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fix state unsafety with a mostly-guaranteed handle (#1755) 

* fix state unsafety with a mostly-guaranteed handle

* ensure_cached takes a closure directly
This commit is contained in:
Robert Habermeier 2016-07-30 15:45:16 +02:00 committed by Gav Wood
parent f56b89010d
commit 53f1d7b6ff
1 changed files with 19 additions and 11 deletions
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30
ethcore/src/state.rs
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@ -167,22 +167,26 @@ impl State {
/// Get the balance of account `a`.
pub fn balance(&self, a: &Address) -> U256 {
self.get(a, false).as_ref().map_or(U256::zero(), |account| *account.balance())
self.ensure_cached(a, false,
|a| a.as_ref().map_or(U256::zero(), |account| *account.balance()))
}
/// Get the nonce of account `a`.
pub fn nonce(&self, a: &Address) -> U256 {
self.get(a, false).as_ref().map_or(U256::zero(), |account| *account.nonce())
self.ensure_cached(a, false,
|a| a.as_ref().map_or(U256::zero(), |account| *account.nonce()))
}
/// Mutate storage of account `address` so that it is `value` for `key`.
pub fn storage_at(&self, address: &Address, key: &H256) -> H256 {
self.get(address, false).as_ref().map_or(H256::new(), |a|a.storage_at(&AccountDB::new(self.db.as_hashdb(), address), key))
self.ensure_cached(address, false,
|a| a.as_ref().map_or(H256::new(), |a|a.storage_at(&AccountDB::new(self.db.as_hashdb(), address), key)))
}
/// Mutate storage of account `a` so that it is `value` for `key`.
pub fn code(&self, a: &Address) -> Option<Bytes> {
self.get(a, true).as_ref().map_or(None, |a|a.code().map(|x|x.to_vec()))
self.ensure_cached(a, true,
|a| a.as_ref().map_or(None, |a|a.code().map(|x|x.to_vec())))
}
/// Add `incr` to the balance of account `a`.
@ -306,11 +310,13 @@ impl State {
fn query_pod(&mut self, query: &PodState) {
for (ref address, ref pod_account) in query.get() {
if self.get(address, true).is_some() {
for key in pod_account.storage.keys() {
self.storage_at(address, key);
self.ensure_cached(address, true, |a| {
if a.is_some() {
for key in pod_account.storage.keys() {
self.storage_at(address, key);
}
}
}
});
}
}
@ -323,9 +329,10 @@ impl State {
pod_state::diff_pod(&state_pre.to_pod(), &pod_state_post)
}
/// Pull account `a` in our cache from the trie DB and return it.
/// Ensure account `a` is in our cache of the trie DB and return a handle for getting it.
/// `require_code` requires that the code be cached, too.
fn get<'a>(&'a self, a: &Address, require_code: bool) -> &'a Option<Account> {
fn ensure_cached<'a, F, U>(&'a self, a: &'a Address, require_code: bool, f: F) -> U
where F: FnOnce(&Option<Account>) -> U {
let have_key = self.cache.borrow().contains_key(a);
if !have_key {
let db = self.trie_factory.readonly(self.db.as_hashdb(), &self.root).expect(SEC_TRIE_DB_UNWRAP_STR);
@ -336,7 +343,8 @@ impl State {
account.cache_code(&AccountDB::new(self.db.as_hashdb(), a));
}
}
unsafe { ::std::mem::transmute(self.cache.borrow().get(a).unwrap()) }
f(self.cache.borrow().get(a).unwrap())
}
/// Pull account `a` in our cache from the trie DB. `require_code` requires that the code be cached, too.