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class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer"></div><main><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">proc_macro2/</div>extra.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap"><div data-nosnippet><pre class="src-line-numbers"> <a href="#1" id="1">1</a> <a href="#2" id="2">2</a> <a href="#3" id="3">3</a> <a href="#4" id="4">4</a> <a href="#5" id="5">5</a> <a href="#6" id="6">6</a> <a href="#7" id="7">7</a> <a href="#8" id="8">8</a> <a href="#9" id="9">9</a> <a href="#10" id="10">10</a> <a href="#11" id="11">11</a> <a href="#12" id="12">12</a> <a href="#13" id="13">13</a> <a href="#14" id="14">14</a> <a href="#15" id="15">15</a> <a href="#16" id="16">16</a> <a href="#17" id="17">17</a> <a href="#18" id="18">18</a> <a href="#19" id="19">19</a> <a href="#20" id="20">20</a> <a href="#21" id="21">21</a> <a href="#22" id="22">22</a> <a href="#23" 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Items which do not have a correspondence to any API in the proc_macro crate, //! but are necessary to include in proc-macro2. </span><span class="kw">use </span><span class="kw">crate</span>::fallback; <span class="kw">use </span><span class="kw">crate</span>::imp; <span class="kw">use </span><span class="kw">crate</span>::marker::{ProcMacroAutoTraits, MARKER}; <span class="kw">use </span><span class="kw">crate</span>::Span; <span class="kw">use </span>core::fmt::{<span class="self">self</span>, Debug}; <span class="doccomment">/// Invalidate any `proc_macro2::Span` that exist on the current thread. /// /// The implementation of `Span` uses thread-local data structures and this /// function clears them. Calling any method on a `Span` on the current thread /// created prior to the invalidation will return incorrect values or crash. /// /// This function is useful for programs that process more than 2<sup>32</sup> /// bytes of Rust source code on the same thread. Just like rustc, proc-macro2 /// uses 32-bit source locations, and these wrap around when the total source /// code processed by the same thread exceeds 2<sup>32</sup> bytes (4 /// gigabytes). After a wraparound, `Span` methods such as `source_text()` can /// return wrong data. /// /// # Example /// /// As of late 2023, there is 200 GB of Rust code published on crates.io. /// Looking at just the newest version of every crate, it is 16 GB of code. So a /// workload that involves parsing it all would overflow a 32-bit source /// location unless spans are being invalidated. /// /// ``` /// use flate2::read::GzDecoder; /// use std::ffi::OsStr; /// use std::io::{BufReader, Read}; /// use std::str::FromStr; /// use tar::Archive; /// /// rayon::scope(|s| { /// for krate in every_version_of_every_crate() { /// s.spawn(move |_| { /// proc_macro2::extra::invalidate_current_thread_spans(); /// /// let reader = BufReader::new(krate); /// let tar = GzDecoder::new(reader); /// let mut archive = Archive::new(tar); /// for entry in archive.entries().unwrap() { /// let mut entry = entry.unwrap(); /// let path = entry.path().unwrap(); /// if path.extension() != Some(OsStr::new("rs")) { /// continue; /// } /// let mut content = String::new(); /// entry.read_to_string(&mut content).unwrap(); /// match proc_macro2::TokenStream::from_str(&content) { /// Ok(tokens) => {/* ... */}, /// Err(_) => continue, /// } /// } /// }); /// } /// }); /// # /// # fn every_version_of_every_crate() -> Vec<std::fs::File> { /// # Vec::new() /// # } /// ``` /// /// # Panics /// /// This function is not applicable to and will panic if called from a /// procedural macro. </span><span class="attr">#[cfg(span_locations)] #[cfg_attr(docsrs, doc(cfg(feature = <span class="string">"span-locations"</span>)))] </span><span class="kw">pub fn </span>invalidate_current_thread_spans() { <span class="kw">crate</span>::imp::invalidate_current_thread_spans(); } <span class="doccomment">/// An object that holds a [`Group`]'s `span_open()` and `span_close()` together /// in a more compact representation than holding those 2 spans individually. /// /// [`Group`]: crate::Group </span><span class="attr">#[derive(Copy, Clone)] </span><span class="kw">pub struct </span>DelimSpan { inner: DelimSpanEnum, _marker: ProcMacroAutoTraits, } <span class="attr">#[derive(Copy, Clone)] </span><span class="kw">enum </span>DelimSpanEnum { <span class="attr">#[cfg(wrap_proc_macro)] </span>Compiler { join: proc_macro::Span, open: proc_macro::Span, close: proc_macro::Span, }, Fallback(fallback::Span), } <span class="kw">impl </span>DelimSpan { <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new(group: <span class="kw-2">&</span>imp::Group) -> <span class="self">Self </span>{ <span class="attr">#[cfg(wrap_proc_macro)] </span><span class="kw">let </span>inner = <span class="kw">match </span>group { imp::Group::Compiler(group) => DelimSpanEnum::Compiler { join: group.span(), open: group.span_open(), close: group.span_close(), }, imp::Group::Fallback(group) => DelimSpanEnum::Fallback(group.span()), }; <span class="attr">#[cfg(not(wrap_proc_macro))] </span><span class="kw">let </span>inner = DelimSpanEnum::Fallback(group.span()); DelimSpan { inner, _marker: MARKER, } } <span class="doccomment">/// Returns a span covering the entire delimited group. </span><span class="kw">pub fn </span>join(<span class="kw-2">&</span><span class="self">self</span>) -> Span { <span class="kw">match </span><span class="kw-2">&</span><span class="self">self</span>.inner { <span class="attr">#[cfg(wrap_proc_macro)] </span>DelimSpanEnum::Compiler { join, .. } => Span::_new(imp::Span::Compiler(<span class="kw-2">*</span>join)), DelimSpanEnum::Fallback(span) => Span::_new_fallback(<span class="kw-2">*</span>span), } } <span class="doccomment">/// Returns a span for the opening punctuation of the group only. </span><span class="kw">pub fn </span>open(<span class="kw-2">&</span><span class="self">self</span>) -> Span { <span class="kw">match </span><span class="kw-2">&</span><span class="self">self</span>.inner { <span class="attr">#[cfg(wrap_proc_macro)] </span>DelimSpanEnum::Compiler { open, .. } => Span::_new(imp::Span::Compiler(<span class="kw-2">*</span>open)), DelimSpanEnum::Fallback(span) => Span::_new_fallback(span.first_byte()), } } <span class="doccomment">/// Returns a span for the closing punctuation of the group only. </span><span class="kw">pub fn </span>close(<span class="kw-2">&</span><span class="self">self</span>) -> Span { <span class="kw">match </span><span class="kw-2">&</span><span class="self">self</span>.inner { <span class="attr">#[cfg(wrap_proc_macro)] </span>DelimSpanEnum::Compiler { close, .. } => Span::_new(imp::Span::Compiler(<span class="kw-2">*</span>close)), DelimSpanEnum::Fallback(span) => Span::_new_fallback(span.last_byte()), } } } <span class="kw">impl </span>Debug <span class="kw">for </span>DelimSpan { <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, f: <span class="kw-2">&mut </span>fmt::Formatter) -> fmt::Result { Debug::fmt(<span class="kw-2">&</span><span class="self">self</span>.join(), f) } } </code></pre></div></section></main></body></html>