Refactored executor to be more like in 2.0 and broke out the priority queue-related...

[casparcg] / common / semaphore.h

diff --git a/common/semaphore.h b/common/semaphore.h
index bd3c6d7ecea49b10b4853133945aa18f8a893a83..1a384397e99c936ab849ed1bacac3cff5023c015 100644 (file)
--- a/common/semaphore.h
+++ b/common/semaphore.h
@@ -155,4 +155,44 @@ public:
        }
 };
 
+/**
+ * Enables RAII-style acquire/release on scope exit unless committed.
+ */
+class acquire_transaction : boost::noncopyable
+{
+       semaphore& semaphore_;
+       bool committed_;
+public:
+       /**
+        * Constructor.
+        *
+        * @param semaphore        The semaphore to acquire one permit from.
+        * @param already_acquired Whether a permit has already been acquired or not.
+        */
+       acquire_transaction(semaphore& semaphore, bool already_acquired = false)
+               : semaphore_(semaphore)
+               , committed_(false)
+       {
+               if (!already_acquired)
+                       semaphore_.acquire();
+       }
+
+       /**
+        * Destructor that will release one permit if commit() has not been called.
+        */
+       ~acquire_transaction()
+       {
+               if (!committed_)
+                       semaphore_.release();
+       }
+
+       /**
+        * Ensure that the acquired permit is kept on destruction.
+        */
+       void commit()
+       {
+               committed_ = true;
+       }
+};
+
 }