mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-02 15:15:23 +00:00
124 lines
3.4 KiB
C++
124 lines
3.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#include "mozilla/WeakPtr.h"
|
|
|
|
using mozilla::SupportsWeakPtr;
|
|
using mozilla::WeakPtr;
|
|
|
|
// To have a class C support weak pointers, inherit from SupportsWeakPtr<C>.
|
|
class C : public SupportsWeakPtr<C>
|
|
{
|
|
public:
|
|
MOZ_DECLARE_REFCOUNTED_TYPENAME(C)
|
|
|
|
int mNum;
|
|
|
|
C()
|
|
: mNum(0)
|
|
{}
|
|
|
|
~C()
|
|
{
|
|
// Setting mNum in the destructor allows us to test against use-after-free below
|
|
mNum = 0xDEAD;
|
|
}
|
|
|
|
void act() {}
|
|
|
|
bool isConst() {
|
|
return false;
|
|
}
|
|
|
|
bool isConst() const {
|
|
return true;
|
|
}
|
|
};
|
|
|
|
bool isConst(C*)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
bool isConst(const C*)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
int
|
|
main()
|
|
{
|
|
C* c1 = new C;
|
|
MOZ_RELEASE_ASSERT(c1->mNum == 0);
|
|
|
|
// Get weak pointers to c1. The first time,
|
|
// a reference-counted WeakReference object is created that
|
|
// can live beyond the lifetime of 'c1'. The WeakReference
|
|
// object will be notified of 'c1's destruction.
|
|
WeakPtr<C> w1 = c1;
|
|
// Test a weak pointer for validity before using it.
|
|
MOZ_RELEASE_ASSERT(w1);
|
|
MOZ_RELEASE_ASSERT(w1 == c1);
|
|
w1->mNum = 1;
|
|
w1->act();
|
|
|
|
// Test taking another WeakPtr<C> to c1
|
|
WeakPtr<C> w2 = c1;
|
|
MOZ_RELEASE_ASSERT(w2);
|
|
MOZ_RELEASE_ASSERT(w2 == c1);
|
|
MOZ_RELEASE_ASSERT(w2 == w1);
|
|
MOZ_RELEASE_ASSERT(w2->mNum == 1);
|
|
|
|
// Test a WeakPtr<const C>
|
|
WeakPtr<const C> w3const = c1;
|
|
MOZ_RELEASE_ASSERT(w3const);
|
|
MOZ_RELEASE_ASSERT(w3const == c1);
|
|
MOZ_RELEASE_ASSERT(w3const == w1);
|
|
MOZ_RELEASE_ASSERT(w3const == w2);
|
|
MOZ_RELEASE_ASSERT(w3const->mNum == 1);
|
|
|
|
// Test const-correctness of operator-> and operator T*
|
|
MOZ_RELEASE_ASSERT(!w1->isConst());
|
|
MOZ_RELEASE_ASSERT(w3const->isConst());
|
|
MOZ_RELEASE_ASSERT(!isConst(w1));
|
|
MOZ_RELEASE_ASSERT(isConst(w3const));
|
|
|
|
// Test that when a WeakPtr is destroyed, it does not destroy the object that it points to,
|
|
// and it does not affect other WeakPtrs pointing to the same object (e.g. it does not
|
|
// destroy the WeakReference object).
|
|
{
|
|
WeakPtr<C> w4local = c1;
|
|
MOZ_RELEASE_ASSERT(w4local == c1);
|
|
}
|
|
// Now w4local has gone out of scope. If that had destroyed c1, then the following would fail
|
|
// for sure (see C::~C()).
|
|
MOZ_RELEASE_ASSERT(c1->mNum == 1);
|
|
// Check that w4local going out of scope hasn't affected other WeakPtr's pointing to c1
|
|
MOZ_RELEASE_ASSERT(w1 == c1);
|
|
MOZ_RELEASE_ASSERT(w2 == c1);
|
|
|
|
// Now construct another C object and test changing what object a WeakPtr points to
|
|
C* c2 = new C;
|
|
c2->mNum = 2;
|
|
MOZ_RELEASE_ASSERT(w2->mNum == 1); // w2 was pointing to c1
|
|
w2 = c2;
|
|
MOZ_RELEASE_ASSERT(w2);
|
|
MOZ_RELEASE_ASSERT(w2 == c2);
|
|
MOZ_RELEASE_ASSERT(w2 != c1);
|
|
MOZ_RELEASE_ASSERT(w2 != w1);
|
|
MOZ_RELEASE_ASSERT(w2->mNum == 2);
|
|
|
|
// Destroying the underlying object clears weak pointers to it.
|
|
// It should not affect pointers that are not currently pointing to it.
|
|
delete c1;
|
|
MOZ_RELEASE_ASSERT(!w1, "Deleting an object should clear WeakPtr's to it.");
|
|
MOZ_RELEASE_ASSERT(!w3const, "Deleting an object should clear WeakPtr's to it.");
|
|
MOZ_RELEASE_ASSERT(w2, "Deleting an object should not clear WeakPtr that are not pointing to it.");
|
|
|
|
delete c2;
|
|
MOZ_RELEASE_ASSERT(!w2, "Deleting an object should clear WeakPtr's to it.");
|
|
}
|