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weakReferenceList.cxx
00001 // Filename: weakReferenceList.cxx
00002 // Created by:  drose (27Sep04)
00003 //
00004 ////////////////////////////////////////////////////////////////////
00005 //
00006 // PANDA 3D SOFTWARE
00007 // Copyright (c) Carnegie Mellon University.  All rights reserved.
00008 //
00009 // All use of this software is subject to the terms of the revised BSD
00010 // license.  You should have received a copy of this license along
00011 // with this source code in a file named "LICENSE."
00012 //
00013 ////////////////////////////////////////////////////////////////////
00014 
00015 #include "weakReferenceList.h"
00016 #include "weakPointerToVoid.h"
00017 #include "pnotify.h"
00018 
00019 ////////////////////////////////////////////////////////////////////
00020 //     Function: WeakReferenceList::Constructor
00021 //       Access: Public
00022 //  Description: 
00023 ////////////////////////////////////////////////////////////////////
00024 WeakReferenceList::
00025 WeakReferenceList() {
00026 }
00027 
00028 ////////////////////////////////////////////////////////////////////
00029 //     Function: WeakReferenceList::Destructor
00030 //       Access: Public
00031 //  Description: The destructor tells all of the owned references that
00032 //               we're gone.
00033 ////////////////////////////////////////////////////////////////////
00034 WeakReferenceList::
00035 ~WeakReferenceList() {
00036   _lock.acquire();
00037   Pointers::iterator pi;
00038   for (pi = _pointers.begin(); pi != _pointers.end(); ++pi) {
00039     (*pi)->mark_deleted();
00040   }
00041   _lock.release();
00042 }
00043 
00044 ////////////////////////////////////////////////////////////////////
00045 //     Function: WeakReferenceList::add_reference
00046 //       Access: Public
00047 //  Description: Intended to be called only by WeakPointerTo (or by
00048 //               any class implementing a weak reference-counting
00049 //               pointer), this adds the indicated PointerToVoid
00050 //               structure to the list of such structures that are
00051 //               maintaining a weak pointer to this object.
00052 //
00053 //               When the WeakReferenceList destructs (presumably
00054 //               because its owning object destructs), the pointer
00055 //               within the PointerToVoid object will be set to NULL.
00056 ////////////////////////////////////////////////////////////////////
00057 void WeakReferenceList::
00058 add_reference(WeakPointerToVoid *ptv) {
00059   _lock.acquire();
00060   bool inserted = _pointers.insert(ptv).second;
00061   _lock.release();
00062   nassertv(inserted);
00063 }
00064 
00065 ////////////////////////////////////////////////////////////////////
00066 //     Function: WeakReferenceList::clear_reference
00067 //       Access: Public
00068 //  Description: Intended to be called only by WeakPointerTo (or by
00069 //               any class implementing a weak reference-counting
00070 //               pointer), this removes the indicated PointerToVoid
00071 //               structure from the list of such structures that are
00072 //               maintaining a weak pointer to this object.
00073 ////////////////////////////////////////////////////////////////////
00074 void WeakReferenceList::
00075 clear_reference(WeakPointerToVoid *ptv) {
00076   _lock.acquire();
00077   Pointers::iterator pi = _pointers.find(ptv);
00078   bool valid = (pi != _pointers.end());
00079   if (valid) {
00080     _pointers.erase(pi);
00081   }
00082   _lock.release();
00083   nassertv(valid);
00084 }
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