From 20431706a863f92cb37dc512fef6e48d192aaf2c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:11:38 +0200 Subject: Merging upstream version 1.66.0+dfsg1. Signed-off-by: Daniel Baumann --- .../src/registry/extensions.rs | 274 +++++++++++++++++++++ 1 file changed, 274 insertions(+) create mode 100644 vendor/tracing-subscriber-0.3.3/src/registry/extensions.rs (limited to 'vendor/tracing-subscriber-0.3.3/src/registry/extensions.rs') diff --git a/vendor/tracing-subscriber-0.3.3/src/registry/extensions.rs b/vendor/tracing-subscriber-0.3.3/src/registry/extensions.rs new file mode 100644 index 000000000..899e1549f --- /dev/null +++ b/vendor/tracing-subscriber-0.3.3/src/registry/extensions.rs @@ -0,0 +1,274 @@ +// taken from https://github.com/hyperium/http/blob/master/src/extensions.rs. + +use crate::sync::{RwLockReadGuard, RwLockWriteGuard}; +use std::{ + any::{Any, TypeId}, + collections::HashMap, + fmt, + hash::{BuildHasherDefault, Hasher}, +}; + +#[allow(warnings)] +type AnyMap = HashMap, BuildHasherDefault>; + +/// With TypeIds as keys, there's no need to hash them. They are already hashes +/// themselves, coming from the compiler. The IdHasher holds the u64 of +/// the TypeId, and then returns it, instead of doing any bit fiddling. +#[derive(Default, Debug)] +struct IdHasher(u64); + +impl Hasher for IdHasher { + fn write(&mut self, _: &[u8]) { + unreachable!("TypeId calls write_u64"); + } + + #[inline] + fn write_u64(&mut self, id: u64) { + self.0 = id; + } + + #[inline] + fn finish(&self) -> u64 { + self.0 + } +} + +/// An immutable, read-only reference to a Span's extensions. +#[derive(Debug)] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub struct Extensions<'a> { + inner: RwLockReadGuard<'a, ExtensionsInner>, +} + +impl<'a> Extensions<'a> { + #[cfg(feature = "registry")] + pub(crate) fn new(inner: RwLockReadGuard<'a, ExtensionsInner>) -> Self { + Self { inner } + } + + /// Immutably borrows a type previously inserted into this `Extensions`. + pub fn get(&self) -> Option<&T> { + self.inner.get::() + } +} + +/// An mutable reference to a Span's extensions. +#[derive(Debug)] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub struct ExtensionsMut<'a> { + inner: RwLockWriteGuard<'a, ExtensionsInner>, +} + +impl<'a> ExtensionsMut<'a> { + #[cfg(feature = "registry")] + pub(crate) fn new(inner: RwLockWriteGuard<'a, ExtensionsInner>) -> Self { + Self { inner } + } + + /// Insert a type into this `Extensions`. + /// + /// Note that extensions are _not_ + /// `Layer`-specific—they are _span_-specific. This means that + /// other layers can access and mutate extensions that + /// a different Layer recorded. For example, an application might + /// have a layer that records execution timings, alongside a layer + /// that reports spans and events to a distributed + /// tracing system that requires timestamps for spans. + /// Ideally, if one layer records a timestamp _x_, the other layer + /// should be able to reuse timestamp _x_. + /// + /// Therefore, extensions should generally be newtypes, rather than common + /// types like [`String`](https://doc.rust-lang.org/std/string/struct.String.html), to avoid accidental + /// cross-`Layer` clobbering. + /// + /// ## Panics + /// + /// If `T` is already present in `Extensions`, then this method will panic. + pub fn insert(&mut self, val: T) { + assert!(self.replace(val).is_none()) + } + + /// Replaces an existing `T` into this extensions. + /// + /// If `T` is not present, `Option::None` will be returned. + pub fn replace(&mut self, val: T) -> Option { + self.inner.insert(val) + } + + /// Get a mutable reference to a type previously inserted on this `ExtensionsMut`. + pub fn get_mut(&mut self) -> Option<&mut T> { + self.inner.get_mut::() + } + + /// Remove a type from this `Extensions`. + /// + /// If a extension of this type existed, it will be returned. + pub fn remove(&mut self) -> Option { + self.inner.remove::() + } +} + +/// A type map of span extensions. +/// +/// [ExtensionsInner] is used by `SpanData` to store and +/// span-specific data. A given `Layer` can read and write +/// data that it is interested in recording and emitting. +#[derive(Default)] +pub(crate) struct ExtensionsInner { + map: AnyMap, +} + +impl ExtensionsInner { + /// Create an empty `Extensions`. + #[cfg(any(test, feature = "registry"))] + #[inline] + #[cfg(any(test, feature = "registry"))] + pub(crate) fn new() -> ExtensionsInner { + ExtensionsInner { + map: AnyMap::default(), + } + } + + /// Insert a type into this `Extensions`. + /// + /// If a extension of this type already existed, it will + /// be returned. + pub(crate) fn insert(&mut self, val: T) -> Option { + self.map + .insert(TypeId::of::(), Box::new(val)) + .and_then(|boxed| { + #[allow(warnings)] + { + (boxed as Box) + .downcast() + .ok() + .map(|boxed| *boxed) + } + }) + } + + /// Get a reference to a type previously inserted on this `Extensions`. + pub(crate) fn get(&self) -> Option<&T> { + self.map + .get(&TypeId::of::()) + .and_then(|boxed| (&**boxed as &(dyn Any + 'static)).downcast_ref()) + } + + /// Get a mutable reference to a type previously inserted on this `Extensions`. + pub(crate) fn get_mut(&mut self) -> Option<&mut T> { + self.map + .get_mut(&TypeId::of::()) + .and_then(|boxed| (&mut **boxed as &mut (dyn Any + 'static)).downcast_mut()) + } + + /// Remove a type from this `Extensions`. + /// + /// If a extension of this type existed, it will be returned. + pub(crate) fn remove(&mut self) -> Option { + self.map.remove(&TypeId::of::()).and_then(|boxed| { + #[allow(warnings)] + { + (boxed as Box) + .downcast() + .ok() + .map(|boxed| *boxed) + } + }) + } + + /// Clear the `ExtensionsInner` in-place, dropping any elements in the map but + /// retaining allocated capacity. + /// + /// This permits the hash map allocation to be pooled by the registry so + /// that future spans will not need to allocate new hashmaps. + #[cfg(any(test, feature = "registry"))] + pub(crate) fn clear(&mut self) { + self.map.clear(); + } +} + +impl fmt::Debug for ExtensionsInner { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Extensions") + .field("len", &self.map.len()) + .field("capacity", &self.map.capacity()) + .finish() + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[derive(Debug, PartialEq)] + struct MyType(i32); + + #[test] + fn test_extensions() { + let mut extensions = ExtensionsInner::new(); + + extensions.insert(5i32); + extensions.insert(MyType(10)); + + assert_eq!(extensions.get(), Some(&5i32)); + assert_eq!(extensions.get_mut(), Some(&mut 5i32)); + + assert_eq!(extensions.remove::(), Some(5i32)); + assert!(extensions.get::().is_none()); + + assert_eq!(extensions.get::(), None); + assert_eq!(extensions.get(), Some(&MyType(10))); + } + + #[test] + fn clear_retains_capacity() { + let mut extensions = ExtensionsInner::new(); + extensions.insert(5i32); + extensions.insert(MyType(10)); + extensions.insert(true); + + assert_eq!(extensions.map.len(), 3); + let prev_capacity = extensions.map.capacity(); + extensions.clear(); + + assert_eq!( + extensions.map.len(), + 0, + "after clear(), extensions map should have length 0" + ); + assert_eq!( + extensions.map.capacity(), + prev_capacity, + "after clear(), extensions map should retain prior capacity" + ); + } + + #[test] + fn clear_drops_elements() { + use std::sync::Arc; + struct DropMePlease(Arc<()>); + struct DropMeTooPlease(Arc<()>); + + let mut extensions = ExtensionsInner::new(); + let val1 = DropMePlease(Arc::new(())); + let val2 = DropMeTooPlease(Arc::new(())); + + let val1_dropped = Arc::downgrade(&val1.0); + let val2_dropped = Arc::downgrade(&val2.0); + extensions.insert(val1); + extensions.insert(val2); + + assert!(val1_dropped.upgrade().is_some()); + assert!(val2_dropped.upgrade().is_some()); + + extensions.clear(); + assert!( + val1_dropped.upgrade().is_none(), + "after clear(), val1 should be dropped" + ); + assert!( + val2_dropped.upgrade().is_none(), + "after clear(), val2 should be dropped" + ); + } +} -- cgit v1.2.3