Struct Metadata 

pub struct Metadata { /* private fields */ }

Structured metadata attached to crate::AppError.

Internally backed by a sorted inline vector for optimal performance with small field counts. Fields are kept sorted by name for deterministic iteration and O(log n) lookup via binary search.

Performance

Most errors have 0-4 metadata fields. For these cases, all storage is inline (no heap allocation), saving ~100-200ns per error creation.

Implementations

impl Metadata

pub const fn new() -> Self

Create an empty metadata container.

pub fn from_fields(fields: impl IntoIterator<Item = Field>) -> Self

Build metadata from an iterator of Field values.

pub fn len(&self) -> usize

Number of fields stored in the metadata.

pub fn is_empty(&self) -> bool

Whether the metadata is empty.

pub fn insert(&mut self, field: Field) -> Option<FieldValue>

Insert or replace a field and return the previous value.

Fields are kept sorted by name for efficient lookup.

pub fn extend(&mut self, fields: impl IntoIterator<Item = Field>)

Extend metadata with additional fields.

pub fn get(&self, name: &'static str) -> Option<&FieldValue>

Borrow a field value by name.

pub fn get_field(&self, name: &'static str) -> Option<&Field>

Borrow the full field entry by name.

pub fn set_redaction(&mut self, name: &'static str, redaction: FieldRedaction)

Override the redaction policy for a specific field.

pub fn redaction(&self, name: &'static str) -> Option<FieldRedaction>

Retrieve the redaction policy for a field if present.

pub fn iter(&self) -> impl Iterator<Item = (&'static str, &FieldValue)>

Iterator over metadata fields in sorted order.

pub fn iter_with_redaction( &self, ) -> impl Iterator<Item = (&'static str, &FieldValue, FieldRedaction)>

Iterator over metadata entries including the redaction policy.

Trait Implementations

impl Clone for Metadata

fn clone(&self) -> Metadata

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Metadata

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

Formats the value using the given formatter.

impl Default for Metadata

fn default() -> Metadata

Returns the “default value” for a type.

impl IntoIterator for Metadata

type Item = Field

The type of the elements being iterated over.

type IntoIter = IntoIter<Field>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl PartialEq for Metadata

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl StructuralPartialEq for Metadata