Google Git
Sign in
apache / incubator-teaclave-website / refs/heads/asf-site / . / api-docs / crates-enclave / src / rusty_leveldb / cache.rs.html
blob: f60ecc48f878a06bc2aca0432fabb0e41744b306 [file] [log] [blame]
<!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 `common/rusty_leveldb_sgx/src/cache.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>cache.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../rusty_leveldb/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../rusty_leveldb/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span>
<span id="2">2</span>
<span id="3">3</span>
<span id="4">4</span>
<span id="5">5</span>
<span id="6">6</span>
<span id="7">7</span>
<span id="8">8</span>
<span id="9">9</span>
<span id="10">10</span>
<span id="11">11</span>
<span id="12">12</span>
<span id="13">13</span>
<span id="14">14</span>
<span id="15">15</span>
<span id="16">16</span>
<span id="17">17</span>
<span id="18">18</span>
<span id="19">19</span>
<span id="20">20</span>
<span id="21">21</span>
<span id="22">22</span>
<span id="23">23</span>
<span id="24">24</span>
<span id="25">25</span>
<span id="26">26</span>
<span id="27">27</span>
<span id="28">28</span>
<span id="29">29</span>
<span id="30">30</span>
<span id="31">31</span>
<span id="32">32</span>
<span id="33">33</span>
<span id="34">34</span>
<span id="35">35</span>
<span id="36">36</span>
<span id="37">37</span>
<span id="38">38</span>
<span id="39">39</span>
<span id="40">40</span>
<span id="41">41</span>
<span id="42">42</span>
<span id="43">43</span>
<span id="44">44</span>
<span id="45">45</span>
<span id="46">46</span>
<span id="47">47</span>
<span id="48">48</span>
<span id="49">49</span>
<span id="50">50</span>
<span id="51">51</span>
<span id="52">52</span>
<span id="53">53</span>
<span id="54">54</span>
<span id="55">55</span>
<span id="56">56</span>
<span id="57">57</span>
<span id="58">58</span>
<span id="59">59</span>
<span id="60">60</span>
<span id="61">61</span>
<span id="62">62</span>
<span id="63">63</span>
<span id="64">64</span>
<span id="65">65</span>
<span id="66">66</span>
<span id="67">67</span>
<span id="68">68</span>
<span id="69">69</span>
<span id="70">70</span>
<span id="71">71</span>
<span id="72">72</span>
<span id="73">73</span>
<span id="74">74</span>
<span id="75">75</span>
<span id="76">76</span>
<span id="77">77</span>
<span id="78">78</span>
<span id="79">79</span>
<span id="80">80</span>
<span id="81">81</span>
<span id="82">82</span>
<span id="83">83</span>
<span id="84">84</span>
<span id="85">85</span>
<span id="86">86</span>
<span id="87">87</span>
<span id="88">88</span>
<span id="89">89</span>
<span id="90">90</span>
<span id="91">91</span>
<span id="92">92</span>
<span id="93">93</span>
<span id="94">94</span>
<span id="95">95</span>
<span id="96">96</span>
<span id="97">97</span>
<span id="98">98</span>
<span id="99">99</span>
<span id="100">100</span>
<span id="101">101</span>
<span id="102">102</span>
<span id="103">103</span>
<span id="104">104</span>
<span id="105">105</span>
<span id="106">106</span>
<span id="107">107</span>
<span id="108">108</span>
<span id="109">109</span>
<span id="110">110</span>
<span id="111">111</span>
<span id="112">112</span>
<span id="113">113</span>
<span id="114">114</span>
<span id="115">115</span>
<span id="116">116</span>
<span id="117">117</span>
<span id="118">118</span>
<span id="119">119</span>
<span id="120">120</span>
<span id="121">121</span>
<span id="122">122</span>
<span id="123">123</span>
<span id="124">124</span>
<span id="125">125</span>
<span id="126">126</span>
<span id="127">127</span>
<span id="128">128</span>
<span id="129">129</span>
<span id="130">130</span>
<span id="131">131</span>
<span id="132">132</span>
<span id="133">133</span>
<span id="134">134</span>
<span id="135">135</span>
<span id="136">136</span>
<span id="137">137</span>
<span id="138">138</span>
<span id="139">139</span>
<span id="140">140</span>
<span id="141">141</span>
<span id="142">142</span>
<span id="143">143</span>
<span id="144">144</span>
<span id="145">145</span>
<span id="146">146</span>
<span id="147">147</span>
<span id="148">148</span>
<span id="149">149</span>
<span id="150">150</span>
<span id="151">151</span>
<span id="152">152</span>
<span id="153">153</span>
<span id="154">154</span>
<span id="155">155</span>
<span id="156">156</span>
<span id="157">157</span>
<span id="158">158</span>
<span id="159">159</span>
<span id="160">160</span>
<span id="161">161</span>
<span id="162">162</span>
<span id="163">163</span>
<span id="164">164</span>
<span id="165">165</span>
<span id="166">166</span>
<span id="167">167</span>
<span id="168">168</span>
<span id="169">169</span>
<span id="170">170</span>
<span id="171">171</span>
<span id="172">172</span>
<span id="173">173</span>
<span id="174">174</span>
<span id="175">175</span>
<span id="176">176</span>
<span id="177">177</span>
<span id="178">178</span>
<span id="179">179</span>
<span id="180">180</span>
<span id="181">181</span>
<span id="182">182</span>
<span id="183">183</span>
<span id="184">184</span>
<span id="185">185</span>
<span id="186">186</span>
<span id="187">187</span>
<span id="188">188</span>
<span id="189">189</span>
<span id="190">190</span>
<span id="191">191</span>
<span id="192">192</span>
<span id="193">193</span>
<span id="194">194</span>
<span id="195">195</span>
<span id="196">196</span>
<span id="197">197</span>
<span id="198">198</span>
<span id="199">199</span>
<span id="200">200</span>
<span id="201">201</span>
<span id="202">202</span>
<span id="203">203</span>
<span id="204">204</span>
<span id="205">205</span>
<span id="206">206</span>
<span id="207">207</span>
<span id="208">208</span>
<span id="209">209</span>
<span id="210">210</span>
<span id="211">211</span>
<span id="212">212</span>
<span id="213">213</span>
<span id="214">214</span>
<span id="215">215</span>
<span id="216">216</span>
<span id="217">217</span>
<span id="218">218</span>
<span id="219">219</span>
<span id="220">220</span>
<span id="221">221</span>
<span id="222">222</span>
<span id="223">223</span>
<span id="224">224</span>
<span id="225">225</span>
<span id="226">226</span>
<span id="227">227</span>
<span id="228">228</span>
<span id="229">229</span>
<span id="230">230</span>
<span id="231">231</span>
<span id="232">232</span>
<span id="233">233</span>
<span id="234">234</span>
<span id="235">235</span>
<span id="236">236</span>
<span id="237">237</span>
<span id="238">238</span>
<span id="239">239</span>
<span id="240">240</span>
<span id="241">241</span>
<span id="242">242</span>
<span id="243">243</span>
<span id="244">244</span>
<span id="245">245</span>
<span id="246">246</span>
<span id="247">247</span>
<span id="248">248</span>
<span id="249">249</span>
<span id="250">250</span>
<span id="251">251</span>
<span id="252">252</span>
<span id="253">253</span>
<span id="254">254</span>
<span id="255">255</span>
<span id="256">256</span>
<span id="257">257</span>
<span id="258">258</span>
<span id="259">259</span>
<span id="260">260</span>
<span id="261">261</span>
<span id="262">262</span>
<span id="263">263</span>
<span id="264">264</span>
<span id="265">265</span>
<span id="266">266</span>
<span id="267">267</span>
<span id="268">268</span>
<span id="269">269</span>
<span id="270">270</span>
<span id="271">271</span>
<span id="272">272</span>
<span id="273">273</span>
<span id="274">274</span>
<span id="275">275</span>
<span id="276">276</span>
<span id="277">277</span>
<span id="278">278</span>
<span id="279">279</span>
<span id="280">280</span>
<span id="281">281</span>
<span id="282">282</span>
<span id="283">283</span>
<span id="284">284</span>
<span id="285">285</span>
<span id="286">286</span>
<span id="287">287</span>
<span id="288">288</span>
<span id="289">289</span>
<span id="290">290</span>
<span id="291">291</span>
<span id="292">292</span>
<span id="293">293</span>
<span id="294">294</span>
<span id="295">295</span>
<span id="296">296</span>
<span id="297">297</span>
<span id="298">298</span>
<span id="299">299</span>
<span id="300">300</span>
<span id="301">301</span>
<span id="302">302</span>
<span id="303">303</span>
<span id="304">304</span>
<span id="305">305</span>
<span id="306">306</span>
<span id="307">307</span>
<span id="308">308</span>
<span id="309">309</span>
<span id="310">310</span>
<span id="311">311</span>
<span id="312">312</span>
<span id="313">313</span>
<span id="314">314</span>
<span id="315">315</span>
<span id="316">316</span>
<span id="317">317</span>
<span id="318">318</span>
<span id="319">319</span>
<span id="320">320</span>
<span id="321">321</span>
<span id="322">322</span>
<span id="323">323</span>
<span id="324">324</span>
<span id="325">325</span>
<span id="326">326</span>
<span id="327">327</span>
<span id="328">328</span>
<span id="329">329</span>
<span id="330">330</span>
<span id="331">331</span>
<span id="332">332</span>
<span id="333">333</span>
<span id="334">334</span>
<span id="335">335</span>
<span id="336">336</span>
<span id="337">337</span>
<span id="338">338</span>
<span id="339">339</span>
<span id="340">340</span>
<span id="341">341</span>
<span id="342">342</span>
<span id="343">343</span>
<span id="344">344</span>
<span id="345">345</span>
<span id="346">346</span>
<span id="347">347</span>
<span id="348">348</span>
<span id="349">349</span>
<span id="350">350</span>
<span id="351">351</span>
<span id="352">352</span>
<span id="353">353</span>
<span id="354">354</span>
<span id="355">355</span>
<span id="356">356</span>
<span id="357">357</span>
<span id="358">358</span>
<span id="359">359</span>
<span id="360">360</span>
<span id="361">361</span>
<span id="362">362</span>
<span id="363">363</span>
<span id="364">364</span>
<span id="365">365</span>
<span id="366">366</span>
<span id="367">367</span>
<span id="368">368</span>
<span id="369">369</span>
<span id="370">370</span>
<span id="371">371</span>
<span id="372">372</span>
<span id="373">373</span>
<span id="374">374</span>
<span id="375">375</span>
<span id="376">376</span>
<span id="377">377</span>
<span id="378">378</span>
<span id="379">379</span>
<span id="380">380</span>
<span id="381">381</span>
<span id="382">382</span>
<span id="383">383</span>
<span id="384">384</span>
<span id="385">385</span>
<span id="386">386</span>
<span id="387">387</span>
<span id="388">388</span>
<span id="389">389</span>
<span id="390">390</span>
<span id="391">391</span>
<span id="392">392</span>
<span id="393">393</span>
<span id="394">394</span>
<span id="395">395</span>
<span id="396">396</span>
<span id="397">397</span>
<span id="398">398</span>
<span id="399">399</span>
<span id="400">400</span>
<span id="401">401</span>
<span id="402">402</span>
<span id="403">403</span>
<span id="404">404</span>
<span id="405">405</span>
<span id="406">406</span>
<span id="407">407</span>
<span id="408">408</span>
<span id="409">409</span>
<span id="410">410</span>
<span id="411">411</span>
<span id="412">412</span>
<span id="413">413</span>
<span id="414">414</span>
<span id="415">415</span>
<span id="416">416</span>
<span id="417">417</span>
<span id="418">418</span>
<span id="419">419</span>
<span id="420">420</span>
<span id="421">421</span>
<span id="422">422</span>
<span id="423">423</span>
<span id="424">424</span>
<span id="425">425</span>
<span id="426">426</span>
<span id="427">427</span>
<span id="428">428</span>
<span id="429">429</span>
<span id="430">430</span>
<span id="431">431</span>
<span id="432">432</span>
<span id="433">433</span>
<span id="434">434</span>
<span id="435">435</span>
<span id="436">436</span>
<span id="437">437</span>
<span id="438">438</span>
<span id="439">439</span>
<span id="440">440</span>
<span id="441">441</span>
<span id="442">442</span>
<span id="443">443</span>
<span id="444">444</span>
<span id="445">445</span>
<span id="446">446</span>
<span id="447">447</span>
<span id="448">448</span>
<span id="449">449</span>
<span id="450">450</span>
<span id="451">451</span>
</pre><pre class="rust"><code><span class="kw">use </span>std::collections::HashMap;
<span class="kw">use </span>std::mem::swap;
<span class="comment">// No clone, no copy! That asserts that an LRUHandle exists only once.
</span><span class="kw">type </span>LRUHandle&lt;T&gt; = <span class="kw-2">*mut </span>LRUNode&lt;T&gt;;
<span class="kw">struct </span>LRUNode&lt;T&gt; {
next: <span class="prelude-ty">Option</span>&lt;Box&lt;LRUNode&lt;T&gt;&gt;&gt;, <span class="comment">// None in the list&#39;s last node
</span>prev: <span class="prelude-ty">Option</span>&lt;<span class="kw-2">*mut </span>LRUNode&lt;T&gt;&gt;,
data: <span class="prelude-ty">Option</span>&lt;T&gt;, <span class="comment">// if None, then we have reached the head node
</span>}
<span class="kw">struct </span>LRUList&lt;T&gt; {
head: LRUNode&lt;T&gt;,
count: usize,
}
<span class="kw">use </span>std::fmt;
<span class="kw">impl</span>&lt;T&gt; fmt::Display <span class="kw">for </span>LRUNode&lt;T&gt; {
<span class="kw">fn </span>fmt(<span class="kw-2">&amp;</span><span class="self">self</span>, f: <span class="kw-2">&amp;mut </span>fmt::Formatter&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; fmt::Result {
<span class="kw">if </span><span class="self">self</span>.next.is_some() {
<span class="kw">let </span>node = <span class="self">self</span>.next.as_ref().unwrap();
<span class="macro">writeln!</span>(
f,
<span class="string">&quot;(self: {:?}, next: {:?}, pre: {:?}, data:{})&quot;</span>,
<span class="self">self </span><span class="kw">as </span><span class="kw-2">*const </span><span class="kw">_</span>,
(<span class="kw-2">*</span>node).as_ref() <span class="kw">as </span><span class="kw-2">*const </span><span class="kw">_</span>,
<span class="self">self</span>.prev,
<span class="self">self</span>.data.is_some()
)
} <span class="kw">else </span>{
<span class="macro">writeln!</span>(
f,
<span class="string">&quot;(self: {:?}, next: None, pre: {:?}, data:{})&quot;</span>,
<span class="self">self </span><span class="kw">as </span><span class="kw-2">*const </span><span class="kw">_</span>,
<span class="self">self</span>.prev,
<span class="self">self</span>.data.is_some()
)
}
}
}
<span class="kw">impl</span>&lt;T&gt; fmt::Display <span class="kw">for </span>LRUList&lt;T&gt; {
<span class="kw">fn </span>fmt(<span class="kw-2">&amp;</span><span class="self">self</span>, f: <span class="kw-2">&amp;mut </span>fmt::Formatter&lt;<span class="lifetime">&#39;_</span>&gt;) -&gt; fmt::Result {
<span class="kw">let _ </span>= <span class="macro">write!</span>(
f,
<span class="string">&quot;\n {:?}, count: {}, head: {}&quot;</span>,
<span class="self">self </span><span class="kw">as </span><span class="kw-2">*const </span><span class="kw">_</span>, <span class="self">self</span>.count, <span class="self">self</span>.head
)<span class="question-mark">?</span>;
<span class="kw">let </span><span class="kw-2">mut </span>opt_node = <span class="kw-2">&amp;</span><span class="self">self</span>.head.next;
<span class="kw">while </span>opt_node.is_some() {
<span class="kw">let </span>node = opt_node.as_ref().unwrap();
<span class="kw">let _ </span>= <span class="macro">write!</span>(f, <span class="string">&quot;\t {}&quot;</span>, node)<span class="question-mark">?</span>;
opt_node = <span class="kw-2">&amp;</span>node.next
}
<span class="macro">writeln!</span>(f,)
}
}
<span class="doccomment">/// This is likely unstable; more investigation is needed into correct behavior!
</span><span class="kw">impl</span>&lt;T&gt; LRUList&lt;T&gt; {
<span class="kw">fn </span>new() -&gt; LRUList&lt;T&gt; {
LRUList {
head: LRUNode {
data: <span class="prelude-val">None</span>,
next: <span class="prelude-val">None</span>,
prev: <span class="prelude-val">None</span>,
},
count: <span class="number">0</span>,
}
}
<span class="doccomment">/// Inserts new element at front (least recently used element)
</span><span class="kw">fn </span>insert(<span class="kw-2">&amp;mut </span><span class="self">self</span>, elem: T) -&gt; LRUHandle&lt;T&gt; {
<span class="self">self</span>.count += <span class="number">1</span>;
<span class="comment">// Not first element
</span><span class="kw">if </span><span class="self">self</span>.head.next.is_some() {
<span class="kw">let </span><span class="kw-2">mut </span>new = Box::new(LRUNode {
data: <span class="prelude-val">Some</span>(elem),
next: <span class="prelude-val">None</span>,
prev: <span class="prelude-val">Some</span>(<span class="kw-2">&amp;mut </span><span class="self">self</span>.head <span class="kw">as </span><span class="kw-2">*mut </span>LRUNode&lt;T&gt;),
});
<span class="kw">let </span>newp = new.as_mut() <span class="kw">as </span><span class="kw-2">*mut </span>LRUNode&lt;T&gt;;
<span class="comment">// Set up the node after the new one
</span><span class="self">self</span>.head.next.as_mut().unwrap().prev = <span class="prelude-val">Some</span>(newp);
<span class="comment">// Replace head.next with None and set the new node&#39;s next to that
</span>new.next = <span class="self">self</span>.head.next.take();
<span class="self">self</span>.head.next = <span class="prelude-val">Some</span>(new);
newp
} <span class="kw">else </span>{
<span class="comment">// First node; the only node right now is an empty head node
</span><span class="kw">let </span><span class="kw-2">mut </span>new = Box::new(LRUNode {
data: <span class="prelude-val">Some</span>(elem),
next: <span class="prelude-val">None</span>,
prev: <span class="prelude-val">Some</span>(<span class="kw-2">&amp;mut </span><span class="self">self</span>.head <span class="kw">as </span><span class="kw-2">*mut </span>LRUNode&lt;T&gt;),
});
<span class="kw">let </span>newp = new.as_mut() <span class="kw">as </span><span class="kw-2">*mut </span>LRUNode&lt;T&gt;;
<span class="comment">// Set tail
</span><span class="self">self</span>.head.prev = <span class="prelude-val">Some</span>(newp);
<span class="comment">// Set first node
</span><span class="self">self</span>.head.next = <span class="prelude-val">Some</span>(new);
newp
}
}
<span class="kw">fn </span>remove_last(<span class="kw-2">&amp;mut </span><span class="self">self</span>) -&gt; <span class="prelude-ty">Option</span>&lt;T&gt; {
<span class="kw">if </span><span class="self">self</span>.count() == <span class="number">0 </span>{
<span class="kw">return </span><span class="prelude-val">None</span>;
}
<span class="kw">let </span><span class="kw-2">mut </span>lasto = <span class="kw">unsafe </span>{ (<span class="kw-2">*</span>((<span class="kw-2">*</span><span class="self">self</span>.head.prev.unwrap()).prev.unwrap())).next.take() };
<span class="macro">assert!</span>(lasto.is_some());
<span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref mut </span>last) = lasto {
<span class="macro">assert!</span>(last.prev.is_some());
<span class="macro">assert!</span>(<span class="self">self</span>.head.prev.is_some());
<span class="self">self</span>.head.prev = last.prev;
<span class="self">self</span>.count -= <span class="number">1</span>;
(<span class="kw-2">*</span>last).data.take()
} <span class="kw">else </span>{
<span class="prelude-val">None
</span>}
}
<span class="kw">fn </span>remove(<span class="kw-2">&amp;mut </span><span class="self">self</span>, node_handle: LRUHandle&lt;T&gt;) -&gt; T {
<span class="kw">unsafe </span>{
<span class="kw">let </span>d = (<span class="kw-2">*</span>node_handle).data.take().unwrap();
<span class="comment">// Take ownership of node to be removed.
</span><span class="kw">let </span><span class="kw-2">mut </span>current = (<span class="kw-2">*</span>(<span class="kw-2">*</span>node_handle).prev.unwrap()).next.take().unwrap();
<span class="kw">let </span>prev = current.prev.unwrap();
<span class="comment">// Update previous node&#39;s successor.
</span><span class="kw">if </span>current.next.is_some() {
<span class="comment">// Update next node&#39;s predecessor.
</span>current.next.as_mut().unwrap().prev = current.prev.take();
}
(<span class="kw-2">*</span>prev).next = current.next.take();
<span class="self">self</span>.count -= <span class="number">1</span>;
d
}
}
<span class="doccomment">/// Reinserts the referenced node at the front.
</span><span class="kw">fn </span>reinsert_front(<span class="kw-2">&amp;mut </span><span class="self">self</span>, node_handle: LRUHandle&lt;T&gt;) {
<span class="kw">unsafe </span>{
<span class="kw">let </span>prevp = (<span class="kw-2">*</span>node_handle).prev.unwrap();
<span class="comment">// If not last node, update following node&#39;s prev
</span><span class="kw">if let </span><span class="prelude-val">Some</span>(next) = (<span class="kw-2">*</span>node_handle).next.as_mut() {
next.prev = <span class="prelude-val">Some</span>(prevp);
} <span class="kw">else </span>{
<span class="comment">// If last node, update head
</span><span class="self">self</span>.head.prev = <span class="prelude-val">Some</span>(prevp);
}
<span class="comment">// Swap this.next with prev.next. After that, this.next refers to this (!)
</span>swap(<span class="kw-2">&amp;mut </span>(<span class="kw-2">*</span>prevp).next, <span class="kw-2">&amp;mut </span>(<span class="kw-2">*</span>node_handle).next);
<span class="comment">// To reinsert at head, swap head&#39;s next with this.next
</span>swap(<span class="kw-2">&amp;mut </span>(<span class="kw-2">*</span>node_handle).next, <span class="kw-2">&amp;mut </span><span class="self">self</span>.head.next);
<span class="comment">// Update this&#39; prev reference to point to head.
// Update the second node&#39;s prev reference.
</span><span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref mut </span>newnext) = (<span class="kw-2">*</span>node_handle).next {
(<span class="kw-2">*</span>node_handle).prev = newnext.prev;
newnext.prev = <span class="prelude-val">Some</span>(node_handle);
} <span class="kw">else </span>{
<span class="comment">// Only one node, being the last one; avoid head.prev pointing to head
</span><span class="self">self</span>.head.prev = <span class="prelude-val">Some</span>(node_handle);
}
<span class="macro">assert!</span>(<span class="self">self</span>.head.next.is_some());
<span class="macro">assert!</span>(<span class="self">self</span>.head.prev.is_some());
}
}
<span class="kw">fn </span>count(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; usize {
<span class="self">self</span>.count
}
<span class="kw">fn </span>_testing_head_ref(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; <span class="prelude-ty">Option</span>&lt;<span class="kw-2">&amp;</span>T&gt; {
<span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref </span>first) = <span class="self">self</span>.head.next {
first.data.as_ref()
} <span class="kw">else </span>{
<span class="prelude-val">None
</span>}
}
}
<span class="kw">pub type </span>CacheKey = [u8; <span class="number">16</span>];
<span class="kw">pub type </span>CacheID = u64;
<span class="kw">type </span>CacheEntry&lt;T&gt; = (T, LRUHandle&lt;CacheKey&gt;);
<span class="doccomment">/// Implementation of `ShardedLRUCache`.
/// Based on a HashMap; the elements are linked in order to support the LRU ordering.
</span><span class="kw">pub struct </span>Cache&lt;T&gt; {
<span class="comment">// note: CacheKeys (Vec&lt;u8&gt;) are duplicated between list and map. If this turns out to be a
// performance bottleneck, another layer of indirection™ can solve this by mapping the key
// to a numeric handle that keys both list and map.
</span>list: LRUList&lt;CacheKey&gt;,
map: HashMap&lt;CacheKey, CacheEntry&lt;T&gt;&gt;,
cap: usize,
id: u64,
}
<span class="kw">impl</span>&lt;T&gt; Cache&lt;T&gt; {
<span class="kw">pub fn </span>new(capacity: usize) -&gt; Cache&lt;T&gt; {
<span class="macro">assert!</span>(capacity &gt; <span class="number">0</span>);
Cache {
list: LRUList::new(),
map: HashMap::with_capacity(<span class="number">1024</span>),
cap: capacity,
id: <span class="number">0</span>,
}
}
<span class="doccomment">/// Returns an ID that is unique for this cache and that can be used to partition the cache
/// among several users.
</span><span class="kw">pub fn </span>new_cache_id(<span class="kw-2">&amp;mut </span><span class="self">self</span>) -&gt; CacheID {
<span class="self">self</span>.id += <span class="number">1</span>;
<span class="kw">return </span><span class="self">self</span>.id;
}
<span class="doccomment">/// How many the cache currently contains
</span><span class="kw">pub fn </span>count(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; usize {
<span class="kw">return </span><span class="self">self</span>.list.count();
}
<span class="doccomment">/// The capacity of this cache
</span><span class="kw">pub fn </span>cap(<span class="kw-2">&amp;</span><span class="self">self</span>) -&gt; usize {
<span class="kw">return </span><span class="self">self</span>.cap;
}
<span class="doccomment">/// Insert a new element into the cache. The returned `CacheHandle` can be used for further
/// operations on that element.
/// If the capacity has been reached, the least recently used element is removed from the
/// cache.
</span><span class="kw">pub fn </span>insert(<span class="kw-2">&amp;mut </span><span class="self">self</span>, key: <span class="kw-2">&amp;</span>CacheKey, elem: T) {
<span class="kw">if </span><span class="self">self</span>.list.count() &gt;= <span class="self">self</span>.cap {
<span class="kw">if let </span><span class="prelude-val">Some</span>(removed_key) = <span class="self">self</span>.list.remove_last() {
<span class="macro">assert!</span>(<span class="self">self</span>.map.remove(<span class="kw-2">&amp;</span>removed_key).is_some());
} <span class="kw">else </span>{
<span class="macro">panic!</span>(<span class="string">&quot;could not remove_last(); bug!&quot;</span>);
}
}
<span class="kw">let </span>lru_handle = <span class="self">self</span>.list.insert(key.clone());
<span class="self">self</span>.map.insert(key.clone(), (elem, lru_handle));
}
<span class="doccomment">/// Retrieve an element from the cache.
/// If the element has been preempted from the cache in the meantime, this returns None.
</span><span class="kw">pub fn </span>get&lt;<span class="lifetime">&#39;a</span>&gt;(<span class="kw-2">&amp;</span><span class="lifetime">&#39;a </span><span class="kw-2">mut </span><span class="self">self</span>, key: <span class="kw-2">&amp;</span>CacheKey) -&gt; <span class="prelude-ty">Option</span>&lt;<span class="kw-2">&amp;</span><span class="lifetime">&#39;a </span>T&gt; {
<span class="kw">match </span><span class="self">self</span>.map.get(key) {
<span class="prelude-val">None </span>=&gt; <span class="prelude-val">None</span>,
<span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span>(<span class="kw-2">ref </span>elem, <span class="kw-2">ref </span>lru_handle)) =&gt; {
<span class="self">self</span>.list.reinsert_front(<span class="kw-2">*</span>lru_handle);
<span class="prelude-val">Some</span>(elem)
}
}
}
<span class="doccomment">/// Remove an element from the cache (for invalidation).
</span><span class="kw">pub fn </span>remove(<span class="kw-2">&amp;mut </span><span class="self">self</span>, key: <span class="kw-2">&amp;</span>CacheKey) -&gt; <span class="prelude-ty">Option</span>&lt;T&gt; {
<span class="kw">match </span><span class="self">self</span>.map.remove(key) {
<span class="prelude-val">None </span>=&gt; <span class="prelude-val">None</span>,
<span class="prelude-val">Some</span>((elem, lru_handle)) =&gt; {
<span class="self">self</span>.list.remove(lru_handle);
<span class="prelude-val">Some</span>(elem)
}
}
}
}
<span class="attribute">#[cfg(feature = <span class="string">&quot;enclave_unit_test&quot;</span>)]
</span><span class="kw">pub mod </span>tests {
<span class="kw">use </span><span class="kw">super</span>::LRUList;
<span class="kw">use super</span>::<span class="kw-2">*</span>;
<span class="kw">use </span>teaclave_test_utils::<span class="kw-2">*</span>;
<span class="kw">pub fn </span>run_tests() -&gt; bool {
<span class="macro">run_tests!</span>(
test_blockcache_cache_add_rm,
test_blockcache_cache_capacity,
test_blockcache_lru_remove,
test_blockcache_lru_1,
test_blockcache_lru_reinsert,
test_blockcache_lru_reinsert_2,
test_blockcache_lru_edge_cases,
)
}
<span class="kw">fn </span>make_key(a: u8, b: u8, c: u8) -&gt; CacheKey {
[a, b, c, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]
}
<span class="kw">fn </span>test_blockcache_cache_add_rm() {
<span class="kw">let </span><span class="kw-2">mut </span>cache = Cache::new(<span class="number">128</span>);
<span class="kw">let </span>h_123 = make_key(<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>);
<span class="kw">let </span>h_521 = make_key(<span class="number">1</span>, <span class="number">2</span>, <span class="number">4</span>);
<span class="kw">let </span>h_372 = make_key(<span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>);
<span class="kw">let </span>h_332 = make_key(<span class="number">6</span>, <span class="number">3</span>, <span class="number">1</span>);
<span class="kw">let </span>h_899 = make_key(<span class="number">8</span>, <span class="number">2</span>, <span class="number">1</span>);
cache.insert(<span class="kw-2">&amp;</span>h_123, <span class="number">123</span>);
cache.insert(<span class="kw-2">&amp;</span>h_332, <span class="number">332</span>);
cache.insert(<span class="kw-2">&amp;</span>h_521, <span class="number">521</span>);
cache.insert(<span class="kw-2">&amp;</span>h_372, <span class="number">372</span>);
cache.insert(<span class="kw-2">&amp;</span>h_899, <span class="number">899</span>);
<span class="macro">assert_eq!</span>(cache.count(), <span class="number">5</span>);
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_123), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">123</span>));
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_372), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">372</span>));
<span class="macro">assert_eq!</span>(cache.remove(<span class="kw-2">&amp;</span>h_521), <span class="prelude-val">Some</span>(<span class="number">521</span>));
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_521), <span class="prelude-val">None</span>);
<span class="macro">assert_eq!</span>(cache.remove(<span class="kw-2">&amp;</span>h_521), <span class="prelude-val">None</span>);
<span class="macro">assert_eq!</span>(cache.count(), <span class="number">4</span>);
}
<span class="kw">fn </span>test_blockcache_cache_capacity() {
<span class="kw">let </span><span class="kw-2">mut </span>cache = Cache::new(<span class="number">3</span>);
<span class="kw">let </span>h_123 = make_key(<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>);
<span class="kw">let </span>h_521 = make_key(<span class="number">1</span>, <span class="number">2</span>, <span class="number">4</span>);
<span class="kw">let </span>h_372 = make_key(<span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>);
<span class="kw">let </span>h_332 = make_key(<span class="number">6</span>, <span class="number">3</span>, <span class="number">1</span>);
<span class="kw">let </span>h_899 = make_key(<span class="number">8</span>, <span class="number">2</span>, <span class="number">1</span>);
cache.insert(<span class="kw-2">&amp;</span>h_123, <span class="number">123</span>);
cache.insert(<span class="kw-2">&amp;</span>h_332, <span class="number">332</span>);
cache.insert(<span class="kw-2">&amp;</span>h_521, <span class="number">521</span>);
cache.insert(<span class="kw-2">&amp;</span>h_372, <span class="number">372</span>);
cache.insert(<span class="kw-2">&amp;</span>h_899, <span class="number">899</span>);
<span class="macro">assert_eq!</span>(cache.count(), <span class="number">3</span>);
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_123), <span class="prelude-val">None</span>);
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_332), <span class="prelude-val">None</span>);
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_521), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">521</span>));
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_372), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">372</span>));
<span class="macro">assert_eq!</span>(cache.get(<span class="kw-2">&amp;</span>h_899), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">899</span>));
}
<span class="kw">fn </span>test_blockcache_lru_remove() {
<span class="kw">let </span><span class="kw-2">mut </span>lru = LRUList::&lt;usize&gt;::new();
<span class="kw">let </span>h_56 = lru.insert(<span class="number">56</span>);
lru.insert(<span class="number">22</span>);
lru.insert(<span class="number">223</span>);
<span class="kw">let </span>h_244 = lru.insert(<span class="number">244</span>);
lru.insert(<span class="number">1111</span>);
<span class="kw">let </span>h_12 = lru.insert(<span class="number">12</span>);
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">6</span>);
<span class="macro">assert_eq!</span>(<span class="number">244</span>, lru.remove(h_244));
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">5</span>);
<span class="macro">assert_eq!</span>(<span class="number">12</span>, lru.remove(h_12));
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">4</span>);
<span class="macro">assert_eq!</span>(<span class="number">56</span>, lru.remove(h_56));
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">3</span>);
}
<span class="kw">fn </span>test_blockcache_lru_1() {
<span class="kw">let </span><span class="kw-2">mut </span>lru = LRUList::&lt;usize&gt;::new();
lru.insert(<span class="number">56</span>);
lru.insert(<span class="number">22</span>);
lru.insert(<span class="number">244</span>);
lru.insert(<span class="number">12</span>);
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">4</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">56</span>), lru.remove_last());
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">22</span>), lru.remove_last());
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">244</span>), lru.remove_last());
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">1</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">12</span>), lru.remove_last());
<span class="macro">assert_eq!</span>(lru.count(), <span class="number">0</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, lru.remove_last());
}
<span class="kw">fn </span>test_blockcache_lru_reinsert() {
<span class="kw">let </span><span class="kw-2">mut </span>lru = LRUList::&lt;usize&gt;::new();
<span class="kw">let </span>handle1 = lru.insert(<span class="number">56</span>);
<span class="kw">let </span>handle2 = lru.insert(<span class="number">22</span>);
<span class="kw">let </span>handle3 = lru.insert(<span class="number">244</span>);
<span class="macro">assert_eq!</span>(lru._testing_head_ref().map(|r| (<span class="kw-2">*</span>r)).unwrap(), <span class="number">244</span>);
lru.reinsert_front(handle1);
<span class="macro">assert_eq!</span>(lru._testing_head_ref().map(|r| (<span class="kw-2">*</span>r)).unwrap(), <span class="number">56</span>);
lru.reinsert_front(handle3);
<span class="macro">assert_eq!</span>(lru._testing_head_ref().map(|r| (<span class="kw-2">*</span>r)).unwrap(), <span class="number">244</span>);
lru.reinsert_front(handle2);
<span class="macro">assert_eq!</span>(lru._testing_head_ref().map(|r| (<span class="kw-2">*</span>r)).unwrap(), <span class="number">22</span>);
<span class="macro">assert_eq!</span>(lru.remove_last(), <span class="prelude-val">Some</span>(<span class="number">56</span>));
<span class="macro">assert_eq!</span>(lru.remove_last(), <span class="prelude-val">Some</span>(<span class="number">244</span>));
<span class="macro">assert_eq!</span>(lru.remove_last(), <span class="prelude-val">Some</span>(<span class="number">22</span>));
}
<span class="kw">fn </span>test_blockcache_lru_reinsert_2() {
<span class="kw">let </span><span class="kw-2">mut </span>lru = LRUList::&lt;usize&gt;::new();
<span class="kw">let </span>handles = <span class="macro">vec!</span>[
lru.insert(<span class="number">0</span>),
lru.insert(<span class="number">1</span>),
lru.insert(<span class="number">2</span>),
lru.insert(<span class="number">3</span>),
lru.insert(<span class="number">4</span>),
lru.insert(<span class="number">5</span>),
lru.insert(<span class="number">6</span>),
lru.insert(<span class="number">7</span>),
lru.insert(<span class="number">8</span>),
];
<span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..<span class="number">9 </span>{
lru.reinsert_front(handles[i]);
<span class="macro">assert_eq!</span>(lru._testing_head_ref().map(|x| <span class="kw-2">*</span>x), <span class="prelude-val">Some</span>(i));
}
}
<span class="kw">fn </span>test_blockcache_lru_edge_cases() {
<span class="kw">let </span><span class="kw-2">mut </span>lru = LRUList::&lt;usize&gt;::new();
<span class="kw">let </span>handle = lru.insert(<span class="number">3</span>);
lru.reinsert_front(handle);
<span class="macro">assert_eq!</span>(lru._testing_head_ref().map(|x| <span class="kw-2">*</span>x), <span class="prelude-val">Some</span>(<span class="number">3</span>));
<span class="macro">assert_eq!</span>(lru.remove_last(), <span class="prelude-val">Some</span>(<span class="number">3</span>));
<span class="macro">assert_eq!</span>(lru.remove_last(), <span class="prelude-val">None</span>);
<span class="macro">assert_eq!</span>(lru.remove_last(), <span class="prelude-val">None</span>);
}
}
</code></pre></div>
</section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rusty_leveldb" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html>