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