Struct kalloc::list::CursorMut

pub struct CursorMut<'a, T: 'a> { /* fields omitted */ }

A cursor over a List with editing operations.

A Cursor is like an iterator, except that it can freely seek back-and-forth, and can safely mutate the list during iteration. This is because the lifetime of its yielded references is tied to its own lifetime, instead of just the underlying list. This means cursors cannot yield multiple elements at once.

Cursors always rest between two elements in the list, and index in a logically circular way. To accommodate this, there is a “ghost” non-element that yields None between the head and tail of the list.

Implementations

impl<'a, T> CursorMut<'a, T>

pub fn index(&self) -> Option<usize>

Returns the cursor position index within the List.

This returns None if the cursor is currently pointing to the “ghost” non-element.

pub fn move_next(&mut self)

Moves the cursor to the next element of the List.

If the cursor is pointing to the “ghost” non-element then this will move it to the first element of the List. If it is pointing to the last element of the List then this will move it to the “ghost” non-element.

pub fn move_prev(&mut self)

Moves the cursor to the previous element of the List.

If the cursor is pointing to the “ghost” non-element then this will move it to the last element of the List. If it is pointing to the first element of the List then this will move it to the “ghost” non-element.

pub fn current(&mut self) -> Option<&mut T>

Returns a reference to the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

pub fn peek_next(&mut self) -> Option<&mut T>

Returns a reference to the next element.

If the cursor is pointing to the “ghost” non-element then this returns the first element of the List. If it is pointing to the last element of the List then this returns None.

pub fn peek_prev(&mut self) -> Option<&mut T>

Returns a reference to the previous element.

If the cursor is pointing to the “ghost” non-element then this returns the last element of the List. If it is pointing to the first element of the List then this returns None.

pub fn as_cursor(&self) -> Cursor<'_, T>

Returns a read-only cursor pointing to the current element.

The lifetime of the returned Cursor is bound to that of the CursorMut, which means it cannot outlive the CursorMut and that the CursorMut is frozen for the lifetime of the Cursor.

impl<'a, T> CursorMut<'a, T>

pub fn insert_after(&mut self, item: T) -> Result<(), AllocError>

Inserts a new element into the List after the current one.

If the cursor is pointing at the “ghost” non-element then the new element is inserted at the front of the List.

pub fn insert_before(&mut self, item: T) -> Result<(), AllocError>

Inserts a new element into the List before the current one.

If the cursor is pointing at the “ghost” non-element then the new element is inserted at the end of the List.

pub fn remove_current(&mut self) -> Option<T>

Removes the current element from the List.

The element that was removed is returned, and the cursor is moved to point to the next element in the List.

If the cursor is currently pointing to the “ghost” non-element then no element is removed and None is returned.

pub fn remove_current_as_list(&mut self) -> Option<List<T>>

Removes the current element from the List without deallocating the list node.

The node that was removed is returned as a new List containing only this node. The cursor is moved to point to the next element in the current List.

If the cursor is currently pointing to the “ghost” non-element then no element is removed and None is returned.

pub fn splice_after(&mut self, list: List<T>)

Inserts the elements from the given List after the current one.

If the cursor is pointing at the “ghost” non-element then the new elements are inserted at the start of the List.

pub fn splice_before(&mut self, list: List<T>)

Inserts the elements from the given List before the current one.

If the cursor is pointing at the “ghost” non-element then the new elements are inserted at the end of the List.

pub fn split_after(&mut self) -> List<T>

Splits the list into two after the current element. This will return a new list consisting of everything after the cursor, with the original list retaining everything before.

If the cursor is pointing at the “ghost” non-element then the entire contents of the List are moved.

pub fn split_before(&mut self) -> List<T>

Splits the list into two before the current element. This will return a new list consisting of everything before the cursor, with the original list retaining everything after.

If the cursor is pointing at the “ghost” non-element then the entire contents of the List are moved.

Trait Implementations

impl<T: Debug> Debug for CursorMut<'_, T>

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

Formats the value using the given formatter.

impl<T: Send> Send for CursorMut<'_, T>

impl<T: Sync> Sync for CursorMut<'_, T>