Teach sp<> how to std::move

Arguably we should migrate to std::shared_ptr
but for now make std::vector<sp<>> a bit less
horrible

Change-Id: Ia458a2daff0b656b2f3310b3ea100565ec844c69

3 files changed, 93 insertions, 0 deletions

diff --git a/include/utils/StrongPointer.h b/include/utils/StrongPointer.h
index aba9577da..50fde35b0 100644
--- a/include/utils/StrongPointer.h
+++ b/include/utils/StrongPointer.h
@@ -62,8 +62,10 @@ public:
 
     sp(T* other);
     sp(const sp<T>& other);
+    sp(sp<T>&& other);
     template<typename U> sp(U* other);
     template<typename U> sp(const sp<U>& other);
+    template<typename U> sp(sp<U>&& other);
 
     ~sp();
 
@@ -71,8 +73,10 @@ public:
 
     sp& operator = (T* other);
     sp& operator = (const sp<T>& other);
+    sp& operator = (sp<T>&& other);
 
     template<typename U> sp& operator = (const sp<U>& other);
+    template<typename U> sp& operator = (sp<U>&& other);
     template<typename U> sp& operator = (U* other);
 
     //! Special optimization for use by ProcessState (and nobody else).
@@ -123,6 +127,12 @@ sp<T>::sp(const sp<T>& other)
         m_ptr->incStrong(this);
 }
 
+template<typename T>
+sp<T>::sp(sp<T>&& other)
+        : m_ptr(other.m_ptr) {
+    other.m_ptr = nullptr;
+}
+
 template<typename T> template<typename U>
 sp<T>::sp(U* other)
         : m_ptr(other) {
@@ -137,6 +147,12 @@ sp<T>::sp(const sp<U>& other)
         m_ptr->incStrong(this);
 }
 
+template<typename T> template<typename U>
+sp<T>::sp(sp<U>&& other)
+        : m_ptr(other.m_ptr) {
+    other.m_ptr = nullptr;
+}
+
 template<typename T>
 sp<T>::~sp() {
     if (m_ptr)
@@ -155,6 +171,15 @@ sp<T>& sp<T>::operator =(const sp<T>& other) {
 }
 
 template<typename T>
+sp<T>& sp<T>::operator =(sp<T>&& other) {
+    if (m_ptr)
+        m_ptr->decStrong(this);
+    m_ptr = other.m_ptr;
+    other.m_ptr = nullptr;
+    return *this;
+}
+
+template<typename T>
 sp<T>& sp<T>::operator =(T* other) {
     if (other)
         other->incStrong(this);
@@ -176,6 +201,15 @@ sp<T>& sp<T>::operator =(const sp<U>& other) {
 }
 
 template<typename T> template<typename U>
+sp<T>& sp<T>::operator =(sp<U>&& other) {
+    if (m_ptr)
+        m_ptr->decStrong(this);
+    m_ptr = other.m_ptr;
+    other.m_ptr = nullptr;
+    return *this;
+}
+
+template<typename T> template<typename U>
 sp<T>& sp<T>::operator =(U* other) {
     if (other)
         ((T*) other)->incStrong(this);
diff --git a/libutils/tests/Android.mk b/libutils/tests/Android.mk
index 514f8c198..cb9e8a255 100644
--- a/libutils/tests/Android.mk
+++ b/libutils/tests/Android.mk
@@ -27,6 +27,7 @@ LOCAL_SRC_FILES := \
     Looper_test.cpp \
     LruCache_test.cpp \
     String8_test.cpp \
+    StrongPointer_test.cpp \
     Unicode_test.cpp \
     Vector_test.cpp \
 
diff --git a/libutils/tests/StrongPointer_test.cpp b/libutils/tests/StrongPointer_test.cpp
new file mode 100644
index 000000000..f46d6d140
--- /dev/null
+++ b/libutils/tests/StrongPointer_test.cpp
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <utils/StrongPointer.h>
+#include <utils/RefBase.h>
+
+using namespace android;
+
+class Foo : public LightRefBase<Foo> {
+public:
+    Foo(bool* deleted_check) : mDeleted(deleted_check) {
+        *mDeleted = false;
+    }
+
+    ~Foo() {
+        *mDeleted = true;
+    }
+private:
+    bool* mDeleted;
+};
+
+TEST(StrongPointer, move) {
+    bool isDeleted;
+    Foo* foo = new Foo(&isDeleted);
+    ASSERT_EQ(0, foo->getStrongCount());
+    ASSERT_FALSE(isDeleted) << "Already deleted...?";
+    sp<Foo> sp1(foo);
+    ASSERT_EQ(1, foo->getStrongCount());
+    {
+        sp<Foo> sp2 = std::move(sp1);
+        ASSERT_EQ(1, foo->getStrongCount()) << "std::move failed, incremented refcnt";
+        ASSERT_EQ(nullptr, sp1.get()) << "std::move failed, sp1 is still valid";
+        // The strong count isn't increasing, let's double check the old object
+        // is properly reset and doesn't early delete
+        sp1 = std::move(sp2);
+    }
+    ASSERT_FALSE(isDeleted) << "deleted too early! still has a reference!";
+    {
+        // Now let's double check it deletes on time
+        sp<Foo> sp2 = std::move(sp1);
+    }
+    ASSERT_TRUE(isDeleted) << "foo was leaked!";
+}