Source code
Revision control
Copy as Markdown
Other Tools
//! A format item with borrowed data.
#[cfg(feature = "alloc")]
use alloc::string::String;
#[cfg(feature = "alloc")]
use core::fmt;
use crate::error;
use crate::format_description::Component;
/// A complete description of how to format and parse a type.
#[non_exhaustive]
#[cfg_attr(not(feature = "alloc"), derive(Debug))]
#[derive(Clone, PartialEq, Eq)]
pub enum BorrowedFormatItem<'a> {
/// Bytes that are formatted as-is.
///
/// **Note**: If you call the `format` method that returns a `String`, these bytes will be
/// passed through `String::from_utf8_lossy`.
Literal(&'a [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(&'a [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(&'a Self),
/// A series of `FormatItem`s where, when parsing, the first successful parse is used. When
/// formatting, the first element of the slice is used. An empty slice is a no-op when
/// formatting or parsing.
First(&'a [Self]),
}
#[cfg(feature = "alloc")]
impl fmt::Debug for BorrowedFormatItem<'_> {
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(),
}
}
}
impl From<Component> for BorrowedFormatItem<'_> {
fn from(component: Component) -> Self {
Self::Component(component)
}
}
impl TryFrom<BorrowedFormatItem<'_>> for Component {
type Error = error::DifferentVariant;
fn try_from(value: BorrowedFormatItem<'_>) -> Result<Self, Self::Error> {
match value {
BorrowedFormatItem::Component(component) => Ok(component),
_ => Err(error::DifferentVariant),
}
}
}
impl<'a> From<&'a [BorrowedFormatItem<'_>]> for BorrowedFormatItem<'a> {
fn from(items: &'a [BorrowedFormatItem<'_>]) -> Self {
Self::Compound(items)
}
}
impl<'a> TryFrom<BorrowedFormatItem<'a>> for &[BorrowedFormatItem<'a>] {
type Error = error::DifferentVariant;
fn try_from(value: BorrowedFormatItem<'a>) -> Result<Self, Self::Error> {
match value {
BorrowedFormatItem::Compound(items) => Ok(items),
_ => Err(error::DifferentVariant),
}
}
}
impl PartialEq<Component> for BorrowedFormatItem<'_> {
fn eq(&self, rhs: &Component) -> bool {
matches!(self, Self::Component(component) if component == rhs)
}
}
impl PartialEq<BorrowedFormatItem<'_>> for Component {
fn eq(&self, rhs: &BorrowedFormatItem<'_>) -> bool {
rhs == self
}
}
impl PartialEq<&[Self]> for BorrowedFormatItem<'_> {
fn eq(&self, rhs: &&[Self]) -> bool {
matches!(self, Self::Compound(compound) if compound == rhs)
}
}
impl PartialEq<BorrowedFormatItem<'_>> for &[BorrowedFormatItem<'_>] {
fn eq(&self, rhs: &BorrowedFormatItem<'_>) -> bool {
rhs == self
}
}