Sweep some more panics (#2848)

* purge unwraps from ethcrypto, ethstore

* sweep panics from util

util/src/common.rs

@@ -95,8 +95,8 @@ macro_rules! flushln {
 
 #[doc(hidden)]
 pub fn flush(s: String) {
-	::std::io::stdout().write(s.as_bytes()).unwrap();
-	::std::io::stdout().flush().unwrap();
+	let _ = ::std::io::stdout().write(s.as_bytes());
+	let _ = ::std::io::stdout().flush();
 }
 
 #[test]

util/src/journaldb/earlymergedb.rs

@@ -383,7 +383,10 @@ impl JournalDB for EarlyMergeDB {
 		let trace = false;
 
 		// record new commit's details.
-		let mut refs = self.refs.as_ref().unwrap().write();
+		let mut refs = match self.refs.as_ref() {
+			Some(refs) => refs.write(),
+			None => return Ok(0),
+		};
 
 		{
 			let mut index = 0usize;

util/src/kvdb.rs

@@ -345,7 +345,8 @@ impl Database {
 				let cfnames: Vec<&str> = cfnames.iter().map(|n| n as &str).collect();
 				match DB::open_cf(&opts, path, &cfnames, &cf_options) {
 					Ok(db) => {
-						cfs = cfnames.iter().map(|n| db.cf_handle(n).unwrap()).collect();
+						cfs = cfnames.iter().map(|n| db.cf_handle(n)
+							.expect("rocksdb opens a cf_handle for each cfname; qed")).collect();
 						assert!(cfs.len() == columns as usize);
 						Ok(db)
 					}
@@ -353,7 +354,7 @@ impl Database {
 						// retry and create CFs
 						match DB::open_cf(&opts, path, &[], &[]) {
 							Ok(mut db) => {
-								cfs = cfnames.iter().enumerate().map(|(i, n)| db.create_cf(n, &cf_options[i]).unwrap()).collect();
+								cfs = try!(cfnames.iter().enumerate().map(|(i, n)| db.create_cf(n, &cf_options[i])).collect());
 								Ok(db)
 							},
 							err @ Err(_) => err,
@@ -537,7 +538,8 @@ impl Database {
 		match *self.db.read() {
 			Some(DBAndColumns { ref db, ref cfs }) => {
 				let mut iter = col.map_or_else(|| db.iterator_opt(IteratorMode::From(prefix, Direction::Forward), &self.read_opts),
-					|c| db.iterator_cf_opt(cfs[c as usize], IteratorMode::From(prefix, Direction::Forward), &self.read_opts).unwrap());
+					|c| db.iterator_cf_opt(cfs[c as usize], IteratorMode::From(prefix, Direction::Forward), &self.read_opts)
+						.expect("iterator params are valid; qed"));
 				match iter.next() {
 					// TODO: use prefix_same_as_start read option (not availabele in C API currently)
 					Some((k, v)) => if k[0 .. prefix.len()] == prefix[..] { Some(v) } else { None },
@@ -554,7 +556,8 @@ impl Database {
 		match *self.db.read() {
 			Some(DBAndColumns { ref db, ref cfs }) => {
 				col.map_or_else(|| DatabaseIterator { iter: db.iterator_opt(IteratorMode::Start, &self.read_opts) },
-					|c| DatabaseIterator { iter: db.iterator_cf_opt(cfs[c as usize], IteratorMode::Start, &self.read_opts).unwrap() })
+					|c| DatabaseIterator { iter: db.iterator_cf_opt(cfs[c as usize], IteratorMode::Start, &self.read_opts)
+						.expect("iterator params are valid; qed") })
 			},
 			None => panic!("Not supported yet") //TODO: return an empty iterator or change return type
 		}

util/src/memorydb.rs

@@ -148,7 +148,7 @@ impl MemoryDB {
 				(*p).insert(key.clone(), (value, 0));
 			}
 		}
-		self.raw(key).unwrap()
+		self.raw(key).expect("entry just inserted into data; qed")
 	}
 
 	/// Returns the size of allocated heap memory

util/src/trie/triedb.rs

@@ -296,7 +296,7 @@ impl<'a> TrieDBIterator<'a> {
 			status: Status::Entering,
 			node: try!(self.db.get_node(d, &mut NoOp, 0)),
 		});
-		match self.trail.last().unwrap().node {
+		match self.trail.last().expect("just pushed item; qed").node {
 			Node::Leaf(n, _) | Node::Extension(n, _) => { self.key_nibbles.extend(n.iter()); },
 			_ => {}
 		}
@@ -346,7 +346,8 @@ impl<'a> Iterator for TrieDBIterator<'a> {
 				(Status::AtChild(i), Node::Branch(children, _)) if children[i].len() > 0 => {
 					match i {
 						0 => self.key_nibbles.push(0),
-						i => *self.key_nibbles.last_mut().unwrap() = i as u8,
+						i => *self.key_nibbles.last_mut()
+							.expect("pushed as 0; moves sequentially; removed afterwards; qed") = i as u8,
 					}
 					if let Err(e) = self.descend(children[i]) {
 						return Some(Err(e));

util/src/trie/triedbmut.rs

@@ -744,7 +744,8 @@ impl<'a> TrieDBMut<'a> {
 					(UsedIndex::One(a), None) => {
 						// only one onward node. make an extension.
 						let new_partial = NibbleSlice::new_offset(&[a], 1).encoded(false);
-						let new_node = Node::Extension(new_partial, children[a as usize].take().unwrap());
+						let child = children[a as usize].take().expect("used_index only set if occupied; qed");
+						let new_node = Node::Extension(new_partial, child);
 						self.fix(new_node)
 					}
 					(UsedIndex::None, Some(value)) => {