Fix wp and sp comparison bugs
Make clear() actually clear wp m_refs, so that nulls compare equal.
Make equality consistent with < and >, ensuring that a weak pointer
cannot be both equal to and greater than another.
Don't rely on the built-in < and > operators to correctly order
different objects. The standard does not guarantee that, and there is
a risk of compiler relying on that lack of guarantee.
Remove unnecessary comparison overloads, especially those
comparing a wp<> to an sp<>.
Change the remaining wp<> to sp<> comparisons to check for equivalence
of the mRefs pointer instead of the object address, thus eliminating
the dubious equal comparison result for a dead wp<> and an sp<> that
happen to point to the same object address.
Add comparison tests.
Test: Treehugger, boot AOSP, atest RefBase
Bug: 126922090
Change-Id: I15911150e0fc85ace2c4b77d337826e12793c690
diff --git a/libutils/RefBase_test.cpp b/libutils/RefBase_test.cpp
index 2e0cf6e..b594ca5 100644
--- a/libutils/RefBase_test.cpp
+++ b/libutils/RefBase_test.cpp
@@ -45,6 +45,44 @@
bool* mDeleted;
};
+// A version of Foo that ensures that all objects are allocated at the same
+// address. No more than one can be allocated at a time. Thread-hostile.
+class FooFixedAlloc : public RefBase {
+public:
+ static void* operator new(size_t size) {
+ if (mAllocCount != 0) {
+ abort();
+ }
+ mAllocCount = 1;
+ if (theMemory == nullptr) {
+ theMemory = malloc(size);
+ }
+ return theMemory;
+ }
+
+ static void operator delete(void *p) {
+ if (mAllocCount != 1 || p != theMemory) {
+ abort();
+ }
+ mAllocCount = 0;
+ }
+
+ FooFixedAlloc(bool* deleted_check) : mDeleted(deleted_check) {
+ *mDeleted = false;
+ }
+
+ ~FooFixedAlloc() {
+ *mDeleted = true;
+ }
+private:
+ bool* mDeleted;
+ static int mAllocCount;
+ static void* theMemory;
+};
+
+int FooFixedAlloc::mAllocCount(0);
+void* FooFixedAlloc::theMemory(nullptr);
+
TEST(RefBase, StrongMoves) {
bool isDeleted;
Foo* foo = new Foo(&isDeleted);
@@ -90,6 +128,91 @@
ASSERT_FALSE(isDeleted) << "Deletion on wp destruction should no longer occur";
}
+TEST(RefBase, Comparisons) {
+ bool isDeleted, isDeleted2;
+ Foo* foo = new Foo(&isDeleted);
+ Foo* foo2 = new Foo(&isDeleted2);
+ sp<Foo> sp1(foo);
+ sp<Foo> sp2(foo2);
+ wp<Foo> wp1(sp1);
+ wp<Foo> wp2(sp1);
+ wp<Foo> wp3(sp2);
+ ASSERT_TRUE(wp1 == wp2);
+ ASSERT_TRUE(wp1 == sp1);
+ ASSERT_TRUE(wp3 == sp2);
+ ASSERT_TRUE(wp1 != sp2);
+ ASSERT_TRUE(wp1 <= wp2);
+ ASSERT_TRUE(wp1 >= wp2);
+ ASSERT_FALSE(wp1 != wp2);
+ ASSERT_FALSE(wp1 > wp2);
+ ASSERT_FALSE(wp1 < wp2);
+ ASSERT_FALSE(sp1 == sp2);
+ ASSERT_TRUE(sp1 != sp2);
+ bool sp1_smaller = sp1 < sp2;
+ wp<Foo>wp_smaller = sp1_smaller ? wp1 : wp3;
+ wp<Foo>wp_larger = sp1_smaller ? wp3 : wp1;
+ ASSERT_TRUE(wp_smaller < wp_larger);
+ ASSERT_TRUE(wp_smaller != wp_larger);
+ ASSERT_TRUE(wp_smaller <= wp_larger);
+ ASSERT_FALSE(wp_smaller == wp_larger);
+ ASSERT_FALSE(wp_smaller > wp_larger);
+ ASSERT_FALSE(wp_smaller >= wp_larger);
+ sp2 = nullptr;
+ ASSERT_TRUE(isDeleted2);
+ ASSERT_FALSE(isDeleted);
+ ASSERT_FALSE(wp3 == sp2);
+ // Comparison results on weak pointers should not be affected.
+ ASSERT_TRUE(wp_smaller < wp_larger);
+ ASSERT_TRUE(wp_smaller != wp_larger);
+ ASSERT_TRUE(wp_smaller <= wp_larger);
+ ASSERT_FALSE(wp_smaller == wp_larger);
+ ASSERT_FALSE(wp_smaller > wp_larger);
+ ASSERT_FALSE(wp_smaller >= wp_larger);
+ wp2 = nullptr;
+ ASSERT_FALSE(wp1 == wp2);
+ ASSERT_TRUE(wp1 != wp2);
+ wp1.clear();
+ ASSERT_TRUE(wp1 == wp2);
+ ASSERT_FALSE(wp1 != wp2);
+ wp3.clear();
+ ASSERT_TRUE(wp1 == wp3);
+ ASSERT_FALSE(wp1 != wp3);
+ ASSERT_FALSE(isDeleted);
+ sp1.clear();
+ ASSERT_TRUE(isDeleted);
+ ASSERT_TRUE(sp1 == sp2);
+}
+
+// Check whether comparison against dead wp works, even if the object referenced
+// by the new wp happens to be at the same address.
+TEST(RefBase, ReplacedComparison) {
+ bool isDeleted, isDeleted2;
+ FooFixedAlloc* foo = new FooFixedAlloc(&isDeleted);
+ sp<FooFixedAlloc> sp1(foo);
+ wp<FooFixedAlloc> wp1(sp1);
+ ASSERT_TRUE(wp1 == sp1);
+ sp1.clear(); // Deallocates the object.
+ ASSERT_TRUE(isDeleted);
+ FooFixedAlloc* foo2 = new FooFixedAlloc(&isDeleted2);
+ ASSERT_FALSE(isDeleted2);
+ ASSERT_EQ(foo, foo2); // Not technically a legal comparison, but ...
+ sp<FooFixedAlloc> sp2(foo2);
+ wp<FooFixedAlloc> wp2(sp2);
+ ASSERT_TRUE(sp2 == wp2);
+ ASSERT_FALSE(sp2 != wp2);
+ ASSERT_TRUE(sp2 != wp1);
+ ASSERT_FALSE(sp2 == wp1);
+ ASSERT_FALSE(sp2 == sp1); // sp1 is null.
+ ASSERT_FALSE(wp1 == wp2); // wp1 refers to old object.
+ ASSERT_TRUE(wp1 != wp2);
+ ASSERT_TRUE(wp1 > wp2 || wp1 < wp2);
+ ASSERT_TRUE(wp1 >= wp2 || wp1 <= wp2);
+ ASSERT_FALSE(wp1 >= wp2 && wp1 <= wp2);
+ ASSERT_FALSE(wp1 == nullptr);
+ wp1 = sp2;
+ ASSERT_TRUE(wp1 == wp2);
+ ASSERT_FALSE(wp1 != wp2);
+}
// Set up a situation in which we race with visit2AndRremove() to delete
// 2 strong references. Bar destructor checks that there are no early