#include "common.h"
#include "model.h"
+/** Constructor */
+Scheduler::Scheduler() :
+ current(NULL)
+{
+}
+
+/**
+ * Add a Thread to the scheduler's ready list.
+ * @param t The Thread to add
+ */
void Scheduler::add_thread(Thread *t)
{
DEBUG("thread %d\n", t->get_id());
readyList.push_back(t);
}
-Thread *Scheduler::next_thread(void)
+/**
+ * Remove a given Thread from the scheduler.
+ * @param t The Thread to remove
+ */
+void Scheduler::remove_thread(Thread *t)
{
- if (readyList.empty())
- return NULL;
+ if (current == t)
+ current = NULL;
+ else
+ readyList.remove(t);
+}
- current = readyList.front();
- readyList.pop_front();
+/**
+ * Prevent a Thread from being scheduled. The sleeping Thread should be
+ * re-awoken via Scheduler::wake.
+ * @param thread The Thread that should sleep
+ */
+void Scheduler::sleep(Thread *t)
+{
+ remove_thread(t);
+ t->set_state(THREAD_BLOCKED);
+}
- return current;
+/**
+ * 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);
}
-Thread *Scheduler::get_current_thread(void)
+/**
+ * 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());
+}