fn fatdb_to_trie() {
 	let mut root = H256::default();
 	{
 		let mut t = FatDBMut::new(&mut memdb, &mut root);
-		t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]);
+		t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
 	}
 	let t = TrieDB::new(&memdb, &root).unwrap();
-	assert_eq!(t.get(&(&[0x01u8, 0x23]).sha3()).unwrap(), &[0x01u8, 0x23]);
+	assert_eq!(t.get(&(&[0x01u8, 0x23]).sha3()).unwrap().unwrap(), &[0x01u8, 0x23]);
 }