time/format_description/
borrowed_format_item.rs

1//! A format item with borrowed data.
2
3#[cfg(feature = "alloc")]
4use alloc::string::String;
5#[cfg(feature = "alloc")]
6use core::fmt;
7
8use crate::error;
9use crate::format_description::Component;
10
11/// A complete description of how to format and parse a type.
12#[non_exhaustive]
13#[cfg_attr(not(feature = "alloc"), derive(Debug))]
14#[derive(Clone, PartialEq, Eq)]
15pub enum BorrowedFormatItem<'a> {
16    /// Bytes that are formatted as-is.
17    ///
18    /// **Note**: These bytes **should** be UTF-8, but are not required to be. The value is passed
19    /// through `String::from_utf8_lossy` when necessary.
20    Literal(&'a [u8]),
21    /// A minimal representation of a single non-literal item.
22    Component(Component),
23    /// A series of literals or components that collectively form a partial or complete
24    /// description.
25    Compound(&'a [Self]),
26    /// A `FormatItem` that may or may not be present when parsing. If parsing fails, there
27    /// will be no effect on the resulting `struct`.
28    ///
29    /// This variant has no effect on formatting, as the value is guaranteed to be present.
30    Optional(&'a Self),
31    /// A series of `FormatItem`s where, when parsing, the first successful parse is used. When
32    /// formatting, the first element of the slice is used.  An empty slice is a no-op when
33    /// formatting or parsing.
34    First(&'a [Self]),
35}
36
37#[cfg(feature = "alloc")]
38impl fmt::Debug for BorrowedFormatItem<'_> {
39    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
40        match self {
41            Self::Literal(literal) => f.write_str(&String::from_utf8_lossy(literal)),
42            Self::Component(component) => component.fmt(f),
43            Self::Compound(compound) => compound.fmt(f),
44            Self::Optional(item) => f.debug_tuple("Optional").field(item).finish(),
45            Self::First(items) => f.debug_tuple("First").field(items).finish(),
46        }
47    }
48}
49
50impl From<Component> for BorrowedFormatItem<'_> {
51    fn from(component: Component) -> Self {
52        Self::Component(component)
53    }
54}
55
56impl TryFrom<BorrowedFormatItem<'_>> for Component {
57    type Error = error::DifferentVariant;
58
59    fn try_from(value: BorrowedFormatItem<'_>) -> Result<Self, Self::Error> {
60        match value {
61            BorrowedFormatItem::Component(component) => Ok(component),
62            _ => Err(error::DifferentVariant),
63        }
64    }
65}
66
67impl<'a> From<&'a [BorrowedFormatItem<'_>]> for BorrowedFormatItem<'a> {
68    fn from(items: &'a [BorrowedFormatItem<'_>]) -> Self {
69        Self::Compound(items)
70    }
71}
72
73impl<'a> TryFrom<BorrowedFormatItem<'a>> for &[BorrowedFormatItem<'a>] {
74    type Error = error::DifferentVariant;
75
76    fn try_from(value: BorrowedFormatItem<'a>) -> Result<Self, Self::Error> {
77        match value {
78            BorrowedFormatItem::Compound(items) => Ok(items),
79            _ => Err(error::DifferentVariant),
80        }
81    }
82}
83
84impl PartialEq<Component> for BorrowedFormatItem<'_> {
85    fn eq(&self, rhs: &Component) -> bool {
86        matches!(self, Self::Component(component) if component == rhs)
87    }
88}
89
90impl PartialEq<BorrowedFormatItem<'_>> for Component {
91    fn eq(&self, rhs: &BorrowedFormatItem<'_>) -> bool {
92        rhs == self
93    }
94}
95
96impl PartialEq<&[Self]> for BorrowedFormatItem<'_> {
97    fn eq(&self, rhs: &&[Self]) -> bool {
98        matches!(self, Self::Compound(compound) if compound == rhs)
99    }
100}
101
102impl PartialEq<BorrowedFormatItem<'_>> for &[BorrowedFormatItem<'_>] {
103    fn eq(&self, rhs: &BorrowedFormatItem<'_>) -> bool {
104        rhs == self
105    }
106}
time/format_description/borrowed_format_item.rs

time/format_description/
borrowed_format_item.rs
