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Handling HSTRING with a vector wrapper

Question

Hello,

I have made a wrapper for handling collections for WinRT components. Exemple, a component "Root" contains some methods that return vectors of elements (HSTRING, a custom type MyData, int). Here is the IDL.

	interface IRoot : IInspectable
	{
		HRESULT GetVector([out][retval] Windows.Foundation.Collections.IVector<HSTRING>** value);
		HRESULT GetVectorData([out][retval] Windows.Foundation.Collections.IVector<IMyData *>** value);
		HRESULT GetVectorInt([out][retval] Windows.Foundation.Collections.IVector<int>** value);
	}

In my C++ code, here is how the methods are implemented:

		STDMETHODIMP Root::GetVector(IVector<HSTRING>** value)
		{
			ComPtr<Vector<HSTRING>> v = Make<Vector<HSTRING>>();
			HString str1;
			str1.Set(L"String1");
			v->Append(str1.Detach());
			HString str2;
			str2.Set(L"String2");
			v->Append(str2.Detach());
			HString str3;
			str3.Set(L"String3");
			v->Append(str3.Detach());
			HString str4;
			str4.Set(L"String4");
			v->Append(str4.Detach());
			*value = v.Detach();
			return S_OK;
		}

		STDMETHODIMP Root::GetVectorData(IVector<IMyData *>** value)
		{
			ComPtr<Vector<IMyData *>> v = Make<Vector<IMyData *>>();

			HString str1;
			str1.Set(L"String1");
			ComPtr<MyData> data1 = Make<MyData>();
			data1->SetName(str1.Detach());
			v->Append(data1.Detach());

			HString str2;
			str2.Set(L"String2");
			ComPtr<MyData> data2 = Make<MyData>();
			data2->SetName(str2.Detach());
			v->Append(data2.Detach());

			*value = v.Detach();
			return S_OK;
		}

		STDMETHODIMP Root::GetVectorInt(IVector<int>** value)
		{
			ComPtr<Vector<int>> v = Make<Vector<int>>();
			v->Append(10);
			v->Append(20);
			v->Append(30);
			v->Append(40);
			*value = v.Detach();
			return S_OK;
		}

All these 3 methods use the same template class named Vector<T> and it looks like that:

		template <class T>
		class Iterator : public RuntimeClass<IIterator<T>>
		{
			InspectableClass(L"Library1.Iterator", BaseTrust)

		private:
			typedef typename std::shared_ptr<std::vector<T>> V;
			typedef typename std::vector<T>::iterator IT;

		public:
			Iterator() {}

			HRESULT Init(const V & item)
			{
				_v = item;
				_it = _v->begin();
				if (_it != _v->end())
				{
					_element = *_it;
					_bElement = TRUE;
				}
				else
					_bElement = FALSE;
				return S_OK;
			}

		public:
			virtual HRESULT STDMETHODCALLTYPE get_Current(T *current)
			{
				if (_it != _v->end())
				{
					_bElement = TRUE;
					_element = *_it;
					*current = _element;
				}
				else
				{
					_bElement = FALSE;
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE get_HasCurrent(boolean *hasCurrent)
			{
				if (_bElement)
					*hasCurrent = TRUE;
				else
					*hasCurrent = FALSE;
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE MoveNext(boolean *hasCurrent)
			{
				if (_it != _v->end())
				{
					++_it;
					if (_it == _v->end())
						*hasCurrent = FALSE;
					else
						*hasCurrent = TRUE;
				}
				else
				{
					*hasCurrent = FALSE;
				}
				return S_OK;
			}

		private:
			V _v;
			IT _it;
			T _element;
			boolean _bElement = FALSE;
		};

		template <typename T>
		class Vector : public RuntimeClass<IVector<T>, IIterable<T>>
		{
			InspectableClass(L"Library1.Vector", BaseTrust)

		public:
			Vector() 
			{
				std::shared_ptr<std::vector<T>> ptr(new std::vector<T>());
				_v = ptr;
			}

		public:

			// read methods
			virtual HRESULT STDMETHODCALLTYPE GetAt(unsigned index, T *item)
			{
				*item = (*_v)[index];
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE get_Size(unsigned *size)
			{
				*size = _v->size();
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE GetView(IVectorView<T> **view)
			{
				return E_NOTIMPL;
			}

			virtual HRESULT STDMETHODCALLTYPE IndexOf(T value, unsigned *index, boolean *found)
			{
				unsigned foundedIndex = 0;
				bool founded = false;
				for (std::vector<T>::const_iterator it = _v->cbegin() ; it != _v->end() ; ++it)
				{
					const T & v = *it;
					if (v == value)
					{
						founded = true;
						break;
					}
					foundedIndex++;
				}
				if (founded == true)
				{
					*found = TRUE;
					*index = foundedIndex;
				}
				else
				{
					*found = FALSE;
				}
				return S_OK;
			}

			// write methods
			virtual HRESULT STDMETHODCALLTYPE SetAt(unsigned index, T item)
			{
				if (index < _v->size())
				{
					(*_v)[index] = item;
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE InsertAt(unsigned index, T item)
			{
				//_v->emplace(_v->begin() + index, item);
				_v->insert(_v->begin() + index, item);
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE RemoveAt(unsigned index)
			{
				if (index < _v->size())
				{
					_v->erase(_v->begin() + index);
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE Append(T item)
			{
				//_v->emplace_back(item);
				_v->push_back(item);
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE RemoveAtEnd()
			{
				if (!_v->empty())
				{
					_v->pop_back();
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE Clear()
			{
				_v->clear();
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE First(IIterator<T> **first)
			{
				ComPtr<Iterator<T>> p = Make<Iterator<T>>();
				p->Init(_v);
				*first = p.Detach();
				return S_OK;
			}

		private:
			std::shared_ptr<std::vector<T>> _v;
		};

The client app (C# XAML) is calling the component via 3 distinct buttons :

        private void Button_Click_VectorInt(object sender, RoutedEventArgs e)
        {
            try
            {
                // C# XAML APP using Root::GetVectorInt()
                Root root = new Root();
                IList<int> list1 = root.GetVectorInt();
                foreach (int i in list1)
                {
                    LogInfo("int: " + i.ToString());
                }
                list1[0] = 11;
                list1[1] = 22;
                list1.Add(1001);
                list1.Insert(0, 1);
                foreach (int i in list1)
                {
                    LogInfo("int: " + i.ToString());
                }
            }
            catch (Exception ex)
            {
                LogInfo("Exception! " + ex.Message + " " + ex.StackTrace);
            }
        }

        private void Button_Click_VectorMyData(object sender, RoutedEventArgs e)
        {
            Root root = new Root();
            LogInfo("root.GetVectorData()...");
            IList<IMyData> list1 = root.GetVectorData();
            LogInfo("foreach...");
            foreach (IMyData data in list1)
            {
                string name = data.GetName();
                LogInfo("MyData name: " + name);
            }
            LogInfo("foreach...");
            foreach (IMyData data in list1)
            {
                string name = data.GetName();
                LogInfo("MyData name: " + name);
            }
        }

        private void Button_Click_VectorString(object sender, RoutedEventArgs e)
        {
            try
            {
                Root root = new Root();
                LogInfo("root.GetVector()...");
                IList<string> list1 = root.GetVector();

                LogInfo("foreach...");
                foreach (string s in list1)
                {
                    LogInfo("string: " + s.ToString());
                }
                // This second iteration fails! -> Exception! Exception of type 'System.OutOfMemoryException' was thrown.
                LogInfo("foreach...");
                foreach (string s2 in list1)
                {
                    LogInfo("string: " + s2.ToString());
                }
                return;

                // This call will produce -> 'list1[0]' threw an exception of type 'System.AccessViolationException'
                list1[0] = "string 0 added";
                list1[1] = "string 1 added";
                list1.Add("a new string");
                list1.Insert(0, "another new string");

                LogInfo("foreach...");
                foreach (string s2 in list1)
                {
                    LogInfo("string: " + s2.ToString());
                }
            }
            catch (Exception ex)
            {
                LogInfo("Exception! " + ex.Message + " " + ex.StackTrace);
            }
        }

It works perfectly well for the collection that return int or MyData custom type. I can enumerate elements, add, append, it works !

But the problem is when I handle the vector of strings (HSTRING). The method seems to return the collection, the debugger tells there is a valid Count of elements but when I try to enumerate the collection one time it is OK but if I enumerate a second time , it fails ! Also, if I try to append or insert data, it fails ! When it's about Vector<int>, it works, when it's about Vector<HSTRING>, It fails !

All the code for the WRL C++ component and the C# client app is available as a sample in the Windows Dev Center: http://code.msdn.microsoft.com/windowsapps/Windows-Runtime-Component-4dc6fa20

Christophe Pichaud

Edited by Christophe Pichaud [MVP]MVP Saturday, April 12, 2014 9:29 AM

Saturday, April 12, 2014 9:05 AM

Answers

0

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I'm not exactly familiar with WinRT and its HSTRING but shouldn't you use a vector<HString> instead of vector<HSTRING>? HSTRING is reference counted, presumably something needs to deal with increasing the reference count of the string when it is handed out to the outside world.
- Edited by Mike Danes Thursday, April 17, 2014 6:07 AM
- Marked as answer by Christophe Pichaud [MVP]MVP Wednesday, April 23, 2014 12:57 AM
Thursday, April 17, 2014 6:07 AM

Hello,

You are partially right. HSTRING is ref counted. So I can't store it directly... I need to increment its ref counter and use a wrapper for my vector handler. This is also true for handling interface pointers for custom types, I can't store them directly, I need to use a ComPtr. So here is the magical wrap stuff:

		template <typename T>
		struct Wrap
		{
			typename typedef T type;
			static const T& MakeWrap(const T& t)
			{
				return t;
			}
			static const T& Unwrap(const T& t)
			{
				return t;
			}
		};

		template <>
		struct Wrap<HSTRING>
		{
			typedef HStringHelper type;
			static HStringHelper MakeWrap(const HSTRING& t)
			{
				HStringHelper str;
				str.Set(t);
				return str;
			}
			static HSTRING Unwrap(const HStringHelper& t)
			{
				HSTRING str;
				HRESULT hr = t.CopyTo(&str);
				// Error check
				return str;
			}
		};

		template <typename T>
		struct Wrap<T*>
		{
			typename typedef ComPtr<T> type;
			static ComPtr<T> MakeWrap(T* t)
			{
				ComPtr<T> ptr;
				ptr.Attach(t);
				return ptr;
			}
			static T* Unwrap(ComPtr<T> t)
			{
				ComPtr<T> ptr(t);
				return t.Detach();
			}
		};

And my vector template class is now made with this:

		template <class T>
		class Iterator : public RuntimeClass<IIterator<T>>
		{
			InspectableClass(L"Library1.Iterator", BaseTrust)

		private:
			typedef typename std::vector<typename Wrap<T>::type> WrappedVector;
			typedef typename std::shared_ptr<WrappedVector> V;
			typedef typename WrappedVector::iterator IT;

		public:
			Iterator() {} 

			void LogVectorContent()
			{
				for (IT it = _v->begin(); it != _v->end(); it++)
				{
					T element = Wrap<T>::Unwrap(*it);
					void * ptr = (void *)element;
					wchar_t sz[255];
					swprintf(sz, 255, L"adress T =0x%08x\n", (int)ptr);
					_LogInfo(sz);
				}
			}

			HRESULT Init(const V& vec)
			{
				try {
					_LogInfo(L"Iterator::Init()...");

				_v = vec;
				
				LogVectorContent();

				_it = _v->begin();
				if (_it != _v->end())
				{
					_element = Wrap<T>::Unwrap(*_it);
					_bElement = TRUE;
				}
				else
					_bElement = FALSE;
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::Init()...");
			}

		public:
			virtual HRESULT STDMETHODCALLTYPE get_Current(T *current)
			{
				try {
					_LogInfo(L"Iterator::get_Current()...");
				if (_it != _v->end())
				{
					_bElement = TRUE;
					_element = Wrap<T>::Unwrap(*_it);
					*current = _element;
				}
				else
				{
					_bElement = FALSE;
				}
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::get_Current()...");
			}

			virtual HRESULT STDMETHODCALLTYPE get_HasCurrent(boolean *hasCurrent)
			{
				try {
					_LogInfo(L"Iterator::get_HasCurrent()...");
				if (_bElement)
					*hasCurrent = TRUE;
				else
					*hasCurrent = FALSE;
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::get_HasCurrent()...");
			}

			virtual HRESULT STDMETHODCALLTYPE MoveNext(boolean *hasCurrent)
			{
				try {
					_LogInfo(L"Iterator::MoveNext()...");
				if (_it != _v->end())
				{
					++_it;
					if (_it == _v->end())
					{
						*hasCurrent = FALSE;
						_bElement = FALSE;
					}
					else
					{
						*hasCurrent = TRUE;
						_bElement = TRUE;
					}
				}
				else
				{
					*hasCurrent = FALSE;
					_bElement = FALSE;
				}
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::MoveNext()...");
			}

		private:
			V _v;
			IT _it;
			T _element;
			boolean _bElement = FALSE;
		};

		template <typename T>
		class Vector : public RuntimeClass<IVector<T>, 
			IIterable<T >>
		{
			InspectableClass(L"Library1.Vector", BaseTrust)

		private:
			typedef typename std::vector<typename Wrap<T>::type> WrappedVector;
			typedef typename WrappedVector::const_iterator CIT;

		public:
			Vector() 
			{
				_LogInfo(L"Vector::Vector()...");
				_v = std::make_shared<WrappedVector>();
			}

		public:
			// read methods
			virtual HRESULT STDMETHODCALLTYPE GetAt(unsigned index, T *item)
			{
				_LogInfo(L"Vector::GetAt()...");
				*item = Wrap<T>::Unwrap((*_v)[index]);
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE get_Size(unsigned *size)
			{
				_LogInfo(L"Vector::get_Size()...");
				*size = _v->size();
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE GetView(IVectorView<T> **view)
			{
				_LogInfo(L"Vector::GetView()...");
				return E_NOTIMPL;
			}

			virtual HRESULT STDMETHODCALLTYPE IndexOf(T value, unsigned *index, boolean *found)
			{
				_LogInfo(L"Vector::IndexOf()...");
				unsigned foundedIndex = 0;
				bool founded = false;
				for (CIT it = _v->cbegin() ; it != _v->end() ; ++it)
				{
					const T & v = Wrap<T>::Unwrap(*it);
					if (v == value)
					{
						founded = true;
						break;
					}
					foundedIndex++;
				}
				if (founded == true)
				{
					*found = TRUE;
					*index = foundedIndex;
				}
				else
				{
					*found = FALSE;
				}
				return S_OK;
			}

			// write methods
			virtual HRESULT STDMETHODCALLTYPE SetAt(unsigned index, T item)
			{
				_LogInfo(L"Vector::SetAt()...");
				if (index < _v->size())
				{
					(*_v)[index] = Wrap<T>::MakeWrap(item);
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE InsertAt(unsigned index, T item)
			{
				_LogInfo(L"Vector::InsertAt()...");
				_v->insert(_v->begin() + index, Wrap<T>::MakeWrap(item));
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE RemoveAt(unsigned index)
			{
				_LogInfo(L"Vector::RemoveAt()...");
				if (index < _v->size())
				{
					_v->erase(_v->begin() + index);
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE Append(T item)
			{
				_LogInfo(L"Vector::Append()...");
				_v->push_back(Wrap<T>::MakeWrap(item));
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE RemoveAtEnd()
			{
				_LogInfo(L"Vector::RemoveAtEnd()...");
				if (!_v->empty())
				{
					_v->pop_back();
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE Clear()
			{
				_LogInfo(L"Vector::Clear()...");
				_v->clear();
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE First(IIterator<T> **first)
			{
				_LogInfo(L"Vector::First()...");
				ComPtr<Iterator<T>> p = Make<Iterator<T>>();
				p->Init(_v);
				*first = p.Detach();
				return S_OK;
			}

		private:
			std::shared_ptr<WrappedVector> _v;
		};

Elements are wrapped and unwrapped.

Christophe Pichaud

Marked as answer by Christophe Pichaud [MVP]MVP Wednesday, April 23, 2014 12:56 AM

Wednesday, April 23, 2014 12:55 AM

All replies

More details! When I try to access a data using that code, sometimes, it fails... sometimes, it works...

I just call the method that return the vector, call count, and get item at position 0.

        private void Button_Click_VectorString(object sender, RoutedEventArgs e)
        {
            try
            {
                Root root = new Root();
                LogInfo("root.GetVector()...");
                IList<string> list1 = root.GetVector();
                int count = list1.Count;
                LogInfo("list Count=" + count.ToString());
                LogInfo("list1[0]=" + list1[0]);
                LogInfo("list1[0]=" + list1[0]);
                LogInfo("list1[0]=" + list1[0]);
            }
            catch (Exception ex)
            {
                LogInfo("Exception! " + ex.Message + " " + ex.StackTrace);
            }
        }

Here is the result from the LogInfo() method:

root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
list1[0]=String1
root.GetVector()...
list Count=4
list1[0]=String1
Exception! Arithmetic operation resulted in an overflow.    at System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeMarshal.HStringToString(IntPtr hstring)
   at System.StubHelpers.HStringMarshaler.ConvertToManaged(IntPtr hstring)
   at System.Runtime.InteropServices.WindowsRuntime.IVector`1.GetAt(UInt32 index)
   at System.Runtime.InteropServices.WindowsRuntime.VectorToListAdapter.GetAt[T](IVector`1 _this, UInt32 index)
   at System.Runtime.InteropServices.WindowsRuntime.VectorToListAdapter.Indexer_Get[T](Int32 index)
   at StoreAppForLibrary1.MainPage.Button_Click_VectorString(Object sender, RoutedEventArgs e)
root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
Exception! Exception of type 'System.OutOfMemoryException' was thrown.    at System.String.CtorCharPtrStartLength(Char* ptr, Int32 startIndex, Int32 length)
   at System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeMarshal.HStringToString(IntPtr hstring)
   at System.StubHelpers.HStringMarshaler.ConvertToManaged(IntPtr hstring)
   at System.Runtime.InteropServices.WindowsRuntime.IVector`1.GetAt(UInt32 index)
   at System.Runtime.InteropServices.WindowsRuntime.VectorToListAdapter.GetAt[T](IVector`1 _this, UInt32 index)
   at System.Runtime.InteropServices.WindowsRuntime.VectorToListAdapter.Indexer_Get[T](Int32 index)
   at StoreAppForLibrary1.MainPage.Button_Click_VectorString(Object sender, RoutedEventArgs e)
root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
list1[0]=String1
root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
list1[0]=String1
root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
list1[0]=String1
root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
list1[0]=String1
root.GetVector()...
list Count=4
list1[0]=String1
list1[0]=String1
list1[0]=String1

Christophe Pichaud

Edited by Christophe Pichaud [MVP]MVP Sunday, April 13, 2014 9:07 AM

Sunday, April 13, 2014 9:06 AM

The point is only about the vector of HSTRING because with the same vector, provided by my Vector<T> template, using integers, there are no problem. This code that enumerates the data, insert and modify works great:

        private void Button_Click_VectorInt(object sender, RoutedEventArgs e)
        {
            try
            {
                // C# XAML APP using Root::GetVectorInt()
                Root root = new Root();
                IList<int> list1 = root.GetVectorInt();
                LogInfo("list Count=" + list1.Count.ToString());
                foreach (int i in list1)
                {
                    LogInfo("int: " + i.ToString());
                }
                list1[0] = 11;
                list1[1] = 22;
                list1.Add(1001);
                list1.Insert(0, 1);
                LogInfo("list Count=" + list1.Count.ToString());
                foreach (int i in list1)
                {
                    LogInfo("int: " + i.ToString());
                }
            }
            catch (Exception ex)
            {
                LogInfo("Exception! " + ex.Message + " " + ex.StackTrace);
            }
        }

Christophe Pichaud

Sunday, April 13, 2014 9:18 AM

0

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Hello,

I have previously asked a question in the Windows Store Apps forum with C++ but I have 0 responses.

Here is my thread: Handling HSTRING with a vector wrapper Question

I have a Vector<T> that basically wraps the std::vector for using it with Windows Runtime Collections. When I deal with integer or custom data types, there are no problem, I can iterate, retrieve, add, update elements... But when I use HSTRING, I have encountered some problems.

The data are retrieved the first time, then it fails !

Christophe Pichaud
- Merged by May Wang - MSFT Monday, April 21, 2014 8:48 AM for professional support
Wednesday, April 16, 2014 1:03 PM
0

Sign in to vote
I'm not exactly familiar with WinRT and its HSTRING but shouldn't you use a vector<HString> instead of vector<HSTRING>? HSTRING is reference counted, presumably something needs to deal with increasing the reference count of the string when it is handed out to the outside world.
- Edited by Mike Danes Thursday, April 17, 2014 6:07 AM
- Marked as answer by Christophe Pichaud [MVP]MVP Wednesday, April 23, 2014 12:57 AM
Thursday, April 17, 2014 6:07 AM
0

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Hi，

Thanks for posting here. But this issue is more related with WinRT, windows store apps forum is more proper for this issue. VC++ forum aims to discuss and ask questions about the Visual C++ IDE, libraries, samples, tools, setup, and windows programming using MFC and ATL. Hope you can understand.

May
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Thursday, April 17, 2014 8:59 AM

Hello,

		template <typename T>
		struct Wrap
		{
			typename typedef T type;
			static const T& MakeWrap(const T& t)
			{
				return t;
			}
			static const T& Unwrap(const T& t)
			{
				return t;
			}
		};

		template <>
		struct Wrap<HSTRING>
		{
			typedef HStringHelper type;
			static HStringHelper MakeWrap(const HSTRING& t)
			{
				HStringHelper str;
				str.Set(t);
				return str;
			}
			static HSTRING Unwrap(const HStringHelper& t)
			{
				HSTRING str;
				HRESULT hr = t.CopyTo(&str);
				// Error check
				return str;
			}
		};

		template <typename T>
		struct Wrap<T*>
		{
			typename typedef ComPtr<T> type;
			static ComPtr<T> MakeWrap(T* t)
			{
				ComPtr<T> ptr;
				ptr.Attach(t);
				return ptr;
			}
			static T* Unwrap(ComPtr<T> t)
			{
				ComPtr<T> ptr(t);
				return t.Detach();
			}
		};

And my vector template class is now made with this:

		template <class T>
		class Iterator : public RuntimeClass<IIterator<T>>
		{
			InspectableClass(L"Library1.Iterator", BaseTrust)

		private:
			typedef typename std::vector<typename Wrap<T>::type> WrappedVector;
			typedef typename std::shared_ptr<WrappedVector> V;
			typedef typename WrappedVector::iterator IT;

		public:
			Iterator() {} 

			void LogVectorContent()
			{
				for (IT it = _v->begin(); it != _v->end(); it++)
				{
					T element = Wrap<T>::Unwrap(*it);
					void * ptr = (void *)element;
					wchar_t sz[255];
					swprintf(sz, 255, L"adress T =0x%08x\n", (int)ptr);
					_LogInfo(sz);
				}
			}

			HRESULT Init(const V& vec)
			{
				try {
					_LogInfo(L"Iterator::Init()...");

				_v = vec;
				
				LogVectorContent();

				_it = _v->begin();
				if (_it != _v->end())
				{
					_element = Wrap<T>::Unwrap(*_it);
					_bElement = TRUE;
				}
				else
					_bElement = FALSE;
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::Init()...");
			}

		public:
			virtual HRESULT STDMETHODCALLTYPE get_Current(T *current)
			{
				try {
					_LogInfo(L"Iterator::get_Current()...");
				if (_it != _v->end())
				{
					_bElement = TRUE;
					_element = Wrap<T>::Unwrap(*_it);
					*current = _element;
				}
				else
				{
					_bElement = FALSE;
				}
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::get_Current()...");
			}

			virtual HRESULT STDMETHODCALLTYPE get_HasCurrent(boolean *hasCurrent)
			{
				try {
					_LogInfo(L"Iterator::get_HasCurrent()...");
				if (_bElement)
					*hasCurrent = TRUE;
				else
					*hasCurrent = FALSE;
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::get_HasCurrent()...");
			}

			virtual HRESULT STDMETHODCALLTYPE MoveNext(boolean *hasCurrent)
			{
				try {
					_LogInfo(L"Iterator::MoveNext()...");
				if (_it != _v->end())
				{
					++_it;
					if (_it == _v->end())
					{
						*hasCurrent = FALSE;
						_bElement = FALSE;
					}
					else
					{
						*hasCurrent = TRUE;
						_bElement = TRUE;
					}
				}
				else
				{
					*hasCurrent = FALSE;
					_bElement = FALSE;
				}
				return S_OK;
				_EXCEPTION_HANDLER(L"Iterator::MoveNext()...");
			}

		private:
			V _v;
			IT _it;
			T _element;
			boolean _bElement = FALSE;
		};

		template <typename T>
		class Vector : public RuntimeClass<IVector<T>, 
			IIterable<T >>
		{
			InspectableClass(L"Library1.Vector", BaseTrust)

		private:
			typedef typename std::vector<typename Wrap<T>::type> WrappedVector;
			typedef typename WrappedVector::const_iterator CIT;

		public:
			Vector() 
			{
				_LogInfo(L"Vector::Vector()...");
				_v = std::make_shared<WrappedVector>();
			}

		public:
			// read methods
			virtual HRESULT STDMETHODCALLTYPE GetAt(unsigned index, T *item)
			{
				_LogInfo(L"Vector::GetAt()...");
				*item = Wrap<T>::Unwrap((*_v)[index]);
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE get_Size(unsigned *size)
			{
				_LogInfo(L"Vector::get_Size()...");
				*size = _v->size();
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE GetView(IVectorView<T> **view)
			{
				_LogInfo(L"Vector::GetView()...");
				return E_NOTIMPL;
			}

			virtual HRESULT STDMETHODCALLTYPE IndexOf(T value, unsigned *index, boolean *found)
			{
				_LogInfo(L"Vector::IndexOf()...");
				unsigned foundedIndex = 0;
				bool founded = false;
				for (CIT it = _v->cbegin() ; it != _v->end() ; ++it)
				{
					const T & v = Wrap<T>::Unwrap(*it);
					if (v == value)
					{
						founded = true;
						break;
					}
					foundedIndex++;
				}
				if (founded == true)
				{
					*found = TRUE;
					*index = foundedIndex;
				}
				else
				{
					*found = FALSE;
				}
				return S_OK;
			}

			// write methods
			virtual HRESULT STDMETHODCALLTYPE SetAt(unsigned index, T item)
			{
				_LogInfo(L"Vector::SetAt()...");
				if (index < _v->size())
				{
					(*_v)[index] = Wrap<T>::MakeWrap(item);
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE InsertAt(unsigned index, T item)
			{
				_LogInfo(L"Vector::InsertAt()...");
				_v->insert(_v->begin() + index, Wrap<T>::MakeWrap(item));
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE RemoveAt(unsigned index)
			{
				_LogInfo(L"Vector::RemoveAt()...");
				if (index < _v->size())
				{
					_v->erase(_v->begin() + index);
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE Append(T item)
			{
				_LogInfo(L"Vector::Append()...");
				_v->push_back(Wrap<T>::MakeWrap(item));
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE RemoveAtEnd()
			{
				_LogInfo(L"Vector::RemoveAtEnd()...");
				if (!_v->empty())
				{
					_v->pop_back();
				}
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE Clear()
			{
				_LogInfo(L"Vector::Clear()...");
				_v->clear();
				return S_OK;
			}

			virtual HRESULT STDMETHODCALLTYPE First(IIterator<T> **first)
			{
				_LogInfo(L"Vector::First()...");
				ComPtr<Iterator<T>> p = Make<Iterator<T>>();
				p->Init(_v);
				*first = p.Detach();
				return S_OK;
			}

		private:
			std::shared_ptr<WrappedVector> _v;
		};

Elements are wrapped and unwrapped.

Christophe Pichaud

Marked as answer by Christophe Pichaud [MVP]MVP Wednesday, April 23, 2014 12:56 AM

Wednesday, April 23, 2014 12:55 AM

Answered by:

Handling HSTRING with a vector wrapper

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