sequence: add enumerate()

This commit is contained in:
Michael Sippel 2022-10-23 14:48:39 +02:00
parent 5dd4773205
commit 906cc51329
2 changed files with 87 additions and 0 deletions

View file

@ -0,0 +1,86 @@
use {
crate::{
core::{Observer, ObserverBroadcast, ObserverExt, OuterViewPort, View, ViewPort},
sequence::SequenceView,
},
std::sync::Arc,
std::sync::RwLock,
};
//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
impl<Item: 'static> OuterViewPort<dyn SequenceView<Item = Item>> {
pub fn enumerate(&self) -> OuterViewPort<dyn SequenceView<Item = (usize, Item)>> {
let port = ViewPort::new();
port.add_update_hook(Arc::new(self.0.clone()));
let map = Arc::new(RwLock::new(EnumerateSequence {
src_view: None,
cast: port.inner().get_broadcast(),
}));
self.add_observer(map.clone());
port.inner().set_view(Some(map));
port.into_outer()
}
}
//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
pub struct EnumerateSequence<SrcView>
where
SrcView: SequenceView + ?Sized,
{
src_view: Option<Arc<SrcView>>,
cast: Arc<RwLock<ObserverBroadcast<dyn SequenceView<Item = (usize, SrcView::Item)>>>>,
}
//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
impl<SrcView> View for EnumerateSequence<SrcView>
where
SrcView: SequenceView + ?Sized,
{
type Msg = usize;
}
impl<SrcView> SequenceView for EnumerateSequence<SrcView>
where
SrcView: SequenceView + ?Sized
{
type Item = (usize, SrcView::Item);
fn len(&self) -> Option<usize> {
self.src_view.len()
}
fn get(&self, idx: &usize) -> Option<(usize, SrcView::Item)> {
self.src_view.get(idx).map(|item| (*idx, item))
}
}
//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
impl<SrcView> Observer<SrcView> for EnumerateSequence<SrcView>
where
SrcView: SequenceView + ?Sized
{
fn reset(&mut self, view: Option<Arc<SrcView>>) {
let old_len = self.len();
self.src_view = view;
let new_len = self.len();
if let Some(len) = old_len {
self.cast.notify_each(0..len);
}
if let Some(len) = new_len {
self.cast.notify_each(0..len);
}
}
fn notify(&mut self, msg: &usize) {
self.cast.notify(msg);
}
}

View file

@ -1,5 +1,6 @@
pub mod filter;
pub mod map;
pub mod enumerate;
pub mod seq2idx;
pub mod flatten;
pub mod decorator;