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/* -*- 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;
static char IamB[] = "B";
static char IamC[] = "C";
static char IamD[] = "D";
class B : public SupportsWeakPtr {
public:
char const* whoAmI() const { return IamB; }
};
// To have a class C support weak pointers, inherit from SupportsWeakPtr.
class C : public SupportsWeakPtr {
public:
int mNum;
C() : mNum(0) {}
~C() {
// Setting mNum in the destructor allows us to test against use-after-free
// below
mNum = 0xDEAD;
}
char const* whoAmI() const { return IamC; }
void act() {}
bool isConst() { return false; }
bool isConst() const { return true; }
};
// Derived from a class that supports weakptr, but doesn't implement itself
// To check upcast works as expected
class D : public B {
public:
char const* whoAmI() const { return IamD; }
};
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.");
// Check that we correctly upcast to the base class supporting weakptr
D* d = new D;
WeakPtr<B> db = d;
// You should be able to use WeakPtr<D> even if it's a base class which
// implements SupportsWeakPtr.
WeakPtr<D> weakd = d;
MOZ_RELEASE_ASSERT(db->whoAmI() == IamB);
MOZ_RELEASE_ASSERT(weakd.get() == db.get());
delete d;
MOZ_RELEASE_ASSERT(!db);
MOZ_RELEASE_ASSERT(!weakd);
}
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