removed unnecessary unwraps, closes #4

Cargo.lock

@@ -91,7 +91,7 @@ dependencies = [
 
 [[package]]
 name = "lamp"
-version = "0.3.0"
+version = "0.3.1"
 dependencies = [
  "clap",
  "clap_complete",

Cargo.toml

@@ -5,7 +5,7 @@
 
 [package]
 name = "lamp"
-version = "0.3.0"
+version = "0.3.1"
 authors = ["crapStone <crapstone01@gmail.com>"]
 license = "GPL-3.0-or-later"
 description = "A Linux backlight utility inspired by acpibacklight"

src/cli.rs

@@ -64,7 +64,7 @@ pub fn build_cli() -> App<'static> {
             Arg::with_name("controller")
                 .short('c')
                 .long("controller")
-                .help("Select device to control")
+                .help("Select device to control, defaults to the first device found")
                 .value_name("DEVICE")
                 .takes_value(true),
         )

src/controllers.rs

@@ -5,7 +5,7 @@
 
 use std::collections::HashMap;
 use std::fs::{File, OpenOptions};
-use std::io::prelude::*;
+use std::io::{self, prelude::*};
 use std::path::{Path, PathBuf};
 use std::process::exit;
 
@@ -174,15 +174,15 @@ fn read_file_to_int(path: PathBuf) -> u32 {
 /// Searches through all paths in `SYS_PATHS` and creates a `HashMap` with the name and absolute path.
 ///
 /// It returns a `Tuple` of the default backlight name and the `HashMap`.
-pub fn get_controllers() -> (String, HashMap<String, PathBuf>) {
+pub fn get_controllers() -> Result<(String, HashMap<String, PathBuf>), io::Error> {
     let mut controllers: HashMap<String, PathBuf> = HashMap::new();
 
     let mut default = None;
 
     for path in SYS_PATHS {
         if Path::new(path).exists() {
-            for name in Path::new(path).read_dir().unwrap() {
+            for name in Path::new(path).read_dir()? {
-                let name = name.unwrap().path();
+                let name = name?.path();
                 let key = String::from(name.file_name().unwrap().to_str().unwrap());
 
                 if default.is_none() {
@@ -194,5 +194,11 @@ pub fn get_controllers() -> (String, HashMap<String, PathBuf>) {
         }
     }
 
-    (default.unwrap(), controllers)
+    Ok((
+        default.unwrap_or_else(|| {
+            eprintln!("no devices found");
+            exit(exitcode::OSFILE)
+        }),
+        controllers,
+    ))
 }

src/main.rs

@@ -16,7 +16,10 @@ fn main() {
     let app = build_cli();
     let matches = app.get_matches();
 
-    let (default_ctrl, ctrls) = controllers::get_controllers();
+    let (default_ctrl, ctrls) = controllers::get_controllers().unwrap_or_else(|why| {
+        eprintln!("an error occured when reading devices: '{why}'");
+        exit(exitcode::IOERR)
+    });
 
     let p = match matches.value_of("controller") {
         Some(ctrl) => {
@@ -48,14 +51,14 @@ fn main() {
         }
         exit(exitcode::OK);
     } else if let Some(value) = matches.value_of("set") {
-        let new_value = value.parse::<u32>().unwrap();
+        let new_value = str_to_int(value);
         controller.set_brightness(new_value);
     } else if let Some(value) = matches.value_of("inc") {
-        let new_value = controller.get_brightness() + value.parse::<u32>().unwrap();
+        let new_value = controller.get_brightness() + str_to_int(value);
         controller.set_brightness(new_value.min(controller.get_max_brightness()));
     } else if let Some(value) = matches.value_of("dec") {
-        let new_value = controller.get_brightness() - value.parse::<u32>().unwrap();
+        let new_value = controller.get_brightness() - str_to_int(value);
-        controller.set_brightness(new_value.max(0));
+        controller.set_brightness(new_value);
     } else if matches.is_present("get") {
         println!("{}", controller.get_brightness());
     } else if matches.is_present("zero") {
@@ -65,8 +68,14 @@ fn main() {
     } else {
         build_cli().print_long_help().unwrap();
     }
+}
 
-    exit(exitcode::OK);
+#[inline(always)]
+fn str_to_int(value: &str) -> u32 {
+    value.parse().unwrap_or_else(|_| {
+        eprintln!("cannot parse '{value}' as positive integer");
+        exit(exitcode::DATAERR);
+    })
 }
 
 // https://xkcd.com/2200/