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AK: Fix ref leaks in RefPtr assignment operators.

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Many of the RefPtr assignment operators would cause ref leaks when we
call them to assign a pointer that's already the one kept.
This commit is contained in:
Andreas Kling 2019-08-02 11:56:55 +02:00
parent 06f82901b7
commit cbc1272810
3 changed files with 89 additions and 37 deletions
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61
AK/RefPtr.h
View file

@ -2,6 +2,7 @@
#include <AK/LogStream.h>
#include <AK/NonnullRefPtr.h>
#include <AK/StdLibExtras.h>
#include <AK/Types.h>
namespace AK {
@ -94,88 +95,76 @@ public:
template<typename U>
RefPtr& operator=(const OwnPtr<U>&) = delete;
template<typename U>
void swap(RefPtr<U>& other)
{
::swap(m_ptr, other.m_ptr);
}
RefPtr& operator=(RefPtr&& other)
{
if (this != &other) {
deref_if_not_null(m_ptr);
m_ptr = other.leak_ref();
}
RefPtr tmp = move(other);
swap(tmp);
return *this;
}
template<typename U>
RefPtr& operator=(RefPtr<U>&& other)
{
if (this != static_cast<void*>(&other)) {
deref_if_not_null(m_ptr);
m_ptr = static_cast<T*>(other.leak_ref());
}
RefPtr tmp = move(other);
swap(tmp);
return *this;
}
template<typename U>
RefPtr& operator=(NonnullRefPtr<U>&& other)
{
deref_if_not_null(m_ptr);
m_ptr = &other.leak_ref();
RefPtr tmp = move(other);
swap(tmp);
return *this;
}
RefPtr& operator=(const NonnullRefPtr<T>& other)
{
if (m_ptr != other.ptr())
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(other.ptr());
ASSERT(m_ptr);
ref_if_not_null(m_ptr);
RefPtr tmp = other;
swap(tmp);
return *this;
}
template<typename U>
RefPtr& operator=(const NonnullRefPtr<U>& other)
{
if (m_ptr != other.ptr())
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(other.ptr());
ASSERT(m_ptr);
ref_if_not_null(m_ptr);
RefPtr tmp = other;
swap(tmp);
return *this;
}
RefPtr& operator=(const RefPtr& other)
{
if (m_ptr != other.ptr())
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(other.ptr());
ref_if_not_null(m_ptr);
RefPtr tmp = other;
swap(tmp);
return *this;
}
template<typename U>
RefPtr& operator=(const RefPtr<U>& other)
{
if (m_ptr != other.ptr())
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(other.ptr());
ref_if_not_null(m_ptr);
RefPtr tmp = other;
swap(tmp);
return *this;
}
RefPtr& operator=(const T* ptr)
{
if (m_ptr != ptr)
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(ptr);
ref_if_not_null(m_ptr);
RefPtr tmp = ptr;
swap(tmp);
return *this;
}
RefPtr& operator=(const T& object)
{
if (m_ptr != &object)
deref_if_not_null(m_ptr);
m_ptr = const_cast<T*>(&object);
ref_if_not_null(m_ptr);
RefPtr tmp = object;
swap(tmp);
return *this;
}

5
AK/Tests/Makefile
View file

@ -1,4 +1,4 @@
PROGRAMS = TestString TestQueue TestVector TestHashMap TestJSON TestWeakPtr TestNonnullRefPtr
PROGRAMS = TestString TestQueue TestVector TestHashMap TestJSON TestWeakPtr TestNonnullRefPtr TestRefPtr
CXXFLAGS = -std=c++17 -Wall -Wextra -ggdb3 -O2 -I../ -I../../
@ -45,6 +45,9 @@ TestWeakPtr: TestWeakPtr.o $(SHARED_TEST_OBJS)
TestNonnullRefPtr: TestNonnullRefPtr.o $(SHARED_TEST_OBJS)
$(PRE_CXX) $(CXX) $(CXXFLAGS) -o $@ TestNonnullRefPtr.o $(SHARED_TEST_OBJS)
TestRefPtr: TestRefPtr.o $(SHARED_TEST_OBJS)
$(PRE_CXX) $(CXX) $(CXXFLAGS) -o $@ TestRefPtr.o $(SHARED_TEST_OBJS)
clean:
rm -f $(SHARED_TEST_OBJS)
rm -f $(PROGRAMS)

60
AK/Tests/TestRefPtr.cpp Normal file
View file

@ -0,0 +1,60 @@
#include <AK/TestSuite.h>
#include <AK/NonnullRefPtr.h>
#include <AK/AKString.h>
struct Object : public RefCounted<Object> {
int x;
};
TEST_CASE(basics)
{
RefPtr<Object> object = adopt(*new Object);
EXPECT(object.ptr() != nullptr);
EXPECT_EQ(object->ref_count(), 1);
object->ref();
EXPECT_EQ(object->ref_count(), 2);
object->deref();
EXPECT_EQ(object->ref_count(), 1);
{
NonnullRefPtr another = *object;
EXPECT_EQ(object->ref_count(), 2);
}
EXPECT_EQ(object->ref_count(), 1);
}
TEST_CASE(assign_reference)
{
RefPtr<Object> object = adopt(*new Object);
EXPECT_EQ(object->ref_count(), 1);
object = *object;
EXPECT_EQ(object->ref_count(), 1);
}
TEST_CASE(assign_ptr)
{
RefPtr<Object> object = adopt(*new Object);
EXPECT_EQ(object->ref_count(), 1);
object = object.ptr();
EXPECT_EQ(object->ref_count(), 1);
}
TEST_CASE(assign_moved_self)
{
RefPtr<Object> object = adopt(*new Object);
EXPECT_EQ(object->ref_count(), 1);
object = move(object);
EXPECT_EQ(object->ref_count(), 1);
}
TEST_CASE(assign_copy_self)
{
RefPtr<Object> object = adopt(*new Object);
EXPECT_EQ(object->ref_count(), 1);
object = object;
EXPECT_EQ(object->ref_count(), 1);
}
TEST_MAIN(String)