Struct tracing::field::FieldSet

pub struct FieldSet {
    names: &'static [&'static str],
    callsite: Identifier,
}

Describes the fields present on a span.

Equality

In well-behaved applications, two FieldSets initialized with equal callsite identifiers will have identical fields. Consequently, in release builds, FieldSet::eq only checks that its arguments have equal callsites. However, the equality of field names is checked in debug builds.

Fields

names: &'static [&'static str]

callsite: Identifier

Implementations

impl FieldSet

pub const fn new( names: &'static [&'static str], callsite: Identifier, ) -> FieldSet

Constructs a new FieldSet with the given array of field names and callsite.

pub fn field<Q>(&self, name: &Q) -> Option<Field>

where Q: Borrow<str> + ?Sized,

Returns the Field named name, or None if no such field exists.

pub fn contains(&self, field: &Field) -> bool

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 iter(&self) -> Iter

Returns an iterator over the Fields in this FieldSet.

pub fn len(&self) -> usize

Returns the number of fields in this FieldSet.

pub fn is_empty(&self) -> bool

Returns whether or not this FieldSet has fields.

Trait Implementations

impl Debug for FieldSet

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Display for FieldSet

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a> IntoIterator for &'a FieldSet

type IntoIter = Iter

Which kind of iterator are we turning this into?

type Item = Field

The type of the elements being iterated over.

fn into_iter(self) -> <&'a FieldSet as IntoIterator>::IntoIter

Creates an iterator from a value.

impl PartialEq for FieldSet

fn eq(&self, other: &FieldSet) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for FieldSet