Replace custom cmd line parser with clap

Cargo.toml

@@ -45,3 +45,4 @@ toml = "0.5"
 rand = "0.7"
 alphanumeric-sort = "1.0"
 trash = "1.0"
+clap = { version = "2.33", default-features = false }

src/cmd_line.rs

@@ -1,106 +1,25 @@
 use crate::Version;
+use clap::{App, Arg};
+use std::path::PathBuf;
 
-static USAGE: &str = "USAGE:
-    emulsion [OPTIONS] <FILE PATH>";
-
-static OPTIONS: &str = "OPTIONS:
-    -h, --help      Prints help information
-    -V, --version   Prints version information";
-
-fn print_usage() {
-	println!("{}", USAGE);
-	println!("\nFor more information try --help");
-}
-
-fn print_help() {
-	print_version();
-	println!("A fast and minimalistic image viewer");
-	println!("Artur Barnabas <kovacs.artur.barnabas@gmail.com>");
-	println!("https://arturkovacs.github.io/emulsion-website/");
-	println!("\n{}", USAGE);
-	println!("\n{}", OPTIONS);
-	print_cfg_paths();
-}
-
-fn print_version() {
-	println!("emulsion {}", Version::cargo_pkg_version());
-}
-
-fn print_cfg_paths() {
-	let (config_path, cache_path) = crate::get_config_and_cache_paths();
-	println!(
-		"\nCONFIGURATION:\n    config file: {}\n    cache file:  {}",
+/// Parses the command-line arguments and returns the file path
+pub fn parse_args(config_path: &PathBuf, cache_path: &PathBuf) -> String {
+	let config = format!(
+		"CONFIGURATION:\n    config file: {}\n    cache file:  {}",
 		config_path.to_string_lossy(),
 		cache_path.to_string_lossy(),
 	);
-}
-
-/// Contains the command-line arguments
-struct Args {
-	help: bool,
-	version: bool,
-	file_path: Option<String>,
-}
-
-/// Parses the command-line arguments
-fn parse_args() -> Result<Args, String> {
-	let mut help = false;
-	let mut version = false;
-	let mut file_path = None;
-
-	for arg in std::env::args().skip(1) {
-		if arg.starts_with("--") {
-			// parse argument
-			match arg.as_str() {
-				"--help" => help = true,
-				"--version" => version = true,
-				_ => return Err(format!("Argument '{}' supported", arg)),
-			}
-		} else if arg == "-help" {
-			help = true;
-		} else if arg.starts_with("-") && arg.len() > 1 {
-			// parse flags
-			for flag in arg[1..].chars() {
-				match flag {
-					'h' => help = true,
-					'V' => version = true,
-					_ => return Err(format!("Flag '-{}' not supported", flag)),
-				}
-			}
-		} else {
-			if file_path.is_some() {
-				return Err(format!("More than one file argument provided"));
-			}
-			file_path = Some(arg);
-		}
-	}
-
-	Ok(Args { help, version, file_path })
-}
 
-/// Return the file path passed to emulsion.
-///
-/// If the help or version flag was used, display the requested information instead.
-pub fn get_file_path() -> Option<String> {
-	match parse_args() {
-		Ok(args) => {
-			if args.help {
-				print_help();
-				return None;
-			} else if args.version {
-				print_version();
-				return None;
-			} else if args.file_path.is_none() {
-				eprintln!("Error: No image file provided\n");
-				print_usage();
-				return None;
-			}
-			return args.file_path;
-		}
-		Err(msg) => {
-			eprintln!("Error: {}\n", msg);
-			print_usage();
-			return None;
-		}
-	}
+	let matches = App::new("emulsion")
+		.version(Version::cargo_pkg_version().to_string().as_str())
+		.author("Artur Barnabas <kovacs.artur.barnabas@gmail.com>")
+		.about(
+			"A fast and minimalistic image viewer\n\
+			https://arturkovacs.github.io/emulsion-website/",
+		)
+		.after_help(config.as_str())
+		.arg(Arg::with_name("PATH").help("The file path of the image").index(1).required(true))
+		.get_matches();
+
+	matches.value_of("PATH").unwrap().to_owned()
 }

src/main.rs

@@ -67,14 +67,11 @@ static USAGE: &[u8] = include_bytes!("../resource/usage.png");
 fn main() {
 	std::panic::set_hook(Box::new(handle_panic::handle_panic));
 
-	let file_path = match cmd_line::get_file_path() {
-		Some(args) => args,
-		None => return,
-	};
-
 	// Load configuration and cache files
 	let (config_path, cache_path) = get_config_and_cache_paths();
 
+	let file_path = cmd_line::parse_args(&config_path, &cache_path);
+
 	let cache = Cache::load(&cache_path);
 	let config = Configuration::load(&config_path);