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-rw-r--r--mfbt/tests/TestWeakPtr.cpp145
1 files changed, 145 insertions, 0 deletions
diff --git a/mfbt/tests/TestWeakPtr.cpp b/mfbt/tests/TestWeakPtr.cpp
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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);
+}