Cursor

Struct Cursor 

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pub struct Cursor<'a, T: Translator, V: Eq> { /* private fields */ }
Expand description

A mutable iterator over the values associated with a translated key, allowing in-place modifications.

The Cursor provides a way to traverse and modify the linked list of Records while maintaining its structure. It supports:

  • Iteration via next() to access values.
  • Modification via update() to change the current value.
  • Insertion via insert() to add new values.
  • Deletion via delete() to remove values.

§Safety

  • Must call next() before update(), insert(), or delete() to establish a valid position.
  • Once next() returns None, only insert() can be called.
  • Dropping the Cursor automatically restores the list structure by reattaching any detached next nodes.

If you don’t need advanced functionality, just use insert(), insert_and_prune(), or remove() instead.

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impl<'a, T: Translator, V: Eq> Cursor<'a, T, V>

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pub fn update(&mut self, v: V)

Updates the value at the current position in the iteration.

Panics if called before next() or after iteration is complete (Status::Done phase).

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pub fn next(&mut self) -> Option<&V>

Advances the cursor to the next value in the chain, returning a reference to it.

This method must be called before any other operations (insert(), delete(), etc.). If either insert() or delete() is called, next() must be called to set a new active item. If after insert(), the next active item is the item after the inserted item. If after delete(), the next active item is the item after the deleted item.

Handles transitions between phases and adjusts for deletions. Returns None when the list is exhausted. It is safe to call next() even after it returns None.

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pub fn insert(&mut self, v: V)

Inserts a new value at the current position.

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pub fn delete(&mut self)

Deletes the current value, adjusting the list structure.

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impl<T: Translator, V: Eq> Drop for Cursor<'_, T, V>

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl<'a, T, V> Send for Cursor<'a, T, V>
where T: Translator + Send, T::Key: Send, V: Eq + Send,

Auto Trait Implementations§

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impl<'a, T, V> Freeze for Cursor<'a, T, V>

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impl<'a, T, V> RefUnwindSafe for Cursor<'a, T, V>

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impl<'a, T, V> !Sync for Cursor<'a, T, V>

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impl<'a, T, V> Unpin for Cursor<'a, T, V>

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impl<'a, T, V> !UnwindSafe for Cursor<'a, T, V>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FutureExt for T

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fn with_context(self, otel_cx: Context) -> WithContext<Self>

Attaches the provided Context to this type, returning a WithContext wrapper. Read more
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Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> Pointable for T

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const ALIGN: usize

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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Dereferences the given pointer. Read more
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Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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fn and<P, B, E>(self, other: P) -> And<T, P>
where T: Policy<B, E>, P: Policy<B, E>,

Create a new Policy that returns Action::Follow only if self and other return Action::Follow. Read more
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where T: Policy<B, E>, P: Policy<B, E>,

Create a new Policy that returns Action::Follow if either self or other returns Action::Follow. Read more
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The type returned in the event of a conversion error.
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Performs the conversion.
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type Error = <U as TryFrom<T>>::Error

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