accounts: fix data race when key is locked after the unlock timeout

While here, also improve the docs and speed up the tests.
The tests used the scrypt keystore with ridiculous settins and took 20s
each.

1 files changed, 8 insertions, 5 deletions

diff --git a/accounts/account_manager.go b/accounts/account_manager.go
index 2a9d9b0ae..c6c2787dc 100644
--- a/accounts/account_manager.go
+++ b/accounts/account_manager.go
@@ -78,8 +78,8 @@ func (am *Manager) DeleteAccount(address common.Address, auth string) error {
 
 func (am *Manager) Sign(a Account, toSign []byte) (signature []byte, err error) {
 	am.mutex.RLock()
+	defer am.mutex.RUnlock()
 	unlockedKey, found := am.unlocked[a.Address]
-	am.mutex.RUnlock()
 	if !found {
 		return nil, ErrLocked
 	}
@@ -87,14 +87,17 @@ func (am *Manager) Sign(a Account, toSign []byte) (signature []byte, err error)
 	return signature, err
 }
 
-// unlock indefinitely
+// Unlock unlocks the given account indefinitely.
 func (am *Manager) Unlock(addr common.Address, keyAuth string) error {
 	return am.TimedUnlock(addr, keyAuth, 0)
 }
 
-// Unlock unlocks the account with the given address. The account
-// stays unlocked for the duration of timeout
-// it timeout is 0 the account is unlocked for the entire session
+// TimedUnlock unlocks the account with the given address. The account
+// stays unlocked for the duration of timeout. A timeout of 0 unlocks the account
+// until the program exits.
+//
+// If the accout is already unlocked, TimedUnlock extends or shortens
+// the active unlock timeout.
 func (am *Manager) TimedUnlock(addr common.Address, keyAuth string, timeout time.Duration) error {
 	key, err := am.keyStore.GetKey(addr, keyAuth)
 	if err != nil {