Merge branch 'norris'

[model-checker.git] / schedule.cc

diff --git a/schedule.cc b/schedule.cc
index abb3e4b3975f34c3cbaf876ead0af680699864d9..be4a92f739a1129bb2aa4bee50bb23ba0a3f8556 100644 (file)
--- a/schedule.cc
+++ b/schedule.cc
@@ -1,26 +1,107 @@
-#include "libthreads.h"
+#include "threads.h"
 #include "schedule.h"
 #include "common.h"
 #include "model.h"
 
-void Scheduler::add_thread(struct thread *t)
+/** Constructor */
+Scheduler::Scheduler() :
+       current(NULL)
 {
-       DEBUG("thread %d\n", t->id);
-       queue.push(t);
 }
 
-struct thread *Scheduler::next_thread(void)
+/**
+ * Add a Thread to the scheduler's ready list.
+ * @param t The Thread to add
+ */
+void Scheduler::add_thread(Thread *t)
 {
-       if (queue.empty())
-               return NULL;
+       DEBUG("thread %d\n", t->get_id());
+       readyList.push_back(t);
+}
 
-       current = queue.front();
-       queue.pop();
+/**
+ * Remove a given Thread from the scheduler.
+ * @param t The Thread to remove
+ */
+void Scheduler::remove_thread(Thread *t)
+{
+       if (current == t)
+               current = NULL;
+       else
+               readyList.remove(t);
+}
 
-       return current;
+/**
+ * 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);
 }
 
-struct thread *Scheduler::get_current_thread(void)
+/**
+ * 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.
+ *
+ * @param t Thread to run, if chosen by an external entity (e.g.,
+ * ModelChecker). May be NULL to indicate no external choice.
+ * @return The next Thread to run
+ */
+Thread * Scheduler::next_thread(Thread *t)
+{
+       if (t != NULL) {
+               current = t;
+               readyList.remove(t);
+       } else if (readyList.empty()) {
+               t = NULL;
+       } else {
+               t = readyList.front();
+               current = t;
+               readyList.pop_front();
+       }
+
+       print();
+
+       return t;
+}
+
+/**
+ * @return The currently-running Thread
+ */
+Thread * Scheduler::get_current_thread() const
 {
        return current;
 }
+
+/**
+ * Print debugging information about the current state of the scheduler. Only
+ * prints something if debugging is enabled.
+ */
+void Scheduler::print() const
+{
+       if (current)
+               DEBUG("Current thread: %d\n", current->get_id());
+       else
+               DEBUG("No current thread\n");
+       DEBUG("Num. threads in ready list: %zu\n", readyList.size());
+
+       std::list<Thread *, MyAlloc< Thread * > >::const_iterator it;
+       for (it = readyList.begin(); it != readyList.end(); it++)
+               DEBUG("In ready list: thread %d\n", (*it)->get_id());
+}