naiveproxy/base/win/scoped_hstring.h
2018-01-29 00:30:36 +08:00

74 lines
2.0 KiB
C++

// Copyright 2017 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_SCOPED_HSTRING_H_
#define BASE_WIN_SCOPED_HSTRING_H_
#include <hstring.h>
#include "base/scoped_generic.h"
#include "base/strings/string_piece_forward.h"
namespace base {
namespace internal {
// Scoped HSTRING class to maintain lifetime of HSTRINGs allocated with
// WindowsCreateString().
struct BASE_EXPORT ScopedHStringTraits {
static HSTRING InvalidValue() { return nullptr; }
static void Free(HSTRING hstr);
};
} // namespace internal
namespace win {
// ScopedHString is a wrapper around an HSTRING. Note that it 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 ScopedHString.
//
// One-time Initialization for ScopedHString:
//
// bool success = ScopedHString::ResolveCoreWinRTStringDelayload();
// if (!success) {
// // ScopeHString can be used.
// } else {
// // Handle error.
// }
//
// Example use:
//
// ScopedHString string = ScopedHString::Create(L"abc");
//
// Also:
//
// HSTRING win_string;
// HRESULT hr = WindowsCreateString(..., &win_string);
// ScopedHString string(win_string);
//
class BASE_EXPORT ScopedHString
: public ScopedGeneric<HSTRING, internal::ScopedHStringTraits> {
public:
// Constructs a ScopedHString from an HSTRING, and takes ownership of |hstr|.
explicit ScopedHString(HSTRING hstr);
static ScopedHString Create(StringPiece16 str);
static ScopedHString Create(StringPiece str);
// Loads all required HSTRING functions, available from Win8 and onwards.
static bool ResolveCoreWinRTStringDelayload();
StringPiece16 Get() const;
std::string GetAsUTF8() const;
};
} // namespace win
} // namespace base
#endif // BASE_WIN_SCOPED_HSTRING_H_