From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- vendor/tracing-core/src/field.rs | 1219 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 1219 insertions(+) create mode 100644 vendor/tracing-core/src/field.rs (limited to 'vendor/tracing-core/src/field.rs') diff --git a/vendor/tracing-core/src/field.rs b/vendor/tracing-core/src/field.rs new file mode 100644 index 000000000..c9869ce2c --- /dev/null +++ b/vendor/tracing-core/src/field.rs @@ -0,0 +1,1219 @@ +//! `Span` and `Event` key-value data. +//! +//! Spans and events may be annotated with key-value data, referred to as known +//! as _fields_. These fields consist of a mapping from a key (corresponding to +//! a `&str` but represented internally as an array index) to a [`Value`]. +//! +//! # `Value`s and `Subscriber`s +//! +//! `Subscriber`s consume `Value`s as fields attached to [span]s or [`Event`]s. +//! The set of field keys on a given span or is defined on its [`Metadata`]. +//! When a span is created, it provides [`Attributes`] to the `Subscriber`'s +//! [`new_span`] method, containing any fields whose values were provided when +//! the span was created; and may call the `Subscriber`'s [`record`] method +//! with additional [`Record`]s if values are added for more of its fields. +//! Similarly, the [`Event`] type passed to the subscriber's [`event`] method +//! will contain any fields attached to each event. +//! +//! `tracing` represents values as either one of a set of Rust primitives +//! (`i64`, `u64`, `f64`, `i128`, `u128`, `bool`, and `&str`) or using a +//! `fmt::Display` or `fmt::Debug` implementation. `Subscriber`s are provided +//! these primitive value types as `dyn Value` trait objects. +//! +//! These trait objects can be formatted using `fmt::Debug`, but may also be +//! recorded as typed data by calling the [`Value::record`] method on these +//! trait objects with a _visitor_ implementing the [`Visit`] trait. This trait +//! represents the behavior used to record values of various types. For example, +//! an implementation of `Visit` might record integers by incrementing counters +//! for their field names rather than printing them. +//! +//! +//! # Using `valuable` +//! +//! `tracing`'s [`Value`] trait is intentionally minimalist: it supports only a small +//! number of Rust primitives as typed values, and only permits recording +//! user-defined types with their [`fmt::Debug`] or [`fmt::Display`] +//! implementations. However, there are some cases where it may be useful to record +//! nested values (such as arrays, `Vec`s, or `HashMap`s containing values), or +//! user-defined `struct` and `enum` types without having to format them as +//! unstructured text. +//! +//! To address `Value`'s limitations, `tracing` offers experimental support for +//! the [`valuable`] crate, which provides object-safe inspection of structured +//! values. User-defined types can implement the [`valuable::Valuable`] trait, +//! and be recorded as a `tracing` field by calling their [`as_value`] method. +//! If the [`Subscriber`] also supports the `valuable` crate, it can +//! then visit those types fields as structured values using `valuable`. +//! +//! 
+//!     Note: valuable support is an
+//!     unstable feature. See
+//!     the documentation on unstable features for details on how to enable it.
+//!
+//! +//! For example: +//! ```ignore +//! // Derive `Valuable` for our types: +//! use valuable::Valuable; +//! +//! #[derive(Clone, Debug, Valuable)] +//! struct User { +//! name: String, +//! age: u32, +//! address: Address, +//! } +//! +//! #[derive(Clone, Debug, Valuable)] +//! struct Address { +//! country: String, +//! city: String, +//! street: String, +//! } +//! +//! let user = User { +//! name: "Arwen Undomiel".to_string(), +//! age: 3000, +//! address: Address { +//! country: "Middle Earth".to_string(), +//! city: "Rivendell".to_string(), +//! street: "leafy lane".to_string(), +//! }, +//! }; +//! +//! // Recording `user` as a `valuable::Value` will allow the `tracing` subscriber +//! // to traverse its fields as a nested, typed structure: +//! tracing::info!(current_user = user.as_value()); +//! ``` +//! +//! Alternatively, the [`valuable()`] function may be used to convert a type +//! implementing [`Valuable`] into a `tracing` field value. +//! +//! When the `valuable` feature is enabled, the [`Visit`] trait will include an +//! optional [`record_value`] method. `Visit` implementations that wish to +//! record `valuable` values can implement this method with custom behavior. +//! If a visitor does not implement `record_value`, the [`valuable::Value`] will +//! be forwarded to the visitor's [`record_debug`] method. +//! +//! [`valuable`]: https://crates.io/crates/valuable +//! [`as_value`]: valuable::Valuable::as_value +//! [`Subscriber`]: crate::Subscriber +//! [`record_value`]: Visit::record_value +//! [`record_debug`]: Visit::record_debug +//! +//! [span]: super::span +//! [`Event`]: super::event::Event +//! [`Metadata`]: super::metadata::Metadata +//! [`Attributes`]: super::span::Attributes +//! [`Record`]: super::span::Record +//! [`new_span`]: super::subscriber::Subscriber::new_span +//! [`record`]: super::subscriber::Subscriber::record +//! [`event`]: super::subscriber::Subscriber::event +//! [`Value::record`]: Value::record +use crate::callsite; +use crate::stdlib::{ + borrow::Borrow, + fmt, + hash::{Hash, Hasher}, + num, + ops::Range, + string::String, +}; + +use self::private::ValidLen; + +/// An opaque key allowing _O_(1) access to a field in a `Span`'s key-value +/// data. +/// +/// As keys are defined by the _metadata_ of a span, rather than by an +/// individual instance of a span, a key may be used to access the same field +/// across all instances of a given span with the same metadata. Thus, when a +/// subscriber observes a new span, it need only access a field by name _once_, +/// and use the key for that name for all other accesses. +#[derive(Debug)] +pub struct Field { + i: usize, + fields: FieldSet, +} + +/// An empty field. +/// +/// This can be used to indicate that the value of a field is not currently +/// present but will be recorded later. +/// +/// When a field's value is `Empty`. it will not be recorded. +#[derive(Debug, Eq, PartialEq)] +pub struct Empty; + +/// Describes the fields present on a span. +pub struct FieldSet { + /// The names of each field on the described span. + names: &'static [&'static str], + /// The callsite where the described span originates. + callsite: callsite::Identifier, +} + +/// A set of fields and values for a span. +pub struct ValueSet<'a> { + values: &'a [(&'a Field, Option<&'a (dyn Value + 'a)>)], + fields: &'a FieldSet, +} + +/// An iterator over a set of fields. +#[derive(Debug)] +pub struct Iter { + idxs: Range, + fields: FieldSet, +} + +/// Visits typed values. +/// +/// An instance of `Visit` ("a visitor") represents the logic necessary to +/// record field values of various types. When an implementor of [`Value`] is +/// [recorded], it calls the appropriate method on the provided visitor to +/// indicate the type that value should be recorded as. +/// +/// When a [`Subscriber`] implementation [records an `Event`] or a +/// [set of `Value`s added to a `Span`], it can pass an `&mut Visit` to the +/// `record` method on the provided [`ValueSet`] or [`Event`]. This visitor +/// will then be used to record all the field-value pairs present on that +/// `Event` or `ValueSet`. +/// +/// # Examples +/// +/// A simple visitor that writes to a string might be implemented like so: +/// ``` +/// # extern crate tracing_core as tracing; +/// use std::fmt::{self, Write}; +/// use tracing::field::{Value, Visit, Field}; +/// pub struct StringVisitor<'a> { +/// string: &'a mut String, +/// } +/// +/// impl<'a> Visit for StringVisitor<'a> { +/// fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { +/// write!(self.string, "{} = {:?}; ", field.name(), value).unwrap(); +/// } +/// } +/// ``` +/// This visitor will format each recorded value using `fmt::Debug`, and +/// append the field name and formatted value to the provided string, +/// regardless of the type of the recorded value. When all the values have +/// been recorded, the `StringVisitor` may be dropped, allowing the string +/// to be printed or stored in some other data structure. +/// +/// The `Visit` trait provides default implementations for `record_i64`, +/// `record_u64`, `record_bool`, `record_str`, and `record_error`, which simply +/// forward the recorded value to `record_debug`. Thus, `record_debug` is the +/// only method which a `Visit` implementation *must* implement. However, +/// visitors may override the default implementations of these functions in +/// order to implement type-specific behavior. +/// +/// Additionally, when a visitor receives a value of a type it does not care +/// about, it is free to ignore those values completely. For example, a +/// visitor which only records numeric data might look like this: +/// +/// ``` +/// # extern crate tracing_core as tracing; +/// # use std::fmt::{self, Write}; +/// # use tracing::field::{Value, Visit, Field}; +/// pub struct SumVisitor { +/// sum: i64, +/// } +/// +/// impl Visit for SumVisitor { +/// fn record_i64(&mut self, _field: &Field, value: i64) { +/// self.sum += value; +/// } +/// +/// fn record_u64(&mut self, _field: &Field, value: u64) { +/// self.sum += value as i64; +/// } +/// +/// fn record_debug(&mut self, _field: &Field, _value: &fmt::Debug) { +/// // Do nothing +/// } +/// } +/// ``` +/// +/// This visitor (which is probably not particularly useful) keeps a running +/// sum of all the numeric values it records, and ignores all other values. A +/// more practical example of recording typed values is presented in +/// `examples/counters.rs`, which demonstrates a very simple metrics system +/// implemented using `tracing`. +/// +///
+/// 
+/// Note: The record_error trait method is only
+/// available when the Rust standard library is present, as it requires the
+/// std::error::Error trait.
+///
+/// +/// [recorded]: Value::record +/// [`Subscriber`]: super::subscriber::Subscriber +/// [records an `Event`]: super::subscriber::Subscriber::event +/// [set of `Value`s added to a `Span`]: super::subscriber::Subscriber::record +/// [`Event`]: super::event::Event +pub trait Visit { + /// Visits an arbitrary type implementing the [`valuable`] crate's `Valuable` trait. + /// + /// [`valuable`]: https://docs.rs/valuable + #[cfg(all(tracing_unstable, feature = "valuable"))] + #[cfg_attr(docsrs, doc(cfg(all(tracing_unstable, feature = "valuable"))))] + fn record_value(&mut self, field: &Field, value: valuable::Value<'_>) { + self.record_debug(field, &value) + } + + /// Visit a double-precision floating point value. + fn record_f64(&mut self, field: &Field, value: f64) { + self.record_debug(field, &value) + } + + /// Visit a signed 64-bit integer value. + fn record_i64(&mut self, field: &Field, value: i64) { + self.record_debug(field, &value) + } + + /// Visit an unsigned 64-bit integer value. + fn record_u64(&mut self, field: &Field, value: u64) { + self.record_debug(field, &value) + } + + /// Visit a signed 128-bit integer value. + fn record_i128(&mut self, field: &Field, value: i128) { + self.record_debug(field, &value) + } + + /// Visit an unsigned 128-bit integer value. + fn record_u128(&mut self, field: &Field, value: u128) { + self.record_debug(field, &value) + } + + /// Visit a boolean value. + fn record_bool(&mut self, field: &Field, value: bool) { + self.record_debug(field, &value) + } + + /// Visit a string value. + fn record_str(&mut self, field: &Field, value: &str) { + self.record_debug(field, &value) + } + + /// Records a type implementing `Error`. + /// + ///
+ /// 
+    /// Note: This is only enabled when the Rust standard library is
+    /// present.
+    ///
+ #[cfg(feature = "std")] + #[cfg_attr(docsrs, doc(cfg(feature = "std")))] + fn record_error(&mut self, field: &Field, value: &(dyn std::error::Error + 'static)) { + self.record_debug(field, &DisplayValue(value)) + } + + /// Visit a value implementing `fmt::Debug`. + fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug); +} + +/// A field value of an erased type. +/// +/// Implementors of `Value` may call the appropriate typed recording methods on +/// the [visitor] passed to their `record` method in order to indicate how +/// their data should be recorded. +/// +/// [visitor]: Visit +pub trait Value: crate::sealed::Sealed { + /// Visits this value with the given `Visitor`. + fn record(&self, key: &Field, visitor: &mut dyn Visit); +} + +/// A `Value` which serializes using `fmt::Display`. +/// +/// Uses `record_debug` in the `Value` implementation to +/// avoid an unnecessary evaluation. +#[derive(Clone)] +pub struct DisplayValue(T); + +/// A `Value` which serializes as a string using `fmt::Debug`. +#[derive(Clone)] +pub struct DebugValue(T); + +/// Wraps a type implementing `fmt::Display` as a `Value` that can be +/// recorded using its `Display` implementation. +pub fn display(t: T) -> DisplayValue +where + T: fmt::Display, +{ + DisplayValue(t) +} + +/// Wraps a type implementing `fmt::Debug` as a `Value` that can be +/// recorded using its `Debug` implementation. +pub fn debug(t: T) -> DebugValue +where + T: fmt::Debug, +{ + DebugValue(t) +} + +/// Wraps a type implementing [`Valuable`] as a `Value` that +/// can be recorded using its `Valuable` implementation. +/// +/// [`Valuable`]: https://docs.rs/valuable/latest/valuable/trait.Valuable.html +#[cfg(all(tracing_unstable, feature = "valuable"))] +#[cfg_attr(docsrs, doc(cfg(all(tracing_unstable, feature = "valuable"))))] +pub fn valuable(t: &T) -> valuable::Value<'_> +where + T: valuable::Valuable, +{ + t.as_value() +} + +// ===== impl Visit ===== + +impl<'a, 'b> Visit for fmt::DebugStruct<'a, 'b> { + fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { + self.field(field.name(), value); + } +} + +impl<'a, 'b> Visit for fmt::DebugMap<'a, 'b> { + fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { + self.entry(&format_args!("{}", field), value); + } +} + +impl Visit for F +where + F: FnMut(&Field, &dyn fmt::Debug), +{ + fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { + (self)(field, value) + } +} + +// ===== impl Value ===== + +macro_rules! impl_values { + ( $( $record:ident( $( $whatever:tt)+ ) ),+ ) => { + $( + impl_value!{ $record( $( $whatever )+ ) } + )+ + } +} + +macro_rules! ty_to_nonzero { + (u8) => { + NonZeroU8 + }; + (u16) => { + NonZeroU16 + }; + (u32) => { + NonZeroU32 + }; + (u64) => { + NonZeroU64 + }; + (u128) => { + NonZeroU128 + }; + (usize) => { + NonZeroUsize + }; + (i8) => { + NonZeroI8 + }; + (i16) => { + NonZeroI16 + }; + (i32) => { + NonZeroI32 + }; + (i64) => { + NonZeroI64 + }; + (i128) => { + NonZeroI128 + }; + (isize) => { + NonZeroIsize + }; +} + +macro_rules! impl_one_value { + (f32, $op:expr, $record:ident) => { + impl_one_value!(normal, f32, $op, $record); + }; + (f64, $op:expr, $record:ident) => { + impl_one_value!(normal, f64, $op, $record); + }; + (bool, $op:expr, $record:ident) => { + impl_one_value!(normal, bool, $op, $record); + }; + ($value_ty:tt, $op:expr, $record:ident) => { + impl_one_value!(normal, $value_ty, $op, $record); + impl_one_value!(nonzero, $value_ty, $op, $record); + }; + (normal, $value_ty:tt, $op:expr, $record:ident) => { + impl $crate::sealed::Sealed for $value_ty {} + impl $crate::field::Value for $value_ty { + fn record(&self, key: &$crate::field::Field, visitor: &mut dyn $crate::field::Visit) { + visitor.$record(key, $op(*self)) + } + } + }; + (nonzero, $value_ty:tt, $op:expr, $record:ident) => { + // This `use num::*;` is reported as unused because it gets emitted + // for every single invocation of this macro, so there are multiple `use`s. + // All but the first are useless indeed. + // We need this import because we can't write a path where one part is + // the `ty_to_nonzero!($value_ty)` invocation. + #[allow(clippy::useless_attribute, unused)] + use num::*; + impl $crate::sealed::Sealed for ty_to_nonzero!($value_ty) {} + impl $crate::field::Value for ty_to_nonzero!($value_ty) { + fn record(&self, key: &$crate::field::Field, visitor: &mut dyn $crate::field::Visit) { + visitor.$record(key, $op(self.get())) + } + } + }; +} + +macro_rules! impl_value { + ( $record:ident( $( $value_ty:tt ),+ ) ) => { + $( + impl_one_value!($value_ty, |this: $value_ty| this, $record); + )+ + }; + ( $record:ident( $( $value_ty:tt ),+ as $as_ty:ty) ) => { + $( + impl_one_value!($value_ty, |this: $value_ty| this as $as_ty, $record); + )+ + }; +} + +// ===== impl Value ===== + +impl_values! { + record_u64(u64), + record_u64(usize, u32, u16, u8 as u64), + record_i64(i64), + record_i64(isize, i32, i16, i8 as i64), + record_u128(u128), + record_i128(i128), + record_bool(bool), + record_f64(f64, f32 as f64) +} + +impl crate::sealed::Sealed for Wrapping {} +impl crate::field::Value for Wrapping { + fn record(&self, key: &crate::field::Field, visitor: &mut dyn crate::field::Visit) { + self.0.record(key, visitor) + } +} + +impl crate::sealed::Sealed for str {} + +impl Value for str { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_str(key, self) + } +} + +#[cfg(feature = "std")] +impl crate::sealed::Sealed for dyn std::error::Error + 'static {} + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl Value for dyn std::error::Error + 'static { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_error(key, self) + } +} + +#[cfg(feature = "std")] +impl crate::sealed::Sealed for dyn std::error::Error + Send + 'static {} + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl Value for dyn std::error::Error + Send + 'static { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + (self as &dyn std::error::Error).record(key, visitor) + } +} + +#[cfg(feature = "std")] +impl crate::sealed::Sealed for dyn std::error::Error + Sync + 'static {} + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl Value for dyn std::error::Error + Sync + 'static { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + (self as &dyn std::error::Error).record(key, visitor) + } +} + +#[cfg(feature = "std")] +impl crate::sealed::Sealed for dyn std::error::Error + Send + Sync + 'static {} + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl Value for dyn std::error::Error + Send + Sync + 'static { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + (self as &dyn std::error::Error).record(key, visitor) + } +} + +impl<'a, T: ?Sized> crate::sealed::Sealed for &'a T where T: Value + crate::sealed::Sealed + 'a {} + +impl<'a, T: ?Sized> Value for &'a T +where + T: Value + 'a, +{ + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + (*self).record(key, visitor) + } +} + +impl<'a, T: ?Sized> crate::sealed::Sealed for &'a mut T where T: Value + crate::sealed::Sealed + 'a {} + +impl<'a, T: ?Sized> Value for &'a mut T +where + T: Value + 'a, +{ + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + // Don't use `(*self).record(key, visitor)`, otherwise would + // cause stack overflow due to `unconditional_recursion`. + T::record(self, key, visitor) + } +} + +impl<'a> crate::sealed::Sealed for fmt::Arguments<'a> {} + +impl<'a> Value for fmt::Arguments<'a> { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_debug(key, self) + } +} + +impl crate::sealed::Sealed for crate::stdlib::boxed::Box where T: Value {} + +impl Value for crate::stdlib::boxed::Box +where + T: Value, +{ + #[inline] + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + self.as_ref().record(key, visitor) + } +} + +impl crate::sealed::Sealed for String {} +impl Value for String { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_str(key, self.as_str()) + } +} + +impl fmt::Debug for dyn Value { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + // We are only going to be recording the field value, so we don't + // actually care about the field name here. + struct NullCallsite; + static NULL_CALLSITE: NullCallsite = NullCallsite; + impl crate::callsite::Callsite for NullCallsite { + fn set_interest(&self, _: crate::subscriber::Interest) { + unreachable!("you somehow managed to register the null callsite?") + } + + fn metadata(&self) -> &crate::Metadata<'_> { + unreachable!("you somehow managed to access the null callsite?") + } + } + + static FIELD: Field = Field { + i: 0, + fields: FieldSet::new(&[], crate::identify_callsite!(&NULL_CALLSITE)), + }; + + let mut res = Ok(()); + self.record(&FIELD, &mut |_: &Field, val: &dyn fmt::Debug| { + res = write!(f, "{:?}", val); + }); + res + } +} + +impl fmt::Display for dyn Value { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(self, f) + } +} + +// ===== impl DisplayValue ===== + +impl crate::sealed::Sealed for DisplayValue {} + +impl Value for DisplayValue +where + T: fmt::Display, +{ + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_debug(key, self) + } +} + +impl fmt::Debug for DisplayValue { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Display::fmt(self, f) + } +} + +impl fmt::Display for DisplayValue { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +// ===== impl DebugValue ===== + +impl crate::sealed::Sealed for DebugValue {} + +impl Value for DebugValue +where + T: fmt::Debug, +{ + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_debug(key, &self.0) + } +} + +impl fmt::Debug for DebugValue { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +// ===== impl ValuableValue ===== + +#[cfg(all(tracing_unstable, feature = "valuable"))] +impl crate::sealed::Sealed for valuable::Value<'_> {} + +#[cfg(all(tracing_unstable, feature = "valuable"))] +#[cfg_attr(docsrs, doc(cfg(all(tracing_unstable, feature = "valuable"))))] +impl Value for valuable::Value<'_> { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_value(key, *self) + } +} + +#[cfg(all(tracing_unstable, feature = "valuable"))] +impl crate::sealed::Sealed for &'_ dyn valuable::Valuable {} + +#[cfg(all(tracing_unstable, feature = "valuable"))] +#[cfg_attr(docsrs, doc(cfg(all(tracing_unstable, feature = "valuable"))))] +impl Value for &'_ dyn valuable::Valuable { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + visitor.record_value(key, self.as_value()) + } +} + +impl crate::sealed::Sealed for Empty {} +impl Value for Empty { + #[inline] + fn record(&self, _: &Field, _: &mut dyn Visit) {} +} + +impl crate::sealed::Sealed for Option {} + +impl Value for Option { + fn record(&self, key: &Field, visitor: &mut dyn Visit) { + if let Some(v) = &self { + v.record(key, visitor) + } + } +} + +// ===== impl Field ===== + +impl Field { + /// Returns an [`Identifier`] that uniquely identifies the [`Callsite`] + /// which defines this field. + /// + /// [`Identifier`]: super::callsite::Identifier + /// [`Callsite`]: super::callsite::Callsite + #[inline] + pub fn callsite(&self) -> callsite::Identifier { + self.fields.callsite() + } + + /// Returns a string representing the name of the field. + pub fn name(&self) -> &'static str { + self.fields.names[self.i] + } +} + +impl fmt::Display for Field { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.pad(self.name()) + } +} + +impl AsRef for Field { + fn as_ref(&self) -> &str { + self.name() + } +} + +impl PartialEq for Field { + fn eq(&self, other: &Self) -> bool { + self.callsite() == other.callsite() && self.i == other.i + } +} + +impl Eq for Field {} + +impl Hash for Field { + fn hash(&self, state: &mut H) + where + H: Hasher, + { + self.callsite().hash(state); + self.i.hash(state); + } +} + +impl Clone for Field { + fn clone(&self) -> Self { + Field { + i: self.i, + fields: FieldSet { + names: self.fields.names, + callsite: self.fields.callsite(), + }, + } + } +} + +// ===== impl FieldSet ===== + +impl FieldSet { + /// Constructs a new `FieldSet` with the given array of field names and callsite. + pub const fn new(names: &'static [&'static str], callsite: callsite::Identifier) -> Self { + Self { names, callsite } + } + + /// Returns an [`Identifier`] that uniquely identifies the [`Callsite`] + /// which defines this set of fields.. + /// + /// [`Identifier`]: super::callsite::Identifier + /// [`Callsite`]: super::callsite::Callsite + pub(crate) fn callsite(&self) -> callsite::Identifier { + callsite::Identifier(self.callsite.0) + } + + /// Returns the [`Field`] named `name`, or `None` if no such field exists. + /// + /// [`Field`]: super::Field + pub fn field(&self, name: &Q) -> Option + where + Q: Borrow, + { + let name = &name.borrow(); + self.names.iter().position(|f| f == name).map(|i| Field { + i, + fields: FieldSet { + names: self.names, + callsite: self.callsite(), + }, + }) + } + + /// Returns `true` if `self` contains the given `field`. + /// + ///
+ /// 
+    /// Note: If field shares a name with a field
+    /// in this FieldSet, but was created by a FieldSet
+    /// with a different callsite, this FieldSet does not
+    /// contain it. This is so that if two separate span callsites define a field
+    /// named "foo", the Field corresponding to "foo" for each
+    /// of those callsites are not equivalent.
+    ///
+ pub fn contains(&self, field: &Field) -> bool { + field.callsite() == self.callsite() && field.i <= self.len() + } + + /// Returns an iterator over the `Field`s in this `FieldSet`. + pub fn iter(&self) -> Iter { + let idxs = 0..self.len(); + Iter { + idxs, + fields: FieldSet { + names: self.names, + callsite: self.callsite(), + }, + } + } + + /// Returns a new `ValueSet` with entries for this `FieldSet`'s values. + /// + /// Note that a `ValueSet` may not be constructed with arrays of over 32 + /// elements. + #[doc(hidden)] + pub fn value_set<'v, V>(&'v self, values: &'v V) -> ValueSet<'v> + where + V: ValidLen<'v>, + { + ValueSet { + fields: self, + values: values.borrow(), + } + } + + /// Returns the number of fields in this `FieldSet`. + #[inline] + pub fn len(&self) -> usize { + self.names.len() + } + + /// Returns whether or not this `FieldSet` has fields. + #[inline] + pub fn is_empty(&self) -> bool { + self.names.is_empty() + } +} + +impl<'a> IntoIterator for &'a FieldSet { + type IntoIter = Iter; + type Item = Field; + #[inline] + fn into_iter(self) -> Self::IntoIter { + self.iter() + } +} + +impl fmt::Debug for FieldSet { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("FieldSet") + .field("names", &self.names) + .field("callsite", &self.callsite) + .finish() + } +} + +impl fmt::Display for FieldSet { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_set() + .entries(self.names.iter().map(display)) + .finish() + } +} + +// ===== impl Iter ===== + +impl Iterator for Iter { + type Item = Field; + fn next(&mut self) -> Option { + let i = self.idxs.next()?; + Some(Field { + i, + fields: FieldSet { + names: self.fields.names, + callsite: self.fields.callsite(), + }, + }) + } +} + +// ===== impl ValueSet ===== + +impl<'a> ValueSet<'a> { + /// Returns an [`Identifier`] that uniquely identifies the [`Callsite`] + /// defining the fields this `ValueSet` refers to. + /// + /// [`Identifier`]: super::callsite::Identifier + /// [`Callsite`]: super::callsite::Callsite + #[inline] + pub fn callsite(&self) -> callsite::Identifier { + self.fields.callsite() + } + + /// Visits all the fields in this `ValueSet` with the provided [visitor]. + /// + /// [visitor]: Visit + pub fn record(&self, visitor: &mut dyn Visit) { + let my_callsite = self.callsite(); + for (field, value) in self.values { + if field.callsite() != my_callsite { + continue; + } + if let Some(value) = value { + value.record(field, visitor); + } + } + } + + /// Returns the number of fields in this `ValueSet` that would be visited + /// by a given [visitor] to the [`ValueSet::record()`] method. + /// + /// [visitor]: Visit + /// [`ValueSet::record()`]: ValueSet::record() + pub fn len(&self) -> usize { + let my_callsite = self.callsite(); + self.values + .iter() + .filter(|(field, _)| field.callsite() == my_callsite) + .count() + } + + /// Returns `true` if this `ValueSet` contains a value for the given `Field`. + pub(crate) fn contains(&self, field: &Field) -> bool { + field.callsite() == self.callsite() + && self + .values + .iter() + .any(|(key, val)| *key == field && val.is_some()) + } + + /// Returns true if this `ValueSet` contains _no_ values. + pub fn is_empty(&self) -> bool { + let my_callsite = self.callsite(); + self.values + .iter() + .all(|(key, val)| val.is_none() || key.callsite() != my_callsite) + } + + pub(crate) fn field_set(&self) -> &FieldSet { + self.fields + } +} + +impl<'a> fmt::Debug for ValueSet<'a> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.values + .iter() + .fold(&mut f.debug_struct("ValueSet"), |dbg, (key, v)| { + if let Some(val) = v { + val.record(key, dbg); + } + dbg + }) + .field("callsite", &self.callsite()) + .finish() + } +} + +impl<'a> fmt::Display for ValueSet<'a> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.values + .iter() + .fold(&mut f.debug_map(), |dbg, (key, v)| { + if let Some(val) = v { + val.record(key, dbg); + } + dbg + }) + .finish() + } +} + +// ===== impl ValidLen ===== + +mod private { + use super::*; + + /// Marker trait implemented by arrays which are of valid length to + /// construct a `ValueSet`. + /// + /// `ValueSet`s may only be constructed from arrays containing 32 or fewer + /// elements, to ensure the array is small enough to always be allocated on the + /// stack. This trait is only implemented by arrays of an appropriate length, + /// ensuring that the correct size arrays are used at compile-time. + pub trait ValidLen<'a>: Borrow<[(&'a Field, Option<&'a (dyn Value + 'a)>)]> {} +} + +macro_rules! impl_valid_len { + ( $( $len:tt ),+ ) => { + $( + impl<'a> private::ValidLen<'a> for + [(&'a Field, Option<&'a (dyn Value + 'a)>); $len] {} + )+ + } +} + +impl_valid_len! { + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, + 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 +} + +#[cfg(test)] +mod test { + use super::*; + use crate::metadata::{Kind, Level, Metadata}; + use crate::stdlib::{borrow::ToOwned, string::String}; + + struct TestCallsite1; + static TEST_CALLSITE_1: TestCallsite1 = TestCallsite1; + static TEST_META_1: Metadata<'static> = metadata! { + name: "field_test1", + target: module_path!(), + level: Level::INFO, + fields: &["foo", "bar", "baz"], + callsite: &TEST_CALLSITE_1, + kind: Kind::SPAN, + }; + + impl crate::callsite::Callsite for TestCallsite1 { + fn set_interest(&self, _: crate::subscriber::Interest) { + unimplemented!() + } + + fn metadata(&self) -> &Metadata<'_> { + &TEST_META_1 + } + } + + struct TestCallsite2; + static TEST_CALLSITE_2: TestCallsite2 = TestCallsite2; + static TEST_META_2: Metadata<'static> = metadata! { + name: "field_test2", + target: module_path!(), + level: Level::INFO, + fields: &["foo", "bar", "baz"], + callsite: &TEST_CALLSITE_2, + kind: Kind::SPAN, + }; + + impl crate::callsite::Callsite for TestCallsite2 { + fn set_interest(&self, _: crate::subscriber::Interest) { + unimplemented!() + } + + fn metadata(&self) -> &Metadata<'_> { + &TEST_META_2 + } + } + + #[test] + fn value_set_with_no_values_is_empty() { + let fields = TEST_META_1.fields(); + let values = &[ + (&fields.field("foo").unwrap(), None), + (&fields.field("bar").unwrap(), None), + (&fields.field("baz").unwrap(), None), + ]; + let valueset = fields.value_set(values); + assert!(valueset.is_empty()); + } + + #[test] + fn empty_value_set_is_empty() { + let fields = TEST_META_1.fields(); + let valueset = fields.value_set(&[]); + assert!(valueset.is_empty()); + } + + #[test] + fn value_sets_with_fields_from_other_callsites_are_empty() { + let fields = TEST_META_1.fields(); + let values = &[ + (&fields.field("foo").unwrap(), Some(&1 as &dyn Value)), + (&fields.field("bar").unwrap(), Some(&2 as &dyn Value)), + (&fields.field("baz").unwrap(), Some(&3 as &dyn Value)), + ]; + let valueset = TEST_META_2.fields().value_set(values); + assert!(valueset.is_empty()) + } + + #[test] + fn sparse_value_sets_are_not_empty() { + let fields = TEST_META_1.fields(); + let values = &[ + (&fields.field("foo").unwrap(), None), + (&fields.field("bar").unwrap(), Some(&57 as &dyn Value)), + (&fields.field("baz").unwrap(), None), + ]; + let valueset = fields.value_set(values); + assert!(!valueset.is_empty()); + } + + #[test] + fn fields_from_other_callsets_are_skipped() { + let fields = TEST_META_1.fields(); + let values = &[ + (&fields.field("foo").unwrap(), None), + ( + &TEST_META_2.fields().field("bar").unwrap(), + Some(&57 as &dyn Value), + ), + (&fields.field("baz").unwrap(), None), + ]; + + struct MyVisitor; + impl Visit for MyVisitor { + fn record_debug(&mut self, field: &Field, _: &dyn (crate::stdlib::fmt::Debug)) { + assert_eq!(field.callsite(), TEST_META_1.callsite()) + } + } + let valueset = fields.value_set(values); + valueset.record(&mut MyVisitor); + } + + #[test] + fn empty_fields_are_skipped() { + let fields = TEST_META_1.fields(); + let values = &[ + (&fields.field("foo").unwrap(), Some(&Empty as &dyn Value)), + (&fields.field("bar").unwrap(), Some(&57 as &dyn Value)), + (&fields.field("baz").unwrap(), Some(&Empty as &dyn Value)), + ]; + + struct MyVisitor; + impl Visit for MyVisitor { + fn record_debug(&mut self, field: &Field, _: &dyn (crate::stdlib::fmt::Debug)) { + assert_eq!(field.name(), "bar") + } + } + let valueset = fields.value_set(values); + valueset.record(&mut MyVisitor); + } + + #[test] + fn record_debug_fn() { + let fields = TEST_META_1.fields(); + let values = &[ + (&fields.field("foo").unwrap(), Some(&1 as &dyn Value)), + (&fields.field("bar").unwrap(), Some(&2 as &dyn Value)), + (&fields.field("baz").unwrap(), Some(&3 as &dyn Value)), + ]; + let valueset = fields.value_set(values); + let mut result = String::new(); + valueset.record(&mut |_: &Field, value: &dyn fmt::Debug| { + use crate::stdlib::fmt::Write; + write!(&mut result, "{:?}", value).unwrap(); + }); + assert_eq!(result, "123".to_owned()); + } + + #[test] + #[cfg(feature = "std")] + fn record_error() { + let fields = TEST_META_1.fields(); + let err: Box = + std::io::Error::new(std::io::ErrorKind::Other, "lol").into(); + let values = &[ + (&fields.field("foo").unwrap(), Some(&err as &dyn Value)), + (&fields.field("bar").unwrap(), Some(&Empty as &dyn Value)), + (&fields.field("baz").unwrap(), Some(&Empty as &dyn Value)), + ]; + let valueset = fields.value_set(values); + let mut result = String::new(); + valueset.record(&mut |_: &Field, value: &dyn fmt::Debug| { + use core::fmt::Write; + write!(&mut result, "{:?}", value).unwrap(); + }); + assert_eq!(result, format!("{}", err)); + } +} -- cgit v1.2.3