| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `crates/stdx/src/anymap.rs`."><title>anymap.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-e56847b5.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="stdx" data-themes="" data-resource-suffix="" data-rustdoc-version="1.91.0 (f8297e351 2025-10-28)" data-channel="1.91.0" data-search-js="search-e256b49e.js" data-stringdex-js="stringdex-c3e638e9.js" data-settings-js="settings-c38705f0.js" ><script src="../../static.files/storage-e2aeef58.js"></script><script defer src="../../static.files/src-script-813739b1.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-6dc2a7f3.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">stdx/</div>anymap.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap digits-3"><pre class="rust"><code><a href=#1 id=1 data-nosnippet>1</a><span class="doccomment">//! This file is a port of only the necessary features from <https://github.com/chris-morgan/anymap> version 1.0.0-beta.2 for use within rust-analyzer. |
| <a href=#2 id=2 data-nosnippet>2</a>//! |
| <a href=#3 id=3 data-nosnippet>3</a>//! Copyright © 2014–2022 Chris Morgan. |
| <a href=#4 id=4 data-nosnippet>4</a>//! COPYING: <https://github.com/chris-morgan/anymap/blob/master/COPYING> |
| <a href=#5 id=5 data-nosnippet>5</a>//! Note that the license is changed from Blue Oak Model 1.0.0 or MIT or Apache-2.0 to MIT OR Apache-2.0 |
| <a href=#6 id=6 data-nosnippet>6</a>//! |
| <a href=#7 id=7 data-nosnippet>7</a>//! This implementation provides a safe and convenient store for one value of each type. |
| <a href=#8 id=8 data-nosnippet>8</a>//! |
| <a href=#9 id=9 data-nosnippet>9</a>//! Your starting point is [`Map`]. It has an example. |
| <a href=#10 id=10 data-nosnippet>10</a>//! |
| <a href=#11 id=11 data-nosnippet>11</a>//! # Cargo features |
| <a href=#12 id=12 data-nosnippet>12</a>//! |
| <a href=#13 id=13 data-nosnippet>13</a>//! This implementation has two independent features, each of which provides an implementation providing |
| <a href=#14 id=14 data-nosnippet>14</a>//! types `Map`, `AnyMap`, `OccupiedEntry`, `VacantEntry`, `Entry` and `RawMap`: |
| <a href=#15 id=15 data-nosnippet>15</a>//! |
| <a href=#16 id=16 data-nosnippet>16</a>//! - **std** (default, *enabled* in this build): |
| <a href=#17 id=17 data-nosnippet>17</a>//! an implementation using `std::collections::hash_map`, placed in the crate root |
| <a href=#18 id=18 data-nosnippet>18</a>//! (e.g. `anymap::AnyMap`). |
| <a href=#19 id=19 data-nosnippet>19</a> |
| <a href=#20 id=20 data-nosnippet>20</a></span><span class="attr">#![warn(missing_docs, unused_results)] |
| <a href=#21 id=21 data-nosnippet>21</a> |
| <a href=#22 id=22 data-nosnippet>22</a></span><span class="kw">use </span>core::hash::Hasher; |
| <a href=#23 id=23 data-nosnippet>23</a> |
| <a href=#24 id=24 data-nosnippet>24</a><span class="doccomment">/// A hasher designed to eke a little more speed out, given `TypeId`'s known characteristics. |
| <a href=#25 id=25 data-nosnippet>25</a>/// |
| <a href=#26 id=26 data-nosnippet>26</a>/// Specifically, this is a no-op hasher that expects to be fed a u64's worth of |
| <a href=#27 id=27 data-nosnippet>27</a>/// randomly-distributed bits. It works well for `TypeId` (eliminating start-up time, so that my |
| <a href=#28 id=28 data-nosnippet>28</a>/// `get_missing` benchmark is ~30ns rather than ~900ns, and being a good deal faster after that, so |
| <a href=#29 id=29 data-nosnippet>29</a>/// that my `insert_and_get_on_260_types` benchmark is ~12μs instead of ~21.5μs), but will |
| <a href=#30 id=30 data-nosnippet>30</a>/// panic in debug mode and always emit zeros in release mode for any other sorts of inputs, so |
| <a href=#31 id=31 data-nosnippet>31</a>/// yeah, don't use it! 😀 |
| <a href=#32 id=32 data-nosnippet>32</a></span><span class="attr">#[derive(Default)] |
| <a href=#33 id=33 data-nosnippet>33</a></span><span class="kw">pub struct </span>TypeIdHasher { |
| <a href=#34 id=34 data-nosnippet>34</a> value: u64, |
| <a href=#35 id=35 data-nosnippet>35</a>} |
| <a href=#36 id=36 data-nosnippet>36</a> |
| <a href=#37 id=37 data-nosnippet>37</a><span class="kw">impl </span>Hasher <span class="kw">for </span>TypeIdHasher { |
| <a href=#38 id=38 data-nosnippet>38</a> <span class="attr">#[inline] |
| <a href=#39 id=39 data-nosnippet>39</a> </span><span class="kw">fn </span>write(<span class="kw-2">&mut </span><span class="self">self</span>, bytes: <span class="kw-2">&</span>[u8]) { |
| <a href=#40 id=40 data-nosnippet>40</a> <span class="comment">// This expects to receive exactly one 64-bit value, and there's no realistic chance of |
| <a href=#41 id=41 data-nosnippet>41</a> // that changing, but I don't want to depend on something that isn't expressly part of the |
| <a href=#42 id=42 data-nosnippet>42</a> // contract for safety. But I'm OK with release builds putting everything in one bucket |
| <a href=#43 id=43 data-nosnippet>43</a> // if it *did* change (and debug builds panicking). |
| <a href=#44 id=44 data-nosnippet>44</a> </span><span class="macro">debug_assert_eq!</span>(bytes.len(), <span class="number">8</span>); |
| <a href=#45 id=45 data-nosnippet>45</a> <span class="kw">let _ </span>= bytes.try_into().map(|array| <span class="self">self</span>.value = u64::from_ne_bytes(array)); |
| <a href=#46 id=46 data-nosnippet>46</a> } |
| <a href=#47 id=47 data-nosnippet>47</a> |
| <a href=#48 id=48 data-nosnippet>48</a> <span class="attr">#[inline] |
| <a href=#49 id=49 data-nosnippet>49</a> </span><span class="kw">fn </span>finish(<span class="kw-2">&</span><span class="self">self</span>) -> u64 { |
| <a href=#50 id=50 data-nosnippet>50</a> <span class="self">self</span>.value |
| <a href=#51 id=51 data-nosnippet>51</a> } |
| <a href=#52 id=52 data-nosnippet>52</a>} |
| <a href=#53 id=53 data-nosnippet>53</a> |
| <a href=#54 id=54 data-nosnippet>54</a><span class="kw">use </span>core::any::{Any, TypeId}; |
| <a href=#55 id=55 data-nosnippet>55</a><span class="kw">use </span>core::hash::BuildHasherDefault; |
| <a href=#56 id=56 data-nosnippet>56</a><span class="kw">use </span>core::marker::PhantomData; |
| <a href=#57 id=57 data-nosnippet>57</a> |
| <a href=#58 id=58 data-nosnippet>58</a><span class="kw">use </span>::std::collections::hash_map; |
| <a href=#59 id=59 data-nosnippet>59</a> |
| <a href=#60 id=60 data-nosnippet>60</a><span class="doccomment">/// Raw access to the underlying `HashMap`. |
| <a href=#61 id=61 data-nosnippet>61</a>/// |
| <a href=#62 id=62 data-nosnippet>62</a>/// This alias is provided for convenience because of the ugly third generic parameter. |
| <a href=#63 id=63 data-nosnippet>63</a></span><span class="attr">#[expect(clippy::disallowed_types, reason = <span class="string">"Uses a custom hasher"</span>)] |
| <a href=#64 id=64 data-nosnippet>64</a></span><span class="kw">pub type </span>RawMap<A> = hash_map::HashMap<TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>; |
| <a href=#65 id=65 data-nosnippet>65</a> |
| <a href=#66 id=66 data-nosnippet>66</a><span class="doccomment">/// A collection containing zero or one values for any given type and allowing convenient, |
| <a href=#67 id=67 data-nosnippet>67</a>/// type-safe access to those values. |
| <a href=#68 id=68 data-nosnippet>68</a>/// |
| <a href=#69 id=69 data-nosnippet>69</a>/// The type parameter `A` allows you to use a different value type; normally you will want |
| <a href=#70 id=70 data-nosnippet>70</a>/// it to be `core::any::Any` (also known as `std::any::Any`), but there are other choices: |
| <a href=#71 id=71 data-nosnippet>71</a>/// |
| <a href=#72 id=72 data-nosnippet>72</a>/// - You can add on `+ Send` or `+ Send + Sync` (e.g. `Map<dyn Any + Send>`) to add those |
| <a href=#73 id=73 data-nosnippet>73</a>/// auto traits. |
| <a href=#74 id=74 data-nosnippet>74</a>/// |
| <a href=#75 id=75 data-nosnippet>75</a>/// Cumulatively, there are thus six forms of map: |
| <a href=#76 id=76 data-nosnippet>76</a>/// |
| <a href=#77 id=77 data-nosnippet>77</a>/// - `[Map]<dyn [core::any::Any]>`, |
| <a href=#78 id=78 data-nosnippet>78</a>/// also spelled [`AnyMap`] for convenience. |
| <a href=#79 id=79 data-nosnippet>79</a>/// - `[Map]<dyn [core::any::Any] + Send>` |
| <a href=#80 id=80 data-nosnippet>80</a>/// - `[Map]<dyn [core::any::Any] + Send + Sync>` |
| <a href=#81 id=81 data-nosnippet>81</a>/// |
| <a href=#82 id=82 data-nosnippet>82</a>/// ## Example |
| <a href=#83 id=83 data-nosnippet>83</a>/// |
| <a href=#84 id=84 data-nosnippet>84</a>/// (Here, the [`AnyMap`] convenience alias is used; |
| <a href=#85 id=85 data-nosnippet>85</a>/// the first line could use `[anymap::Map][Map]::<[core::any::Any]>::default()` |
| <a href=#86 id=86 data-nosnippet>86</a>/// instead if desired.) |
| <a href=#87 id=87 data-nosnippet>87</a>/// |
| <a href=#88 id=88 data-nosnippet>88</a>/// ``` |
| <a href=#89 id=89 data-nosnippet>89</a>/// # use stdx::anymap; |
| <a href=#90 id=90 data-nosnippet>90</a>/// let mut data = anymap::AnyMap::default(); |
| <a href=#91 id=91 data-nosnippet>91</a>/// assert_eq!(data.get(), None::<&i32>); |
| <a href=#92 id=92 data-nosnippet>92</a>/// ``` |
| <a href=#93 id=93 data-nosnippet>93</a>/// |
| <a href=#94 id=94 data-nosnippet>94</a>/// Values containing non-static references are not permitted. |
| <a href=#95 id=95 data-nosnippet>95</a></span><span class="attr">#[derive(Debug)] |
| <a href=#96 id=96 data-nosnippet>96</a></span><span class="kw">pub struct </span>Map<A: <span class="question-mark">?</span>Sized + Downcast = <span class="kw">dyn </span>Any> { |
| <a href=#97 id=97 data-nosnippet>97</a> raw: RawMap<A>, |
| <a href=#98 id=98 data-nosnippet>98</a>} |
| <a href=#99 id=99 data-nosnippet>99</a> |
| <a href=#100 id=100 data-nosnippet>100</a><span class="doccomment">/// The most common type of `Map`: just using `Any`; `[Map]<dyn [Any]>`. |
| <a href=#101 id=101 data-nosnippet>101</a>/// |
| <a href=#102 id=102 data-nosnippet>102</a>/// Why is this a separate type alias rather than a default value for `Map<A>`? |
| <a href=#103 id=103 data-nosnippet>103</a>/// `Map::default()` doesn't seem to be happy to infer that it should go with the default |
| <a href=#104 id=104 data-nosnippet>104</a>/// value. It's a bit sad, really. Ah well, I guess this approach will do. |
| <a href=#105 id=105 data-nosnippet>105</a></span><span class="kw">pub type </span>AnyMap = Map<<span class="kw">dyn </span>Any>; |
| <a href=#106 id=106 data-nosnippet>106</a> |
| <a href=#107 id=107 data-nosnippet>107</a><span class="kw">impl</span><A: <span class="question-mark">?</span>Sized + Downcast> Default <span class="kw">for </span>Map<A> { |
| <a href=#108 id=108 data-nosnippet>108</a> <span class="attr">#[inline] |
| <a href=#109 id=109 data-nosnippet>109</a> </span><span class="kw">fn </span>default() -> Map<A> { |
| <a href=#110 id=110 data-nosnippet>110</a> Map { raw: RawMap::with_hasher(Default::default()) } |
| <a href=#111 id=111 data-nosnippet>111</a> } |
| <a href=#112 id=112 data-nosnippet>112</a>} |
| <a href=#113 id=113 data-nosnippet>113</a> |
| <a href=#114 id=114 data-nosnippet>114</a><span class="kw">impl</span><A: <span class="question-mark">?</span>Sized + Downcast> Map<A> { |
| <a href=#115 id=115 data-nosnippet>115</a> <span class="doccomment">/// Returns a reference to the value stored in the collection for the type `T`, |
| <a href=#116 id=116 data-nosnippet>116</a> /// if it exists. |
| <a href=#117 id=117 data-nosnippet>117</a> </span><span class="attr">#[inline] |
| <a href=#118 id=118 data-nosnippet>118</a> #[must_use] |
| <a href=#119 id=119 data-nosnippet>119</a> </span><span class="kw">pub fn </span>get<T: IntoBox<A>>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>T> { |
| <a href=#120 id=120 data-nosnippet>120</a> <span class="self">self</span>.raw.get(<span class="kw-2">&</span>TypeId::of::<T>()).map(|any| <span class="kw">unsafe </span>{ any.downcast_ref_unchecked::<T>() }) |
| <a href=#121 id=121 data-nosnippet>121</a> } |
| <a href=#122 id=122 data-nosnippet>122</a> |
| <a href=#123 id=123 data-nosnippet>123</a> <span class="doccomment">/// Gets the entry for the given type in the collection for in-place manipulation |
| <a href=#124 id=124 data-nosnippet>124</a> </span><span class="attr">#[inline] |
| <a href=#125 id=125 data-nosnippet>125</a> </span><span class="kw">pub fn </span>entry<T: IntoBox<A>>(<span class="kw-2">&mut </span><span class="self">self</span>) -> Entry<<span class="lifetime">'_</span>, A, T> { |
| <a href=#126 id=126 data-nosnippet>126</a> <span class="kw">match </span><span class="self">self</span>.raw.entry(TypeId::of::<T>()) { |
| <a href=#127 id=127 data-nosnippet>127</a> hash_map::Entry::Occupied(e) => { |
| <a href=#128 id=128 data-nosnippet>128</a> Entry::Occupied(OccupiedEntry { inner: e, type_: PhantomData }) |
| <a href=#129 id=129 data-nosnippet>129</a> } |
| <a href=#130 id=130 data-nosnippet>130</a> hash_map::Entry::Vacant(e) => { |
| <a href=#131 id=131 data-nosnippet>131</a> Entry::Vacant(VacantEntry { inner: e, type_: PhantomData }) |
| <a href=#132 id=132 data-nosnippet>132</a> } |
| <a href=#133 id=133 data-nosnippet>133</a> } |
| <a href=#134 id=134 data-nosnippet>134</a> } |
| <a href=#135 id=135 data-nosnippet>135</a>} |
| <a href=#136 id=136 data-nosnippet>136</a> |
| <a href=#137 id=137 data-nosnippet>137</a><span class="doccomment">/// A view into a single occupied location in an `Map`. |
| <a href=#138 id=138 data-nosnippet>138</a></span><span class="kw">pub struct </span>OccupiedEntry<<span class="lifetime">'map</span>, A: <span class="question-mark">?</span>Sized + Downcast, V: <span class="lifetime">'map</span>> { |
| <a href=#139 id=139 data-nosnippet>139</a> inner: hash_map::OccupiedEntry<<span class="lifetime">'map</span>, TypeId, Box<A>>, |
| <a href=#140 id=140 data-nosnippet>140</a> type_: PhantomData<V>, |
| <a href=#141 id=141 data-nosnippet>141</a>} |
| <a href=#142 id=142 data-nosnippet>142</a> |
| <a href=#143 id=143 data-nosnippet>143</a><span class="doccomment">/// A view into a single empty location in an `Map`. |
| <a href=#144 id=144 data-nosnippet>144</a></span><span class="kw">pub struct </span>VacantEntry<<span class="lifetime">'map</span>, A: <span class="question-mark">?</span>Sized + Downcast, V: <span class="lifetime">'map</span>> { |
| <a href=#145 id=145 data-nosnippet>145</a> inner: hash_map::VacantEntry<<span class="lifetime">'map</span>, TypeId, Box<A>>, |
| <a href=#146 id=146 data-nosnippet>146</a> type_: PhantomData<V>, |
| <a href=#147 id=147 data-nosnippet>147</a>} |
| <a href=#148 id=148 data-nosnippet>148</a> |
| <a href=#149 id=149 data-nosnippet>149</a><span class="doccomment">/// A view into a single location in an `Map`, which may be vacant or occupied. |
| <a href=#150 id=150 data-nosnippet>150</a></span><span class="kw">pub enum </span>Entry<<span class="lifetime">'map</span>, A: <span class="question-mark">?</span>Sized + Downcast, V> { |
| <a href=#151 id=151 data-nosnippet>151</a> <span class="doccomment">/// An occupied Entry |
| <a href=#152 id=152 data-nosnippet>152</a> </span>Occupied(OccupiedEntry<<span class="lifetime">'map</span>, A, V>), |
| <a href=#153 id=153 data-nosnippet>153</a> <span class="doccomment">/// A vacant Entry |
| <a href=#154 id=154 data-nosnippet>154</a> </span>Vacant(VacantEntry<<span class="lifetime">'map</span>, A, V>), |
| <a href=#155 id=155 data-nosnippet>155</a>} |
| <a href=#156 id=156 data-nosnippet>156</a> |
| <a href=#157 id=157 data-nosnippet>157</a><span class="kw">impl</span><<span class="lifetime">'map</span>, A: <span class="question-mark">?</span>Sized + Downcast, V: IntoBox<A>> Entry<<span class="lifetime">'map</span>, A, V> { |
| <a href=#158 id=158 data-nosnippet>158</a> <span class="doccomment">/// Ensures a value is in the entry by inserting the result of the default function if |
| <a href=#159 id=159 data-nosnippet>159</a> /// empty, and returns a mutable reference to the value in the entry. |
| <a href=#160 id=160 data-nosnippet>160</a> </span><span class="attr">#[inline] |
| <a href=#161 id=161 data-nosnippet>161</a> </span><span class="kw">pub fn </span>or_insert_with<F: FnOnce() -> V>(<span class="self">self</span>, default: F) -> <span class="kw-2">&</span><span class="lifetime">'map </span><span class="kw-2">mut </span>V { |
| <a href=#162 id=162 data-nosnippet>162</a> <span class="kw">match </span><span class="self">self </span>{ |
| <a href=#163 id=163 data-nosnippet>163</a> Entry::Occupied(inner) => inner.into_mut(), |
| <a href=#164 id=164 data-nosnippet>164</a> Entry::Vacant(inner) => inner.insert(default()), |
| <a href=#165 id=165 data-nosnippet>165</a> } |
| <a href=#166 id=166 data-nosnippet>166</a> } |
| <a href=#167 id=167 data-nosnippet>167</a>} |
| <a href=#168 id=168 data-nosnippet>168</a> |
| <a href=#169 id=169 data-nosnippet>169</a><span class="kw">impl</span><<span class="lifetime">'map</span>, A: <span class="question-mark">?</span>Sized + Downcast, V: IntoBox<A>> OccupiedEntry<<span class="lifetime">'map</span>, A, V> { |
| <a href=#170 id=170 data-nosnippet>170</a> <span class="doccomment">/// Converts the `OccupiedEntry` into a mutable reference to the value in the entry |
| <a href=#171 id=171 data-nosnippet>171</a> /// with a lifetime bound to the collection itself |
| <a href=#172 id=172 data-nosnippet>172</a> </span><span class="attr">#[inline] |
| <a href=#173 id=173 data-nosnippet>173</a> #[must_use] |
| <a href=#174 id=174 data-nosnippet>174</a> </span><span class="kw">pub fn </span>into_mut(<span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'map </span><span class="kw-2">mut </span>V { |
| <a href=#175 id=175 data-nosnippet>175</a> <span class="kw">unsafe </span>{ <span class="self">self</span>.inner.into_mut().downcast_mut_unchecked() } |
| <a href=#176 id=176 data-nosnippet>176</a> } |
| <a href=#177 id=177 data-nosnippet>177</a>} |
| <a href=#178 id=178 data-nosnippet>178</a> |
| <a href=#179 id=179 data-nosnippet>179</a><span class="kw">impl</span><<span class="lifetime">'map</span>, A: <span class="question-mark">?</span>Sized + Downcast, V: IntoBox<A>> VacantEntry<<span class="lifetime">'map</span>, A, V> { |
| <a href=#180 id=180 data-nosnippet>180</a> <span class="doccomment">/// Sets the value of the entry with the `VacantEntry`'s key, |
| <a href=#181 id=181 data-nosnippet>181</a> /// and returns a mutable reference to it |
| <a href=#182 id=182 data-nosnippet>182</a> </span><span class="attr">#[inline] |
| <a href=#183 id=183 data-nosnippet>183</a> </span><span class="kw">pub fn </span>insert(<span class="self">self</span>, value: V) -> <span class="kw-2">&</span><span class="lifetime">'map </span><span class="kw-2">mut </span>V { |
| <a href=#184 id=184 data-nosnippet>184</a> <span class="kw">unsafe </span>{ <span class="self">self</span>.inner.insert(value.into_box()).downcast_mut_unchecked() } |
| <a href=#185 id=185 data-nosnippet>185</a> } |
| <a href=#186 id=186 data-nosnippet>186</a>} |
| <a href=#187 id=187 data-nosnippet>187</a> |
| <a href=#188 id=188 data-nosnippet>188</a><span class="attr">#[cfg(test)] |
| <a href=#189 id=189 data-nosnippet>189</a></span><span class="kw">mod </span>tests { |
| <a href=#190 id=190 data-nosnippet>190</a> <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| <a href=#191 id=191 data-nosnippet>191</a> |
| <a href=#192 id=192 data-nosnippet>192</a> <span class="attr">#[test] |
| <a href=#193 id=193 data-nosnippet>193</a> </span><span class="kw">fn </span>test_varieties() { |
| <a href=#194 id=194 data-nosnippet>194</a> <span class="kw">fn </span>assert_send<T: Send>() {} |
| <a href=#195 id=195 data-nosnippet>195</a> <span class="kw">fn </span>assert_sync<T: Sync>() {} |
| <a href=#196 id=196 data-nosnippet>196</a> <span class="kw">fn </span>assert_debug<T: ::core::fmt::Debug>() {} |
| <a href=#197 id=197 data-nosnippet>197</a> assert_send::<Map<<span class="kw">dyn </span>Any + Send>>(); |
| <a href=#198 id=198 data-nosnippet>198</a> assert_send::<Map<<span class="kw">dyn </span>Any + Send + Sync>>(); |
| <a href=#199 id=199 data-nosnippet>199</a> assert_sync::<Map<<span class="kw">dyn </span>Any + Send + Sync>>(); |
| <a href=#200 id=200 data-nosnippet>200</a> assert_debug::<Map<<span class="kw">dyn </span>Any>>(); |
| <a href=#201 id=201 data-nosnippet>201</a> assert_debug::<Map<<span class="kw">dyn </span>Any + Send>>(); |
| <a href=#202 id=202 data-nosnippet>202</a> assert_debug::<Map<<span class="kw">dyn </span>Any + Send + Sync>>(); |
| <a href=#203 id=203 data-nosnippet>203</a> } |
| <a href=#204 id=204 data-nosnippet>204</a> |
| <a href=#205 id=205 data-nosnippet>205</a> <span class="attr">#[test] |
| <a href=#206 id=206 data-nosnippet>206</a> </span><span class="kw">fn </span>type_id_hasher() { |
| <a href=#207 id=207 data-nosnippet>207</a> <span class="kw">use </span>core::any::TypeId; |
| <a href=#208 id=208 data-nosnippet>208</a> <span class="kw">use </span>core::hash::Hash <span class="kw">as _</span>; |
| <a href=#209 id=209 data-nosnippet>209</a> <span class="kw">fn </span>verify_hashing_with(type_id: TypeId) { |
| <a href=#210 id=210 data-nosnippet>210</a> <span class="kw">let </span><span class="kw-2">mut </span>hasher = TypeIdHasher::default(); |
| <a href=#211 id=211 data-nosnippet>211</a> type_id.hash(<span class="kw-2">&mut </span>hasher); |
| <a href=#212 id=212 data-nosnippet>212</a> <span class="kw">_ </span>= hasher.finish(); |
| <a href=#213 id=213 data-nosnippet>213</a> } |
| <a href=#214 id=214 data-nosnippet>214</a> <span class="comment">// Pick a variety of types, just to demonstrate it's all sane. Normal, zero-sized, unsized, &c. |
| <a href=#215 id=215 data-nosnippet>215</a> </span>verify_hashing_with(TypeId::of::<usize>()); |
| <a href=#216 id=216 data-nosnippet>216</a> verify_hashing_with(TypeId::of::<()>()); |
| <a href=#217 id=217 data-nosnippet>217</a> verify_hashing_with(TypeId::of::<str>()); |
| <a href=#218 id=218 data-nosnippet>218</a> verify_hashing_with(TypeId::of::<<span class="kw-2">&</span>str>()); |
| <a href=#219 id=219 data-nosnippet>219</a> verify_hashing_with(TypeId::of::<Vec<u8>>()); |
| <a href=#220 id=220 data-nosnippet>220</a> } |
| <a href=#221 id=221 data-nosnippet>221</a>} |
| <a href=#222 id=222 data-nosnippet>222</a> |
| <a href=#223 id=223 data-nosnippet>223</a><span class="doccomment">/// Methods for downcasting from an `Any`-like trait object. |
| <a href=#224 id=224 data-nosnippet>224</a>/// |
| <a href=#225 id=225 data-nosnippet>225</a>/// This should only be implemented on trait objects for subtraits of `Any`, though you can |
| <a href=#226 id=226 data-nosnippet>226</a>/// implement it for other types and it'll work fine, so long as your implementation is correct. |
| <a href=#227 id=227 data-nosnippet>227</a></span><span class="kw">pub trait </span>Downcast { |
| <a href=#228 id=228 data-nosnippet>228</a> <span class="doccomment">/// Gets the `TypeId` of `self`. |
| <a href=#229 id=229 data-nosnippet>229</a> </span><span class="kw">fn </span>type_id(<span class="kw-2">&</span><span class="self">self</span>) -> TypeId; |
| <a href=#230 id=230 data-nosnippet>230</a> |
| <a href=#231 id=231 data-nosnippet>231</a> <span class="comment">// Note the bound through these downcast methods is 'static, rather than the inexpressible |
| <a href=#232 id=232 data-nosnippet>232</a> // concept of Self-but-as-a-trait (where Self is `dyn Trait`). This is sufficient, exceeding |
| <a href=#233 id=233 data-nosnippet>233</a> // TypeId's requirements. Sure, you *can* do CloneAny.downcast_unchecked::<NotClone>() and the |
| <a href=#234 id=234 data-nosnippet>234</a> // type system won't protect you, but that doesn't introduce any unsafety: the method is |
| <a href=#235 id=235 data-nosnippet>235</a> // already unsafe because you can specify the wrong type, and if this were exposing safe |
| <a href=#236 id=236 data-nosnippet>236</a> // downcasting, CloneAny.downcast::<NotClone>() would just return an error, which is just as |
| <a href=#237 id=237 data-nosnippet>237</a> // correct. |
| <a href=#238 id=238 data-nosnippet>238</a> // |
| <a href=#239 id=239 data-nosnippet>239</a> // Now in theory we could also add T: ?Sized, but that doesn't play nicely with the common |
| <a href=#240 id=240 data-nosnippet>240</a> // implementation, so I'm doing without it. |
| <a href=#241 id=241 data-nosnippet>241</a> |
| <a href=#242 id=242 data-nosnippet>242</a> </span><span class="doccomment">/// Downcast from `&Any` to `&T`, without checking the type matches. |
| <a href=#243 id=243 data-nosnippet>243</a> /// |
| <a href=#244 id=244 data-nosnippet>244</a> /// # Safety |
| <a href=#245 id=245 data-nosnippet>245</a> /// |
| <a href=#246 id=246 data-nosnippet>246</a> /// The caller must ensure that `T` matches the trait object, on pain of *undefined behavior*. |
| <a href=#247 id=247 data-nosnippet>247</a> </span><span class="kw">unsafe fn </span>downcast_ref_unchecked<T: <span class="lifetime">'static</span>>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>T; |
| <a href=#248 id=248 data-nosnippet>248</a> |
| <a href=#249 id=249 data-nosnippet>249</a> <span class="doccomment">/// Downcast from `&mut Any` to `&mut T`, without checking the type matches. |
| <a href=#250 id=250 data-nosnippet>250</a> /// |
| <a href=#251 id=251 data-nosnippet>251</a> /// # Safety |
| <a href=#252 id=252 data-nosnippet>252</a> /// |
| <a href=#253 id=253 data-nosnippet>253</a> /// The caller must ensure that `T` matches the trait object, on pain of *undefined behavior*. |
| <a href=#254 id=254 data-nosnippet>254</a> </span><span class="kw">unsafe fn </span>downcast_mut_unchecked<T: <span class="lifetime">'static</span>>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>T; |
| <a href=#255 id=255 data-nosnippet>255</a>} |
| <a href=#256 id=256 data-nosnippet>256</a> |
| <a href=#257 id=257 data-nosnippet>257</a><span class="doccomment">/// A trait for the conversion of an object into a boxed trait object. |
| <a href=#258 id=258 data-nosnippet>258</a></span><span class="kw">pub trait </span>IntoBox<A: <span class="question-mark">?</span>Sized + Downcast>: Any { |
| <a href=#259 id=259 data-nosnippet>259</a> <span class="doccomment">/// Convert self into the appropriate boxed form. |
| <a href=#260 id=260 data-nosnippet>260</a> </span><span class="kw">fn </span>into_box(<span class="self">self</span>) -> Box<A>; |
| <a href=#261 id=261 data-nosnippet>261</a>} |
| <a href=#262 id=262 data-nosnippet>262</a> |
| <a href=#263 id=263 data-nosnippet>263</a><span class="macro">macro_rules!</span> implement { |
| <a href=#264 id=264 data-nosnippet>264</a> (<span class="macro-nonterminal">$any_trait</span>:ident $(+ <span class="macro-nonterminal">$auto_traits</span>:ident)<span class="kw-2">*</span>) => { |
| <a href=#265 id=265 data-nosnippet>265</a> <span class="kw">impl </span>Downcast <span class="kw">for dyn </span><span class="macro-nonterminal">$any_trait </span>$(+ <span class="macro-nonterminal">$auto_traits</span>)* { |
| <a href=#266 id=266 data-nosnippet>266</a> <span class="attr">#[inline] |
| <a href=#267 id=267 data-nosnippet>267</a> </span><span class="kw">fn </span>type_id(<span class="kw-2">&</span><span class="self">self</span>) -> TypeId { |
| <a href=#268 id=268 data-nosnippet>268</a> <span class="self">self</span>.type_id() |
| <a href=#269 id=269 data-nosnippet>269</a> } |
| <a href=#270 id=270 data-nosnippet>270</a> |
| <a href=#271 id=271 data-nosnippet>271</a> <span class="attr">#[inline] |
| <a href=#272 id=272 data-nosnippet>272</a> </span><span class="kw">unsafe fn </span>downcast_ref_unchecked<T: <span class="lifetime">'static</span>>(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>T { |
| <a href=#273 id=273 data-nosnippet>273</a> <span class="kw">unsafe </span>{ <span class="kw-2">&*</span>std::ptr::from_ref::<<span class="self">Self</span>>(<span class="self">self</span>).cast::<T>() } |
| <a href=#274 id=274 data-nosnippet>274</a> } |
| <a href=#275 id=275 data-nosnippet>275</a> |
| <a href=#276 id=276 data-nosnippet>276</a> <span class="attr">#[inline] |
| <a href=#277 id=277 data-nosnippet>277</a> </span><span class="kw">unsafe fn </span>downcast_mut_unchecked<T: <span class="lifetime">'static</span>>(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span>T { |
| <a href=#278 id=278 data-nosnippet>278</a> <span class="kw">unsafe </span>{ <span class="kw-2">&mut *</span>std::ptr::from_mut::<<span class="self">Self</span>>(<span class="self">self</span>).cast::<T>() } |
| <a href=#279 id=279 data-nosnippet>279</a> } |
| <a href=#280 id=280 data-nosnippet>280</a> } |
| <a href=#281 id=281 data-nosnippet>281</a> |
| <a href=#282 id=282 data-nosnippet>282</a> <span class="kw">impl</span><T: <span class="macro-nonterminal">$any_trait </span>$(+ <span class="macro-nonterminal">$auto_traits</span>)<span class="kw-2">*</span>> IntoBox<<span class="kw">dyn </span><span class="macro-nonterminal">$any_trait </span>$(+ <span class="macro-nonterminal">$auto_traits</span>)<span class="kw-2">*</span>> <span class="kw">for </span>T { |
| <a href=#283 id=283 data-nosnippet>283</a> <span class="attr">#[inline] |
| <a href=#284 id=284 data-nosnippet>284</a> </span><span class="kw">fn </span>into_box(<span class="self">self</span>) -> Box<<span class="kw">dyn </span><span class="macro-nonterminal">$any_trait </span>$(+ <span class="macro-nonterminal">$auto_traits</span>)<span class="kw-2">*</span>> { |
| <a href=#285 id=285 data-nosnippet>285</a> Box::new(<span class="self">self</span>) |
| <a href=#286 id=286 data-nosnippet>286</a> } |
| <a href=#287 id=287 data-nosnippet>287</a> } |
| <a href=#288 id=288 data-nosnippet>288</a> } |
| <a href=#289 id=289 data-nosnippet>289</a>} |
| <a href=#290 id=290 data-nosnippet>290</a> |
| <a href=#291 id=291 data-nosnippet>291</a><span class="macro">implement!</span>(Any); |
| <a href=#292 id=292 data-nosnippet>292</a><span class="macro">implement!</span>(Any + Send); |
| <a href=#293 id=293 data-nosnippet>293</a><span class="macro">implement!</span>(Any + Send + Sync);</code></pre></div></section></main></body></html> |
