// 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_HSTRING_REFERENCE_H_ #define BASE_WIN_HSTRING_REFERENCE_H_ #include #include "base/base_export.h" namespace base { namespace win { // HStringReference is an HSTRING representation of a null terminated // string backed by memory that outlives the HStringReference instance. // // If you need an HSTRING class that manages its own memory, you should // use ScopedHString instead. // // Note that HStringReference requires certain functions that are only // available on Windows 8 and later, and that these functions need to be // delayloaded to avoid breaking Chrome on Windows 7. // // Callers MUST check the return value of ResolveCoreWinRTStringDelayLoad() // *before* using HStringReference. // // One-time Initialization for HStringReference: // // const bool success = HStringReference::ResolveCoreWinRTStringDelayload(); // if (success) { // // HStringReference can be used. // } else { // // Handle error. // } // // Example use: // // HStringReference string(L"abc"); // class BASE_EXPORT HStringReference { public: // Loads all required HSTRING functions, available from Win8 and onwards. static bool ResolveCoreWinRTStringDelayload(); HStringReference(const wchar_t* str, size_t len); explicit HStringReference(const wchar_t* str); HSTRING Get() const { return hstring_; } // HSTRING_HEADER is a structure that contains a pointer to the string // passed into the constructor, along with its length. // Since HSTRING is a pointer to HSTRING_HEADER, HStringReference // cannot be copyable, moveable or assignable, as that would invalidate // the HSTRING we're passing out to clients. // In the future, we can consider implementing these methods by storing // the string passed in the constructor and re-creating the HSTRING and // HSTRING_HEADER datastructures. For now, we'll keep things simple and // forbid these operations. HStringReference(const HStringReference&) = delete; HStringReference& operator=(const HStringReference&) = delete; private: HSTRING hstring_ = nullptr; HSTRING_HEADER hstring_header_; }; } // namespace win } // namespace base #endif // BASE_WIN_HSTRING_REFERENCE_H_