Merge changes I66c97386,Id205c88d am: 05a7dfa104 am: 25d87e4419

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1668805

Change-Id: I3b48cc428b332122b8e445eef9b9e1e23152e9e2

libutils/RefBase_test.cpp

@@ -242,12 +242,12 @@ TEST(RefBase, ReplacedComparison) {
 }
 
 TEST(RefBase, AssertWeakRefExistsSuccess) {
-    // uses some other refcounting method, or non at all
     bool isDeleted;
     sp<Foo> foo = sp<Foo>::make(&isDeleted);
     wp<Foo> weakFoo = foo;
 
     EXPECT_EQ(weakFoo, wp<Foo>::fromExisting(foo.get()));
+    EXPECT_EQ(weakFoo.unsafe_get(), wp<Foo>::fromExisting(foo.get()).unsafe_get());
 
     EXPECT_FALSE(isDeleted);
     foo = nullptr;
@@ -255,7 +255,7 @@ TEST(RefBase, AssertWeakRefExistsSuccess) {
 }
 
 TEST(RefBase, AssertWeakRefExistsDeath) {
-    // uses some other refcounting method, or non at all
+    // uses some other refcounting method, or none at all
     bool isDeleted;
     Foo* foo = new Foo(&isDeleted);
 

libutils/include/utils/RefBase.h

@@ -547,6 +547,7 @@ wp<T> wp<T>::fromExisting(T* other) {
     refs->incWeakRequireWeak(other);
 
     wp<T> ret;
+    ret.m_ptr = other;
     ret.m_refs = refs;
     return ret;
 }

libutils/include/utils/StrongPointer.h

@@ -72,6 +72,12 @@ public:
     template<typename U> sp(const sp<U>& other);  // NOLINT(implicit)
     template<typename U> sp(sp<U>&& other);  // NOLINT(implicit)
 
+    // Cast a strong pointer directly from one type to another. Constructors
+    // allow changing types, but only if they are pointer-compatible. This does
+    // a static_cast internally.
+    template <typename U>
+    static inline sp<T> cast(const sp<U>& other);
+
     ~sp();
 
     // Assignment
@@ -279,6 +285,12 @@ sp<T>::sp(sp<U>&& other)
     other.m_ptr = nullptr;
 }
 
+template <typename T>
+template <typename U>
+sp<T> sp<T>::cast(const sp<U>& other) {
+    return sp<T>::fromExisting(static_cast<T*>(other.get()));
+}
+
 template<typename T>
 sp<T>::~sp() {
     if (m_ptr)