SharedPointerTesting.inl

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
 
#define WITH_SHARED_POINTER_TESTS 0 && !(UE_BUILD_SHIPPING || UE_BUILD_TEST)
 
#if WITH_SHARED_POINTER_TESTS
 
enum class ESPMode : uint8;
template<typename KeyType,typename ValueType,typename SetAllocator ,typename KeyFuncs > class TMap;
 
namespace SharedPointerTesting
{
    template< ESPMode Mode >        // Used to test *with* and *without* thread-safety features
    static void TestSharedPointer()
    {
        {
            // Empty shared ptr, not valid to deference
            TSharedPtr< bool, Mode > MyEmptyBoolPtr;
 
            // Test validity check
            check( !MyEmptyBoolPtr.IsValid() );
 
            // Test access to raw pointer
            if( MyEmptyBoolPtr.Get() == nullptr )
            {
                // ...
            }
        }
 
        {
            // Construct owned shared pointer from object instance
            TSharedPtr< int32, Mode > MyIntSharedPtr( new int32( 123 ) );
 
            // Test validity check
            check( MyIntSharedPtr.IsValid() );
 
            // Check uniqueness
            check( MyIntSharedPtr.IsUnique() );
 
            // Test dereference operator
            const int32 DeferenceTest = *MyIntSharedPtr;
 
            // Test reference count zero destructing owned object
            MyIntSharedPtr.Reset();
 
 
            // Check number of references
            check( MyIntSharedPtr.GetSharedReferenceCount() == 0 );
 
            // MyIntSharedPtr goes out of scope, but object already deleted, nothing to do
        }
 
        {
            // Test implicit conversion (not currently allowed because constructor is explicit!)
#if 0
            TSharedPtr< double, Mode > MyBool = 45.0;
#endif
        }
 
        {
            // Test copying shared reference
            TSharedPtr< bool, Mode > FirstBoolRef( new bool( false ) );
            TSharedPtr< bool, Mode > SecondBoolRef( FirstBoolRef );
        }
 
        {
            // Test copying shared reference using = operator
            TSharedPtr< bool, Mode > FirstBoolRef( new bool( false ) );
            TSharedPtr< bool, Mode > SecondBoolRef = FirstBoolRef;
        }
 
        {
            // Test arrow operator
            struct FSharedTest
            {
                bool bFoo;
            };
            TSharedPtr< FSharedTest, Mode > SharedArray( new FSharedTest() );
            SharedArray->bFoo = true;
 
            // Test dereference operator
            ( *SharedArray ).bFoo = false;
 
            // Create an additional reference to an existing shared pointer
            TSharedPtr< FSharedTest, Mode > OtherSharedArrayReference( SharedArray );
 
            // Release original reference (object should not be destroyed)
            SharedArray.Reset();
 
            // NOTE: OtherSharedArrayReference goes out of scope here (object is destroyed)
        }
 
        {
            // Test casting
            class FBase
            {
                bool bFoo;
            };
            class FDerived
                : public FBase
            { };
 
            {
                // Explicit downcast to derived shared ptr
                TSharedPtr< FBase, Mode > DerivedAsBasePtr( new FDerived() );
                TSharedPtr< FDerived, Mode > DerivedPtr( StaticCastSharedPtr< FDerived >( DerivedAsBasePtr ) );
            }
 
            {
                // Initialize base from derived (implicit upcast)
                TSharedPtr< FDerived, Mode > DerivedPtr( new FDerived() );
                TSharedPtr< FBase, Mode > BasePtr( DerivedPtr );
            }
 
            {
                // Assign derived to base (implicit upcast)
                TSharedPtr< FDerived, Mode > DerivedPtr( new FDerived() );
                TSharedPtr< FBase, Mode > BasePtr = DerivedPtr;
            }
        }
 
        // Create a shared pointer to nullptr.  Consistent with std::shared_ptr, this results
        // in a non-empty TSharedPtr (heap allocated reference count)
        {
            bool* Foo = nullptr;
            TSharedPtr< bool, Mode > NullPtr( Foo );
            check( !NullPtr.IsValid() );
        }
 
        // Simple validity test syntax
        {
            TSharedPtr< bool, Mode > BoolPtr( new bool( true ) );
            check( BoolPtr.IsValid() );
        }
 
        // Empty weak pointer
        {
            TWeakPtr< bool, Mode > EmptyBoolWeakPtr;
 
            // Pin should fail on empty weak ptr
            check( !EmptyBoolWeakPtr.Pin().IsValid() );
        }
 
        // Create weak pointer from shared pointer
        {
            TSharedPtr< int32, Mode > SharedInt( new int32( 64 ) );
            TWeakPtr< int32, Mode > WeakInt( SharedInt );
 
            // Pin should succeed on this valid weak ptr
            check( WeakInt.Pin().IsValid() );
        }
 
        // Create weak pointer from shared pointer (assignment)
        {
            TSharedPtr< int32, Mode > SharedInt( new int32( 64 ) );
            TWeakPtr< int32, Mode > WeakInt = SharedInt;
 
            // Pin should succeed on this valid weak ptr
            check( WeakInt.Pin().IsValid() );
 
            // Reset a weak pointer
            WeakInt.Reset();
            check( !WeakInt.Pin().IsValid() );
        }
 
        // Test weak pointer becoming invalid
        {
            TSharedPtr< int32, Mode > SharedInt( new int32( 64 ) );
            TWeakPtr< int32, Mode > WeakInt = SharedInt;
            SharedInt.Reset();
            check( !WeakInt.Pin().IsValid() );
        }
 
        // Compare shared pointers
        {
            TSharedPtr< int32, Mode > SharedA( new int32( 64 ) );
            TSharedPtr< int32, Mode > SharedB( new int32( 21 ) );
            TSharedPtr< int32, Mode > SharedC( SharedB );
 
            check( !( SharedA == SharedB ) );
            check( SharedA != SharedB );
            check( SharedB == SharedC );
        }
 
        // Compare weak pointers
        {
            TSharedPtr< int32, Mode > SharedA( new int32( 64 ) );
            TSharedPtr< int32, Mode > SharedB( new int32( 21 ) );
 
            TWeakPtr< int32, Mode > WeakA( SharedA );
            TWeakPtr< int32, Mode > WeakB( SharedB  );
            TWeakPtr< int32, Mode > WeakC( SharedB  );
 
            {
                check( !( WeakA.Pin() == WeakB.Pin() ) );
                check( WeakA.Pin() != WeakB.Pin() );
                check( WeakB.Pin() == WeakC.Pin() );
            }
 
            // NOTE: Weak pointer direct comparisons not supported (consistent with std::weak_ptr)
#if 0       // Should not compile
            {
                check( !( WeakA == WeakB ) );
                check( WeakA != WeakB );
                check( WeakB == WeakC );
            }
#endif
        }
 
        // Test 'const'
        {
            TSharedPtr< const int32, Mode > IntPtr( new int32( 10 ) );
            TSharedPtr< const float, Mode > FloatPtrA( new float( 1.0f ) );
            TSharedPtr< const float, Mode > FloatPtrB( new float( 2.0f ) );
            
            if( FloatPtrA == FloatPtrB )
            {
            }
 
#if 0       // Won't compile as int32 is not compatible with float
            if( FloatPtrB == IntPtr )
            {
            }
#endif
 
            // Assigning const pointers (references only, this is OK!)
            FloatPtrA = FloatPtrB;
 
            // Test const conversion (not allowed!)
            TSharedPtr< float, Mode > MutableFloat( new float( 123.0f ) );
#if 0       // Won't compile as implicit const_cast is not allowed
            MutableFloat = FloatPtrA;
#endif
 
            // Test conversion from mutable to const (this is OK!)
            FloatPtrA = MutableFloat;
 
            if( FloatPtrB.IsValid() )
            {
#if 0           // Won't compile as value is const
                *FloatPtrB = 10.0f;
#endif
            }
 
            TWeakPtr< const float, Mode > ConstWeakFloat = FloatPtrA;   // Preserving const
#if 0       // Won't compile as value is const
            *ConstWeakFloat.Pin() = 20.0f;
#endif
 
            // Test implicit const_cast (not allowed!)
            TWeakPtr< float, Mode > WeakFloat;
#if 0       // Won't compile as const cannot convert to mutable implicitly
            WeakFloat = FloatPtrB;  // NOTE: 'const' not preserved here
#endif
            
            // Test const cast
            WeakFloat = ConstCastSharedPtr< float >( FloatPtrB );
 
            *WeakFloat.Pin() = 20.0f;
        }
 
        // Test forward declaring a smart pointer to an incomplete type
        {
            TSharedPtr< struct FBarFoo, Mode > VecPtr;
            struct FBarFoo
            {
                int32 Val;
            };
            VecPtr = TSharedPtr< FBarFoo, Mode >( new FBarFoo() );
            VecPtr->Val = 20;
        }
        
        // Test Unreal non-standard extensions (expanded syntax)
        {
            // Initialize with nullptr
            TSharedPtr< bool, Mode > EmptyPtr( nullptr );
            TSharedPtr< float, Mode > FloatPtr = nullptr;
 
            // Initialize with nullptr
            TWeakPtr< bool, Mode > EmptyWeakPtr( nullptr );
            TWeakPtr< float, Mode > FloatWeakPtr = nullptr;
 
            // Reassign to nullptr directly (instead of calling Reset)
            FloatPtr = TSharedPtr< float, Mode >( new float( 0.1f ) );
            FloatPtr = nullptr;
 
            // Test implicit construction helper (MakeShareable)
            FloatPtr = MakeShareable( new float( 30.0f ) );
            TSharedPtr< double, Mode >( MakeShareable( new double( 2.0 ) ) );
 
            struct FFooBar
            {
                // Test function return value
                TSharedPtr< float, Mode > GetFloatMember()
                {
                    return FloatVal;
                }
 
                TSharedPtr< float, Mode > FloatVal;
 
 
                // Test implicit construction on return
                TSharedPtr< float, Mode > GetFloatValue()
                {
                    return MakeShareable( new float( 123.0f ) );
                }
            };
        }
 
        // Test TSharedRef
        {
            // Empty TSharedRef is not allowed
            {
#if 0           // Won't compile as TSharedRef has no default constructor
                TSharedRef< bool, Mode > EmptyRef;
#endif
 
#if 0           // Won't compile as TSharedRef has no implicit constructor that a pointer (including nullptr)
                TSharedRef< bool, Mode > NullRef = nullptr;
#endif
 
                // TSharedRef initialized in constructor
                {
                    TSharedRef< float, Mode > FloatRef( new float( 123.0f ) );
                }
 
                // Test reference access
                {
                    TSharedRef< float, Mode > FloatRef( new float( 123.0f ) );
 
                    // Grab a C++ reference to the float object
                    const float& MyFloat = *FloatRef;
 
                    // Grab another C++ reference to the float object
                    const float& MyFloat2 = FloatRef.Get();
                }
 
                // Implicit conversion to TSharedRef is never allowed (use MakeShareable!)
                {
#if 0               // Won't compile as constructor is explicit
                    TSharedRef< float, Mode > FloatRef = new float( 123.0f );
#endif
                }
 
                // Test MakeShareable with TSharedRef
                {
                    TSharedRef< float, Mode > FloatRef = MakeShareable( new float( 123.0f ) );
                }
 
                // New shared ref with nullptr object pointer is not allowed!  The following code will compile
                // correctly, but will trigger a runtime assertion.
                if( 0 )
                {
                    // NOTE: The following code is unsafe and will trigger an assert
                    int32* NullInt = nullptr;
                    TSharedRef< int32, Mode > RefWithNullObject( NullInt );
                }
 
                // Implicit conversion from a TSharedRef to a TSharedPtr (always OK)
                {
                    TSharedRef< int32, Mode > MySharedRef( new int32( 1 ) );
                    TSharedPtr< int32, Mode > MySharedPtr( MySharedRef );
                }
 
                // Explicit TSharedRef construction from a TSharedPtr is not allowed
                {
                    TSharedPtr< int32, Mode > MySharedPtr( new int32( 1 ) );
#if 0               // Won't compile as this constructor is intentionally private.  Use ToSharedRef() instead!
                    TSharedRef< int32, Mode > MySharedRef( MySharedPtr );
#endif
                }
 
                // Explicit TSharedRef assignment from a TSharedPtr is not allowed
                {
                    TSharedPtr< int32, Mode > MySharedPtr( new int32( 1 ) );
#if 0               // Won't compile as this constructor is intentionally private.  Use ToSharedRef() instead!
                    TSharedRef< int32, Mode > MySharedRef = MySharedPtr;
#endif
                }
 
                // Conversion from a TSharedPtr to a TSharedRef.  Only safe when ( MySharedPtr.IsValid() == true )
                {
                    TSharedPtr< int32, Mode > MySharedPtr( new int32( 1 ) );
                    TSharedRef< int32, Mode > MySharedRef( MySharedPtr.ToSharedRef() );
                }
 
                // Conversion from an invalid TSharedPtr to a TSharedRef.  Never safe, will assert at runtime.
                if( 0 )     // Will trigger a runtime assert as MySharedPtr.IsValid() == false
                {
                    int32* NullInt = nullptr;
                    TSharedPtr< int32, Mode > MySharedPtr( NullInt );
                    TSharedRef< int32, Mode > MySharedRef( MySharedPtr.ToSharedRef() );
                }
 
                // TSharedRef reassignment.  Safe as long as new object is not nullptr.
                {
                    TSharedRef< int32, Mode > IntRef( new int32( 10 ) );
                    IntRef = TSharedRef< int32, Mode >( new int32( 20 ) );
                }
 
                // TSharedRef reassignment to nullptr object is not allowed (asserts at runtime)
                if( 0 )
                {
                    TSharedRef< int32, Mode > IntRef( new int32( 10 ) );
                    int32* NullInt = nullptr;
                    IntRef = TSharedRef< int32, Mode >( NullInt );
                }
 
                // Get a weak pointer from a shared ref.  Always OK!
                {
                    TSharedRef< int32, Mode > IntRef( new int32( 99 ) );
                    TWeakPtr< int32, Mode > WeakInt = IntRef;
                    if( WeakInt.IsValid() )
                    {
                        // ...
                    }
                }
 
                // Compare two shared refs
                {
                    TSharedRef< int32, Mode > IntRef1( new int32( 99 ) );
                    TSharedRef< int32, Mode > IntRef2( new int32( 21 ) );
                    if( IntRef1 == IntRef2 )
                    {
                        // ...
                    }
                    if( IntRef1 != IntRef2 )
                    {
                        // ...
                    }
                }
 
                // Compare a shared pointer with a shared ref
                {
                    // @todo: Use complex types, not int32 (has operator==)!!
                    TSharedRef< int32, Mode > IntRef( new int32( 21 ) );
                    TSharedPtr< int32, Mode > IntPtr( IntRef );
                    
                    // Pointer is equal to reference because they point to the same valid object
                    check( IntRef == IntPtr && IntPtr == IntRef );
                    {
                        // ...
                    }
 
                    // Test not equal operator
                    check( !( IntRef != IntPtr || IntPtr != IntRef ) );
                    {
                        // ...
                    }
 
                    // Null pointer is never equal to a reference
                    TSharedPtr< int32, Mode > NullPtr;
                    check( !( IntRef == NullPtr ) && ( IntRef != NullPtr ) );
                    {
                        // ...
                    }
                }
            }
        }
 
        // SharedFromThis
        {
            class FMyClass
                : public TSharedFromThis< FMyClass, Mode >
            {
            public:
                TSharedRef< FMyClass, Mode > GetSelfAsShared()
                {
                    return AsShared();
                }
            };
 
            // Grab shared pointer to stack-allocated class, before ever assigning it to
            // a shared pointer reference.  This will trigger an assertion!
            if( 0 )
            {
                FMyClass MyClass;
                TSharedRef< FMyClass, Mode > TheClassPtr( MyClass.GetSelfAsShared() );
            }
 
            TSharedPtr< FMyClass, Mode > TheClassPtr1( new FMyClass() );
            {
                FMyClass* MyClass = TheClassPtr1.Get();
                TSharedRef< FMyClass, Mode > TheClassPtr2( MyClass->GetSelfAsShared() );
            }
        }
 
        // Hash tables
        {
            TSharedRef< int32, Mode > FooRef( new int32( 1 ) );
            TSharedPtr< int32, Mode > FooPtr( FooRef );
 
            // Map shared pointers to a type
            TMap< TSharedPtr< int32, Mode >, bool > SharedPointerHash;
            SharedPointerHash.Add( FooPtr, true );
 
            // Map shared refs to a type
            TMap< TSharedRef< int32, Mode >, bool > SharedRefHash;
            SharedRefHash.Add( FooRef, true );
            const bool Value = SharedRefHash.FindRef( FooRef );
 
            // Map a type to shared refs
            {
                TMap< int32, TSharedRef< int32, Mode > > SharedRefValueHash;
                SharedRefValueHash.Add(10, FooRef);
                const int32* FoundKey = SharedRefValueHash.FindKey(FooRef);
                check(FoundKey != nullptr && *FoundKey == 10);
            }
 
            // Maps and 'const'
            {
                TSharedRef< const int32, Mode > ConstFooRef( new int32( 1 ) );
                TMap< int32, TSharedRef< const int32, Mode > > ConstSharedRefValueHash;
                ConstSharedRefValueHash.Add( 10, ConstFooRef );
                const int32* FoundKey = ConstSharedRefValueHash.FindKey( ConstFooRef );
                check( FoundKey != nullptr && *FoundKey == 10 );
            }
        }
    }
}
 
 
#endif      // WITH_SHARED_POINTER_TESTS