| <!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/prost-derive-0.9.0/src/field/oneof.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>oneof.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="../../../prost_derive/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="../../../prost_derive/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> |
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| </pre><pre class="rust"><code><span class="kw">use </span>anyhow::{bail, Error}; |
| <span class="kw">use </span>proc_macro2::TokenStream; |
| <span class="kw">use </span>quote::quote; |
| <span class="kw">use </span>syn::{parse_str, Lit, Meta, MetaNameValue, NestedMeta, Path}; |
| |
| <span class="kw">use </span><span class="kw">crate</span>::field::{set_option, tags_attr}; |
| |
| <span class="attribute">#[derive(Clone)] |
| </span><span class="kw">pub struct </span>Field { |
| <span class="kw">pub </span>ty: Path, |
| <span class="kw">pub </span>tags: Vec<u32>, |
| } |
| |
| <span class="kw">impl </span>Field { |
| <span class="kw">pub fn </span>new(attrs: <span class="kw-2">&</span>[Meta]) -> <span class="prelude-ty">Result</span><<span class="prelude-ty">Option</span><Field>, Error> { |
| <span class="kw">let </span><span class="kw-2">mut </span>ty = <span class="prelude-val">None</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>tags = <span class="prelude-val">None</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>unknown_attrs = Vec::new(); |
| |
| <span class="kw">for </span>attr <span class="kw">in </span>attrs { |
| <span class="kw">if </span>attr.path().is_ident(<span class="string">"oneof"</span>) { |
| <span class="kw">let </span>t = <span class="kw">match </span><span class="kw-2">*</span>attr { |
| Meta::NameValue(MetaNameValue { |
| lit: Lit::Str(<span class="kw-2">ref </span>lit), |
| .. |
| }) => parse_str::<Path>(<span class="kw-2">&</span>lit.value())<span class="question-mark">?</span>, |
| Meta::List(<span class="kw-2">ref </span>list) <span class="kw">if </span>list.nested.len() == <span class="number">1 </span>=> { |
| <span class="comment">// TODO(rustlang/rust#23121): slice pattern matching would make this much nicer. |
| </span><span class="kw">if let </span>NestedMeta::Meta(Meta::Path(<span class="kw-2">ref </span>path)) = list.nested[<span class="number">0</span>] { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(ident) = path.get_ident() { |
| Path::from(ident.clone()) |
| } <span class="kw">else </span>{ |
| <span class="macro">bail!</span>(<span class="string">"invalid oneof attribute: item must be an identifier"</span>); |
| } |
| } <span class="kw">else </span>{ |
| <span class="macro">bail!</span>(<span class="string">"invalid oneof attribute: item must be an identifier"</span>); |
| } |
| } |
| <span class="kw">_ </span>=> <span class="macro">bail!</span>(<span class="string">"invalid oneof attribute: {:?}"</span>, attr), |
| }; |
| set_option(<span class="kw-2">&mut </span>ty, t, <span class="string">"duplicate oneof attribute"</span>)<span class="question-mark">?</span>; |
| } <span class="kw">else if let </span><span class="prelude-val">Some</span>(t) = tags_attr(attr)<span class="question-mark">? </span>{ |
| set_option(<span class="kw-2">&mut </span>tags, t, <span class="string">"duplicate tags attributes"</span>)<span class="question-mark">?</span>; |
| } <span class="kw">else </span>{ |
| unknown_attrs.push(attr); |
| } |
| } |
| |
| <span class="kw">let </span>ty = <span class="kw">match </span>ty { |
| <span class="prelude-val">Some</span>(ty) => ty, |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">Ok</span>(<span class="prelude-val">None</span>), |
| }; |
| |
| <span class="kw">match </span>unknown_attrs.len() { |
| <span class="number">0 </span>=> (), |
| <span class="number">1 </span>=> <span class="macro">bail!</span>( |
| <span class="string">"unknown attribute for message field: {:?}"</span>, |
| unknown_attrs[<span class="number">0</span>] |
| ), |
| <span class="kw">_ </span>=> <span class="macro">bail!</span>(<span class="string">"unknown attributes for message field: {:?}"</span>, unknown_attrs), |
| } |
| |
| <span class="kw">let </span>tags = <span class="kw">match </span>tags { |
| <span class="prelude-val">Some</span>(tags) => tags, |
| <span class="prelude-val">None </span>=> <span class="macro">bail!</span>(<span class="string">"oneof field is missing a tags attribute"</span>), |
| }; |
| |
| <span class="prelude-val">Ok</span>(<span class="prelude-val">Some</span>(Field { ty, tags })) |
| } |
| |
| <span class="doccomment">/// Returns a statement which encodes the oneof field. |
| </span><span class="kw">pub fn </span>encode(<span class="kw-2">&</span><span class="self">self</span>, ident: TokenStream) -> TokenStream { |
| <span class="macro">quote! </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(<span class="kw-2">ref </span>oneof) = #ident { |
| oneof.encode(buf) |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Returns an expression which evaluates to the result of decoding the oneof field. |
| </span><span class="kw">pub fn </span>merge(<span class="kw-2">&</span><span class="self">self</span>, ident: TokenStream) -> TokenStream { |
| <span class="kw">let </span>ty = <span class="kw-2">&</span><span class="self">self</span>.ty; |
| <span class="macro">quote! </span>{ |
| #ty::merge(#ident, tag, wire_type, buf, ctx) |
| } |
| } |
| |
| <span class="doccomment">/// Returns an expression which evaluates to the encoded length of the oneof field. |
| </span><span class="kw">pub fn </span>encoded_len(<span class="kw-2">&</span><span class="self">self</span>, ident: TokenStream) -> TokenStream { |
| <span class="kw">let </span>ty = <span class="kw-2">&</span><span class="self">self</span>.ty; |
| <span class="macro">quote! </span>{ |
| #ident.as_ref().map_or(<span class="number">0</span>, #ty::encoded_len) |
| } |
| } |
| |
| <span class="kw">pub fn </span>clear(<span class="kw-2">&</span><span class="self">self</span>, ident: TokenStream) -> TokenStream { |
| <span class="macro">quote!</span>(#ident = ::core::option::Option::None) |
| } |
| } |
| </code></pre></div> |
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