1 files changed, 127 insertions, 0 deletions
diff --git a/mfbt/tests/TestThreadSafeWeakPtr.cpp b/mfbt/tests/TestThreadSafeWeakPtr.cpp
new file mode 100644
index 0000000000..3670d15bc0
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+++ b/mfbt/tests/TestThreadSafeWeakPtr.cpp
@@ -0,0 +1,127 @@
+/* -*- 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/RefPtr.h"
+#include "mozilla/ThreadSafeWeakPtr.h"
+
+using mozilla::SupportsThreadSafeWeakPtr;
+using mozilla::ThreadSafeWeakPtr;
+
+// To have a class C support weak pointers, inherit from
+// SupportsThreadSafeWeakPtr<C>.
+class C : public SupportsThreadSafeWeakPtr<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() {}
+};
+
+// Test that declaring a ThreadSafeWeakPtr pointing to an incomplete type
+// builds.
+class Incomplete;
+class D {
+  ThreadSafeWeakPtr<Incomplete> mMember;
+};
+
+int main() {
+  RefPtr<C> c1 = new C;
+  MOZ_RELEASE_ASSERT(c1->mNum == 0);
+
+  // Get weak pointers to c1. The first time,
+  // a reference-counted ThreadSafeWeakReference object is created that
+  // can live beyond the lifetime of 'c1'. The ThreadSafeWeakReference
+  // object will be notified of 'c1's destruction.
+  ThreadSafeWeakPtr<C> w1(c1);
+  {
+    RefPtr<C> s1(w1);
+    // Test a weak pointer for validity before using it.
+    MOZ_RELEASE_ASSERT(s1);
+    MOZ_RELEASE_ASSERT(s1 == c1);
+    s1->mNum = 1;
+    s1->act();
+  }
+
+  // Test taking another ThreadSafeWeakPtr<C> to c1
+  ThreadSafeWeakPtr<C> w2(c1);
+  {
+    RefPtr<C> s2(w2);
+    MOZ_RELEASE_ASSERT(s2);
+    MOZ_RELEASE_ASSERT(s2 == c1);
+    MOZ_RELEASE_ASSERT(w1 == s2);
+    MOZ_RELEASE_ASSERT(s2->mNum == 1);
+  }
+
+  // Test that when a ThreadSafeWeakPtr is destroyed, it does not destroy the
+  // object that it points to, and it does not affect other ThreadSafeWeakPtrs
+  // pointing to the same object (e.g. it does not destroy the
+  // ThreadSafeWeakReference object).
+  {
+    ThreadSafeWeakPtr<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
+  // ThreadSafeWeakPtr'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
+  // ThreadSafeWeakPtr points to
+  RefPtr<C> c2 = new C;
+  c2->mNum = 2;
+  {
+    RefPtr<C> s2(w2);
+    MOZ_RELEASE_ASSERT(s2->mNum == 1);  // w2 was pointing to c1
+  }
+  w2 = c2;
+  {
+    RefPtr<C> s2(w2);
+    MOZ_RELEASE_ASSERT(s2);
+    MOZ_RELEASE_ASSERT(s2 == c2);
+    MOZ_RELEASE_ASSERT(s2 != c1);
+    MOZ_RELEASE_ASSERT(w1 != s2);
+    MOZ_RELEASE_ASSERT(s2->mNum == 2);
+  }
+
+  // Destroying the underlying object clears weak pointers to it.
+  // It should not affect pointers that are not currently pointing to it.
+  c1 = nullptr;
+  {
+    RefPtr<C> s1(w1);
+    MOZ_RELEASE_ASSERT(
+        !s1, "Deleting an object should clear ThreadSafeWeakPtr's to it.");
+    MOZ_RELEASE_ASSERT(w1.IsDead(), "The weak pointer is now dead");
+    MOZ_RELEASE_ASSERT(!w1.IsNull(), "The weak pointer isn't null");
+
+    RefPtr<C> s2(w2);
+    MOZ_RELEASE_ASSERT(s2,
+                       "Deleting an object should not clear ThreadSafeWeakPtr "
+                       "that are not pointing to it.");
+    MOZ_RELEASE_ASSERT(!w2.IsDead(), "The weak pointer isn't dead");
+    MOZ_RELEASE_ASSERT(!w2.IsNull(), "The weak pointer isn't null");
+  }
+
+  c2 = nullptr;
+  {
+    RefPtr<C> s2(w2);
+    MOZ_RELEASE_ASSERT(
+        !s2, "Deleting an object should clear ThreadSafeWeakPtr's to it.");
+    MOZ_RELEASE_ASSERT(w2.IsDead(), "The weak pointer is now dead");
+    MOZ_RELEASE_ASSERT(!w2.IsNull(), "The weak pointer isn't null");
+  }
+}