It shows that making the stateless GUI work with list scrolling... ne…

…eds state

Either we keep the GUI elements around and let them handle it, or the
main app has additional update calls to compute what it has to.

src/interactive/app.rs

@@ -1,12 +1,15 @@
-use super::widgets::{DisplayState, MainWindow};
-use crate::{path_of, sorted_entries, traverse::Traversal, ByteFormat, WalkOptions, WalkResult};
+use crate::{
+ interactive::widgets::{DisplayState, MainWindow},
+ path_of, sorted_entries,
+ traverse::Traversal,
+ ByteFormat, WalkOptions, WalkResult,
+};
 use failure::Error;
 use itertools::Itertools;
 use petgraph::Direction;
 use std::{io, path::PathBuf};
 use termion::input::{Keys, TermReadEventsAndRaw};
-use tui::widgets::Widget;
-use tui::{backend::Backend, Terminal};
+use tui::{backend::Backend, widgets::Widget, Terminal};
 
 /// Options to configure how we display things
 #[derive(Clone, Copy)]
@@ -159,9 +162,10 @@ impl TerminalApp {
  let full_screen = f.size();
  let state = DisplayState {
  root: traversal.root_index,
- selected: None,
  sorting: Default::default(),
  message: Some("-> scanning <-".into()),
+ selected: None,
+ entries_list_start: 0,
  };
  MainWindow {
  traversal,
@@ -181,9 +185,10 @@ impl TerminalApp {
  Ok(TerminalApp {
  state: DisplayState {
  root,
- selected,
  sorting,
  message: None,
+ selected,
+ entries_list_start: 0,
  },
  display: display_options,
  traversal,

src/interactive/widgets/entries.rs

@@ -18,6 +18,7 @@ pub struct Entries<'a> {
  pub display: DisplayOptions,
  pub sorting: SortMode,
  pub selected: Option<TreeIndex>,
+ pub list_start: usize,
 }
 
 impl<'a> Widget for Entries<'a> {
@@ -28,6 +29,7 @@ impl<'a> Widget for Entries<'a> {
  display,
  sorting,
  selected,
+ list_start: _,
  } = self;
  let is_top = |node_idx| {
  tree.neighbors_directed(node_idx, petgraph::Incoming)

src/interactive/widgets/main.rs

@@ -36,6 +36,7 @@ impl Default for SortMode {
 pub struct DisplayState {
  pub root: TreeIndex,
  pub selected: Option<TreeIndex>,
+ pub entries_list_start: usize,
  pub sorting: SortMode,
  pub message: Option<String>,
 }
@@ -70,6 +71,7 @@ impl<'a, 'b, 'c> Widget for MainWindow<'a, 'b> {
  display: *display,
  sorting: state.sorting,
  selected: state.selected,
+ list_start: state.entries_list_start,
  }
  .draw(entries, buf);