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//! A format item with owned data.
use alloc::boxed::Box;
use alloc::string::String;
use alloc::vec::Vec;
use core::fmt;
use crate::error;
use crate::format_description::{BorrowedFormatItem, Component};
/// A complete description of how to format and parse a type.
#[non_exhaustive]
#[derive(Clone, PartialEq, Eq)]
pub enum OwnedFormatItem {
/// Bytes that are formatted as-is.
///
/// **Note**: These bytes **should** be UTF-8, but are not required to be. The value is passed
/// through `String::from_utf8_lossy` when necessary.
Literal(Box<[u8]>),
/// A minimal representation of a single non-literal item.
Component(Component),
/// A series of literals or components that collectively form a partial or complete
/// description.
Compound(Box<[Self]>),
/// A `FormatItem` that may or may not be present when parsing. If parsing fails, there
/// will be no effect on the resulting `struct`.
///
/// This variant has no effect on formatting, as the value is guaranteed to be present.
Optional(Box<Self>),
/// A series of `FormatItem`s where, when parsing, the first successful parse is used. When
/// formatting, the first element of the [`Vec`] is used. An empty [`Vec`] is a no-op when
/// formatting or parsing.
First(Box<[Self]>),
}
impl fmt::Debug for OwnedFormatItem {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Literal(literal) => f.write_str(&String::from_utf8_lossy(literal)),
Self::Component(component) => component.fmt(f),
Self::Compound(compound) => compound.fmt(f),
Self::Optional(item) => f.debug_tuple("Optional").field(item).finish(),
Self::First(items) => f.debug_tuple("First").field(items).finish(),
}
}
}
// region: conversions from FormatItem
impl From<BorrowedFormatItem<'_>> for OwnedFormatItem {
fn from(item: BorrowedFormatItem<'_>) -> Self {
(&item).into()
}
}
impl From<&BorrowedFormatItem<'_>> for OwnedFormatItem {
fn from(item: &BorrowedFormatItem<'_>) -> Self {
match item {
BorrowedFormatItem::Literal(literal) => {
Self::Literal(literal.to_vec().into_boxed_slice())
}
BorrowedFormatItem::Component(component) => Self::Component(*component),
BorrowedFormatItem::Compound(compound) => Self::Compound(
compound
.iter()
.cloned()
.map(Into::into)
.collect::<Vec<_>>()
.into_boxed_slice(),
),
BorrowedFormatItem::Optional(item) => Self::Optional(Box::new((*item).into())),
BorrowedFormatItem::First(items) => Self::First(
items
.iter()
.cloned()
.map(Into::into)
.collect::<Vec<_>>()
.into_boxed_slice(),
),
}
}
}
impl From<Vec<BorrowedFormatItem<'_>>> for OwnedFormatItem {
fn from(items: Vec<BorrowedFormatItem<'_>>) -> Self {
items.as_slice().into()
}
}
impl<'a, T: AsRef<[BorrowedFormatItem<'a>]> + ?Sized> From<&T> for OwnedFormatItem {
fn from(items: &T) -> Self {
Self::Compound(
items
.as_ref()
.iter()
.cloned()
.map(Into::into)
.collect::<Vec<_>>()
.into_boxed_slice(),
)
}
}
// endregion conversions from FormatItem
// region: from variants
impl From<Component> for OwnedFormatItem {
fn from(component: Component) -> Self {
Self::Component(component)
}
}
impl TryFrom<OwnedFormatItem> for Component {
type Error = error::DifferentVariant;
fn try_from(value: OwnedFormatItem) -> Result<Self, Self::Error> {
match value {
OwnedFormatItem::Component(component) => Ok(component),
_ => Err(error::DifferentVariant),
}
}
}
impl From<Vec<Self>> for OwnedFormatItem {
fn from(items: Vec<Self>) -> Self {
Self::Compound(items.into_boxed_slice())
}
}
impl TryFrom<OwnedFormatItem> for Vec<OwnedFormatItem> {
type Error = error::DifferentVariant;
fn try_from(value: OwnedFormatItem) -> Result<Self, Self::Error> {
match value {
OwnedFormatItem::Compound(items) => Ok(items.into_vec()),
_ => Err(error::DifferentVariant),
}
}
}
// endregion from variants
// region: equality
impl PartialEq<Component> for OwnedFormatItem {
fn eq(&self, rhs: &Component) -> bool {
matches!(self, Self::Component(component) if component == rhs)
}
}
impl PartialEq<OwnedFormatItem> for Component {
fn eq(&self, rhs: &OwnedFormatItem) -> bool {
rhs == self
}
}
impl PartialEq<&[Self]> for OwnedFormatItem {
fn eq(&self, rhs: &&[Self]) -> bool {
matches!(self, Self::Compound(compound) if &&**compound == rhs)
}
}
impl PartialEq<OwnedFormatItem> for &[OwnedFormatItem] {
fn eq(&self, rhs: &OwnedFormatItem) -> bool {
rhs == self
}
}
// endregion equality