Enum Facts

pub enum Facts {
    Artist(ArtistFacts),
    Release(ReleaseFacts),
    Track(TrackFacts),
    Label(LabelFacts),
}

What a source says, for one kind of entity.

An enum rather than a flat bag of (field, value) strings: the display, the query grammar and doctor all have to know what a field means, and a generic bag pushes that knowledge into string literals scattered through the program. crate::analysis::FileAnalysis made the same choice.

The two variants are not the same size, on purpose

An artist carries twelve fields, one of them a paragraph; a release carries four. Clippy points out that a Facts is therefore as large as its larger variant, and the usual remedy is to box that one. It is the wrong remedy here: artist records are the majority of this layer, so boxing them puts a heap allocation and a pointer chase on the common path in order to shrink the rare one. The whole store is a few hundred rows of a few hundred bytes — under a hundred kilobytes — and it is read once at start-up.

Variants

Artist(ArtistFacts)

About an artist.

Release(ReleaseFacts)

About a release.

Track(TrackFacts)

About one recorded performance, identified by its sound.

Label(LabelFacts)

About a record label, including attributed prose when available.

Implementations

impl Facts

pub fn kind(&self) -> EntityKind

The kind of entity these facts can describe.

This is what makes a record’s entity kind and its contents impossible to contradict each other: the kind is derived from the facts rather than stored beside them.

pub fn is_empty(&self) -> bool

true when the source answered but said nothing at all.

Distinct from having no record: “asked, and it holds nothing about this” and “never asked” are two different states, and the whole layer exists to keep them apart.

Trait Implementations

impl Clone for Facts

fn clone(&self) -> Facts

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Facts

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

Formats the value using the given formatter.

impl PartialEq for Facts

fn eq(&self, other: &Facts) -> 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 Eq for Facts

impl StructuralPartialEq for Facts