From 409f1d65a510124ab64b4617f5bcfbe58e0c4fae Mon Sep 17 00:00:00 2001
From: Austen Adler <agadler@austenadler.com>
Date: Sat, 7 Aug 2021 00:29:40 -0400
Subject: [PATCH] Start work on errors

---
 src/errors.rs | 37 +++++++++++++++++++++++++++++++++++++
 src/main.rs   | 17 +++++++++++------
 src/strip.rs  | 15 ++++++++-------
 src/ui.rs     | 16 ++++++++++------
 4 files changed, 66 insertions(+), 19 deletions(-)
 create mode 100644 src/errors.rs

diff --git a/src/errors.rs b/src/errors.rs
new file mode 100644
index 0000000..c5b2915
--- /dev/null
+++ b/src/errors.rs
@@ -0,0 +1,37 @@
+use core::any::Any;
+use std::fmt;
+
+#[derive(Debug)]
+pub enum ProgramError {
+    General(String),
+    UiError(String),
+    Boxed(Box<dyn Any + Send>),
+}
+
+impl From<String> for ProgramError {
+    fn from(e: String) -> Self {
+        Self::General(e)
+    }
+}
+
+impl From<&str> for ProgramError {
+    fn from(e: &str) -> Self {
+        Self::General(e.to_string())
+    }
+}
+
+impl From<Box<dyn Any + Send>> for ProgramError {
+    fn from(e: Box<dyn Any + Send>) -> Self {
+        Self::Boxed(e)
+    }
+}
+
+impl fmt::Display for ProgramError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        match self {
+            Self::General(s) => write!(f, "{}", s),
+            Self::UiError(s) => write!(f, "Critial UI error: {}", s),
+            Self::Boxed(s) => write!(f, "{:?}", s),
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index f953262..dc23fcf 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,24 +21,25 @@
     clippy::indexing_slicing,
     clippy::integer_arithmetic,
     clippy::integer_division,
-    // Expect prints a message when there is a critical error, so this is valid
     clippy::expect_used,
     clippy::unwrap_used,
 )]
 // See https://rust-lang.github.io/rust-clippy/master/index.html for more lints
 
 mod color;
+mod errors;
 mod pattern;
 mod strip;
 mod ui;
+use errors::ProgramError;
 use std::sync::mpsc::channel;
 use std::thread;
 use strip::{LEDStrip, Message};
 use ui::console_ui_loop;
 
-fn main() {
+fn main() -> Result<(), ProgramError> {
     let (tx, rx) = channel::<Message>();
-    thread::spawn(move || {
+    let handle = thread::spawn(move || -> Result<(), ProgramError> {
         let mut strip = LEDStrip::new(strip::Config {
             // I have 89 right now, but start off with 20
             num_lights: 20,
@@ -47,10 +48,14 @@ fn main() {
             // Scaling factor (scale 0..255)
             global_brightness_max: 20,
             tick_time_ms: strip::DEFAULT_TICK_TIME_MS,
-        });
+        })?;
         strip.strip_loop(&rx);
-        panic!("Dead strip thread. Terminating");
+        Err(ProgramError::General(String::from(
+            "Dead strip thread. Terminating",
+        )))
     });
 
-    console_ui_loop(&tx);
+    console_ui_loop(&tx)?;
+
+    handle.join()?
 }
diff --git a/src/strip.rs b/src/strip.rs
index a66d39f..55750c9 100644
--- a/src/strip.rs
+++ b/src/strip.rs
@@ -1,4 +1,5 @@
 use crate::color;
+use crate::errors::ProgramError;
 use crate::pattern::{self, Pattern};
 use std::cmp;
 use std::ops::Add;
@@ -43,9 +44,10 @@ pub struct LEDStrip {
 }
 
 impl LEDStrip {
-    pub fn new(config: Config) -> Self {
+    pub fn new(config: Config) -> Result<Self, ProgramError> {
         let adapter = Box::new(
-            Ws28xxSpiAdapter::new("/dev/spidev0.0").expect("Cannot locate device /dev/spidev0.0!"),
+            Ws28xxSpiAdapter::new("/dev/spidev0.0")
+                .map_err(|_| "Cannot start device /dev/spidev0.0!")?,
         );
         let pattern = Box::new(pattern::Solid::new(color::BLACK));
         let num_lights = config.num_lights;
@@ -55,10 +57,10 @@ impl LEDStrip {
             config,
         };
         ret.set_num_lights(num_lights);
-        ret
+        Ok(ret)
     }
 
-    fn write_buf_from_pattern(&mut self) {
+    fn write_buf_from_pattern(&mut self) -> Result<(), ProgramError> {
         let global_brightness_max = self.config.global_brightness_max;
         let data = vec![color::BLACK]
             .iter()
@@ -81,9 +83,8 @@ impl LEDStrip {
             })
             // TODO: Do not re-collect as u8s
             .collect::<Vec<(u8, u8, u8)>>();
-        self.adapter
-            .write_rgb(data.as_slice())
-            .expect("TODO: Critical data write error!");
+        self.adapter.write_rgb(data.as_slice())?;
+        Ok(())
     }
 
     fn set_num_lights(&mut self, num_lights: u16) {
diff --git a/src/ui.rs b/src/ui.rs
index eec884f..1f1106d 100644
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -1,13 +1,15 @@
 use crate::color::Rgb;
+use crate::errors::ProgramError;
 use crate::pattern::{self, Pattern};
 use crate::strip;
 use std::io;
 use std::io::Write;
 use std::sync::mpsc::Sender;
 
-pub fn console_ui_loop(tx: &Sender<strip::Message>) {
+pub fn console_ui_loop(tx: &Sender<strip::Message>) -> Result<(), ProgramError> {
     loop {
-        if let Err(msg) = parse_cmd(tx, &get_line("Command (cfqs)")) {
+        let line = get_line("Command (cfqs)")?;
+        if let Err(msg) = parse_cmd(tx, &line) {
             println!("Command error: {}", msg);
         }
     }
@@ -105,12 +107,14 @@ fn change_pattern(tx: &Sender<strip::Message>, pat: Box<dyn Pattern + Send>) ->
         .map_err(|e| e.to_string())
 }
 
-fn get_line(prompt: &str) -> String {
+fn get_line(prompt: &str) -> Result<String, ProgramError> {
     print!("{}: ", prompt);
-    std::io::stdout().flush().expect("Could not flush stdout");
+    std::io::stdout()
+        .flush()
+        .map_err(|_| ProgramError::UiError(String::from("Could not flush stdout")))?;
     let mut input_text = String::new();
     io::stdin()
         .read_line(&mut input_text)
-        .expect("Could not read from stdin");
-    input_text.trim().to_string()
+        .map_err(|_| ProgramError::UiError(String::from("Could not read from stdin")))?;
+    Ok(input_text.trim().to_string())
 }