gecko-dev/xpcom/string/nsTLiteralString.h

78 строки
2.2 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
/**
* nsTLiteralString_CharT
*
* Stores a null-terminated, immutable sequence of characters.
*
* nsTString-lookalike that restricts its string value to a literal character
* sequence. Can be implicitly cast to const nsTString& (the const is
* essential, since this class's data are not writable). The data are assumed
* to be static (permanent) and therefore, as an optimization, this class
* does not have a destructor.
*/
class nsTLiteralString_CharT : public mozilla::detail::nsTStringRepr_CharT
{
public:
typedef nsTLiteralString_CharT self_type;
public:
/**
* constructor
*/
template<size_type N>
explicit nsTLiteralString_CharT(const char_type (&aStr)[N])
: base_string_type(const_cast<char_type*>(aStr), N - 1, F_TERMINATED | F_LITERAL)
{
}
/**
* For compatibility with existing code that requires const ns[C]String*.
* Use sparingly. If possible, rewrite code to use const ns[C]String&
* and the implicit cast will just work.
*/
const nsTString_CharT& AsString() const
{
return *reinterpret_cast<const nsTString_CharT*>(this);
}
operator const nsTString_CharT&() const
{
return AsString();
}
/**
* Prohibit get() on temporaries as in nsLiteralCString("x").get().
* These should be written as just "x", using a string literal directly.
*/
#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
char16ptr_t get() const && = delete;
char16ptr_t get() const &
#else
const char_type* get() const && = delete;
const char_type* get() const &
#endif
{
return mData;
}
private:
// NOT TO BE IMPLEMENTED
template<size_type N>
nsTLiteralString_CharT(char_type (&aStr)[N]) = delete;
self_type& operator=(const self_type&) = delete;
};
static_assert(sizeof(nsTLiteralString_CharT) == sizeof(nsTString_CharT),
"nsTLiteralString_CharT can masquerade as nsTString_CharT, "
"so they must have identical layout");