Struct jammdb::Cursor [−][src]
An iterator over a bucket
A cursor is created by using the cursor
function on a [Bucket
]. It's primary purpose is to be an Iterator
over
the bucket's Data
. By default, a newly created cursor will start at the first
element in the bucket (sorted by key), but you can use the seek
method to
move the cursor to a certain key / prefix before beginning to iterate.
Note that if the key you seek to exists, the cursor will begin to iterate after the
Examples
use jammdb::{DB, Data}; let db = DB::open("my.db")?; let mut tx = db.tx(false)?; let bucket = tx.get_bucket("my-bucket")?; // create a cursor and use it to iterate over the entire bucket for data in bucket.cursor() { match &*data { Data::Bucket(b) => println!("found a bucket with the name {:?}", b.name()), Data::KeyValue(kv) => println!("found a kv pair {:?} {:?}", kv.key(), kv.value()), } } let mut cursor = bucket.cursor(); // seek to the key "f" // if it doesn't exist, it will start at the position wh cursor.seek("f"); // for data in cursor { }
Implementations
impl<'a> Cursor<'a>
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pub fn seek<T: AsRef<[u8]>>(&mut self, key: T) -> bool
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Moves the cursor to the given key. If the key does not exist, the cursor stops "just before" where the key would be.
Returns whether or not the key exists in the bucket.
pub fn current(&self) -> Option<Data>
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Returns the data at the cursor's current position.
You can use this to get data after doing a seek
.
Trait Implementations
impl<'a> Iterator for Cursor<'a>
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type Item = Ref<'a, Data>
The type of the elements being iterated over.
fn next(&mut self) -> Option<Self::Item>
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pub fn size_hint(&self) -> (usize, Option<usize>)
1.0.0[src]
pub fn count(self) -> usize
1.0.0[src]
pub fn last(self) -> Option<Self::Item>
1.0.0[src]
pub fn advance_by(&mut self, n: usize) -> Result<(), usize>
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pub fn nth(&mut self, n: usize) -> Option<Self::Item>
1.0.0[src]
pub fn step_by(self, step: usize) -> StepBy<Self>
1.28.0[src]
pub fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator<Item = Self::Item>,
1.0.0[src]
U: IntoIterator<Item = Self::Item>,
pub fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator,
1.0.0[src]
U: IntoIterator,
pub fn intersperse(self, separator: Self::Item) -> Intersperse<Self> where
Self::Item: Clone,
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Self::Item: Clone,
pub fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G> where
G: FnMut() -> Self::Item,
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G: FnMut() -> Self::Item,
pub fn map<B, F>(self, f: F) -> Map<Self, F> where
F: FnMut(Self::Item) -> B,
1.0.0[src]
F: FnMut(Self::Item) -> B,
pub fn for_each<F>(self, f: F) where
F: FnMut(Self::Item),
1.21.0[src]
F: FnMut(Self::Item),
pub fn filter<P>(self, predicate: P) -> Filter<Self, P> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
pub fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
F: FnMut(Self::Item) -> Option<B>,
1.0.0[src]
F: FnMut(Self::Item) -> Option<B>,
pub fn enumerate(self) -> Enumerate<Self>
1.0.0[src]
pub fn peekable(self) -> Peekable<Self>
1.0.0[src]
pub fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
pub fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
pub fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P> where
P: FnMut(Self::Item) -> Option<B>,
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P: FnMut(Self::Item) -> Option<B>,
pub fn skip(self, n: usize) -> Skip<Self>
1.0.0[src]
pub fn take(self, n: usize) -> Take<Self>
1.0.0[src]
pub fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
F: FnMut(&mut St, Self::Item) -> Option<B>,
1.0.0[src]
F: FnMut(&mut St, Self::Item) -> Option<B>,
pub fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
F: FnMut(Self::Item) -> U,
U: IntoIterator,
1.0.0[src]
F: FnMut(Self::Item) -> U,
U: IntoIterator,
pub fn flatten(self) -> Flatten<Self> where
Self::Item: IntoIterator,
1.29.0[src]
Self::Item: IntoIterator,
pub fn fuse(self) -> Fuse<Self>
1.0.0[src]
pub fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnMut(&Self::Item),
1.0.0[src]
F: FnMut(&Self::Item),
pub fn by_ref(&mut self) -> &mut Self
1.0.0[src]
#[must_use =
"if you really need to exhaust the iterator, consider `.for_each(drop)` instead"]pub fn collect<B>(self) -> B where
B: FromIterator<Self::Item>,
1.0.0[src]
B: FromIterator<Self::Item>,
pub fn partition<B, F>(self, f: F) -> (B, B) where
F: FnMut(&Self::Item) -> bool,
B: Default + Extend<Self::Item>,
1.0.0[src]
F: FnMut(&Self::Item) -> bool,
B: Default + Extend<Self::Item>,
pub fn partition_in_place<'a, T, P>(self, predicate: P) -> usize where
Self: DoubleEndedIterator<Item = &'a mut T>,
T: 'a,
P: FnMut(&T) -> bool,
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Self: DoubleEndedIterator<Item = &'a mut T>,
T: 'a,
P: FnMut(&T) -> bool,
pub fn is_partitioned<P>(self, predicate: P) -> bool where
P: FnMut(Self::Item) -> bool,
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P: FnMut(Self::Item) -> bool,
pub fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, Self::Item) -> R,
R: Try<Ok = B>,
1.27.0[src]
F: FnMut(B, Self::Item) -> R,
R: Try<Ok = B>,
pub fn try_for_each<F, R>(&mut self, f: F) -> R where
F: FnMut(Self::Item) -> R,
R: Try<Ok = ()>,
1.27.0[src]
F: FnMut(Self::Item) -> R,
R: Try<Ok = ()>,
pub fn fold<B, F>(self, init: B, f: F) -> B where
F: FnMut(B, Self::Item) -> B,
1.0.0[src]
F: FnMut(B, Self::Item) -> B,
pub fn reduce<F>(self, f: F) -> Option<Self::Item> where
F: FnMut(Self::Item, Self::Item) -> Self::Item,
1.51.0[src]
F: FnMut(Self::Item, Self::Item) -> Self::Item,
pub fn all<F>(&mut self, f: F) -> bool where
F: FnMut(Self::Item) -> bool,
1.0.0[src]
F: FnMut(Self::Item) -> bool,
pub fn any<F>(&mut self, f: F) -> bool where
F: FnMut(Self::Item) -> bool,
1.0.0[src]
F: FnMut(Self::Item) -> bool,
pub fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
pub fn find_map<B, F>(&mut self, f: F) -> Option<B> where
F: FnMut(Self::Item) -> Option<B>,
1.30.0[src]
F: FnMut(Self::Item) -> Option<B>,
pub fn try_find<F, R>(
&mut self,
f: F
) -> Result<Option<Self::Item>, <R as Try>::Error> where
F: FnMut(&Self::Item) -> R,
R: Try<Ok = bool>,
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&mut self,
f: F
) -> Result<Option<Self::Item>, <R as Try>::Error> where
F: FnMut(&Self::Item) -> R,
R: Try<Ok = bool>,
pub fn position<P>(&mut self, predicate: P) -> Option<usize> where
P: FnMut(Self::Item) -> bool,
1.0.0[src]
P: FnMut(Self::Item) -> bool,
pub fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
Self: ExactSizeIterator + DoubleEndedIterator,
P: FnMut(Self::Item) -> bool,
1.0.0[src]
Self: ExactSizeIterator + DoubleEndedIterator,
P: FnMut(Self::Item) -> bool,
pub fn max(self) -> Option<Self::Item> where
Self::Item: Ord,
1.0.0[src]
Self::Item: Ord,
pub fn min(self) -> Option<Self::Item> where
Self::Item: Ord,
1.0.0[src]
Self::Item: Ord,
pub fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where
F: FnMut(&Self::Item) -> B,
B: Ord,
1.6.0[src]
F: FnMut(&Self::Item) -> B,
B: Ord,
pub fn max_by<F>(self, compare: F) -> Option<Self::Item> where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.15.0[src]
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
pub fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where
F: FnMut(&Self::Item) -> B,
B: Ord,
1.6.0[src]
F: FnMut(&Self::Item) -> B,
B: Ord,
pub fn min_by<F>(self, compare: F) -> Option<Self::Item> where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
1.15.0[src]
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
pub fn rev(self) -> Rev<Self> where
Self: DoubleEndedIterator,
1.0.0[src]
Self: DoubleEndedIterator,
pub fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
Self: Iterator<Item = (A, B)>,
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
1.0.0[src]
Self: Iterator<Item = (A, B)>,
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
pub fn copied<'a, T>(self) -> Copied<Self> where
Self: Iterator<Item = &'a T>,
T: 'a + Copy,
1.36.0[src]
Self: Iterator<Item = &'a T>,
T: 'a + Copy,
pub fn cloned<'a, T>(self) -> Cloned<Self> where
Self: Iterator<Item = &'a T>,
T: 'a + Clone,
1.0.0[src]
Self: Iterator<Item = &'a T>,
T: 'a + Clone,
pub fn cycle(self) -> Cycle<Self> where
Self: Clone,
1.0.0[src]
Self: Clone,
pub fn sum<S>(self) -> S where
S: Sum<Self::Item>,
1.11.0[src]
S: Sum<Self::Item>,
pub fn product<P>(self) -> P where
P: Product<Self::Item>,
1.11.0[src]
P: Product<Self::Item>,
pub fn cmp<I>(self, other: I) -> Ordering where
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
1.5.0[src]
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
pub fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
I: IntoIterator,
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F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
I: IntoIterator,
pub fn partial_cmp<I>(self, other: I) -> Option<Ordering> where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
pub fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
I: IntoIterator,
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F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
I: IntoIterator,
pub fn eq<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
pub fn eq_by<I, F>(self, other: I, eq: F) -> bool where
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
I: IntoIterator,
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F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
I: IntoIterator,
pub fn ne<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
pub fn lt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
pub fn le<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
pub fn gt<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
pub fn ge<I>(self, other: I) -> bool where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
1.5.0[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
pub fn is_sorted(self) -> bool where
Self::Item: PartialOrd<Self::Item>,
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Self::Item: PartialOrd<Self::Item>,
pub fn is_sorted_by<F>(self, compare: F) -> bool where
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
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F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
pub fn is_sorted_by_key<F, K>(self, f: F) -> bool where
K: PartialOrd<K>,
F: FnMut(Self::Item) -> K,
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K: PartialOrd<K>,
F: FnMut(Self::Item) -> K,
Auto Trait Implementations
impl<'a> !RefUnwindSafe for Cursor<'a>
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impl<'a> !Send for Cursor<'a>
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impl<'a> !Sync for Cursor<'a>
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impl<'a> Unpin for Cursor<'a>
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impl<'a> !UnwindSafe for Cursor<'a>
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Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<I> IntoIterator for I where
I: Iterator,
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I: Iterator,
type Item = <I as Iterator>::Item
The type of the elements being iterated over.
type IntoIter = I
Which kind of iterator are we turning this into?
pub fn into_iter(self) -> I
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impl<T> Same<T> for T
type Output = T
Should always be Self
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,