Initial version

code/threads/synchlist.h

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+// synchlist.h 
+//      Data structures for synchronized access to a list.
+//
+//      Implemented by surrounding the List abstraction
+//      with synchronization routines.
+//
+// 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 SYNCHLIST_H
+#define SYNCHLIST_H
+
+#include "copyright.h"
+#include "list.h"
+#include "synch.h"
+
+// The following class defines a "synchronized list" -- a list for which:
+// these constraints hold:
+//      1. Threads trying to remove an item from a list will
+//      wait until the list has an element on it.
+//      2. One thread at a time can access list data structures
+
+class SynchList:public dontcopythis
+{
+  public:
+    SynchList ();		// initialize a synchronized list
+    ~SynchList ();		// de-allocate a synchronized list
+
+    void Append (void *item);	// append item to the end of the list,
+    // and wake up any thread waiting in remove
+    void *Remove ();		// remove the first item from the front of
+    // the list, waiting if the list is empty
+    // apply function to every item in the list
+    void Mapcar (VoidFunctionPtr func);
+
+  private:
+      List * list;		// the unsynchronized list
+    Lock *lock;			// enforce mutual exclusive access to the list
+    Condition *listEmpty;	// wait in Remove if the list is empty
+};
+
+#endif // SYNCHLIST_H