gecko-dev/xpcom/string/public/nsLiteralString.h

88 строки
3.6 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsLiteralString_h___
#define nsLiteralString_h___
#ifndef nscore_h___
#include "nscore.h"
#endif
#ifndef nsDependentString_h___
#include "nsDependentString.h"
#endif
namespace mozilla {
namespace internal {
// This is the same as sizeof(c) - 1, except it won't compile if c isn't a
// string literal. This ensures that NS_LITERAL_CSTRING doesn't compile if you
// pass it a char* (or something else for that matter).
template<int n>
inline uint32_t LiteralStringLength(const char (&c)[n])
{
return n - 1;
}
#if defined(HAVE_CPP_CHAR16_T)
template<int n>
inline uint32_t LiteralWStringLength(const char16_t (&c)[n])
{
return n - 1;
}
#elif defined(HAVE_CPP_2BYTE_WCHAR_T)
template<int n>
inline uint32_t LiteralWStringLength(const wchar_t (&c)[n])
{
return n - 1;
}
#endif
} // namespace internal
} // namespace mozilla
#if defined(HAVE_CPP_CHAR16_T) || defined(HAVE_CPP_2BYTE_WCHAR_T)
#if defined(HAVE_CPP_CHAR16_T)
//PR_STATIC_ASSERT(sizeof(char16_t) == 2);
#define NS_LL(s) u##s
#else
//PR_STATIC_ASSERT(sizeof(wchar_t) == 2);
#define NS_LL(s) L##s
#endif
#define NS_MULTILINE_LITERAL_STRING(s) nsDependentString(reinterpret_cast<const nsAString::char_type*>(s), mozilla::internal::LiteralWStringLength(s))
#define NS_MULTILINE_LITERAL_STRING_INIT(n,s) n(reinterpret_cast<const nsAString::char_type*>(s), mozilla::internal::LiteralWStringLength(s))
#define NS_NAMED_MULTILINE_LITERAL_STRING(n,s) const nsDependentString n(reinterpret_cast<const nsAString::char_type*>(s), mozilla::internal::LiteralWStringLength(s))
typedef nsDependentString nsLiteralString;
#else
#define NS_LL(s) s
#define NS_MULTILINE_LITERAL_STRING(s) NS_ConvertASCIItoUTF16(s, mozilla::internal::LiteralStringLength(s))
#define NS_MULTILINE_LITERAL_STRING_INIT(n,s) n(s, mozilla::internal::LiteralStringLength(s))
#define NS_NAMED_MULTILINE_LITERAL_STRING(n,s) const NS_ConvertASCIItoUTF16 n(s, mozilla::internal::LiteralStringLength(s))
typedef NS_ConvertASCIItoUTF16 nsLiteralString;
#endif
/*
* Macro arguments used in concatenation or stringification won't be expanded.
* Therefore, in order for |NS_L(FOO)| to work as expected (which is to expand
* |FOO| before doing whatever |NS_L| needs to do to it) a helper macro needs
* to be inserted in between to allow the macro argument to expand.
* See "3.10.6 Separate Expansion of Macro Arguments" of the CPP manual for a
* more accurate and precise explanation.
*/
#define NS_L(s) NS_LL(s)
#define NS_LITERAL_STRING(s) static_cast<const nsAFlatString&>(NS_MULTILINE_LITERAL_STRING(NS_LL(s)))
#define NS_LITERAL_STRING_INIT(n,s) NS_MULTILINE_LITERAL_STRING_INIT(n, NS_LL(s))
#define NS_NAMED_LITERAL_STRING(n,s) NS_NAMED_MULTILINE_LITERAL_STRING(n, NS_LL(s))
#define NS_LITERAL_CSTRING(s) static_cast<const nsDependentCString&>(nsDependentCString(s, mozilla::internal::LiteralStringLength(s)))
#define NS_LITERAL_CSTRING_INIT(n,s) n(s, mozilla::internal::LiteralStringLength(s))
#define NS_NAMED_LITERAL_CSTRING(n,s) const nsDependentCString n(s, mozilla::internal::LiteralStringLength(s))
typedef nsDependentCString nsLiteralCString;
#endif /* !defined(nsLiteralString_h___) */