Don't quit on small terminals

Fix #511

6 files changed, 40 insertions, 48 deletions

diff --git a/src/app/app.rs b/src/app/app.rs
index d7d1839..bd5cf68 100644
--- a/src/app/app.rs
+++ b/src/app/app.rs
@@ -88,7 +88,7 @@ impl App {
                 )?
                 .expect("Failed to create BrowserState"),
             ),
-            Areas::create(&mut Vec::new(), 0, screen, false)?,
+            Areas::create(&mut Vec::new(), 0, screen, false),
             con,
         );
         let (tx_seqs, rx_seqs) = unbounded::<Sequence>();
@@ -168,8 +168,7 @@ impl App {
                 self.panels.as_mut_slice(),
                 self.screen,
                 self.preview_panel.is_some(),
-            )
-            .expect("removing a panel should be easy");
+            );
             self.active_panel_idx = self
                 .panels
                 .iter()
@@ -560,33 +559,29 @@ impl App {
             self.active_panel_idx
         };
         let with_preview = purpose.is_preview() || self.preview_panel.is_some();
-        match Areas::create(
+        let areas = Areas::create(
             self.panels.as_mut_slice(),
             insertion_idx,
             self.screen,
             with_preview,
-        ) {
-            Ok(areas) => {
-                let panel_id = self.created_panels_count.into();
-                match state.get_type() {
-                    PanelStateType::Preview => {
-                        self.preview_panel = Some(panel_id);
-                    }
-                    PanelStateType::Stage => {
-                        self.stage_panel = Some(panel_id);
-                    }
-                    _ => {
-                        self.active_panel_idx = insertion_idx;
-                    }
-                }
-                let mut panel = Panel::new(panel_id, state, areas, con);
-                panel.purpose = purpose;
-                self.created_panels_count += 1;
-                self.panels.insert(insertion_idx, panel);
-                Ok(())
+        );
+        let panel_id = self.created_panels_count.into();
+        match state.get_type() {
+            PanelStateType::Preview => {
+                self.preview_panel = Some(panel_id);
+            }
+            PanelStateType::Stage => {
+                self.stage_panel = Some(panel_id);
+            }
+            _ => {
+                self.active_panel_idx = insertion_idx;
             }
-            Err(e) => Err(e.to_string())
         }
+        let mut panel = Panel::new(panel_id, state, areas, con);
+        panel.purpose = purpose;
+        self.created_panels_count += 1;
+        self.panels.insert(insertion_idx, panel);
+        Ok(())
     }
 
     /// do the pending tasks, if any, and refresh the screen accordingly
@@ -731,7 +726,7 @@ impl App {
                             self.panels.as_mut_slice(),
                             self.screen,
                             self.preview_panel.is_some(),
-                        )?;
+                        );
                         for panel in &mut self.panels {
                             panel.mut_state().refresh(self.screen, con);
                         }
diff --git a/src/app/panel_state.rs b/src/app/panel_state.rs
index 83a0138..f1f2375 100644
--- a/src/app/panel_state.rs
+++ b/src/app/panel_state.rs
@@ -796,7 +796,7 @@ pub fn get_arg<T: Copy + FromStr>(
 ) -> T {
     verb_invocation
         .and_then(|vi| vi.args.as_ref())
-        .or_else(|| internal_exec.arg.as_ref())
+        .or(internal_exec.arg.as_ref())
         .and_then(|s| s.parse::<T>().ok())
         .unwrap_or(default)
 }
diff --git a/src/display/areas.rs b/src/display/areas.rs
index b974184..d05131e 100644
--- a/src/display/areas.rs
+++ b/src/display/areas.rs
@@ -5,7 +5,6 @@ use {
     },
     crate::{
         app::Panel,
-        errors::ProgramError,
     },
     termimad::Area,
 };
@@ -23,8 +22,9 @@ pub struct Areas {
     pub nb_pos: usize,  // number of displayed panels
 }
 
-const MINIMAL_PANEL_HEIGHT: u16 = 10;
-const MINIMAL_PANEL_WIDTH: u16 = 20;
+const MINIMAL_PANEL_HEIGHT: u16 = 4;
+const MINIMAL_PANEL_WIDTH: u16 = 4;
+const MINIMAL_SCREEN_WIDTH: u16 = 8;
 
 enum Slot<'a> {
     Panel(usize),
@@ -39,7 +39,7 @@ impl Areas {
         mut insertion_idx: usize,
         screen: Screen,
         with_preview: bool, // slightly larger last panel
-    ) -> Result<Self, ProgramError> {
+    ) -> Self {
         if insertion_idx > present_panels.len() {
             insertion_idx = present_panels.len();
         }
@@ -59,15 +59,15 @@ impl Areas {
         for i in insertion_idx..present_panels.len() {
             slots.push(Slot::Panel(i));
         }
-        Self::compute_areas(present_panels, &mut slots, screen, with_preview)?;
-        Ok(areas)
+        Self::compute_areas(present_panels, &mut slots, screen, with_preview);
+        areas
     }
 
     pub fn resize_all(
         panels: &mut [Panel],
         screen: Screen,
         with_preview: bool, // slightly larger last panel
-    ) -> Result<(), ProgramError> {
+    ) {
         let mut slots = Vec::new();
         for i in 0..panels.len() {
             slots.push(Slot::Panel(i));
@@ -80,34 +80,33 @@ impl Areas {
         slots: &mut Vec<Slot>,
         screen: Screen,
         with_preview: bool, // slightly larger last panel
-    ) -> Result<(), ProgramError> {
-        if screen.height < MINIMAL_PANEL_HEIGHT {
-            return Err(ProgramError::TerminalTooSmallError);
-        }
+    ) {
+        let screen_height = screen.height.max(MINIMAL_PANEL_HEIGHT);
+        let screen_width = screen.width.max(MINIMAL_SCREEN_WIDTH);
         let n = slots.len() as u16;
         let mut panel_width = if with_preview {
-            3 * screen.width / (3 * n + 1)
+            3 * screen_width / (3 * n + 1)
         } else {
-            screen.width / n
+            screen_width / n
         };
         if panel_width < MINIMAL_PANEL_WIDTH {
-            return Err(ProgramError::TerminalTooSmallError);
+            panel_width = panel_width.max(MINIMAL_PANEL_WIDTH);
         }
         let mut x = 0;
         let nb_pos = slots.len();
         #[allow(clippy::needless_range_loop)]
         for slot_idx in 0..nb_pos {
             if slot_idx == nb_pos - 1 {
-                panel_width = screen.width - x;
+                panel_width = screen_width - x;
             }
             let areas: &mut Areas = match &mut slots[slot_idx] {
                 Slot::Panel(panel_idx) => &mut panels[*panel_idx].areas,
                 Slot::New(areas) => areas,
             };
-            let y = screen.height - 2;
+            let y = screen_height - 2;
             areas.state = Area::new(x, 0, panel_width, y);
             areas.status = if WIDE_STATUS {
-                Area::new(0, y, screen.width, 1)
+                Area::new(0, y, screen_width, 1)
             } else {
                 Area::new(x, y, panel_width, 1)
             };
@@ -128,7 +127,6 @@ impl Areas {
             areas.nb_pos = nb_pos;
             x += panel_width;
         }
-        Ok(())
     }
 
     pub fn is_first(&self) -> bool {
diff --git a/src/errors.rs b/src/errors.rs
index 78e2124..33a65e2 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -20,7 +20,6 @@ custom_error! {pub ProgramError
     LaunchError {program: String, source: io::Error} = "Unable to launch {program}: {source}",
     UnknowShell {shell: String} = "Unknown shell: {shell}",
     InternalError {details: String} = "Internal error: {details}", // should not happen
-    TerminalTooSmallError = "Terminal too small", // unable to open panel or app
     InvalidGlobError {pattern: String} = "Invalid glob: {pattern}",
     Unrecognized {token: String} = "Unrecognized: {token}",
     NetError {source: NetError} = "{}",
diff --git a/src/filesystems/filesystems_state.rs b/src/filesystems/filesystems_state.rs
index 903e909..67e8715 100644
--- a/src/filesystems/filesystems_state.rs
+++ b/src/filesystems/filesystems_state.rs
@@ -360,8 +360,8 @@ impl PanelState for FilesystemState {
             let mut cw = CropWriter::new(w, width - 1); // -1 for scrollbar
             let txt_style = if selected { &styles.selected_line } else { &styles.default };
             if let Some(mount) = mounts.get(idx) {
-                let match_style = if selected { &selected_match_style } else { &match_style };
-                let border_style = if selected { &selected_border_style } else { &border_style };
+                let match_style = if selected { &selected_match_style } else { match_style };
+                let border_style = if selected { &selected_border_style } else { border_style };
                 if con.show_selection_mark {
                     cw.queue_char(txt_style, if selected { '▶' } else { ' ' })?;
                 }
diff --git a/src/verb/verb.rs b/src/verb/verb.rs
index 701f3d9..d94c293 100644
--- a/src/verb/verb.rs
+++ b/src/verb/verb.rs
@@ -222,7 +222,7 @@ impl Verb {
         if let VerbExecution::Internal(internal_exec) = &self.execution {
             if internal_exec.internal == Internal::focus {
                 if let Some(sel) = sel_info.one_sel() {
-                    let arg = invocation.args.as_ref().or_else(|| internal_exec.arg.as_ref());
+                    let arg = invocation.args.as_ref().or(internal_exec.arg.as_ref());
                     let pb;
                     let arg_path = if let Some(arg) = arg {
                         pb = path::path_from(sel.path, PathAnchor::Unspecified, arg);