synchlist.h

Go to the documentation of this file.

// 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:
    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

---