From: Brian Norris <banorris@uci.edu>
Date: Thu, 6 Sep 2012 20:37:35 +0000 (-0700)
Subject: schedule: add wait and wake functions
X-Git-Tag: pldi2013~235^2^2~4
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9b99c30c39f17b485eeca827a9e83806bf67ffac;p=model-checker.git

schedule: add wait and wake functions

These functions will be used to prevent execution of threads that should be
waiting for another event (e.g., a THREAD_JOIN should cause a thread to wait
for another thread's exit).
---

diff --git a/schedule.cc b/schedule.cc
index d96172e..be4a92f 100644
--- a/schedule.cc
+++ b/schedule.cc
@@ -31,6 +31,30 @@ void Scheduler::remove_thread(Thread *t)
 		readyList.remove(t);
 }
 
+/**
+ * Force one Thread to wait on another Thread. The "join" Thread should
+ * eventually wake up the waiting Thread via Scheduler::wake.
+ * @param wait The Thread that should wait
+ * @param join The Thread on which we are waiting.
+ */
+void Scheduler::wait(Thread *wait, Thread *join)
+{
+	ASSERT(!join->is_complete());
+	remove_thread(wait);
+	join->push_wait_list(wait);
+	wait->set_state(THREAD_BLOCKED);
+}
+
+/**
+ * Wake a Thread up that was previously waiting (see Scheduler::wait)
+ * @param t The Thread to wake up
+ */
+void Scheduler::wake(Thread *t)
+{
+	add_thread(t);
+	t->set_state(THREAD_READY);
+}
+
 /**
  * Remove one Thread from the scheduler. This implementation defaults to FIFO,
  * if a thread is not already provided.
diff --git a/schedule.h b/schedule.h
index c3d029f..664b2d2 100644
--- a/schedule.h
+++ b/schedule.h
@@ -18,6 +18,8 @@ public:
 	Scheduler();
 	void add_thread(Thread *t);
 	void remove_thread(Thread *t);
+	void wait(Thread *wait, Thread *join);
+	void wake(Thread *t);
 	Thread * next_thread(Thread *t);
 	Thread * get_current_thread() const;
 	void print() const;