Struct tikv_client::BoundRange

pub struct BoundRange {
    pub from: Bound<Key>,
    pub to: Bound<Key>,
}

A struct for expressing ranges. This type is semi-opaque and is not really meant for users to deal with directly. Most functions which operate on ranges will accept any types which implement Into<BoundRange>.

In TiKV, keys are an ordered sequence of bytes. This means we can have ranges over those bytes. Eg 001 is before 010.

Minimum key: there is the minimum key: empty key. So a range may not be unbounded below. The unbounded lower bound in a Range will be converted to an empty key.

Maximum key: There is no limit of the maximum key. When an empty key is used as the upper bound, it means upper unbounded. The unbounded upper bound in a Range. The range covering all keys is just Key::EMPTY...

But, you should not need to worry about all this: Most functions which operate on ranges will accept any types which implement Into<BoundRange>. Common range types like a..b, a..=b has implemented Into<BoundRange>where a and b impl Into<Key>. You can implement Into<BoundRange> for your own types by using try_from. It means all of the following types in the example can be passed directly to those functions.

Examples

let explict_range: Range<Key> = Range { start: Key::from("Rust".to_owned()), end: Key::from("TiKV".to_owned()) };
let from_explict_range: BoundRange = explict_range.into();

let range: Range<String> = "Rust".to_owned().."TiKV".to_owned();
let from_range: BoundRange = range.into();
assert_eq!(from_explict_range, from_range);

let range: RangeInclusive<String> = "Rust".to_owned()..="TiKV".to_owned();
let from_range: BoundRange = range.into();
assert_eq!(
    from_range,
    (Bound::Included(Key::from("Rust".to_owned())), Bound::Included(Key::from("TiKV".to_owned()))),
);

let range_from: RangeFrom<String> = "Rust".to_owned()..;
let from_range_from: BoundRange = range_from.into();
assert_eq!(
    from_range_from,
    (Bound::Included(Key::from("Rust".to_owned())), Bound::Unbounded),
);

Fields

from: Bound<Key>

to: Bound<Key>

Implementations

impl BoundRange

pub fn new(from: Bound<Key>, to: Bound<Key>) -> BoundRange

Create a new BoundRange.

The caller must ensure that from is not Unbounded.

pub fn range_from(from: Key) -> BoundRange

Create a new BoundRange bounded below by from and unbounded above.

pub fn into_keys(self) -> (Key, Option<Key>)

Ranges used in scanning TiKV have a particularity to them.

The start of a scan is inclusive, unless appended with an ‘\0’, then it is exclusive.

The end of a scan is exclusive, unless appended with an ‘\0’, then it is inclusive.

Examples

use tikv_client::{BoundRange, Key, IntoOwnedRange};
// Exclusive
let range = "a".."z";
assert_eq!(
    BoundRange::from(range.into_owned()).into_keys(),
    (Key::from("a".to_owned()), Some(Key::from("z".to_owned()))),
);
// Inclusive
let range = "a"..="z";
assert_eq!(
    BoundRange::from(range.into_owned()).into_keys(),
    (Key::from("a".to_owned()), Some(Key::from("z\0".to_owned()))),
);
// Open right
let range = "a".to_owned()..;
assert_eq!(
    BoundRange::from(range).into_keys(),
    (Key::from("a".to_owned()), None),
);
// Left open right exclusive
let range = .."z";
assert_eq!(
    BoundRange::from(range.into_owned()).into_keys(),
    (Key::from("".to_owned()), Some(Key::from("z".to_owned()))),
);
// Left open right inclusive
let range = ..="z";
assert_eq!(
    BoundRange::from(range.into_owned()).into_keys(),
    (Key::from("".to_owned()), Some(Key::from("z\0".to_owned()))),
);
// Full range
let range = ..;
assert_eq!(
    BoundRange::from(range).into_keys(),
    (Key::from("".to_owned()), None),
);

Trait Implementations

impl Clone for BoundRange

fn clone(&self) -> BoundRange

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for BoundRange

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

Formats the value using the given formatter.

impl<T: Into<Key> + Eq> From<(Bound<T>, Bound<T>)> for BoundRange

fn from(bounds: (Bound<T>, Bound<T>)) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<(T, Option<T>)> for BoundRange

fn from(other: (T, Option<T>)) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<(T, T)> for BoundRange

fn from(other: (T, T)) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<Range<T>> for BoundRange

fn from(other: Range<T>) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<RangeFrom<T>> for BoundRange

fn from(other: RangeFrom<T>) -> BoundRange

Converts to this type from the input type.

impl From<RangeFull> for BoundRange

fn from(_other: RangeFull) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<RangeInclusive<T>> for BoundRange

fn from(other: RangeInclusive<T>) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<RangeTo<T>> for BoundRange

fn from(other: RangeTo<T>) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key>> From<RangeToInclusive<T>> for BoundRange

fn from(other: RangeToInclusive<T>) -> BoundRange

Converts to this type from the input type.

impl<T: Into<Key> + Clone> PartialEq<(Bound<T>, Bound<T>)> for BoundRange

fn eq(&self, other: &(Bound<T>, Bound<T>)) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for BoundRange

fn eq(&self, other: &BoundRange) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RangeBounds<Key> for BoundRange

fn start_bound(&self) -> Bound<&Key>

Start index bound.

fn end_bound(&self) -> Bound<&Key>

End index bound.

fn contains<U>(&self, item: &U) -> boolwhere T: PartialOrd<U>, U: PartialOrd<T> + ?Sized,

Returns true if item is contained in the range.

impl Eq for BoundRange

impl StructuralEq for BoundRange

impl StructuralPartialEq for BoundRange