| <!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-core-0.1.31/src/span.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>span.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_core/index.html"><div class="logo-container"> |
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| </pre><pre class="rust"><code><span class="doccomment">//! Spans represent periods of time in the execution of a program. |
| </span><span class="kw">use </span><span class="kw">crate</span>::field::FieldSet; |
| <span class="kw">use </span><span class="kw">crate</span>::parent::Parent; |
| <span class="kw">use </span><span class="kw">crate</span>::stdlib::num::NonZeroU64; |
| <span class="kw">use crate</span>::{field, Metadata}; |
| |
| <span class="doccomment">/// Identifies a span within the context of a subscriber. |
| /// |
| /// They are generated by [`Subscriber`]s for each span as it is created, by |
| /// the [`new_span`] trait method. See the documentation for that method for |
| /// more information on span ID generation. |
| /// |
| /// [`Subscriber`]: super::subscriber::Subscriber |
| /// [`new_span`]: super::subscriber::Subscriber::new_span |
| </span><span class="attribute">#[derive(Clone, Debug, PartialEq, Eq, Hash)] |
| </span><span class="kw">pub struct </span>Id(NonZeroU64); |
| |
| <span class="doccomment">/// Attributes provided to a `Subscriber` describing a new span when it is |
| /// created. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>Attributes<<span class="lifetime">'a</span>> { |
| metadata: <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>, |
| values: <span class="kw-2">&</span><span class="lifetime">'a </span>field::ValueSet<<span class="lifetime">'a</span>>, |
| parent: Parent, |
| } |
| |
| <span class="doccomment">/// A set of fields recorded by a span. |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>Record<<span class="lifetime">'a</span>> { |
| values: <span class="kw-2">&</span><span class="lifetime">'a </span>field::ValueSet<<span class="lifetime">'a</span>>, |
| } |
| |
| <span class="doccomment">/// Indicates what [the `Subscriber` considers] the "current" span. |
| /// |
| /// As subscribers may not track a notion of a current span, this has three |
| /// possible states: |
| /// - "unknown", indicating that the subscriber does not track a current span, |
| /// - "none", indicating that the current context is known to not be in a span, |
| /// - "some", with the current span's [`Id`] and [`Metadata`]. |
| /// |
| /// [the `Subscriber` considers]: super::subscriber::Subscriber::current_span |
| /// [`Metadata`]: super::metadata::Metadata |
| </span><span class="attribute">#[derive(Debug)] |
| </span><span class="kw">pub struct </span>Current { |
| inner: CurrentInner, |
| } |
| |
| <span class="attribute">#[derive(Debug)] |
| </span><span class="kw">enum </span>CurrentInner { |
| Current { |
| id: Id, |
| metadata: <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>, |
| }, |
| <span class="prelude-val">None</span>, |
| Unknown, |
| } |
| |
| <span class="comment">// ===== impl Span ===== |
| |
| </span><span class="kw">impl </span>Id { |
| <span class="doccomment">/// Constructs a new span ID from the given `u64`. |
| /// |
| /// <pre class="ignore" style="white-space:normal;font:inherit;"> |
| /// <strong>Note</strong>: Span IDs must be greater than zero. |
| /// </pre> |
| /// |
| /// # Panics |
| /// - If the provided `u64` is 0. |
| </span><span class="kw">pub fn </span>from_u64(u: u64) -> <span class="self">Self </span>{ |
| Id(NonZeroU64::new(u).expect(<span class="string">"span IDs must be > 0"</span>)) |
| } |
| |
| <span class="doccomment">/// Constructs a new span ID from the given `NonZeroU64`. |
| /// |
| /// Unlike [`Id::from_u64`](Id::from_u64()), this will never panic. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub const fn </span>from_non_zero_u64(id: NonZeroU64) -> <span class="self">Self </span>{ |
| Id(id) |
| } |
| |
| <span class="comment">// Allow `into` by-ref since we don't want to impl Copy for Id |
| </span><span class="attribute">#[allow(clippy::wrong_self_convention)] |
| </span><span class="doccomment">/// Returns the span's ID as a `u64`. |
| </span><span class="kw">pub fn </span>into_u64(<span class="kw-2">&</span><span class="self">self</span>) -> u64 { |
| <span class="self">self</span>.<span class="number">0</span>.get() |
| } |
| |
| <span class="comment">// Allow `into` by-ref since we don't want to impl Copy for Id |
| </span><span class="attribute">#[allow(clippy::wrong_self_convention)] |
| </span><span class="doccomment">/// Returns the span's ID as a `NonZeroU64`. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub const fn </span>into_non_zero_u64(<span class="kw-2">&</span><span class="self">self</span>) -> NonZeroU64 { |
| <span class="self">self</span>.<span class="number">0 |
| </span>} |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> From<<span class="kw-2">&</span><span class="lifetime">'a </span>Id> <span class="kw">for </span><span class="prelude-ty">Option</span><Id> { |
| <span class="kw">fn </span>from(id: <span class="kw-2">&</span><span class="lifetime">'a </span>Id) -> <span class="self">Self </span>{ |
| <span class="prelude-val">Some</span>(id.clone()) |
| } |
| } |
| |
| <span class="comment">// ===== impl Attributes ===== |
| |
| </span><span class="kw">impl</span><<span class="lifetime">'a</span>> Attributes<<span class="lifetime">'a</span>> { |
| <span class="doccomment">/// Returns `Attributes` describing a new child span of the current span, |
| /// with the provided metadata and values. |
| </span><span class="kw">pub fn </span>new(metadata: <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>, values: <span class="kw-2">&</span><span class="lifetime">'a </span>field::ValueSet<<span class="lifetime">'a</span>>) -> <span class="self">Self </span>{ |
| Attributes { |
| metadata, |
| values, |
| parent: Parent::Current, |
| } |
| } |
| |
| <span class="doccomment">/// Returns `Attributes` describing a new span at the root of its own trace |
| /// tree, with the provided metadata and values. |
| </span><span class="kw">pub fn </span>new_root(metadata: <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>, values: <span class="kw-2">&</span><span class="lifetime">'a </span>field::ValueSet<<span class="lifetime">'a</span>>) -> <span class="self">Self </span>{ |
| Attributes { |
| metadata, |
| values, |
| parent: Parent::Root, |
| } |
| } |
| |
| <span class="doccomment">/// Returns `Attributes` describing a new child span of the specified |
| /// parent span, with the provided metadata and values. |
| </span><span class="kw">pub fn </span>child_of( |
| parent: Id, |
| metadata: <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>, |
| values: <span class="kw-2">&</span><span class="lifetime">'a </span>field::ValueSet<<span class="lifetime">'a</span>>, |
| ) -> <span class="self">Self </span>{ |
| Attributes { |
| metadata, |
| values, |
| parent: Parent::Explicit(parent), |
| } |
| } |
| |
| <span class="doccomment">/// Returns a reference to the new span's metadata. |
| </span><span class="kw">pub fn </span>metadata(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>> { |
| <span class="self">self</span>.metadata |
| } |
| |
| <span class="doccomment">/// Returns a reference to a `ValueSet` containing any values the new span |
| /// was created with. |
| </span><span class="kw">pub fn </span>values(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>field::ValueSet<<span class="lifetime">'a</span>> { |
| <span class="self">self</span>.values |
| } |
| |
| <span class="doccomment">/// Returns true if the new span should be a root. |
| </span><span class="kw">pub fn </span>is_root(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="macro">matches!</span>(<span class="self">self</span>.parent, Parent::Root) |
| } |
| |
| <span class="doccomment">/// Returns true if the new span's parent should be determined based on the |
| /// current context. |
| /// |
| /// If this is true and the current thread is currently inside a span, then |
| /// that span should be the new span's parent. Otherwise, if the current |
| /// thread is _not_ inside a span, then the new span will be the root of its |
| /// own trace tree. |
| </span><span class="kw">pub fn </span>is_contextual(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="macro">matches!</span>(<span class="self">self</span>.parent, Parent::Current) |
| } |
| |
| <span class="doccomment">/// Returns the new span's explicitly-specified parent, if there is one. |
| /// |
| /// Otherwise (if the new span is a root or is a child of the current span), |
| /// returns `None`. |
| </span><span class="kw">pub fn </span>parent(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>Id> { |
| <span class="kw">match </span><span class="self">self</span>.parent { |
| Parent::Explicit(<span class="kw-2">ref </span>p) => <span class="prelude-val">Some</span>(p), |
| <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Records all the fields in this set of `Attributes` with the provided |
| /// [Visitor]. |
| /// |
| /// [visitor]: super::field::Visit |
| </span><span class="kw">pub fn </span>record(<span class="kw-2">&</span><span class="self">self</span>, visitor: <span class="kw-2">&mut </span><span class="kw">dyn </span>field::Visit) { |
| <span class="self">self</span>.values.record(visitor) |
| } |
| |
| <span class="doccomment">/// Returns `true` if this set of `Attributes` contains a value for the |
| /// given `Field`. |
| </span><span class="kw">pub fn </span>contains(<span class="kw-2">&</span><span class="self">self</span>, field: <span class="kw-2">&</span>field::Field) -> bool { |
| <span class="self">self</span>.values.contains(field) |
| } |
| |
| <span class="doccomment">/// Returns true if this set of `Attributes` contains _no_ values. |
| </span><span class="kw">pub fn </span>is_empty(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.values.is_empty() |
| } |
| |
| <span class="doccomment">/// Returns the set of all [fields] defined by this span's [`Metadata`]. |
| /// |
| /// Note that the [`FieldSet`] returned by this method includes *all* the |
| /// fields declared by this span, not just those with values that are recorded |
| /// as part of this set of `Attributes`. Other fields with values not present in |
| /// this `Attributes`' value set may [record] values later. |
| /// |
| /// [fields]: crate::field |
| /// [record]: Attributes::record() |
| /// [`Metadata`]: crate::metadata::Metadata |
| /// [`FieldSet`]: crate::field::FieldSet |
| </span><span class="kw">pub fn </span>fields(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>FieldSet { |
| <span class="self">self</span>.values.field_set() |
| } |
| } |
| |
| <span class="comment">// ===== impl Record ===== |
| |
| </span><span class="kw">impl</span><<span class="lifetime">'a</span>> Record<<span class="lifetime">'a</span>> { |
| <span class="doccomment">/// Constructs a new `Record` from a `ValueSet`. |
| </span><span class="kw">pub fn </span>new(values: <span class="kw-2">&</span><span class="lifetime">'a </span>field::ValueSet<<span class="lifetime">'a</span>>) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ values } |
| } |
| |
| <span class="doccomment">/// Records all the fields in this `Record` with the provided [Visitor]. |
| /// |
| /// [visitor]: super::field::Visit |
| </span><span class="kw">pub fn </span>record(<span class="kw-2">&</span><span class="self">self</span>, visitor: <span class="kw-2">&mut </span><span class="kw">dyn </span>field::Visit) { |
| <span class="self">self</span>.values.record(visitor) |
| } |
| |
| <span class="doccomment">/// Returns the number of fields that would be visited from this `Record` |
| /// when [`Record::record()`] is called |
| /// |
| /// [`Record::record()`]: Record::record() |
| </span><span class="kw">pub fn </span>len(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.values.len() |
| } |
| |
| <span class="doccomment">/// Returns `true` if this `Record` contains a value for the given `Field`. |
| </span><span class="kw">pub fn </span>contains(<span class="kw-2">&</span><span class="self">self</span>, field: <span class="kw-2">&</span>field::Field) -> bool { |
| <span class="self">self</span>.values.contains(field) |
| } |
| |
| <span class="doccomment">/// Returns true if this `Record` contains _no_ values. |
| </span><span class="kw">pub fn </span>is_empty(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.values.is_empty() |
| } |
| } |
| |
| <span class="comment">// ===== impl Current ===== |
| |
| </span><span class="kw">impl </span>Current { |
| <span class="doccomment">/// Constructs a new `Current` that indicates the current context is a span |
| /// with the given `metadata` and `metadata`. |
| </span><span class="kw">pub fn </span>new(id: Id, metadata: <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>) -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| inner: CurrentInner::Current { id, metadata }, |
| } |
| } |
| |
| <span class="doccomment">/// Constructs a new `Current` that indicates the current context is *not* |
| /// in a span. |
| </span><span class="kw">pub fn </span>none() -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| inner: CurrentInner::None, |
| } |
| } |
| |
| <span class="doccomment">/// Constructs a new `Current` that indicates the `Subscriber` does not |
| /// track a current span. |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>unknown() -> <span class="self">Self </span>{ |
| <span class="self">Self </span>{ |
| inner: CurrentInner::Unknown, |
| } |
| } |
| |
| <span class="doccomment">/// Returns `true` if the `Subscriber` that constructed this `Current` tracks a |
| /// current span. |
| /// |
| /// If this returns `true` and [`id`], [`metadata`], or [`into_inner`] |
| /// return `None`, that indicates that we are currently known to *not* be |
| /// inside a span. If this returns `false`, those methods will also return |
| /// `None`, but in this case, that is because the subscriber does not keep |
| /// track of the currently-entered span. |
| /// |
| /// [`id`]: Current::id() |
| /// [`metadata`]: Current::metadata() |
| /// [`into_inner`]: Current::into_inner() |
| </span><span class="kw">pub fn </span>is_known(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| !<span class="macro">matches!</span>(<span class="self">self</span>.inner, CurrentInner::Unknown) |
| } |
| |
| <span class="doccomment">/// Consumes `self` and returns the span `Id` and `Metadata` of the current |
| /// span, if one exists and is known. |
| </span><span class="kw">pub fn </span>into_inner(<span class="self">self</span>) -> <span class="prelude-ty">Option</span><(Id, <span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>)> { |
| <span class="kw">match </span><span class="self">self</span>.inner { |
| CurrentInner::Current { id, metadata } => <span class="prelude-val">Some</span>((id, metadata)), |
| <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Borrows the `Id` of the current span, if one exists and is known. |
| </span><span class="kw">pub fn </span>id(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span>Id> { |
| <span class="kw">match </span><span class="self">self</span>.inner { |
| CurrentInner::Current { <span class="kw-2">ref </span>id, .. } => <span class="prelude-val">Some</span>(id), |
| <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="doccomment">/// Borrows the `Metadata` of the current span, if one exists and is known. |
| </span><span class="kw">pub fn </span>metadata(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>> { |
| <span class="kw">match </span><span class="self">self</span>.inner { |
| CurrentInner::Current { metadata, .. } => <span class="prelude-val">Some</span>(metadata), |
| <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> From<<span class="kw-2">&</span><span class="lifetime">'a </span>Current> <span class="kw">for </span><span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'a </span>Id> { |
| <span class="kw">fn </span>from(cur: <span class="kw-2">&</span><span class="lifetime">'a </span>Current) -> <span class="self">Self </span>{ |
| cur.id() |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> From<<span class="kw-2">&</span><span class="lifetime">'a </span>Current> <span class="kw">for </span><span class="prelude-ty">Option</span><Id> { |
| <span class="kw">fn </span>from(cur: <span class="kw-2">&</span><span class="lifetime">'a </span>Current) -> <span class="self">Self </span>{ |
| cur.id().cloned() |
| } |
| } |
| |
| <span class="kw">impl </span>From<Current> <span class="kw">for </span><span class="prelude-ty">Option</span><Id> { |
| <span class="kw">fn </span>from(cur: Current) -> <span class="self">Self </span>{ |
| <span class="kw">match </span>cur.inner { |
| CurrentInner::Current { id, .. } => <span class="prelude-val">Some</span>(id), |
| <span class="kw">_ </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> From<<span class="kw-2">&</span><span class="lifetime">'a </span>Current> <span class="kw">for </span><span class="prelude-ty">Option</span><<span class="kw-2">&</span><span class="lifetime">'static </span>Metadata<<span class="lifetime">'static</span>>> { |
| <span class="kw">fn </span>from(cur: <span class="kw-2">&</span><span class="lifetime">'a </span>Current) -> <span class="self">Self </span>{ |
| cur.metadata() |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="tracing_core" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |