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PyGWeakReference.cpp
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00001 /* ***** BEGIN LICENSE BLOCK *****
00002  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00003  *
00004  * The contents of this file are subject to the Mozilla Public License Version
00005  * 1.1 (the "License"); you may not use this file except in compliance with
00006  * the License. You may obtain a copy of the License at
00007  * http://www.mozilla.org/MPL/
00008  *
00009  * Software distributed under the License is distributed on an "AS IS" basis,
00010  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00011  * for the specific language governing rights and limitations under the
00012  * License.
00013  *
00014  * The Original Code is the Python XPCOM language bindings.
00015  *
00016  * The Initial Developer of the Original Code is
00017  * ActiveState Tool Corp.
00018  * Portions created by the Initial Developer are Copyright (C) 2000
00019  * the Initial Developer. All Rights Reserved.
00020  *
00021  * Contributor(s):
00022  *   Mark Hammond <MarkH@ActiveState.com> (original author)
00023  *
00024  * Alternatively, the contents of this file may be used under the terms of
00025  * either the GNU General Public License Version 2 or later (the "GPL"), or
00026  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00027  * in which case the provisions of the GPL or the LGPL are applicable instead
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00036  * ***** END LICENSE BLOCK ***** */
00037 
00038 // PyGWeakReference - implements weak references for gateways.
00039 //
00040 // This code is part of the XPCOM extensions for Python.
00041 //
00042 // Written November 2000 by Mark Hammond.
00043 //
00044 // Based heavily on the Python COM support, which is
00045 // (c) Mark Hammond and Greg Stein.
00046 //
00047 // (c) 2000, ActiveState corp.
00048 
00049 #include "PyXPCOM_std.h"
00050 
00051 PyXPCOM_GatewayWeakReference::PyXPCOM_GatewayWeakReference( PyG_Base *base )
00052 {
00053        m_pBase = base;
00054 
00055 #ifdef NS_BUILD_REFCNT_LOGGING
00056        // bloat view uses 40 chars - stick "(WR)" at the end of this position.
00057        strncpy(refcntLogRepr, m_pBase->refcntLogRepr, sizeof(refcntLogRepr));
00058        refcntLogRepr[sizeof(refcntLogRepr)-1] = '\0';
00059        char *dest = refcntLogRepr + ((strlen(refcntLogRepr) > 36) ? 36 : strlen(refcntLogRepr));
00060        strcpy(dest, "(WR)");
00061 #endif // NS_BUILD_REFCNT_LOGGING
00062 }
00063 
00064 PyXPCOM_GatewayWeakReference::~PyXPCOM_GatewayWeakReference()
00065 {
00066        // Simply zap my reference to the gateway!
00067        // No need to zap my gateway's reference to me, as
00068        // it already holds a reference, so if we are destructing,
00069        // then it can't possibly hold one.
00070        m_pBase = NULL;
00071 }
00072 
00073 nsrefcnt
00074 PyXPCOM_GatewayWeakReference::AddRef(void)
00075 {
00076        nsrefcnt cnt = (nsrefcnt) PR_AtomicIncrement((PRInt32*)&mRefCnt);
00077 #ifdef NS_BUILD_REFCNT_LOGGING
00078        NS_LOG_ADDREF(this, cnt, refcntLogRepr, sizeof(*this));
00079 #endif
00080        return cnt;
00081 }
00082 
00083 nsrefcnt
00084 PyXPCOM_GatewayWeakReference::Release(void)
00085 {
00086        nsrefcnt cnt = (nsrefcnt) PR_AtomicDecrement((PRInt32*)&mRefCnt);
00087 #ifdef NS_BUILD_REFCNT_LOGGING
00088        NS_LOG_RELEASE(this, cnt, refcntLogRepr);
00089 #endif
00090        if ( cnt == 0 )
00091               delete this;
00092        return cnt;
00093 }
00094 
00095 NS_IMPL_THREADSAFE_QUERY_INTERFACE1(PyXPCOM_GatewayWeakReference, nsIWeakReference)
00096 
00097 NS_IMETHODIMP
00098 PyXPCOM_GatewayWeakReference::QueryReferent(REFNSIID iid, void * *ret)
00099 {
00100        { 
00101        // Temp scope for lock.  We can't hold the lock during
00102        // a QI, as this may itself need the lock.
00103        // Make sure our object isn't dieing right now on another thread.
00104        CEnterLeaveXPCOMFramework _celf;
00105        if (m_pBase == NULL)
00106               return NS_ERROR_NULL_POINTER;
00107        m_pBase->AddRef(); // Can't die while we have a ref.
00108        } // end of lock scope - lock unlocked.
00109        nsresult nr = m_pBase->QueryInterface(iid, ret);
00110        m_pBase->Release();
00111        return nr;
00112 }