From e5ca5e09265a0cff60e9262897b02fbd4b171957 Mon Sep 17 00:00:00 2001
From: Robert Habermeier <rphmeier@gmail.com>
Date: Mon, 13 Jun 2016 12:48:19 +0200
Subject: [PATCH] [REQUIRES DB UPGRADE] have account_db use address hash

---
 ethcore/src/account_db.rs | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/ethcore/src/account_db.rs b/ethcore/src/account_db.rs
index c21ea2993..dc36a40af 100644
--- a/ethcore/src/account_db.rs
+++ b/ethcore/src/account_db.rs
@@ -8,19 +8,26 @@ static NULL_RLP_STATIC: [u8; 1] = [0x80; 1];
 /// Transforms trie node keys for the database
 pub struct AccountDB<'db> {
 	db: &'db HashDB,
-	address: H256,
+	address_hash: H256,
 }
 
+// used to ensure that account storage keys are unique in the database.
 #[inline]
 fn combine_key<'a>(address: &'a H256, key: &'a H256) -> H256 {
 	address ^ key
 }
 
 impl<'db> AccountDB<'db> {
+	/// Create an AccountDB from an address.
 	pub fn new(db: &'db HashDB, address: &Address) -> AccountDB<'db> {
+		Self::from_hash(db, address.sha3())
+	}
+
+	/// Create an AccountDB from an address' hash.
+	pub fn from_hash(db: &'db HashDB, address_hash: H256) -> AccountDB<'db> {
 		AccountDB {
 			db: db,
-			address: address.into(),
+			address_hash: address_hash
 		}
 	}
 }
@@ -34,14 +41,14 @@ impl<'db> HashDB for AccountDB<'db>{
 		if key == &SHA3_NULL_RLP {
 			return Some(&NULL_RLP_STATIC);
 		}
-		self.db.lookup(&combine_key(&self.address, key))
+		self.db.lookup(&combine_key(&self.address_hash, key))
 	}
 
 	fn exists(&self, key: &H256) -> bool {
 		if key == &SHA3_NULL_RLP {
 			return true;
 		}
-		self.db.exists(&combine_key(&self.address, key))
+		self.db.exists(&combine_key(&self.address_hash, key))
 	}
 
 	fn insert(&mut self, _value: &[u8]) -> H256 {
@@ -60,20 +67,26 @@ impl<'db> HashDB for AccountDB<'db>{
 /// DB backend wrapper for Account trie
 pub struct AccountDBMut<'db> {
 	db: &'db mut HashDB,
-	address: H256,
+	address_hash: H256,
 }
 
 impl<'db> AccountDBMut<'db> {
+	/// Create an AccountDBMut from an address.
 	pub fn new(db: &'db mut HashDB, address: &Address) -> AccountDBMut<'db> {
+		Self::from_hash(db, address.sha3())
+	}
+
+	/// Create an AccountDBMut from an address' hash.
+	pub fn from_hash(db: &'db mut HashDB, address_hash: H256) -> AccountDBMut<'db> {
 		AccountDBMut {
 			db: db,
-			address: address.into(),
+			address_hash: address_hash,
 		}
 	}
 
 	#[allow(dead_code)]
 	pub fn immutable(&'db self) -> AccountDB<'db> {
-		AccountDB { db: self.db, address: self.address.clone() }
+		AccountDB { db: self.db, address_hash: self.address_hash.clone() }
 	}
 }
 
@@ -86,14 +99,14 @@ impl<'db> HashDB for AccountDBMut<'db>{
 		if key == &SHA3_NULL_RLP {
 			return Some(&NULL_RLP_STATIC);
 		}
-		self.db.lookup(&combine_key(&self.address, key))
+		self.db.lookup(&combine_key(&self.address_hash, key))
 	}
 
 	fn exists(&self, key: &H256) -> bool {
 		if key == &SHA3_NULL_RLP {
 			return true;
 		}
-		self.db.exists(&combine_key(&self.address, key))
+		self.db.exists(&combine_key(&self.address_hash, key))
 	}
 
 	fn insert(&mut self, value: &[u8]) -> H256 {
@@ -101,7 +114,7 @@ impl<'db> HashDB for AccountDBMut<'db>{
 			return SHA3_NULL_RLP.clone();
 		}
 		let k = value.sha3();
-		let ak = combine_key(&self.address, &k);
+		let ak = combine_key(&self.address_hash, &k);
 		self.db.emplace(ak, value.to_vec());
 		k
 	}
@@ -110,7 +123,7 @@ impl<'db> HashDB for AccountDBMut<'db>{
 		if key == SHA3_NULL_RLP {
 			return;
 		}
-		let key = combine_key(&self.address, &key);
+		let key = combine_key(&self.address_hash, &key);
 		self.db.emplace(key, value.to_vec())
 	}
 
@@ -118,7 +131,7 @@ impl<'db> HashDB for AccountDBMut<'db>{
 		if key == &SHA3_NULL_RLP {
 			return;
 		}
-		let key = combine_key(&self.address, key);
+		let key = combine_key(&self.address_hash, key);
 		self.db.kill(&key)
 	}
 }