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Diffstat (limited to 'xpcom/string/nsTString.h')
| -rw-r--r-- | xpcom/string/nsTString.h | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/xpcom/string/nsTString.h b/xpcom/string/nsTString.h new file mode 100644 index 0000000000..9793f70e3b --- /dev/null +++ b/xpcom/string/nsTString.h @@ -0,0 +1,447 @@ +/* -*- 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/. */ +// IWYU pragma: private, include "nsString.h" + +#ifndef nsTString_h +#define nsTString_h + +#include "nsTSubstring.h" + +/** + * This is the canonical null-terminated string class. All subclasses + * promise null-terminated storage. Instances of this class allocate + * strings on the heap. + * + * NAMES: + * nsString for wide characters + * nsCString for narrow characters + * + * This class is also known as nsAFlat[C]String, where "flat" is used + * to denote a null-terminated string. + */ +template <typename T> +class nsTString : public nsTSubstring<T> { + public: + typedef nsTString<T> self_type; + + using repr_type = mozilla::detail::nsTStringRepr<T>; + +#ifdef __clang__ + // bindgen w/ clang 3.9 at least chokes on a typedef, but using is okay. + using typename nsTSubstring<T>::substring_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 nsTSubstring<T>::substring_type substring_type; +#endif + + typedef typename substring_type::fallible_t fallible_t; + + typedef typename substring_type::char_type char_type; + typedef typename substring_type::char_traits char_traits; + typedef + typename substring_type::incompatible_char_type incompatible_char_type; + + typedef typename substring_type::substring_tuple_type substring_tuple_type; + + typedef typename substring_type::const_iterator const_iterator; + typedef typename substring_type::iterator iterator; + + typedef typename substring_type::comparator_type comparator_type; + + typedef typename substring_type::const_char_iterator const_char_iterator; + + typedef typename substring_type::string_view string_view; + + typedef typename substring_type::index_type index_type; + typedef typename substring_type::size_type size_type; + + // These are only for internal use within the string classes: + typedef typename substring_type::DataFlags DataFlags; + typedef typename substring_type::ClassFlags ClassFlags; + + public: + /** + * constructors + */ + + nsTString() : substring_type(ClassFlags::NULL_TERMINATED) {} + + explicit nsTString(const char_type* aData, size_type aLength = size_type(-1)) + : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(aData, aLength); + } + + explicit nsTString(mozilla::Span<const char_type> aData) + : nsTString(aData.Elements(), aData.Length()) {} + +#if defined(MOZ_USE_CHAR16_WRAPPER) + template <typename Q = T, typename EnableIfChar16 = mozilla::Char16OnlyT<Q>> + explicit nsTString(char16ptr_t aStr, size_type aLength = size_type(-1)) + : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(static_cast<const char16_t*>(aStr), aLength); + } +#endif + + nsTString(const self_type& aStr) + : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(aStr); + } + + nsTString(self_type&& aStr) : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(std::move(aStr)); + } + + MOZ_IMPLICIT nsTString(const substring_tuple_type& aTuple) + : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(aTuple); + } + + explicit nsTString(const substring_type& aReadable) + : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(aReadable); + } + + explicit nsTString(substring_type&& aReadable) + : substring_type(ClassFlags::NULL_TERMINATED) { + this->Assign(std::move(aReadable)); + } + + // |operator=| does not inherit, so we must define our own + self_type& operator=(char_type aChar) { + this->Assign(aChar); + return *this; + } + self_type& operator=(const char_type* aData) { + this->Assign(aData); + return *this; + } + self_type& operator=(const self_type& aStr) { + this->Assign(aStr); + return *this; + } + self_type& operator=(self_type&& aStr) { + this->Assign(std::move(aStr)); + return *this; + } +#if defined(MOZ_USE_CHAR16_WRAPPER) + template <typename Q = T, typename EnableIfChar16 = mozilla::Char16OnlyT<Q>> + self_type& operator=(const char16ptr_t aStr) { + this->Assign(static_cast<const char16_t*>(aStr)); + return *this; + } +#endif + self_type& operator=(const substring_type& aStr) { + this->Assign(aStr); + return *this; + } + self_type& operator=(substring_type&& aStr) { + this->Assign(std::move(aStr)); + return *this; + } + self_type& operator=(const substring_tuple_type& aTuple) { + this->Assign(aTuple); + return *this; + } + + /** + * returns the null-terminated string + */ + + template <typename U, typename Dummy> + struct raw_type { + typedef const U* type; + }; +#if defined(MOZ_USE_CHAR16_WRAPPER) + template <typename Dummy> + struct raw_type<char16_t, Dummy> { + typedef char16ptr_t type; + }; +#endif + + MOZ_NO_DANGLING_ON_TEMPORARIES typename raw_type<T, int>::type get() const { + return this->mData; + } + + /** + * returns character at specified index. + * + * NOTE: unlike nsTSubstring::CharAt, this function allows you to index + * the null terminator character. + */ + + char_type CharAt(index_type aIndex) const { + MOZ_ASSERT(aIndex <= this->Length(), "index exceeds allowable range"); + return this->mData[aIndex]; + } + + char_type operator[](index_type aIndex) const { return CharAt(aIndex); } + + /** + * Set a char inside this string at given index + * + * @param aChar is the char you want to write into this string + * @param anIndex is the ofs where you want to write the given char + * @return TRUE if successful + */ + bool SetCharAt(char16_t aChar, index_type aIndex); + + /** + * Allow this string to be bound to a character buffer + * until the string is rebound or mutated; the caller + * must ensure that the buffer outlives the string. + */ + void Rebind(const char_type* aData, size_type aLength); + + /** + * verify restrictions for dependent strings + */ + void AssertValidDependentString() { + MOZ_ASSERT(this->mData, "nsTDependentString must wrap a non-NULL buffer"); + MOZ_ASSERT(this->mData[substring_type::mLength] == 0, + "nsTDependentString must wrap only null-terminated strings. " + "You are probably looking for nsTDependentSubstring."); + } + + protected: + // allow subclasses to initialize fields directly + nsTString(char_type* aData, size_type aLength, DataFlags aDataFlags, + ClassFlags aClassFlags) + : substring_type(aData, aLength, aDataFlags, + aClassFlags | ClassFlags::NULL_TERMINATED) {} + + friend const nsTString<char>& VoidCString(); + friend const nsTString<char16_t>& VoidString(); + + // Used by Null[C]String. + explicit nsTString(DataFlags aDataFlags) + : substring_type(char_traits::sEmptyBuffer, 0, + aDataFlags | DataFlags::TERMINATED, + ClassFlags::NULL_TERMINATED) {} +}; + +extern template class nsTString<char>; +extern template class nsTString<char16_t>; + +/** + * nsTAutoStringN + * + * Subclass of nsTString that adds support for stack-based string + * allocation. It is normally not a good idea to use this class on the + * heap, because it will allocate space which may be wasted if the string + * it contains is significantly smaller or any larger than 64 characters. + * + * NAMES: + * nsAutoStringN / nsTAutoString for wide characters + * nsAutoCStringN / nsTAutoCString for narrow characters + */ +template <typename T, size_t N> +class MOZ_NON_MEMMOVABLE nsTAutoStringN : public nsTString<T> { + public: + typedef nsTAutoStringN<T, N> self_type; + + typedef nsTString<T> base_string_type; + typedef typename base_string_type::string_type string_type; + typedef typename base_string_type::char_type char_type; + typedef typename base_string_type::char_traits char_traits; + typedef typename base_string_type::substring_type substring_type; + typedef typename base_string_type::size_type size_type; + typedef typename base_string_type::substring_tuple_type substring_tuple_type; + + // These are only for internal use within the string classes: + typedef typename base_string_type::DataFlags DataFlags; + typedef typename base_string_type::ClassFlags ClassFlags; + typedef typename base_string_type::LengthStorage LengthStorage; + + public: + /** + * constructors + */ + + nsTAutoStringN() + : string_type(mStorage, 0, DataFlags::TERMINATED | DataFlags::INLINE, + ClassFlags::INLINE), + mInlineCapacity(N - 1) { + // null-terminate + mStorage[0] = char_type(0); + } + + explicit nsTAutoStringN(char_type aChar) : self_type() { + this->Assign(aChar); + } + + explicit nsTAutoStringN(const char_type* aData, + size_type aLength = size_type(-1)) + : self_type() { + this->Assign(aData, aLength); + } + +#if defined(MOZ_USE_CHAR16_WRAPPER) + template <typename Q = T, typename EnableIfChar16 = mozilla::Char16OnlyT<Q>> + explicit nsTAutoStringN(char16ptr_t aData, size_type aLength = size_type(-1)) + : self_type(static_cast<const char16_t*>(aData), aLength) {} +#endif + + nsTAutoStringN(const self_type& aStr) : self_type() { this->Assign(aStr); } + + nsTAutoStringN(self_type&& aStr) : self_type() { + this->Assign(std::move(aStr)); + } + + explicit nsTAutoStringN(const substring_type& aStr) : self_type() { + this->Assign(aStr); + } + + explicit nsTAutoStringN(substring_type&& aStr) : self_type() { + this->Assign(std::move(aStr)); + } + + MOZ_IMPLICIT nsTAutoStringN(const substring_tuple_type& aTuple) + : self_type() { + this->Assign(aTuple); + } + + // |operator=| does not inherit, so we must define our own + self_type& operator=(char_type aChar) { + this->Assign(aChar); + return *this; + } + self_type& operator=(const char_type* aData) { + this->Assign(aData); + return *this; + } +#if defined(MOZ_USE_CHAR16_WRAPPER) + template <typename Q = T, typename EnableIfChar16 = mozilla::Char16OnlyT<Q>> + self_type& operator=(char16ptr_t aStr) { + this->Assign(aStr); + return *this; + } +#endif + self_type& operator=(const self_type& aStr) { + this->Assign(aStr); + return *this; + } + self_type& operator=(self_type&& aStr) { + this->Assign(std::move(aStr)); + return *this; + } + self_type& operator=(const substring_type& aStr) { + this->Assign(aStr); + return *this; + } + self_type& operator=(substring_type&& aStr) { + this->Assign(std::move(aStr)); + return *this; + } + self_type& operator=(const substring_tuple_type& aTuple) { + this->Assign(aTuple); + return *this; + } + + static const size_t kStorageSize = N; + + protected: + friend class nsTSubstring<T>; + + const LengthStorage mInlineCapacity; + + private: + char_type mStorage[N]; +}; + +// Externs for the most common nsTAutoStringN variations. +extern template class nsTAutoStringN<char, 64>; +extern template class nsTAutoStringN<char16_t, 64>; + +// +// nsAutoString stores pointers into itself which are invalidated when an +// nsTArray is resized, so nsTArray must not be instantiated with nsAutoString +// elements! +// +template <class E> +class nsTArrayElementTraits; +template <typename T> +class nsTArrayElementTraits<nsTAutoString<T>> { + public: + template <class A> + struct Dont_Instantiate_nsTArray_of; + template <class A> + struct Instead_Use_nsTArray_of; + + static Dont_Instantiate_nsTArray_of<nsTAutoString<T>>* Construct( + Instead_Use_nsTArray_of<nsTString<T>>* aE) { + return 0; + } + template <class A> + static Dont_Instantiate_nsTArray_of<nsTAutoString<T>>* Construct( + Instead_Use_nsTArray_of<nsTString<T>>* aE, const A& aArg) { + return 0; + } + template <class... Args> + static Dont_Instantiate_nsTArray_of<nsTAutoString<T>>* Construct( + Instead_Use_nsTArray_of<nsTString<T>>* aE, Args&&... aArgs) { + return 0; + } + static Dont_Instantiate_nsTArray_of<nsTAutoString<T>>* Destruct( + Instead_Use_nsTArray_of<nsTString<T>>* aE) { + return 0; + } +}; + +/** + * getter_Copies support for adopting raw string out params that are + * heap-allocated, e.g.: + * + * char* gStr; + * void GetBlah(char** aStr) + * { + * *aStr = strdup(gStr); + * } + * + * // This works, but is clumsy. + * void Inelegant() + * { + * char* buf; + * GetBlah(&buf); + * nsCString str; + * str.Adopt(buf); + * // ... + * } + * + * // This is nicer. + * void Elegant() + * { + * nsCString str; + * GetBlah(getter_Copies(str)); + * // ... + * } + */ +template <typename T> +class MOZ_STACK_CLASS nsTGetterCopies { + public: + typedef T char_type; + + explicit nsTGetterCopies(nsTSubstring<T>& aStr) + : mString(aStr), mData(nullptr) {} + + ~nsTGetterCopies() { + mString.Adopt(mData); // OK if mData is null + } + + operator char_type**() { return &mData; } + + private: + nsTSubstring<T>& mString; + char_type* mData; +}; + +// See the comment above nsTGetterCopies_CharT for how to use this. +template <typename T> +inline nsTGetterCopies<T> getter_Copies(nsTSubstring<T>& aString) { + return nsTGetterCopies<T>(aString); +} + +#endif |