Clean the code using a lock guard

kernel/include/semaphore.hpp

@@ -8,6 +8,8 @@
 #ifndef SEMAPHORE_H
 #define SEMAPHORE_H
 
+#include "stl/lock_guard.hpp"
+
 #include "spinlock.hpp"
 #include "vector.hpp"
 
@@ -25,7 +27,7 @@ public:
     }
 
     void wait(){
-        lock.acquire();
+        std::lock_guard<spinlock> l(lock);
 
         if(value > 0){
             --value;
@@ -33,12 +35,10 @@ public:
             queue.push_back(scheduler::get_pid());
             scheduler::block_process(scheduler::get_pid());
         }
-
-        lock.release();
     }
 
     void signal(){
-        lock.acquire();
+        std::lock_guard<spinlock> l(lock);
 
         if(queue.empty()){
             ++value;
@@ -49,8 +49,6 @@ public:
             //No need to increment value, the process won't
             //decrement it
         }
-
-        lock.release();
     }
 };
 

kernel/include/stl/lock_guard.hpp

@@ -0,0 +1,24 @@
+//=======================================================================
+// Copyright Baptiste Wicht 2013-2014.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//=======================================================================
+
+#ifndef LOCK_GUARD_HPP
+#define LOCK_GUARD_HPP
+
+template<typename Lock>
+struct lock_guard {
+    Lock& lock;
+
+    lock_guard(Lock& lock) : lock(lock) {
+        lock.acquire();
+    }
+
+    ~lock_guard(){
+        lock.release();
+    }
+}
+
+#endif