Struct ostd::collections::xarray::CursorMut

pub struct CursorMut<'a, I, M>
where
    I: ItemEntry,
    M: Into<XMark>,
{ /* private fields */ }

A CursorMut can traverse in the XArray by setting or increasing the target index and can perform read-write operations to the target item represented by the target index.

CursorMuts act like exclusive references, so multiple cursors are not allowed to operate on a single XArray at the same time.

The typical way to obtain a CursorMut instance is to call XArray::cursor_mut.

Features for COW (Copy-On-Write). Due to COW, multiple XArrays can share the same piece of data. As a result, CursorMut does not always have exclusive access to the items stored in the XArray. However, just before performing the modification, CursorMut will create exclusive copies by cloning shared items, which guarantees the isolation of data stored in different XArrays.

Implementations

impl<'a, I, M> CursorMut<'a, I, M>

where I: ItemEntry, M: Into<XMark>,

pub fn reset_to(&mut self, index: u64)

Resets the target index to index.

Once set, the cursor will be positioned on the corresponding leaf node, if the leaf node exists.

pub fn index(&self) -> u64

Returns the target index of the cursor.

pub fn next(&mut self)

Increases the target index of the cursor by one.

Once increased, the cursor will be positioned on the corresponding leaf node, if the leaf node exists.

pub fn load(&mut self) -> Option<<I as ItemEntry>::Ref<'_>>

Loads the item at the target index.

If the target item exists, this method will return a ItemEntry::Ref that acts exactly like a &'_ I wrapped in Some(_). Otherwises, it will return None.

pub fn is_marked(&mut self, mark: M) -> bool

Checks whether the target item is marked with the input mark.

If the target item does not exist, this method will also return false.

pub fn store(&mut self, item: I) -> Option<I>

Stores a new item at the target index, and returns the old item if it previously exists.

pub fn remove(&mut self) -> Option<I>

Removes the item at the target index, and returns the removed item if it previously exists.

pub fn set_mark(&mut self, mark: M) -> Result<(), ()>

Sets the input mark for the item at the target index if the target item exists, otherwise returns an error.

pub fn unset_mark(&mut self, mark: M) -> Result<(), ()>

Unsets the input mark for the item at the target index if the target item exists, otherwise returns an error.

Trait Implementations

impl<'a, I, M> Drop for CursorMut<'a, I, M>

where I: ItemEntry, M: Into<XMark>,

fn drop(&mut self)

Executes the destructor for this type.