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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_WEAKREFERENCE_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.");
}
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