improvements based on PR feedback

editor/Cargo.toml

@@ -67,6 +67,7 @@ itertools = "0.9.0"
 snafu = { version = "0.6", features = ["backtraces"] }
 colored = "2"
 
+
 [dependencies.bytemuck]
 version = "1.4"
 features = ["derive"]

editor/src/buffer.rs

@@ -3,6 +3,7 @@
 use crate::rect::Rect;
 use crate::util::size_of_slice;
 use crate::vertex::Vertex;
+use bumpalo::collections::Vec as BumpVec;
 use wgpu::util::{BufferInitDescriptor, DeviceExt};
 
 pub struct QuadBufferBuilder {
@@ -87,7 +88,7 @@ pub struct RectBuffers {
 pub fn create_rect_buffers(
     gpu_device: &wgpu::Device,
     encoder: &mut wgpu::CommandEncoder,
-    rects: &[Rect],
+    rects: &BumpVec<Rect>,
 ) -> RectBuffers {
     let nr_of_rects = rects.len() as u64;
 

editor/src/lib.rs

@@ -16,6 +16,7 @@ use crate::selection::create_selection_rects;
 use crate::tea::{model, update};
 use crate::text::{build_glyph_brush, is_newline, Text};
 use crate::vertex::Vertex;
+use bumpalo::Bump;
 use model::Position;
 use std::error::Error;
 use std::io;
@@ -121,6 +122,8 @@ fn run_event_loop() -> Result<(), Box<dyn Error>> {
     let mut ed_model = model::init_model();
     let mut keyboard_modifiers = ModifiersState::empty();
 
+    let arena = Bump::new();
+
     // Render loop
     window.request_redraw();
 
@@ -216,7 +219,7 @@ fn run_event_loop() -> Result<(), Box<dyn Error>> {
 
                 if let Some(selection) = ed_model.selection_opt {
                     let selection_rects_res =
-                        create_selection_rects(selection, &glyph_bounds_rects);
+                        create_selection_rects(selection, &glyph_bounds_rects, &arena);
 
                     match selection_rects_res {
                         Ok(selection_rects) => {

editor/src/selection.rs

@@ -3,6 +3,8 @@ use crate::error::{EdResult, InvalidSelection};
 use crate::rect::Rect;
 use crate::tea::model::RawSelection;
 use crate::vec_result::get_res;
+use bumpalo::collections::Vec as BumpVec;
+use bumpalo::Bump;
 use snafu::ensure;
 
 //using the "parse don't validate" pattern
@@ -39,14 +41,15 @@ fn validate_selection(selection: RawSelection) -> EdResult<ValidSelection> {
     })
 }
 
-pub fn create_selection_rects(
+pub fn create_selection_rects<'a>(
     raw_sel: RawSelection,
     glyph_bound_rects: &[Vec<Rect>],
-) -> EdResult<Vec<Rect>> {
+    arena: &'a Bump,
+) -> EdResult<BumpVec<'a, Rect>> {
     let valid_sel = validate_selection(raw_sel)?;
     let RawSelection { start_pos, end_pos } = valid_sel.selection;
 
-    let mut all_rects = Vec::new();
+    let mut all_rects: BumpVec<Rect> = BumpVec::new_in(arena);
 
     if start_pos.line == end_pos.line {
         let start_glyph_rect = get_res(

editor/src/tea/update.rs

@@ -11,13 +11,13 @@ pub fn move_txt_cursor_left(
     let old_line_nr = old_txt_cursor_pos.line;
     let old_col_nr = old_txt_cursor_pos.column;
 
-    let (line_nr, col_nr) = if old_txt_cursor_pos.column == 0 {
+    let (line_nr, col_nr) = if old_col_nr == 0 {
-        if old_txt_cursor_pos.line == 0 {
+        if old_line_nr == 0 {
             (0, 0)
         } else if let Some(curr_line) = lines.get(old_line_nr - 1) {
             (old_line_nr - 1, curr_line.len() - 1)
         } else {
-            (0, 0) // this should never happen, should this method return Result?
+            unreachable!()
         }
     } else {
         (old_line_nr, old_col_nr - 1)
@@ -84,7 +84,7 @@ pub fn move_txt_cursor_right(
             (old_line_nr, old_col_nr)
         }
     } else {
-        (0, 0) // this should never happen, should this method return Result?
+        unreachable!()
     };
 
     let new_txt_cursor_pos = Position {
@@ -140,7 +140,7 @@ pub fn move_txt_cursor_up(
             (old_line_nr - 1, old_col_nr)
         }
     } else {
-        (0, 0) // this should never happen, should this method return Result?
+        unreachable!()
     };
 
     let new_txt_cursor_pos = Position {
@@ -195,7 +195,7 @@ pub fn move_txt_cursor_down(
             (old_line_nr + 1, old_col_nr)
         }
     } else {
-        (0, 0) // this should never happen, should this method return Result?
+        unreachable!()
     };
 
     let new_txt_cursor_pos = Position {