xpcom/base/ClearOnShutdown.h@129ffea94266
xpcom/base/ClearOnShutdown.h
Sat, 03 Jan 2015 20:18:00 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Sat, 03 Jan 2015 20:18:00 +0100
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
- permissions
- -rw-r--r--
Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set sw=2 ts=8 et ft=cpp : */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
7 #ifndef mozilla_ClearOnShutdown_h
8 #define mozilla_ClearOnShutdown_h
10 #include "mozilla/LinkedList.h"
11 #include "mozilla/StaticPtr.h"
12 #include "MainThreadUtils.h"
14 /*
15 * This header exports one public method in the mozilla namespace:
16 *
17 * template<class SmartPtr>
18 * void ClearOnShutdown(SmartPtr *aPtr)
19 *
20 * This function takes a pointer to a smart pointer and nulls the smart pointer
21 * on shutdown.
22 *
23 * This is useful if you have a global smart pointer object which you don't
24 * want to "leak" on shutdown.
25 *
26 * Although ClearOnShutdown will work with any smart pointer (i.e., nsCOMPtr,
27 * nsRefPtr, nsAutoPtr, StaticRefPtr, and StaticAutoPtr), you probably want to
28 * use it only with StaticRefPtr and StaticAutoPtr. There is no way to undo a
29 * call to ClearOnShutdown, so you can call it only on smart pointers which you
30 * know will live until the program shuts down. In practice, these are likely
31 * global variables, which should be Static{Ref,Auto}Ptr.
32 *
33 * ClearOnShutdown is currently main-thread only because we don't want to
34 * accidentally free an object from a different thread than the one it was
35 * created on.
36 */
38 namespace mozilla {
39 namespace ClearOnShutdown_Internal {
41 class ShutdownObserver : public LinkedListElement<ShutdownObserver>
42 {
43 public:
44 virtual void Shutdown() = 0;
45 virtual ~ShutdownObserver() {}
46 };
48 template<class SmartPtr>
49 class PointerClearer : public ShutdownObserver
50 {
51 public:
52 PointerClearer(SmartPtr *aPtr)
53 : mPtr(aPtr)
54 {}
56 virtual void Shutdown()
57 {
58 if (mPtr) {
59 *mPtr = nullptr;
60 }
61 }
63 private:
64 SmartPtr *mPtr;
65 };
67 extern bool sHasShutDown;
68 extern StaticAutoPtr<LinkedList<ShutdownObserver> > sShutdownObservers;
70 } // namespace ClearOnShutdown_Internal
72 template<class SmartPtr>
73 inline void ClearOnShutdown(SmartPtr *aPtr)
74 {
75 using namespace ClearOnShutdown_Internal;
77 MOZ_ASSERT(NS_IsMainThread());
78 MOZ_ASSERT(!sHasShutDown);
80 if (!sShutdownObservers) {
81 sShutdownObservers = new LinkedList<ShutdownObserver>();
82 }
83 sShutdownObservers->insertBack(new PointerClearer<SmartPtr>(aPtr));
84 }
86 // Called when XPCOM is shutting down, after all shutdown notifications have
87 // been sent and after all threads' event loops have been purged.
88 inline void KillClearOnShutdown()
89 {
90 using namespace ClearOnShutdown_Internal;
92 MOZ_ASSERT(NS_IsMainThread());
94 if (sShutdownObservers) {
95 ShutdownObserver *observer;
96 while ((observer = sShutdownObservers->popFirst())) {
97 observer->Shutdown();
98 delete observer;
99 }
100 }
102 sShutdownObservers = nullptr;
103 sHasShutDown = true;
104 }
106 } // namespace mozilla
108 #endif
