From f393b600d43bef1f2ac5becc9850c8ed5ee45bf8 Mon Sep 17 00:00:00 2001
From: Radu Ioan Fericean <radu@fericean.ro>
Date: Fri, 10 Jan 2014 11:46:18 +0200
Subject: [PATCH] better locking for account guard

---
 engine/accountlock.go | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/engine/accountlock.go b/engine/accountlock.go
index a781447ed..6ea5c104d 100644
--- a/engine/accountlock.go
+++ b/engine/accountlock.go
@@ -30,7 +30,7 @@ func init() {
 
 type AccountLock struct {
 	queue map[string]chan bool
-	sync.Mutex
+	sync.RWMutex
 }
 
 func NewAccountLock() *AccountLock {
@@ -38,13 +38,15 @@ func NewAccountLock() *AccountLock {
 }
 
 func (cm *AccountLock) GuardGetCost(name string, handler func() (*CallCost, error)) (reply *CallCost, err error) {
-	cm.Lock()
+	cm.RLock()
 	lock, exists := AccLock.queue[name]
+	cm.RUnlock()
 	if !exists {
+		cm.Lock()
 		lock = make(chan bool, 1)
 		AccLock.queue[name] = lock
+		cm.Unlock()
 	}
-	cm.Unlock()
 	lock <- true
 	reply, err = handler()
 	<-lock
@@ -52,13 +54,35 @@ func (cm *AccountLock) GuardGetCost(name string, handler func() (*CallCost, erro
 }
 
 func (cm *AccountLock) Guard(name string, handler func() (float64, error)) (reply float64, err error) {
+	cm.RLock()
 	lock, exists := AccLock.queue[name]
+	cm.RUnlock()
 	if !exists {
+		cm.Lock()
 		lock = make(chan bool, 1)
 		AccLock.queue[name] = lock
+		cm.Unlock()
 	}
 	lock <- true
 	reply, err = handler()
 	<-lock
 	return
 }
+
+func (cm *AccountLock) GuardMany(names []string, handler func() (float64, error)) (reply float64, err error) {
+	for _, name := range names {
+		cm.RLock()
+		lock, exists := AccLock.queue[name]
+		cm.RUnlock()
+		if !exists {
+			cm.Lock()
+			lock = make(chan bool, 1)
+			AccLock.queue[name] = lock
+			cm.Unlock()
+		}
+		lock <- true
+		reply, err = handler()
+		<-lock
+	}
+	return
+}