Struct YUndoEvent 

#[repr(C)]
pub struct YUndoEvent {
    pub kind: c_char,
    pub origin: *const c_char,
    pub origin_len: u32,
    pub meta: *mut c_void,
}

Event type related to UndoManager observer operations, such as yundo_manager_observe_popped and yundo_manager_observe_added. It contains various informations about the context in which undo/redo operations are executed.

Fields

kind: c_char

Informs if current event is related to executed undo (Y_KIND_UNDO) or redo (Y_KIND_REDO) operation.

origin: *const c_char

Origin assigned to a transaction, in context of which this event is being executed. Transaction origin is specified via ydoc_write_transaction(doc, origin_len, origin).

origin_len: u32

Length of an origin field assigned to a transaction, in context of which this event is being executed. Transaction origin is specified via ydoc_write_transaction(doc, origin_len, origin).

meta: *mut c_void

Pointer to a custom metadata object that can be passed between yundo_manager_observe_popped and yundo_manager_observe_added. It’s useful for passing around custom user data ie. cursor position, that needs to be remembered and restored as part of undo/redo operations.

This field always starts with no value (NULL) assigned to it and can be set/unset in corresponding callback calls. In such cases it’s up to a programmer to handle allocation and deallocation of memory that this pointer will point to. Not releasing it properly may lead to memory leaks.