| <!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 `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/tracing-attributes-0.1.24/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.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="../../tracing_attributes/index.html"><div class="logo-container"> |
| <img src="https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/logo-type.png" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../tracing_attributes/index.html"> |
| <img src="https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/logo-type.png" 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> |
| <span id="452">452</span> |
| <span id="453">453</span> |
| <span id="454">454</span> |
| <span id="455">455</span> |
| <span id="456">456</span> |
| <span id="457">457</span> |
| <span id="458">458</span> |
| <span id="459">459</span> |
| <span id="460">460</span> |
| <span id="461">461</span> |
| <span id="462">462</span> |
| <span id="463">463</span> |
| <span id="464">464</span> |
| <span id="465">465</span> |
| <span id="466">466</span> |
| <span id="467">467</span> |
| <span id="468">468</span> |
| <span id="469">469</span> |
| <span id="470">470</span> |
| <span id="471">471</span> |
| <span id="472">472</span> |
| <span id="473">473</span> |
| <span id="474">474</span> |
| <span id="475">475</span> |
| <span id="476">476</span> |
| <span id="477">477</span> |
| <span id="478">478</span> |
| <span id="479">479</span> |
| <span id="480">480</span> |
| <span id="481">481</span> |
| <span id="482">482</span> |
| <span id="483">483</span> |
| <span id="484">484</span> |
| <span id="485">485</span> |
| <span id="486">486</span> |
| <span id="487">487</span> |
| <span id="488">488</span> |
| <span id="489">489</span> |
| <span id="490">490</span> |
| <span id="491">491</span> |
| <span id="492">492</span> |
| <span id="493">493</span> |
| <span id="494">494</span> |
| <span id="495">495</span> |
| <span id="496">496</span> |
| <span id="497">497</span> |
| <span id="498">498</span> |
| <span id="499">499</span> |
| <span id="500">500</span> |
| <span id="501">501</span> |
| <span id="502">502</span> |
| <span id="503">503</span> |
| <span id="504">504</span> |
| <span id="505">505</span> |
| <span id="506">506</span> |
| <span id="507">507</span> |
| <span id="508">508</span> |
| <span id="509">509</span> |
| <span id="510">510</span> |
| <span id="511">511</span> |
| <span id="512">512</span> |
| <span id="513">513</span> |
| <span id="514">514</span> |
| <span id="515">515</span> |
| <span id="516">516</span> |
| <span id="517">517</span> |
| <span id="518">518</span> |
| <span id="519">519</span> |
| <span id="520">520</span> |
| <span id="521">521</span> |
| <span id="522">522</span> |
| <span id="523">523</span> |
| <span id="524">524</span> |
| <span id="525">525</span> |
| <span id="526">526</span> |
| <span id="527">527</span> |
| <span id="528">528</span> |
| <span id="529">529</span> |
| <span id="530">530</span> |
| <span id="531">531</span> |
| <span id="532">532</span> |
| <span id="533">533</span> |
| <span id="534">534</span> |
| <span id="535">535</span> |
| <span id="536">536</span> |
| <span id="537">537</span> |
| <span id="538">538</span> |
| <span id="539">539</span> |
| <span id="540">540</span> |
| <span id="541">541</span> |
| <span id="542">542</span> |
| <span id="543">543</span> |
| <span id="544">544</span> |
| <span id="545">545</span> |
| <span id="546">546</span> |
| <span id="547">547</span> |
| <span id="548">548</span> |
| <span id="549">549</span> |
| <span id="550">550</span> |
| <span id="551">551</span> |
| <span id="552">552</span> |
| <span id="553">553</span> |
| <span id="554">554</span> |
| <span id="555">555</span> |
| <span id="556">556</span> |
| <span id="557">557</span> |
| <span id="558">558</span> |
| <span id="559">559</span> |
| <span id="560">560</span> |
| <span id="561">561</span> |
| <span id="562">562</span> |
| <span id="563">563</span> |
| <span id="564">564</span> |
| <span id="565">565</span> |
| <span id="566">566</span> |
| <span id="567">567</span> |
| <span id="568">568</span> |
| <span id="569">569</span> |
| <span id="570">570</span> |
| <span id="571">571</span> |
| <span id="572">572</span> |
| <span id="573">573</span> |
| <span id="574">574</span> |
| <span id="575">575</span> |
| <span id="576">576</span> |
| <span id="577">577</span> |
| <span id="578">578</span> |
| <span id="579">579</span> |
| <span id="580">580</span> |
| <span id="581">581</span> |
| <span id="582">582</span> |
| <span id="583">583</span> |
| <span id="584">584</span> |
| <span id="585">585</span> |
| <span id="586">586</span> |
| <span id="587">587</span> |
| <span id="588">588</span> |
| <span id="589">589</span> |
| <span id="590">590</span> |
| <span id="591">591</span> |
| <span id="592">592</span> |
| <span id="593">593</span> |
| <span id="594">594</span> |
| <span id="595">595</span> |
| <span id="596">596</span> |
| <span id="597">597</span> |
| <span id="598">598</span> |
| <span id="599">599</span> |
| <span id="600">600</span> |
| <span id="601">601</span> |
| <span id="602">602</span> |
| <span id="603">603</span> |
| <span id="604">604</span> |
| <span id="605">605</span> |
| <span id="606">606</span> |
| <span id="607">607</span> |
| <span id="608">608</span> |
| <span id="609">609</span> |
| <span id="610">610</span> |
| <span id="611">611</span> |
| <span id="612">612</span> |
| <span id="613">613</span> |
| <span id="614">614</span> |
| <span id="615">615</span> |
| <span id="616">616</span> |
| <span id="617">617</span> |
| <span id="618">618</span> |
| <span id="619">619</span> |
| <span id="620">620</span> |
| <span id="621">621</span> |
| <span id="622">622</span> |
| <span id="623">623</span> |
| <span id="624">624</span> |
| <span id="625">625</span> |
| <span id="626">626</span> |
| <span id="627">627</span> |
| <span id="628">628</span> |
| <span id="629">629</span> |
| <span id="630">630</span> |
| <span id="631">631</span> |
| <span id="632">632</span> |
| <span id="633">633</span> |
| <span id="634">634</span> |
| <span id="635">635</span> |
| <span id="636">636</span> |
| <span id="637">637</span> |
| <span id="638">638</span> |
| <span id="639">639</span> |
| <span id="640">640</span> |
| <span id="641">641</span> |
| <span id="642">642</span> |
| <span id="643">643</span> |
| <span id="644">644</span> |
| <span id="645">645</span> |
| <span id="646">646</span> |
| <span id="647">647</span> |
| <span id="648">648</span> |
| <span id="649">649</span> |
| <span id="650">650</span> |
| <span id="651">651</span> |
| <span id="652">652</span> |
| <span id="653">653</span> |
| <span id="654">654</span> |
| <span id="655">655</span> |
| <span id="656">656</span> |
| <span id="657">657</span> |
| <span id="658">658</span> |
| <span id="659">659</span> |
| <span id="660">660</span> |
| <span id="661">661</span> |
| <span id="662">662</span> |
| <span id="663">663</span> |
| <span id="664">664</span> |
| <span id="665">665</span> |
| <span id="666">666</span> |
| <span id="667">667</span> |
| <span id="668">668</span> |
| <span id="669">669</span> |
| <span id="670">670</span> |
| <span id="671">671</span> |
| <span id="672">672</span> |
| <span id="673">673</span> |
| <span id="674">674</span> |
| <span id="675">675</span> |
| <span id="676">676</span> |
| <span id="677">677</span> |
| <span id="678">678</span> |
| <span id="679">679</span> |
| <span id="680">680</span> |
| <span id="681">681</span> |
| <span id="682">682</span> |
| <span id="683">683</span> |
| <span id="684">684</span> |
| <span id="685">685</span> |
| <span id="686">686</span> |
| <span id="687">687</span> |
| <span id="688">688</span> |
| <span id="689">689</span> |
| <span id="690">690</span> |
| <span id="691">691</span> |
| <span id="692">692</span> |
| <span id="693">693</span> |
| <span id="694">694</span> |
| <span id="695">695</span> |
| </pre><pre class="rust"><code><span class="doccomment">//! A procedural macro attribute for instrumenting functions with [`tracing`]. |
| //! |
| //! [`tracing`] is a framework for instrumenting Rust programs to collect |
| //! structured, event-based diagnostic information. This crate provides the |
| //! [`#[instrument]`][instrument] procedural macro attribute. |
| //! |
| //! Note that this macro is also re-exported by the main `tracing` crate. |
| //! |
| //! *Compiler support: [requires `rustc` 1.56+][msrv]* |
| //! |
| //! [msrv]: #supported-rust-versions |
| //! |
| //! ## Usage |
| //! |
| //! In the `Cargo.toml`: |
| //! |
| //! ```toml |
| //! [dependencies] |
| //! tracing-attributes = "0.1.24" |
| //! ``` |
| //! |
| //! The [`#[instrument]`][instrument] attribute can now be added to a function |
| //! to automatically create and enter `tracing` [span] when that function is |
| //! called. For example: |
| //! |
| //! ``` |
| //! use tracing::instrument; |
| //! |
| //! #[instrument] |
| //! pub fn my_function(my_arg: usize) { |
| //! // ... |
| //! } |
| //! |
| //! # fn main() {} |
| //! ``` |
| //! |
| //! [`tracing`]: https://crates.io/crates/tracing |
| //! [span]: https://docs.rs/tracing/latest/tracing/span/index.html |
| //! [instrument]: macro@self::instrument |
| //! |
| //! ## Supported Rust Versions |
| //! |
| //! Tracing is built against the latest stable release. The minimum supported |
| //! version is 1.56. The current Tracing version is not guaranteed to build on |
| //! Rust versions earlier than the minimum supported version. |
| //! |
| //! Tracing follows the same compiler support policies as the rest of the Tokio |
| //! project. The current stable Rust compiler and the three most recent minor |
| //! versions before it will always be supported. For example, if the current |
| //! stable compiler version is 1.69, the minimum supported version will not be |
| //! increased past 1.66, three minor versions prior. Increasing the minimum |
| //! supported compiler version is not considered a semver breaking change as |
| //! long as doing so complies with this policy. |
| //! |
| </span><span class="attribute">#![doc( |
| html_logo_url = <span class="string">"https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/logo-type.png"</span>, |
| issue_tracker_base_url = <span class="string">"https://github.com/tokio-rs/tracing/issues/" |
| </span>)] |
| #![cfg_attr(docsrs, deny(rustdoc::broken_intra_doc_links))] |
| #![warn( |
| missing_debug_implementations, |
| missing_docs, |
| rust_2018_idioms, |
| unreachable_pub, |
| bad_style, |
| dead_code, |
| improper_ctypes, |
| non_shorthand_field_patterns, |
| no_mangle_generic_items, |
| overflowing_literals, |
| path_statements, |
| patterns_in_fns_without_body, |
| private_in_public, |
| unconditional_recursion, |
| unused_allocation, |
| unused_comparisons, |
| unused_parens, |
| while_true |
| )] |
| </span><span class="comment">// TODO: once `tracing` bumps its MSRV to 1.42, remove this allow. |
| </span><span class="attribute">#![allow(unused)] |
| </span><span class="kw">extern crate </span>proc_macro; |
| |
| <span class="kw">use </span>proc_macro2::TokenStream; |
| <span class="kw">use </span>quote::{quote, ToTokens}; |
| <span class="kw">use </span>syn::parse::{Parse, ParseStream}; |
| <span class="kw">use </span>syn::{Attribute, ItemFn, Signature, Visibility}; |
| |
| <span class="kw">mod </span>attr; |
| <span class="kw">mod </span>expand; |
| <span class="doccomment">/// Instruments a function to create and enter a `tracing` [span] every time |
| /// the function is called. |
| /// |
| /// Unless overriden, a span with the [`INFO`] [level] will be generated. |
| /// The generated span's name will be the name of the function. |
| /// By default, all arguments to the function are included as fields on the |
| /// span. Arguments that are `tracing` [primitive types] implementing the |
| /// [`Value` trait] will be recorded as fields of that type. Types which do |
| /// not implement `Value` will be recorded using [`std::fmt::Debug`]. |
| /// |
| /// [primitive types]: https://docs.rs/tracing/latest/tracing/field/trait.Value.html#foreign-impls |
| /// [`Value` trait]: https://docs.rs/tracing/latest/tracing/field/trait.Value.html. |
| /// |
| /// # Overriding Span Attributes |
| /// |
| /// To change the [name] of the generated span, add a `name` argument to the |
| /// `#[instrument]` macro, followed by an equals sign and a string literal. For |
| /// example: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// |
| /// // The generated span's name will be "my_span" rather than "my_function". |
| /// #[instrument(name = "my_span")] |
| /// pub fn my_function() { |
| /// // ... do something incredibly interesting and important ... |
| /// } |
| /// ``` |
| /// |
| /// To override the [target] of the generated span, add a `target` argument to |
| /// the `#[instrument]` macro, followed by an equals sign and a string literal |
| /// for the new target. The [module path] is still recorded separately. For |
| /// example: |
| /// |
| /// ``` |
| /// pub mod my_module { |
| /// # use tracing_attributes::instrument; |
| /// // The generated span's target will be "my_crate::some_special_target", |
| /// // rather than "my_crate::my_module". |
| /// #[instrument(target = "my_crate::some_special_target")] |
| /// pub fn my_function() { |
| /// // ... all kinds of neat code in here ... |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// Finally, to override the [level] of the generated span, add a `level` |
| /// argument, followed by an equals sign and a string literal with the name of |
| /// the desired level. Level names are not case sensitive. For example: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// // The span's level will be TRACE rather than INFO. |
| /// #[instrument(level = "trace")] |
| /// pub fn my_function() { |
| /// // ... I have written a truly marvelous implementation of this function, |
| /// // which this example is too narrow to contain ... |
| /// } |
| /// ``` |
| /// |
| /// # Skipping Fields |
| /// |
| /// To skip recording one or more arguments to a function or method, pass |
| /// the argument's name inside the `skip()` argument on the `#[instrument]` |
| /// macro. This can be used when an argument to an instrumented function does |
| /// not implement [`fmt::Debug`], or to exclude an argument with a verbose or |
| /// costly `Debug` implementation. Note that: |
| /// |
| /// - multiple argument names can be passed to `skip`. |
| /// - arguments passed to `skip` do _not_ need to implement `fmt::Debug`. |
| /// |
| /// You can also use `skip_all` to skip all arguments. |
| /// |
| /// ## Examples |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// # use std::collections::HashMap; |
| /// // This type doesn't implement `fmt::Debug`! |
| /// struct NonDebug; |
| /// |
| /// // `arg` will be recorded, while `non_debug` will not. |
| /// #[instrument(skip(non_debug))] |
| /// fn my_function(arg: usize, non_debug: NonDebug) { |
| /// // ... |
| /// } |
| /// |
| /// // These arguments are huge |
| /// #[instrument(skip_all)] |
| /// fn my_big_data_function(large: Vec<u8>, also_large: HashMap<String, String>) { |
| /// // ... |
| /// } |
| /// ``` |
| /// |
| /// Skipping the `self` parameter: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[derive(Debug)] |
| /// struct MyType { |
| /// data: Vec<u8>, // Suppose this buffer is often quite long... |
| /// } |
| /// |
| /// impl MyType { |
| /// // Suppose we don't want to print an entire kilobyte of `data` |
| /// // every time this is called... |
| /// #[instrument(skip(self))] |
| /// pub fn my_method(&mut self, an_interesting_argument: usize) { |
| /// // ... do something (hopefully, using all that `data`!) |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// # Adding Fields |
| /// |
| /// Additional fields (key-value pairs with arbitrary data) can be passed to |
| /// to the generated span through the `fields` argument on the |
| /// `#[instrument]` macro. Strings, integers or boolean literals are accepted values |
| /// for each field. The name of the field must be a single valid Rust |
| /// identifier, nested (dotted) field names are not supported. Any |
| /// Rust expression can be used as a field value in this manner. These |
| /// expressions will be evaluated at the beginning of the function's body, so |
| /// arguments to the function may be used in these expressions. Field names may |
| /// also be specified *without* values. Doing so will result in an [empty field] |
| /// whose value may be recorded later within the function body. |
| /// |
| /// Note that overlap between the names of fields and (non-skipped) arguments |
| /// will result in a compile error. |
| /// |
| /// ## Examples |
| /// |
| /// Adding a new field based on the value of an argument: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// |
| /// // This will record a field named "i" with the value of `i` *and* a field |
| /// // named "next" with the value of `i` + 1. |
| /// #[instrument(fields(next = i + 1))] |
| /// pub fn my_function(i: usize) { |
| /// // ... |
| /// } |
| /// ``` |
| /// |
| /// Recording specific properties of a struct as their own fields: |
| /// |
| /// ``` |
| /// # mod http { |
| /// # pub struct Error; |
| /// # pub struct Response<B> { pub(super) _b: std::marker::PhantomData<B> } |
| /// # pub struct Request<B> { _b: B } |
| /// # impl<B> std::fmt::Debug for Request<B> { |
| /// # fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| /// # f.pad("request") |
| /// # } |
| /// # } |
| /// # impl<B> Request<B> { |
| /// # pub fn uri(&self) -> &str { "fake" } |
| /// # pub fn method(&self) -> &str { "GET" } |
| /// # } |
| /// # } |
| /// # use tracing_attributes::instrument; |
| /// |
| /// // This will record the request's URI and HTTP method as their own separate |
| /// // fields. |
| /// #[instrument(fields(http.uri = req.uri(), http.method = req.method()))] |
| /// pub fn handle_request<B>(req: http::Request<B>) -> http::Response<B> { |
| /// // ... handle the request ... |
| /// # http::Response { _b: std::marker::PhantomData } |
| /// } |
| /// ``` |
| /// |
| /// This can be used in conjunction with `skip` or `skip_all` to record only |
| /// some fields of a struct: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// // Remember the struct with the very large `data` field from the earlier |
| /// // example? Now it also has a `name`, which we might want to include in |
| /// // our span. |
| /// #[derive(Debug)] |
| /// struct MyType { |
| /// name: &'static str, |
| /// data: Vec<u8>, |
| /// } |
| /// |
| /// impl MyType { |
| /// // This will skip the `data` field, but will include `self.name`, |
| /// // formatted using `fmt::Display`. |
| /// #[instrument(skip(self), fields(self.name = %self.name))] |
| /// pub fn my_method(&mut self, an_interesting_argument: usize) { |
| /// // ... do something (hopefully, using all that `data`!) |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// Adding an empty field to be recorded later: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// |
| /// // This function does a very interesting and important mathematical calculation. |
| /// // Suppose we want to record both the inputs to the calculation *and* its result... |
| /// #[instrument(fields(result))] |
| /// pub fn do_calculation(input_1: usize, input_2: usize) -> usize { |
| /// // Rerform the calculation. |
| /// let result = input_1 + input_2; |
| /// |
| /// // Record the result as part of the current span. |
| /// tracing::Span::current().record("result", &result); |
| /// |
| /// // Now, the result will also be included on this event! |
| /// tracing::info!("calculation complete!"); |
| /// |
| /// // ... etc ... |
| /// # 0 |
| /// } |
| /// ``` |
| /// |
| /// # Examples |
| /// |
| /// Instrumenting a function: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument] |
| /// pub fn my_function(my_arg: usize) { |
| /// // This event will be recorded inside a span named `my_function` with the |
| /// // field `my_arg`. |
| /// tracing::info!("inside my_function!"); |
| /// // ... |
| /// } |
| /// ``` |
| /// Setting the level for the generated span: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// # use tracing::Level; |
| /// #[instrument(level = Level::DEBUG)] |
| /// pub fn my_function() { |
| /// // ... |
| /// } |
| /// ``` |
| /// Levels can be specified either with [`Level`] constants, literal strings |
| /// (e.g., `"debug"`, `"info"`) or numerically (1—5, corresponding to [`Level::TRACE`]—[`Level::ERROR`]). |
| /// |
| /// Overriding the generated span's name: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(name = "my_name")] |
| /// pub fn my_function() { |
| /// // ... |
| /// } |
| /// ``` |
| /// Overriding the generated span's target: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(target = "my_target")] |
| /// pub fn my_function() { |
| /// // ... |
| /// } |
| /// ``` |
| /// Overriding the generated span's parent: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(parent = None)] |
| /// pub fn my_function() { |
| /// // ... |
| /// } |
| /// ``` |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// // A struct which owns a span handle. |
| /// struct MyStruct |
| /// { |
| /// span: tracing::Span |
| /// } |
| /// |
| /// impl MyStruct |
| /// { |
| /// // Use the struct's `span` field as the parent span |
| /// #[instrument(parent = &self.span, skip(self))] |
| /// fn my_method(&self) {} |
| /// } |
| /// ``` |
| /// Specifying [`follows_from`] relationships: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(follows_from = causes)] |
| /// pub fn my_function(causes: &[tracing::Id]) { |
| /// // ... |
| /// } |
| /// ``` |
| /// Any expression of type `impl IntoIterator<Item = impl Into<Option<Id>>>` |
| /// may be provided to `follows_from`; e.g.: |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(follows_from = [cause])] |
| /// pub fn my_function(cause: &tracing::span::EnteredSpan) { |
| /// // ... |
| /// } |
| /// ``` |
| /// |
| /// |
| /// To skip recording an argument, pass the argument's name to the `skip`: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// struct NonDebug; |
| /// |
| /// #[instrument(skip(non_debug))] |
| /// fn my_function(arg: usize, non_debug: NonDebug) { |
| /// // ... |
| /// } |
| /// ``` |
| /// |
| /// To add additional context to the span, pass key-value pairs to `fields`: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(fields(foo="bar", id=1, show=true))] |
| /// fn my_function(arg: usize) { |
| /// // ... |
| /// } |
| /// ``` |
| /// |
| /// Adding the `ret` argument to `#[instrument]` will emit an event with the function's |
| /// return value when the function returns: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(ret)] |
| /// fn my_function() -> i32 { |
| /// 42 |
| /// } |
| /// ``` |
| /// The return value event will have the same level as the span generated by `#[instrument]`. |
| /// By default, this will be [`INFO`], but if the level is overridden, the event will be at the same |
| /// level. |
| /// |
| /// It's also possible to override the level for the `ret` event independently: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// # use tracing::Level; |
| /// #[instrument(ret(level = Level::WARN))] |
| /// fn my_function() -> i32 { |
| /// 42 |
| /// } |
| /// ``` |
| /// |
| /// **Note**: if the function returns a `Result<T, E>`, `ret` will record returned values if and |
| /// only if the function returns [`Result::Ok`]. |
| /// |
| /// By default, returned values will be recorded using their [`std::fmt::Debug`] implementations. |
| /// If a returned value implements [`std::fmt::Display`], it can be recorded using its `Display` |
| /// implementation instead, by writing `ret(Display)`: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(ret(Display))] |
| /// fn my_function() -> i32 { |
| /// 42 |
| /// } |
| /// ``` |
| /// |
| /// If the function returns a `Result<T, E>` and `E` implements `std::fmt::Display`, adding |
| /// `err` or `err(Display)` will emit error events when the function returns `Err`: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(err)] |
| /// fn my_function(arg: usize) -> Result<(), std::io::Error> { |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// The level of the error value event defaults to `ERROR`. |
| /// |
| /// Similarly, overriding the level of the `err` event : |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// # use tracing::Level; |
| /// #[instrument(err(level = Level::INFO))] |
| /// fn my_function(arg: usize) -> Result<(), std::io::Error> { |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// By default, error values will be recorded using their `std::fmt::Display` implementations. |
| /// If an error implements `std::fmt::Debug`, it can be recorded using its `Debug` implementation |
| /// instead by writing `err(Debug)`: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(err(Debug))] |
| /// fn my_function(arg: usize) -> Result<(), std::io::Error> { |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// If a `target` is specified, both the `ret` and `err` arguments will emit outputs to |
| /// the declared target (or the default channel if `target` is not specified). |
| /// |
| /// The `ret` and `err` arguments can be combined in order to record an event if a |
| /// function returns [`Result::Ok`] or [`Result::Err`]: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument(err, ret)] |
| /// fn my_function(arg: usize) -> Result<(), std::io::Error> { |
| /// Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// `async fn`s may also be instrumented: |
| /// |
| /// ``` |
| /// # use tracing_attributes::instrument; |
| /// #[instrument] |
| /// pub async fn my_function() -> Result<(), ()> { |
| /// // ... |
| /// # Ok(()) |
| /// } |
| /// ``` |
| /// |
| /// It also works with [async-trait](https://crates.io/crates/async-trait) |
| /// (a crate that allows defining async functions in traits, |
| /// something not currently possible in Rust), |
| /// and hopefully most libraries that exhibit similar behaviors: |
| /// |
| /// ``` |
| /// # use tracing::instrument; |
| /// use async_trait::async_trait; |
| /// |
| /// #[async_trait] |
| /// pub trait Foo { |
| /// async fn foo(&self, arg: usize); |
| /// } |
| /// |
| /// #[derive(Debug)] |
| /// struct FooImpl(usize); |
| /// |
| /// #[async_trait] |
| /// impl Foo for FooImpl { |
| /// #[instrument(fields(value = self.0, tmp = std::any::type_name::<Self>()))] |
| /// async fn foo(&self, arg: usize) {} |
| /// } |
| /// ``` |
| /// |
| /// `const fn` cannot be instrumented, and will result in a compilation failure: |
| /// |
| /// ```compile_fail |
| /// # use tracing_attributes::instrument; |
| /// #[instrument] |
| /// const fn my_const_function() {} |
| /// ``` |
| /// |
| /// [span]: https://docs.rs/tracing/latest/tracing/span/index.html |
| /// [name]: https://docs.rs/tracing/latest/tracing/struct.Metadata.html#method.name |
| /// [target]: https://docs.rs/tracing/latest/tracing/struct.Metadata.html#method.target |
| /// [level]: https://docs.rs/tracing/latest/tracing/struct.Level.html |
| /// [module path]: https://docs.rs/tracing/latest/tracing/struct.Metadata.html#method.module_path |
| /// [`INFO`]: https://docs.rs/tracing/latest/tracing/struct.Level.html#associatedconstant.INFO |
| /// [empty field]: https://docs.rs/tracing/latest/tracing/field/struct.Empty.html |
| /// [field syntax]: https://docs.rs/tracing/latest/tracing/#recording-fields |
| /// [`follows_from`]: https://docs.rs/tracing/latest/tracing/struct.Span.html#method.follows_from |
| /// [`tracing`]: https://github.com/tokio-rs/tracing |
| /// [`fmt::Debug`]: std::fmt::Debug |
| /// [`Level`]: https://docs.rs/tracing/latest/tracing/struct.Level.html |
| /// [`Level::TRACE`]: https://docs.rs/tracing/latest/tracing/struct.Level.html#associatedconstant.TRACE |
| /// [`Level::ERROR`]: https://docs.rs/tracing/latest/tracing/struct.Level.html#associatedconstant.ERROR |
| </span><span class="attribute">#[proc_macro_attribute] |
| </span><span class="kw">pub fn </span>instrument( |
| args: proc_macro::TokenStream, |
| item: proc_macro::TokenStream, |
| ) -> proc_macro::TokenStream { |
| <span class="kw">let </span>args = <span class="macro">syn::parse_macro_input!</span>(args <span class="kw">as </span>attr::InstrumentArgs); |
| <span class="comment">// Cloning a `TokenStream` is cheap since it's reference counted internally. |
| </span>instrument_precise(args.clone(), item.clone()) |
| .unwrap_or_else(|_err| instrument_speculative(args, item)) |
| } |
| |
| <span class="doccomment">/// Instrument the function, without parsing the function body (instead using the raw tokens). |
| </span><span class="kw">fn </span>instrument_speculative( |
| args: attr::InstrumentArgs, |
| item: proc_macro::TokenStream, |
| ) -> proc_macro::TokenStream { |
| <span class="kw">let </span>input = <span class="macro">syn::parse_macro_input!</span>(item <span class="kw">as </span>MaybeItemFn); |
| <span class="kw">let </span>instrumented_function_name = input.sig.ident.to_string(); |
| expand::gen_function( |
| input.as_ref(), |
| args, |
| instrumented_function_name.as_str(), |
| <span class="prelude-val">None</span>, |
| ) |
| .into() |
| } |
| |
| <span class="doccomment">/// Instrument the function, by fully parsing the function body, |
| /// which allows us to rewrite some statements related to async-like patterns. |
| </span><span class="kw">fn </span>instrument_precise( |
| args: attr::InstrumentArgs, |
| item: proc_macro::TokenStream, |
| ) -> <span class="prelude-ty">Result</span><proc_macro::TokenStream, syn::Error> { |
| <span class="kw">let </span>input = syn::parse::<ItemFn>(item)<span class="question-mark">?</span>; |
| <span class="kw">let </span>instrumented_function_name = input.sig.ident.to_string(); |
| |
| <span class="kw">if </span>input.sig.constness.is_some() { |
| <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="macro">quote! </span>{ |
| <span class="macro">compile_error!</span>(<span class="string">"the `#[instrument]` attribute may not be used with `const fn`s"</span>) |
| } |
| .into()); |
| } |
| |
| <span class="comment">// check for async_trait-like patterns in the block, and instrument |
| // the future instead of the wrapper |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(async_like) = expand::AsyncInfo::from_fn(<span class="kw-2">&</span>input) { |
| <span class="kw">return </span>async_like.gen_async(args, instrumented_function_name.as_str()); |
| } |
| |
| <span class="kw">let </span>input = MaybeItemFn::from(input); |
| |
| <span class="prelude-val">Ok</span>(expand::gen_function( |
| input.as_ref(), |
| args, |
| instrumented_function_name.as_str(), |
| <span class="prelude-val">None</span>, |
| ) |
| .into()) |
| } |
| |
| <span class="doccomment">/// This is a more flexible/imprecise `ItemFn` type, |
| /// which's block is just a `TokenStream` (it may contain invalid code). |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">struct </span>MaybeItemFn { |
| outer_attrs: Vec<Attribute>, |
| inner_attrs: Vec<Attribute>, |
| vis: Visibility, |
| sig: Signature, |
| block: TokenStream, |
| } |
| |
| <span class="kw">impl </span>MaybeItemFn { |
| <span class="kw">fn </span>as_ref(<span class="kw-2">&</span><span class="self">self</span>) -> MaybeItemFnRef<<span class="lifetime">'_</span>, TokenStream> { |
| MaybeItemFnRef { |
| outer_attrs: <span class="kw-2">&</span><span class="self">self</span>.outer_attrs, |
| inner_attrs: <span class="kw-2">&</span><span class="self">self</span>.inner_attrs, |
| vis: <span class="kw-2">&</span><span class="self">self</span>.vis, |
| sig: <span class="kw-2">&</span><span class="self">self</span>.sig, |
| block: <span class="kw-2">&</span><span class="self">self</span>.block, |
| } |
| } |
| } |
| |
| <span class="doccomment">/// This parses a `TokenStream` into a `MaybeItemFn` |
| /// (just like `ItemFn`, but skips parsing the body). |
| </span><span class="kw">impl </span>Parse <span class="kw">for </span>MaybeItemFn { |
| <span class="kw">fn </span>parse(input: ParseStream<<span class="lifetime">'_</span>>) -> syn::Result<<span class="self">Self</span>> { |
| <span class="kw">let </span>outer_attrs = input.call(Attribute::parse_outer)<span class="question-mark">?</span>; |
| <span class="kw">let </span>vis: Visibility = input.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>sig: Signature = input.parse()<span class="question-mark">?</span>; |
| <span class="kw">let </span>inner_attrs = input.call(Attribute::parse_inner)<span class="question-mark">?</span>; |
| <span class="kw">let </span>block: TokenStream = input.parse()<span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(<span class="self">Self </span>{ |
| outer_attrs, |
| inner_attrs, |
| vis, |
| sig, |
| block, |
| }) |
| } |
| } |
| |
| <span class="kw">impl </span>From<ItemFn> <span class="kw">for </span>MaybeItemFn { |
| <span class="kw">fn </span>from( |
| ItemFn { |
| attrs, |
| vis, |
| sig, |
| block, |
| }: ItemFn, |
| ) -> <span class="self">Self </span>{ |
| <span class="kw">let </span>(outer_attrs, inner_attrs) = attrs |
| .into_iter() |
| .partition(|attr| attr.style == syn::AttrStyle::Outer); |
| <span class="self">Self </span>{ |
| outer_attrs, |
| inner_attrs, |
| vis, |
| sig, |
| block: block.to_token_stream(), |
| } |
| } |
| } |
| |
| <span class="doccomment">/// A generic reference type for `MaybeItemFn`, |
| /// that takes a generic block type `B` that implements `ToTokens` (eg. `TokenStream`, `Block`). |
| </span><span class="attribute">#[derive(Debug, Clone)] |
| </span><span class="kw">struct </span>MaybeItemFnRef<<span class="lifetime">'a</span>, B: ToTokens> { |
| outer_attrs: <span class="kw-2">&</span><span class="lifetime">'a </span>Vec<Attribute>, |
| inner_attrs: <span class="kw-2">&</span><span class="lifetime">'a </span>Vec<Attribute>, |
| vis: <span class="kw-2">&</span><span class="lifetime">'a </span>Visibility, |
| sig: <span class="kw-2">&</span><span class="lifetime">'a </span>Signature, |
| block: <span class="kw-2">&</span><span class="lifetime">'a </span>B, |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="tracing_attributes" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
