Initial version

code/threads/scheduler.h

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+// scheduler.h 
+//      Data structures for the thread dispatcher and scheduler.
+//      Primarily, the list of threads that are ready to run.
+//
+// Copyright (c) 1992-1993 The Regents of the University of California.
+// All rights reserved.  See copyright.h for copyright notice and limitation 
+// of liability and disclaimer of warranty provisions.
+
+#ifndef SCHEDULER_H
+#define SCHEDULER_H
+
+#include "copyright.h"
+#include "list.h"
+#include "thread.h"
+
+// The following class defines the scheduler/dispatcher abstraction -- 
+// the data structures and operations needed to keep track of which 
+// thread is running, and which threads are ready but not running.
+
+class Scheduler:public dontcopythis
+{
+  public:
+    Scheduler ();		// Initialize list of ready threads 
+    void Stop ();		// Prevent further context switches
+    ~Scheduler ();		// De-allocate ready list
+
+    void ReadyToRun (Thread * thread);	// Thread can be dispatched.
+    Thread *FindNextToRun ();	// Dequeue first thread on the ready 
+    // list, if any, and return thread.
+    void Run (Thread * nextThread);	// Cause nextThread to start running
+    void Print ();		// Print contents of ready list
+
+  private:
+    List * readyList;		// queue of threads that are ready to run,
+    				// but not running
+    bool halted;		// Whether we should prevent context switches
+};
+
+#endif // SCHEDULER_H