| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | // | ||
| 2 | // Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com) | ||
| 3 | // | ||
| 4 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | ||
| 5 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | ||
| 6 | // | ||
| 7 | // Official repository: https://github.com/boostorg/json | ||
| 8 | // | ||
| 9 | |||
| 10 | #ifndef BOOST_JSON_SERIALIZER_HPP | ||
| 11 | #define BOOST_JSON_SERIALIZER_HPP | ||
| 12 | |||
| 13 | #include <boost/json/detail/config.hpp> | ||
| 14 | #include <boost/json/detail/format.hpp> | ||
| 15 | #include <boost/json/detail/stream.hpp> | ||
| 16 | #include <boost/json/detail/writer.hpp> | ||
| 17 | #include <boost/json/serialize_options.hpp> | ||
| 18 | #include <boost/json/value.hpp> | ||
| 19 | |||
| 20 | namespace boost { | ||
| 21 | namespace json { | ||
| 22 | |||
| 23 | /** A serializer for JSON. | ||
| 24 | |||
| 25 | This class traverses an instance of a library | ||
| 26 | type and emits serialized JSON text by filling | ||
| 27 | in one or more caller-provided buffers. To use, | ||
| 28 | declare a variable and call @ref reset with | ||
| 29 | a pointer to the variable you want to serialize. | ||
| 30 | Then call @ref read over and over until | ||
| 31 | @ref done returns `true`. | ||
| 32 | |||
| 33 | @par Example | ||
| 34 | |||
| 35 | This demonstrates how the serializer may | ||
| 36 | be used to print a JSON value to an output | ||
| 37 | stream. | ||
| 38 | |||
| 39 | @code | ||
| 40 | |||
| 41 | void print( std::ostream& os, value const& jv) | ||
| 42 | { | ||
| 43 | serializer sr; | ||
| 44 | sr.reset( &jv ); | ||
| 45 | while( ! sr.done() ) | ||
| 46 | { | ||
| 47 | char buf[ 4000 ]; | ||
| 48 | os << sr.read( buf ); | ||
| 49 | } | ||
| 50 | } | ||
| 51 | |||
| 52 | @endcode | ||
| 53 | |||
| 54 | @par Thread Safety | ||
| 55 | |||
| 56 | The same instance may not be accessed concurrently. | ||
| 57 | */ | ||
| 58 | class serializer | ||
| 59 | : detail::writer | ||
| 60 | { | ||
| 61 | using fn_t = bool (*)(writer&, detail::stream&); | ||
| 62 | |||
| 63 | fn_t fn0_ = nullptr; | ||
| 64 | fn_t fn1_ = nullptr; | ||
| 65 | bool done_ = false; | ||
| 66 | |||
| 67 | public: | ||
| 68 | /// Move constructor (deleted) | ||
| 69 | serializer(serializer&&) = delete; | ||
| 70 | |||
| 71 | /** Destructor | ||
| 72 | |||
| 73 | All temporary storage is deallocated. | ||
| 74 | |||
| 75 | @par Complexity | ||
| 76 | Constant | ||
| 77 | |||
| 78 | @par Exception Safety | ||
| 79 | No-throw guarantee. | ||
| 80 | */ | ||
| 81 | #ifdef BOOST_JSON_DOCS | ||
| 82 | BOOST_JSON_DECL | ||
| 83 | ~serializer() noexcept; | ||
| 84 | #endif // BOOST_JSON_DOCS | ||
| 85 | |||
| 86 | /** Constructor | ||
| 87 | |||
| 88 | This constructs a serializer with no value. | ||
| 89 | The value may be set later by calling @ref reset. | ||
| 90 | If serialization is attempted with no value, | ||
| 91 | the output is as if a null value is serialized. | ||
| 92 | |||
| 93 | @par Complexity | ||
| 94 | Constant. | ||
| 95 | |||
| 96 | @par Exception Safety | ||
| 97 | No-throw guarantee. | ||
| 98 | |||
| 99 | @param opts The options for the serializer. If this parameter | ||
| 100 | is omitted, the serializer will output only standard JSON. | ||
| 101 | */ | ||
| 102 | BOOST_JSON_DECL | ||
| 103 | serializer( serialize_options const& opts = {} ) noexcept; | ||
| 104 | |||
| 105 | /** Constructor | ||
| 106 | |||
| 107 | This constructs a serializer with no value. | ||
| 108 | The value may be set later by calling @ref reset. | ||
| 109 | If serialization is attempted with no value, | ||
| 110 | the output is as if a null value is serialized. | ||
| 111 | |||
| 112 | @par Complexity | ||
| 113 | Constant. | ||
| 114 | |||
| 115 | @par Exception Safety | ||
| 116 | No-throw guarantee. | ||
| 117 | |||
| 118 | @param sp A pointer to the `boost::container::pmr::memory_resource` to | ||
| 119 | use when producing partial output. Shared ownership of the memory | ||
| 120 | resource is retained until the serializer is destroyed. | ||
| 121 | |||
| 122 | @param buf An optional static buffer to | ||
| 123 | use for temporary storage when producing | ||
| 124 | partial output. | ||
| 125 | |||
| 126 | @param buf_size The number of bytes of | ||
| 127 | valid memory pointed to by `buf`. | ||
| 128 | |||
| 129 | @param opts The options for the serializer. If this parameter | ||
| 130 | is omitted, the serializer will output only standard JSON. | ||
| 131 | */ | ||
| 132 | BOOST_JSON_DECL | ||
| 133 | serializer( | ||
| 134 | storage_ptr sp, | ||
| 135 | unsigned char* buf = nullptr, | ||
| 136 | std::size_t buf_size = 0, | ||
| 137 | serialize_options const& opts = {}) noexcept; | ||
| 138 | |||
| 139 | /** Returns `true` if the serialization is complete | ||
| 140 | |||
| 141 | This function returns `true` when all of the | ||
| 142 | characters in the serialized representation of | ||
| 143 | the value have been read. | ||
| 144 | |||
| 145 | @par Complexity | ||
| 146 | Constant. | ||
| 147 | |||
| 148 | @par Exception Safety | ||
| 149 | No-throw guarantee. | ||
| 150 | */ | ||
| 151 | bool | ||
| 152 | 26927 | done() const noexcept | |
| 153 | { | ||
| 154 | 26927 | return done_; | |
| 155 | } | ||
| 156 | |||
| 157 | /** Reset the serializer for a new element | ||
| 158 | |||
| 159 | This function prepares the serializer to emit | ||
| 160 | a new serialized JSON representing `*p`. | ||
| 161 | Any internally allocated memory is | ||
| 162 | preserved and re-used for the new output. | ||
| 163 | |||
| 164 | @param p A pointer to the element to serialize. | ||
| 165 | Ownership is not transferred; The caller is | ||
| 166 | responsible for ensuring that the lifetime of | ||
| 167 | `*p` extends until it is no longer needed. | ||
| 168 | */ | ||
| 169 | /** @{ */ | ||
| 170 | BOOST_JSON_DECL | ||
| 171 | void | ||
| 172 | reset(value const* p) noexcept; | ||
| 173 | |||
| 174 | BOOST_JSON_DECL | ||
| 175 | void | ||
| 176 | reset(array const* p) noexcept; | ||
| 177 | |||
| 178 | BOOST_JSON_DECL | ||
| 179 | void | ||
| 180 | reset(object const* p) noexcept; | ||
| 181 | |||
| 182 | BOOST_JSON_DECL | ||
| 183 | void | ||
| 184 | reset(string const* p) noexcept; | ||
| 185 | |||
| 186 | template<class T> | ||
| 187 | void | ||
| 188 | reset(T const* p) noexcept; | ||
| 189 | /** @} */ | ||
| 190 | |||
| 191 | /** Reset the serializer for a new string | ||
| 192 | |||
| 193 | This function prepares the serializer to emit | ||
| 194 | a new serialized JSON representing the string. | ||
| 195 | Any internally allocated memory is | ||
| 196 | preserved and re-used for the new output. | ||
| 197 | |||
| 198 | @param sv The characters representing the string. | ||
| 199 | Ownership is not transferred; The caller is | ||
| 200 | responsible for ensuring that the lifetime of | ||
| 201 | the characters reference by `sv` extends | ||
| 202 | until it is no longer needed. | ||
| 203 | */ | ||
| 204 | BOOST_JSON_DECL | ||
| 205 | void | ||
| 206 | reset(string_view sv) noexcept; | ||
| 207 | |||
| 208 | /** Reset the serializer for std::nullptr_t | ||
| 209 | |||
| 210 | This function prepares the serializer to emit | ||
| 211 | a new serialized JSON representing null. | ||
| 212 | Any internally allocated memory is | ||
| 213 | preserved and re-used for the new output. | ||
| 214 | */ | ||
| 215 | BOOST_JSON_DECL | ||
| 216 | void | ||
| 217 | reset(std::nullptr_t) noexcept; | ||
| 218 | |||
| 219 | /** Read the next buffer of serialized JSON | ||
| 220 | |||
| 221 | This function attempts to fill the caller | ||
| 222 | provided buffer starting at `dest` with | ||
| 223 | up to `size` characters of the serialized | ||
| 224 | JSON that represents the value. If the | ||
| 225 | buffer is not large enough, multiple calls | ||
| 226 | may be required. | ||
| 227 | \n | ||
| 228 | If serialization completes during this call; | ||
| 229 | that is, that all of the characters belonging | ||
| 230 | to the serialized value have been written to | ||
| 231 | caller-provided buffers, the function | ||
| 232 | @ref done will return `true`. | ||
| 233 | |||
| 234 | @par Preconditions | ||
| 235 | @code | ||
| 236 | this->done() == false | ||
| 237 | @endcode | ||
| 238 | |||
| 239 | @par Complexity | ||
| 240 | Linear in `size`. | ||
| 241 | |||
| 242 | @par Exception Safety | ||
| 243 | Basic guarantee. | ||
| 244 | Calls to `memory_resource::allocate` may throw. | ||
| 245 | |||
| 246 | @return A @ref string_view containing the | ||
| 247 | characters written, which may be less than | ||
| 248 | `size`. | ||
| 249 | |||
| 250 | @param dest A pointer to valid memory of at | ||
| 251 | least `size` bytes. | ||
| 252 | |||
| 253 | @param size The maximum number of characters | ||
| 254 | to write to the memory pointed to by `dest`. | ||
| 255 | */ | ||
| 256 | BOOST_JSON_DECL | ||
| 257 | string_view | ||
| 258 | read(char* dest, std::size_t size); | ||
| 259 | |||
| 260 | /** Read the next buffer of serialized JSON | ||
| 261 | |||
| 262 | This function allows reading into a | ||
| 263 | character array, with a deduced maximum size. | ||
| 264 | |||
| 265 | @par Preconditions | ||
| 266 | @code | ||
| 267 | this->done() == false | ||
| 268 | @endcode | ||
| 269 | |||
| 270 | @par Effects | ||
| 271 | @code | ||
| 272 | return this->read( dest, N ); | ||
| 273 | @endcode | ||
| 274 | |||
| 275 | @par Complexity | ||
| 276 | Linear in `N`. | ||
| 277 | |||
| 278 | @par Exception Safety | ||
| 279 | Basic guarantee. | ||
| 280 | Calls to `memory_resource::allocate` may throw. | ||
| 281 | |||
| 282 | @return A @ref string_view containing the | ||
| 283 | characters written, which may be less than | ||
| 284 | `size`. | ||
| 285 | |||
| 286 | @param dest The character array to write to. | ||
| 287 | */ | ||
| 288 | template<std::size_t N> | ||
| 289 | string_view | ||
| 290 | 18916 | read(char(&dest)[N]) | |
| 291 | { | ||
| 292 | 18916 | return read(dest, N); | |
| 293 | } | ||
| 294 | |||
| 295 | #ifndef BOOST_JSON_DOCS | ||
| 296 | // Safety net for accidental buffer overflows | ||
| 297 | template<std::size_t N> | ||
| 298 | string_view | ||
| 299 | read(char(&dest)[N], std::size_t n) | ||
| 300 | { | ||
| 301 | // If this goes off, check your parameters | ||
| 302 | // closely, chances are you passed an array | ||
| 303 | // thinking it was a pointer. | ||
| 304 | BOOST_ASSERT(n <= N); | ||
| 305 | return read(dest, n); | ||
| 306 | } | ||
| 307 | #endif | ||
| 308 | }; | ||
| 309 | |||
| 310 | } // namespace json | ||
| 311 | } // namespace boost | ||
| 312 | |||
| 313 | #include <boost/json/impl/serializer.hpp> | ||
| 314 | |||
| 315 | #endif | ||
| 316 |