projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0.1 Transitional//EN"> |
| 2 | ||
| 3 | <html> | |
| 4 | <head> | |
| 5 | <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> | |
| 6 | <title>Boost.Flyweight Documentation - Holders reference</title> | |
| 7 | <link rel="stylesheet" href="../style.css" type="text/css"> | |
| 8 | <link rel="start" href="../index.html"> | |
| 9 | <link rel="prev" href="factories.html"> | |
| 10 | <link rel="up" href="index.html"> | |
| 11 | <link rel="next" href="locking.html"> | |
| 12 | </head> | |
| 13 | ||
| 14 | <body> | |
| 15 | <h1><img src="../../../../boost.png" alt="Boost logo" align= | |
| 16 | "middle" width="277" height="86">Boost.Flyweight | |
| 17 | Holders reference</h1> | |
| 18 | ||
| 19 | <div class="prev_link"><a href="factories.html"><img src="../prev.gif" alt="factories" border="0"><br> | |
| 20 | Factories | |
| 21 | </a></div> | |
| 22 | <div class="up_link"><a href="index.html"><img src="../up.gif" alt="Boost.Flyweight reference" border="0"><br> | |
| 23 | Boost.Flyweight reference | |
| 24 | </a></div> | |
| 25 | <div class="next_link"><a href="locking.html"><img src="../next.gif" alt="locking policies" border="0"><br> | |
| 26 | Locking policies | |
| 27 | </a></div><br clear="all" style="clear: all;"> | |
| 28 | ||
| 29 | <hr> | |
| 30 | ||
| 31 | <h2>Contents</h2> | |
| 32 | ||
| 33 | <ul> | |
| 34 | <li><a href="#holder">Holders and holder specifiers</a></li> | |
| 35 | <li><a href="#holder_tag_synopsis">Header | |
| 36 | <code>"boost/flyweight/holder_tag.hpp"</code> synopsis</a> | |
| 37 | <ul> | |
| 38 | <li><a href="#is_holder">Class template <code>is_holder</code></a></li> | |
| 39 | <li><a href="#holder_construct">Class template <code>holder</code></a></li> | |
| 40 | </ul> | |
| 41 | </li> | |
| 42 | <li><a href="#static_holder_fwd_synopsis">Header | |
| 43 | <code>"boost/flyweight/static_holder_fwd.hpp"</code> synopsis</a> | |
| 44 | </li> | |
| 45 | <li><a href="#static_holder_synopsis">Header | |
| 46 | <code>"boost/flyweight/static_holder.hpp"</code> synopsis</a> | |
| 47 | <ul> | |
| 48 | <li><a href="#static_holder_class">Class template <code>static_holder_class</code></a></li> | |
| 49 | <li><a href="#static_holder">Class <code>static_holder</code></a></li> | |
| 50 | </ul> | |
| 51 | </li> | |
| 52 | <li><a href="#intermodule_holder_fwd_synopsis">Header | |
| 53 | <code>"boost/flyweight/intermodule_holder_fwd.hpp"</code> synopsis</a> | |
| 54 | </li> | |
| 55 | <li><a href="#intermodule_holder_synopsis">Header | |
| 56 | <code>"boost/flyweight/intermodule_holder.hpp"</code> synopsis</a> | |
| 57 | <ul> | |
| 58 | <li><a href="#intermodule_holder_class">Class template <code>intermodule_holder_class</code></a></li> | |
| 59 | <li><a href="#intermodule_holder">Class <code>intermodule_holder</code></a></li> | |
| 60 | </ul> | |
| 61 | </li> | |
| 62 | </ul> | |
| 63 | ||
| 64 | <h2><a name="holder">Holders and holder specifiers</a></h2> | |
| 65 | ||
| 66 | <p> | |
| 67 | Given a type <code>C</code>, a type <code>Holder</code> is said to be a <i>holder | |
| 68 | of <code>C</code></i> if the expression <code>Holder::get()</code> returns | |
| 69 | a reference to a default initialized <code>C</code> object unique to | |
| 70 | <code>Holder</code>. No invocation of <code>Holder::get()</code>, except possibly | |
| 71 | the first one in the program, does throw. | |
| 72 | <a href="flyweight.html#flyweight"><code>flyweight</code></a> | |
| 73 | privately uses a holder to instantiate a <a href="factories.html#factory">factory</a> | |
| 74 | and some additional data (like a <a href="locking.html#preliminary">mutex</a> for | |
| 75 | internal synchronization) unique to each instantiation type of the class template. | |
| 76 | </p> | |
| 77 | ||
| 78 | <p> | |
| 79 | A type <code>S</code> is a <i>holder specifier</i> if: | |
| 80 | <ol> | |
| 81 | <li>One of the following conditions is satisfied: | |
| 82 | <ol type="a"> | |
| 83 | <li><a href="#is_holder"><code>is_holder<S>::type</code></a> is | |
| 84 | <a href="../../../mpl/doc/refmanual/bool.html"><code>boost::mpl::true_</code></a>,</li> | |
| 85 | <li><code>S</code> is of the form <a href="#holder_construct"><code>holder<S'></code></a>.</li> | |
| 86 | </ol> | |
| 87 | </li> | |
| 88 | <li><code>S</code>, or <code>S'</code> if (b) applies, is an | |
| 89 | <a href="../../../mpl/doc/refmanual/lambda-expression.html"><code>MPL Lambda | |
| 90 | Expression</code></a> such that invoking it with type <code>C</code> resolves to | |
| 91 | a holder of <code>C</code>. | |
| 92 | </li> | |
| 93 | </ol> | |
| 94 | </p> | |
| 95 | ||
| 96 | <h2><a name="holder_tag_synopsis">Header | |
| 97 | <a href="../../../../boost/flyweight/holder_tag.hpp"><code>"boost/flyweight/holder_tag.hpp"</code></a> synopsis</a></h2> | |
| 98 | ||
| 99 | <blockquote><pre> | |
| 100 | <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span> | |
| 101 | ||
| 102 | <span class=keyword>namespace</span> <span class=identifier>flyweights</span><span class=special>{</span> | |
| 103 | ||
| 104 | <span class=keyword>struct</span> <span class=identifier>holder_marker</span><span class=special>;</span> | |
| 105 | ||
| 106 | <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>T</span><span class=special>></span> | |
| 107 | <span class=keyword>struct</span> <span class=identifier>is_holder</span><span class=special>;</span> | |
| 108 | ||
| 109 | <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>T</span><span class=special>></span> | |
| 110 | <span class=keyword>struct</span> <span class=identifier>holder</span><span class=special>;</span> | |
| 111 | ||
| 112 | <span class=special>}</span> <span class=comment>// namespace boost::flyweights</span> | |
| 113 | ||
| 114 | <span class=special>}</span> <span class=comment>// namespace boost</span> | |
| 115 | </pre></blockquote> | |
| 116 | ||
| 117 | <h3><a name="is_holder">Class template <code>is_holder</code></a></h3> | |
| 118 | ||
| 119 | <p> | |
| 120 | Unless specialized by the user, <code>is_holder<T>::type</code> is | |
| 121 | <a href="../../../mpl/doc/refmanual/bool.html"><code>boost::mpl::true_</code></a> | |
| 122 | if <code>T</code> is derived from <code>holder_marker</code>, and it is | |
| 123 | <a href="../../../mpl/doc/refmanual/bool.html"><code>boost::mpl::false_</code></a> | |
| 124 | otherwise. | |
| 125 | </p> | |
| 126 | ||
| 127 | <h3><a name="holder_construct">Class template <code>holder</code></a></h3> | |
| 128 | ||
| 129 | <p> | |
| 130 | <code>holder<T></code> is a syntactic construct meant to indicate | |
| 131 | that <code>T</code> is a holder specifier without resorting to the | |
| 132 | mechanisms provided by the <code>is_holder</code> class template. | |
| 133 | </p> | |
| 134 | ||
| 135 | <h2><a name="static_holder_fwd_synopsis">Header | |
| 136 | <a href="../../../../boost/flyweight/static_holder_fwd.hpp"><code>"boost/flyweight/static_holder_fwd.hpp"</code></a> synopsis</a></h2> | |
| 137 | ||
| 138 | <blockquote><pre> | |
| 139 | <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span> | |
| 140 | ||
| 141 | <span class=keyword>namespace</span> <span class=identifier>flyweights</span><span class=special>{</span> | |
| 142 | ||
| 143 | <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>C</span><span class=special>></span> | |
| 144 | <span class=keyword>struct</span> <span class=identifier>static_holder_class</span><span class=special>;</span> | |
| 145 | ||
| 146 | <span class=keyword>struct</span> <span class=identifier>static_holder</span><span class=special>;</span> | |
| 147 | ||
| 148 | <span class=special>}</span> <span class=comment>// namespace boost::flyweights</span> | |
| 149 | ||
| 150 | <span class=special>}</span> <span class=comment>// namespace boost</span> | |
| 151 | </pre></blockquote> | |
| 152 | ||
| 153 | <p> | |
| 154 | <code>static_holder_fwd.hpp</code> forward declares | |
| 155 | <a href="#static_holder_class"><code>static_holder_class</code></a> | |
| 156 | and <a href="#static_holder"><code>static_holder</code></a>. | |
| 157 | </p> | |
| 158 | ||
| 159 | <h2><a name="static_holder_synopsis">Header | |
| 160 | <a href="../../../../boost/flyweight/static_holder.hpp"><code>"boost/flyweight/static_holder.hpp"</code></a> synopsis</a></h2> | |
| 161 | ||
| 162 | <h3><a name="static_holder_class">Class template <code>static_holder_class</code></a></h3> | |
| 163 | ||
| 164 | <p> | |
| 165 | <code>static_holder_class<C></code> keeps its unique instance of <code>C</code> as a | |
| 166 | local static object. | |
| 167 | </p> | |
| 168 | ||
| 169 | <h3><a name="static_holder">Class <code>static_holder</code></a></h3> | |
| 170 | ||
| 171 | <p> | |
| 172 | <a href="#holder"><code>Holder Specifier</code></a> for <a href="#static_holder_class"><code>static_holder_class</code></a>. | |
| 173 | </p> | |
| 174 | ||
| 175 | <h2><a name="intermodule_holder_fwd_synopsis">Header | |
| 176 | <a href="../../../../boost/flyweight/intermodule_holder_fwd.hpp"><code>"boost/flyweight/intermodule_holder_fwd.hpp"</code></a> synopsis</a></h2> | |
| 177 | ||
| 178 | <blockquote><pre> | |
| 179 | <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span> | |
| 180 | ||
| 181 | <span class=keyword>namespace</span> <span class=identifier>flyweights</span><span class=special>{</span> | |
| 182 | ||
| 183 | <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>C</span><span class=special>></span> | |
| 184 | <span class=keyword>struct</span> <span class=identifier>intermodule_holder_class</span><span class=special>;</span> | |
| 185 | ||
| 186 | <span class=keyword>struct</span> <span class=identifier>intermodule_holder</span><span class=special>;</span> | |
| 187 | ||
| 188 | <span class=special>}</span> <span class=comment>// namespace boost::flyweights</span> | |
| 189 | ||
| 190 | <span class=special>}</span> <span class=comment>// namespace boost</span> | |
| 191 | </pre></blockquote> | |
| 192 | ||
| 193 | <p> | |
| 194 | <code>intermodule_holder_fwd.hpp</code> forward declares | |
| 195 | <a href="#intermodule_holder_class"><code>intermodule_holder_class</code></a> | |
| 196 | and <a href="#intermodule_holder"><code>intermodule_holder</code></a>. | |
| 197 | </p> | |
| 198 | ||
| 199 | <h2><a name="intermodule_holder_synopsis">Header | |
| 200 | <a href="../../../../boost/flyweight/intermodule_holder.hpp"><code>"boost/flyweight/intermodule_holder.hpp"</code></a> synopsis</a></h2> | |
| 201 | ||
| 202 | <h3><a name="intermodule_holder_class">Class template <code>intermodule_holder_class</code></a></h3> | |
| 203 | ||
| 204 | <p> | |
| 205 | <code>intermodule_holder_class<C></code> maintains a <code>C</code> | |
| 206 | instance which is unique even across different dynamically linked modules of | |
| 207 | the program using this same type. In general, this guarantee is not provided by | |
| 208 | <a href="#static_holder_class"><code>static_holder_class</code></a>, as most | |
| 209 | C++ implementations are not able to merge duplicates of static variables stored | |
| 210 | in different dynamic modules of a program. | |
| 211 | </p> | |
| 212 | ||
| 213 | <h3><a name="intermodule_holder">Class <code>intermodule_holder</code></a></h3> | |
| 214 | ||
| 215 | <p> | |
| 216 | <a href="#holder"><code>Holder Specifier</code></a> for <a href="#intermodule_holder_class"><code>intermodule_holder_class</code></a>. | |
| 217 | </p> | |
| 218 | ||
| 219 | <hr> | |
| 220 | ||
| 221 | <div class="prev_link"><a href="factories.html"><img src="../prev.gif" alt="factories" border="0"><br> | |
| 222 | Factories | |
| 223 | </a></div> | |
| 224 | <div class="up_link"><a href="index.html"><img src="../up.gif" alt="Boost.Flyweight reference" border="0"><br> | |
| 225 | Boost.Flyweight reference | |
| 226 | </a></div> | |
| 227 | <div class="next_link"><a href="locking.html"><img src="../next.gif" alt="locking policies" border="0"><br> | |
| 228 | Locking policies | |
| 229 | </a></div><br clear="all" style="clear: all;"> | |
| 230 | ||
| 231 | <br> | |
| 232 | ||
| 233 | <p>Revised August 11th 2008</p> | |
| 234 | ||
| 235 | <p>© Copyright 2006-2008 Joaquín M López Muñoz. | |
| 236 | Distributed under the Boost Software | |
| 237 | License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt"> | |
| 238 | LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt"> | |
| 239 | http://www.boost.org/LICENSE_1_0.txt</a>) | |
| 240 | </p> | |
| 241 | ||
| 242 | </body> | |
| 243 | </html> |