support common nav for syntax view (closes #725)

Author: Stephan Dilly

filetree/src/filetree.rs

@@ -13,6 +13,8 @@ pub enum MoveSelection {
     Right,
     Top,
     End,
+    PageDown,
+    PageUp,
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -121,6 +123,9 @@ impl FileTree {
                     Self::selection_start(selection)
                 }
                 MoveSelection::End => self.selection_end(selection),
+                MoveSelection::PageDown | MoveSelection::PageUp => {
+                    None
+                }
             };
 
             let changed_index =

src/components/revision_files.rs

@@ -6,7 +6,7 @@ use crate::{
     keys::SharedKeyConfig,
     queue::{InternalEvent, Queue},
     strings::{self, order},
-    ui::{self, style::SharedTheme},
+    ui::{self, common_nav, style::SharedTheme},
 };
 use anyhow::Result;
 use asyncgit::{
@@ -15,7 +15,7 @@ use asyncgit::{
 };
 use crossbeam_channel::Sender;
 use crossterm::event::Event;
-use filetree::{FileTree, MoveSelection};
+use filetree::FileTree;
 use std::{
     cell::Cell, collections::BTreeSet, convert::From, path::Path,
 };
@@ -376,18 +376,8 @@ fn tree_nav(
     key_config: &SharedKeyConfig,
     key: crossterm::event::KeyEvent,
 ) -> bool {
-    if key == key_config.move_down {
-        tree.move_selection(MoveSelection::Down)
-    } else if key == key_config.move_up {
-        tree.move_selection(MoveSelection::Up)
-    } else if key == key_config.move_right {
-        tree.move_selection(MoveSelection::Right)
-    } else if key == key_config.move_left {
-        tree.move_selection(MoveSelection::Left)
-    } else if key == key_config.home || key == key_config.shift_up {
-        tree.move_selection(MoveSelection::Top)
-    } else if key == key_config.end || key == key_config.shift_down {
-        tree.move_selection(MoveSelection::End)
+    if let Some(common_nav) = common_nav(key, key_config) {
+        tree.move_selection(common_nav)
     } else if key == key_config.tree_collapse_recursive {
         tree.collapse_recursive();
         true

src/components/syntax_text.rs

@@ -6,8 +6,8 @@ use crate::{
     keys::SharedKeyConfig,
     strings,
     ui::{
-        self, style::SharedTheme, AsyncSyntaxJob, ParagraphState,
-        ScrollPos, StatefulParagraph,
+        self, common_nav, style::SharedTheme, AsyncSyntaxJob,
+        ParagraphState, ScrollPos, StatefulParagraph,
     },
 };
 use anyhow::Result;
@@ -18,6 +18,7 @@ use asyncgit::{
 };
 use crossbeam_channel::Sender;
 use crossterm::event::Event;
+use filetree::MoveSelection;
 use itertools::Either;
 use std::{cell::Cell, convert::From, path::Path};
 use tui::{
@@ -120,34 +121,50 @@ impl SyntaxTextComponent {
         }
     }
 
-    fn scroll(&self, down: Option<bool>) {
+    fn scroll(&self, nav: MoveSelection) -> bool {
+        let state = self.paragraph_state.get();
+
+        let new_scroll_pos = match nav {
+            MoveSelection::Down => state.scroll().y.saturating_add(1),
+            MoveSelection::Up => state.scroll().y.saturating_sub(1),
+            MoveSelection::Top => 0,
+            MoveSelection::End => state
+                .lines()
+                .saturating_sub(state.height().saturating_sub(2)),
+            MoveSelection::PageUp => state
+                .scroll()
+                .y
+                .saturating_sub(state.height().saturating_sub(2)),
+            MoveSelection::PageDown => state
+                .scroll()
+                .y
+                .saturating_add(state.height().saturating_sub(2)),
+            _ => state.scroll().y,
+        };
+
+        self.set_scroll(new_scroll_pos)
+    }
+
+    fn set_scroll(&self, pos: u16) -> bool {
         let mut state = self.paragraph_state.get();
-        let new_scroll_pos = down.map_or_else(
-            || state.scroll().y,
-            |down| {
-                if down {
-                    state.scroll().y.saturating_add(1)
-                } else {
-                    state.scroll().y.saturating_sub(1)
-                }
-            },
-        );
 
-        let new_scroll_pos = new_scroll_pos.min(
+        let new_scroll_pos = pos.min(
             state
                 .lines()
                 .saturating_sub(state.height().saturating_sub(2)),
         );
 
         if new_scroll_pos == state.scroll().y {
-            return;
+            return false;
         }
 
         state.set_scroll(ScrollPos {
             x: 0,
             y: new_scroll_pos,
         });
         self.paragraph_state.set(state);
+
+        true
     }
 }
 
@@ -185,7 +202,7 @@ impl DrawableComponent for SyntaxTextComponent {
 
         self.paragraph_state.set(state);
 
-        self.scroll(None);
+        self.set_scroll(state.scroll().y);
 
         if self.focused() {
             ui::draw_scrollbar(
@@ -227,10 +244,11 @@ impl Component for SyntaxTextComponent {
         event: crossterm::event::Event,
     ) -> Result<EventState> {
         if let Event::Key(key) = event {
-            if key == self.key_config.move_down {
-                self.scroll(Some(true));
-            } else if key == self.key_config.move_up {
-                self.scroll(Some(false));
+            if let Some(nav) = common_nav(key, &self.key_config) {
+                return Ok(self
+                    .scroll(nav)
+                    .then(|| EventState::Consumed)
+                    .unwrap_or(EventState::NotConsumed));
             }
         }
 

src/ui/mod.rs

@@ -5,6 +5,7 @@ mod stateful_paragraph;
 pub mod style;
 mod syntax_text;
 
+use filetree::MoveSelection;
 pub use scrollbar::draw_scrollbar;
 pub use scrolllist::{draw_list, draw_list_block};
 pub use stateful_paragraph::{
@@ -13,6 +14,8 @@ pub use stateful_paragraph::{
 pub use syntax_text::{AsyncSyntaxJob, SyntaxText};
 use tui::layout::{Constraint, Direction, Layout, Rect};
 
+use crate::keys::SharedKeyConfig;
+
 /// return the scroll position (line) necessary to have the `selection` in view if it is not already
 pub const fn calc_scroll_top(
     current_top: usize,
@@ -109,3 +112,29 @@ pub fn centered_rect_absolute(
         height.min(r.height),
     )
 }
+
+///
+pub fn common_nav(
+    key: crossterm::event::KeyEvent,
+    key_config: &SharedKeyConfig,
+) -> Option<MoveSelection> {
+    if key == key_config.move_down {
+        Some(MoveSelection::Down)
+    } else if key == key_config.move_up {
+        Some(MoveSelection::Up)
+    } else if key == key_config.page_up {
+        Some(MoveSelection::PageUp)
+    } else if key == key_config.page_down {
+        Some(MoveSelection::PageDown)
+    } else if key == key_config.move_right {
+        Some(MoveSelection::Right)
+    } else if key == key_config.move_left {
+        Some(MoveSelection::Left)
+    } else if key == key_config.home || key == key_config.shift_up {
+        Some(MoveSelection::Top)
+    } else if key == key_config.end || key == key_config.shift_down {
+        Some(MoveSelection::End)
+    } else {
+        None
+    }
+}