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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /xpcom/string/nsTLiteralString.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'xpcom/string/nsTLiteralString.h')
-rw-r--r-- | xpcom/string/nsTLiteralString.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/xpcom/string/nsTLiteralString.h b/xpcom/string/nsTLiteralString.h new file mode 100644 index 0000000000..b233183a73 --- /dev/null +++ b/xpcom/string/nsTLiteralString.h @@ -0,0 +1,113 @@ +/* -*- 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/. */ + +#ifndef nsTLiteralString_h +#define nsTLiteralString_h + +#include "nsTStringRepr.h" + +/** + * 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. + */ +template <typename T> +class nsTLiteralString : public mozilla::detail::nsTStringRepr<T> { + public: + typedef nsTLiteralString<T> self_type; + +#ifdef __clang__ + // bindgen w/ clang 3.9 at least chokes on a typedef, but using is okay. + using typename mozilla::detail::nsTStringRepr<T>::base_string_type; +#else + // On the other hand msvc chokes on the using statement. It seems others + // don't care either way so we lump them in here. + typedef typename mozilla::detail::nsTStringRepr<T>::base_string_type + base_string_type; +#endif + + typedef typename base_string_type::char_type char_type; + typedef typename base_string_type::size_type size_type; + typedef typename base_string_type::DataFlags DataFlags; + typedef typename base_string_type::ClassFlags ClassFlags; + + public: + /** + * constructor + */ + + template <size_type N> + explicit constexpr nsTLiteralString(const char_type (&aStr)[N]) + : nsTLiteralString(aStr, N - 1) {} + + nsTLiteralString(const nsTLiteralString&) = default; + + /** + * 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. + */ + MOZ_LIFETIME_BOUND const nsTString<T>& AsString() const { + return *reinterpret_cast<const nsTString<T>*>(this); + } + + MOZ_LIFETIME_BOUND operator const nsTString<T>&() const { return AsString(); } + + template <typename N, typename Dummy> + struct raw_type { + typedef N* type; + }; + +#ifdef MOZ_USE_CHAR16_WRAPPER + template <typename Dummy> + struct raw_type<char16_t, Dummy> { + typedef char16ptr_t type; + }; +#endif + + /** + * Prohibit get() on temporaries as in "x"_ns.get(). + * These should be written as just "x", using a string literal directly. + */ + const typename raw_type<T, int>::type get() const&& = delete; + const typename raw_type<T, int>::type get() const& { return this->mData; } + +// At least older gcc versions do not accept these friend declarations, +// complaining about an "invalid argument list" here, but not where the actual +// operators are defined or used. We make the supposed-to-be-private constructor +// public when building with gcc, relying on the default clang builds to fail if +// any non-private use of that constructor would get into the codebase. +#if defined(__clang__) + private: + friend constexpr auto operator"" _ns(const char* aStr, std::size_t aLen); + friend constexpr auto operator"" _ns(const char16_t* aStr, std::size_t aLen); +#else + public: +#endif + // Only for use by operator"" + constexpr nsTLiteralString(const char_type* aStr, size_t aLen) + : base_string_type(const_cast<char_type*>(aStr), aLen, + DataFlags::TERMINATED | DataFlags::LITERAL, + ClassFlags::NULL_TERMINATED) {} + + public: + // NOT TO BE IMPLEMENTED + template <size_type N> + nsTLiteralString(char_type (&aStr)[N]) = delete; + + nsTLiteralString& operator=(const nsTLiteralString&) = delete; +}; + +extern template class nsTLiteralString<char>; +extern template class nsTLiteralString<char16_t>; + +#endif |