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// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_WIN_WINRT_FOUNDATION_HELPERS_H_
#define BASE_WIN_WINRT_FOUNDATION_HELPERS_H_
#include <windows.foundation.h>
#include <wrl/client.h>
#include <vector>
#include "base/optional.h"
#include "base/win/hstring_compare.h"
// This file provides helpers for WinRT types.
namespace base {
namespace win {
namespace internal {
// Template tricks needed to dispatch to the correct implementation.
//
// For all types which are neither InterfaceGroups nor RuntimeClasses, the
// following three typedefs are synonyms for a single C++ type. But for
// InterfaceGroups and RuntimeClasses, they are different types:
// LogicalT: The C++ Type for the InterfaceGroup or RuntimeClass, when
// used as a template parameter. Eg "RCFoo*"
// AbiT: The C++ type for the default interface used to represent the
// InterfaceGroup or RuntimeClass when passed as a method parameter.
// Eg "IFoo*"
// ComplexT: An instantiation of the Internal "AggregateType" template that
// combines LogicalT with AbiT. Eg "AggregateType<RCFoo*,IFoo*>".
// ComplexT is tightly coupled to the interface being implemented,
// hence defined in headers which include this file.
// For instance base/win/async_operation.h or
// base/win/collection_helpers.h
//
// windows.foundation.collections.h defines the following template and
// semantics in Windows::Foundation::Internal:
//
// template <class LogicalType, class AbiType>
// struct AggregateType;
//
// LogicalType - the Windows Runtime type (eg, runtime class, interface group,
// etc) being provided as an argument to an _impl template, when
// that type cannot be represented at the ABI.
// AbiType - the type used for marshalling, ie "at the ABI", for the
// logical type.
template <typename TComplex>
using AbiType =
typename ABI::Windows::Foundation::Internal::GetAbiType<TComplex>::type;
template <typename TComplex>
using LogicalType =
typename ABI::Windows::Foundation::Internal::GetLogicalType<TComplex>::type;
// Compile time switch to decide what container to use for |TComplex|.
// Depends on whether the underlying Abi type is a pointer to IUnknown or not.
// It queries the internals of Windows::Foundation to obtain this information.
template <typename TComplex>
using StorageType = std::conditional_t<
std::is_convertible<AbiType<TComplex>, IUnknown*>::value,
Microsoft::WRL::ComPtr<std::remove_pointer_t<AbiType<TComplex>>>,
AbiType<TComplex>>;
// Similar to StorageType, but returns a base::Optional in case underlying Abi
// type is not a pointer to IUnknown.
template <typename TComplex>
using OptionalStorageType = std::conditional_t<
std::is_convertible<AbiType<TComplex>, IUnknown*>::value,
Microsoft::WRL::ComPtr<std::remove_pointer_t<AbiType<TComplex>>>,
base::Optional<AbiType<TComplex>>>;
template <typename T>
HRESULT CopyTo(const T& value, T* ptr) {
*ptr = value;
return S_OK;
}
template <typename T>
HRESULT CopyTo(const Microsoft::WRL::ComPtr<T>& value, T** ptr) {
return value.CopyTo(ptr);
}
template <typename T>
HRESULT CopyTo(const base::Optional<T>& value, T* ptr) {
*ptr = *value;
return S_OK;
}
template <typename T>
HRESULT CopyN(typename std::vector<T>::const_iterator first,
unsigned count,
T* result) {
std::copy_n(first, count, result);
return S_OK;
}
template <typename T>
HRESULT CopyN(
typename std::vector<Microsoft::WRL::ComPtr<T>>::const_iterator first,
unsigned count,
T** result) {
for (unsigned i = 0; i < count; ++i)
CopyTo(*first++, result++);
return S_OK;
}
inline bool IsEqual(const HSTRING& lhs, const HSTRING& rhs) {
INT32 result;
HRESULT hr = HStringCompare(lhs, rhs, &result);
DCHECK(SUCCEEDED(hr));
return result == 0;
}
template <typename T>
bool IsEqual(const T& lhs, const T& rhs) {
return lhs == rhs;
}
template <typename T>
bool IsEqual(const Microsoft::WRL::ComPtr<T>& com_ptr, const T* ptr) {
return com_ptr.Get() == ptr;
}
struct Less {
bool operator()(const HSTRING& lhs, const HSTRING& rhs) const {
INT32 result;
HRESULT hr = HStringCompare(lhs, rhs, &result);
DCHECK(SUCCEEDED(hr));
return result < 0;
}
template <typename T>
bool operator()(const Microsoft::WRL::ComPtr<T>& com_ptr,
const T* ptr) const {
return com_ptr.Get() < ptr;
}
template <typename T>
constexpr bool operator()(const T& lhs, const T& rhs) const {
return lhs < rhs;
}
};
} // namespace internal
} // namespace win
} // namespace base
#endif // BASE_WIN_WINRT_FOUNDATION_HELPERS_H_