improve ui for opening files, read stdin if no files (unless on macos :/)

src/app/mod.rs

@@ -1,10 +1,12 @@
-use std::{env::{self}, io::{self}, process::exit, time::Duration};
+use std::{env, io, path::PathBuf, process::exit, time::Duration};
 use crossterm::{ExecutableCommand, event::{self, DisableMouseCapture, Event, KeyCode, KeyEvent, KeyModifiers, MouseEvent, MouseEventKind}, terminal::window_size};
 use ratatui::{DefaultTerminal, style::Stylize, text::Span};
 use crate::{BYTES_PER_LINE, action::AppAction, buffer::Buffer, config::{Config, ConfigInitError}, cursor::Cursor};
 
 mod widget;
 
+const MACOS_STDIN_BROKEN_MESSAGE: &str = "reading from stdin on macOS does not work due to a limitation in crossterm. see https://github.com/crossterm-rs/crossterm/issues/396";
+
 pub struct App {
 	pub config: Config,
 	
@@ -52,17 +54,46 @@ impl App {
 			config.unwrap_or_default()
 		};
 		
-		let buffers: Vec<Buffer> = env::args()
+		let mut error_alert: Option<Span> = None;
+		
+		let mut buffers: Vec<Buffer> = env::args()
 			.skip(1)
 			.map(Into::into)
-				.map(Buffer::new)
+			.filter_map(|path: PathBuf| {
+				Buffer::from_file_at(path.clone())
+					.inspect_err(|error| {
+						error_alert = Some(
+							Span::raw(format!("error reading '{}': {error}", path.display())).red()
+						);
+					})
+					.ok()
+			})
 			.collect();
 		
-		if buffers.is_empty() {
-			println!("please provide at least one file as input");
+		if env::args().len() <= 1 {
+			#[cfg(target_os = "macos")] {
+				eprintln!("{MACOS_STDIN_BROKEN_MESSAGE}");
 				exit(1);
 			}
 			
+			#[cfg(not(target_os = "macos"))] {
+				use io::{Read, stdin};
+				
+				let mut standard_input = Vec::new();
+				stdin().read_to_end(&mut standard_input).unwrap();
+				buffers.push(Buffer::new("-".into(), standard_input));
+			}
+		}
+		
+		if let Some(error_alert) = error_alert {
+			if buffers.is_empty() {
+				eprintln!("{error_alert}");
+				exit(1);
+			} else {
+				buffers[0].alert_message = error_alert;
+			}
+		}
+		
 		let window_size = WindowSize {
 			rows: window_size().unwrap().rows as usize,
 			covered_rows: if buffers.len() > 1 {
@@ -98,7 +129,23 @@ impl App {
 	}
 	
 	pub fn handle_event(&mut self, terminal: &mut DefaultTerminal) {
-		match event::read().unwrap() {
+		let event = event::read()
+			.inspect_err(|error| {
+				#[cfg(target_os = "macos")] {
+					use io::ErrorKind;
+
+					if error.kind() == ErrorKind::Other {
+						let error_message = error.to_string();
+						if error_message == "Failed to initialize input reader" {
+							eprintln!("{MACOS_STDIN_BROKEN_MESSAGE}");
+							exit(1);
+						}
+					}
+				}
+			})
+			.unwrap();
+		
+		match event {
 			Event::Resize(_, height) => {
 				self.window_size.rows = height as usize;
 			

src/buffer/mod.rs

@@ -1,5 +1,5 @@
 use core::slice::GetDisjointMutIndex;
-use std::{collections::HashSet, fs::File, io::Read, path::PathBuf};
+use std::{collections::HashSet, fs::File, io::{self, Read}, path::PathBuf};
 use crossterm::event::KeyEvent;
 use ratatui::{layout::{Constraint, Rect}, style::{Color, Style, Stylize}, text::Span, widgets::{Block, Borders, Clear, Widget}};
 use serde::{Deserialize, Serialize};
@@ -171,11 +171,15 @@ impl Widget for Popup {
 }
 
 impl Buffer {
-	pub fn new(file_path: PathBuf) -> Self {
-		let file = File::open(&file_path);
+	pub fn from_file_at(file_path: PathBuf) -> io::Result<Self> {
+		let mut file = File::open(&file_path)?;
 		let mut contents = Vec::new();
-		file.unwrap().read_to_end(&mut contents).unwrap();
+		file.read_to_end(&mut contents)?;
 		
+		Ok(Self::new(file_path, contents))
+	}
+	
+	pub fn new(file_path: PathBuf, contents: Vec<u8>) -> Self {
 		Self {
 			file_name: file_path.file_name().unwrap().to_str().unwrap().to_owned(),
 			file_path,