Struct DataKey

pub struct DataKey { /* private fields */ }

Used for loading data from an ICU4X data provider.

A resource key is tightly coupled with the code that uses it to load data at runtime. Executables can be searched for DataKey instances to produce optimized data files. Therefore, users should not generally create DataKey instances; they should instead use the ones exported by a component.

DataKeys are created with the data_key! macro:

const K: DataKey = icu_provider::data_key!("foo/bar@1");

The human-readable path string ends with @ followed by one or more digits (the version number). Paths do not contain characters other than ASCII letters and digits, _, /.

Invalid paths are compile-time errors (as data_key! uses const).

const K: DataKey = icu_provider::data_key!("foo/../bar@1");

Implementations

impl DataKey

pub const fn path(self) -> DataKeyPath

Gets a human-readable representation of a DataKey.

The human-readable path string ends with @ followed by one or more digits (the version number). Paths do not contain characters other than ASCII letters and digits, _, /.

Useful for reading and writing data to a file system.

pub const fn hashed(self) -> DataKeyHash

Gets a platform-independent hash of a DataKey.

The hash is 4 bytes and allows for fast key comparison.

Example

use icu_provider::DataKey;
use icu_provider::DataKeyHash;

const KEY: DataKey = icu_provider::data_key!("foo@1");
const KEY_HASH: DataKeyHash = KEY.hashed();

assert_eq!(KEY_HASH.to_bytes(), [0xe2, 0xb6, 0x17, 0x71]);

pub const fn metadata(self) -> DataKeyMetadata

Gets the metadata associated with this DataKey.

pub const fn fallback_config(self) -> LocaleFallbackConfig

Returns the [LocaleFallbackConfig] for this DataKey.

pub const fn from_path_and_metadata( path: DataKeyPath, metadata: DataKeyMetadata, ) -> Self

Constructs a DataKey from a path and metadata.

Examples

use icu_provider::data_key;
use icu_provider::DataKey;

const CONST_KEY: DataKey = data_key!("foo@1");

let runtime_key =
    DataKey::from_path_and_metadata(CONST_KEY.path(), CONST_KEY.metadata());

assert_eq!(CONST_KEY, runtime_key);

pub fn match_key(self, key: Self) -> Result<(), DataError>

Returns Ok if this data key matches the argument, or the appropriate error.

Convenience method for data providers that support a single DataKey.

Examples

use icu_provider::prelude::*;

const FOO_BAR: DataKey = icu_provider::data_key!("foo/bar@1");
const FOO_BAZ: DataKey = icu_provider::data_key!("foo/baz@1");
const BAR_BAZ: DataKey = icu_provider::data_key!("bar/baz@1");

assert!(matches!(FOO_BAR.match_key(FOO_BAR), Ok(())));
assert!(matches!(
    FOO_BAR.match_key(FOO_BAZ),
    Err(DataError {
        kind: DataErrorKind::MissingDataKey,
        ..
    })
));
assert!(matches!(
    FOO_BAR.match_key(BAR_BAZ),
    Err(DataError {
        kind: DataErrorKind::MissingDataKey,
        ..
    })
));

// The error context contains the argument:
assert_eq!(FOO_BAR.match_key(BAR_BAZ).unwrap_err().key, Some(BAR_BAZ));

Trait Implementations

impl Clone for DataKey

fn clone(&self) -> DataKey

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for DataKey

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

Formats the value using the given formatter.

impl Display for DataKey

This trait is implemented for compatibility with fmt!. To create a string, Writeable::write_to_string is usually more efficient.

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

Formats the value using the given formatter.

impl Hash for DataKey

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for DataKey

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for DataKey

fn eq(&self, other: &Self) -> 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 PartialOrd for DataKey

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Writeable for DataKey

fn write_to<W: Write + ?Sized>(&self, sink: &mut W) -> Result

Writes a string to the given sink. Errors from the sink are bubbled up. The default implementation delegates to write_to_parts, and discards any Part annotations.

fn writeable_length_hint(&self) -> LengthHint

Returns a hint for the number of UTF-8 bytes that will be written to the sink.

fn write_to_string(&self) -> Cow<'_, str>

Creates a new String with the data from this Writeable. Like ToString, but smaller and faster.

fn write_to_parts<S>(&self, sink: &mut S) -> Result<(), Error>

where S: PartsWrite + ?Sized,

Write bytes and Part annotations to the given sink. Errors from the sink are bubbled up. The default implementation delegates to write_to, and doesn’t produce any Part annotations.

fn writeable_cmp_bytes(&self, other: &[u8]) -> Ordering

Compares the contents of this Writeable to the given bytes without allocating a String to hold the Writeable contents.

impl Copy for DataKey

impl Eq for DataKey