Enum TreeChange 

enum TreeChange {
    New,
    Moved,
    PendingMove,
    Removed,
}

Tracks changes to a node’s relation to the tree within an update.

This is used to remove nodes from the accessibility tree’s cache when they are no longer in the tree.

Variants

New

The node was newly created in this update.

Moved

The node has been re-parented in this update.

PendingMove

The node has been added to its new parent, but not yet removed from its old parent.

When a node is moved within the tree, it must be both removed from its old parent and added to its new parent within the same update. This may happen in either order, depending on the relative positions of the node before and after it moves.

• If a node’s new parent is updated before its old parent, the node will be in a TreeChange::PendingMove state until its old parent is updated. We expect that it must later be removed from its old parent, at which point its state will be updated to TreeChange::Moved.
• If a node’s old parent is updated before its new parent, the node will be first TreeChange::Removed and then TreeChange::Moved.

At the end of the update, we assert that there are no pending moves remaining.

Removed

The node is no longer a child of its previous parent.

Trait Implementations

impl Clone for TreeChange

fn clone(&self) -> TreeChange

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TreeChange

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

Formats the value using the given formatter.

impl PartialEq for TreeChange

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Copy for TreeChange

impl StructuralPartialEq for TreeChange