Added --version.

Cargo.toml

@@ -3,6 +3,7 @@ name = "tuigreet"
 version = "0.1.0"
 authors = ["Antoine POPINEAU <antoine.popineau@appscho.com>"]
 edition = "2018"
+build = "build.rs"
 
 [dependencies]
 getopts = "0.2.21"

README.md

@@ -9,6 +9,7 @@ Usage: tuigreet [OPTIONS]
 
 Options:
     -h, --help          show this usage information
+    -v, --version       print version information
     -c, --cmd COMMAND   command to run
     -w, --width WIDTH   width of the main prompt (default: 80)
     -i, --issue         show the host's issue file

build.rs

@@ -0,0 +1,24 @@
+use std::{env, error::Error, process::Command};
+
+fn main() {
+  let version = get_version().unwrap_or_else(|_| String::from("unknown"));
+
+  println!("cargo:rustc-env=VERSION={}", version);
+  println!("cargo:rustc-env=TARGET={}", env::var("TARGET").unwrap());
+}
+
+fn get_version() -> Result<String, Box<dyn Error>> {
+  let tag = Command::new("git").args(&["describe", "--tags", "--abbrev=0"]).output()?;
+  let tag = match tag.status.code() {
+    Some(0) => String::from_utf8(tag.stdout)?,
+    _ => "0.0.0".to_string(),
+  };
+  let count = String::from_utf8(Command::new("git").args(&["rev-list", "--count", "HEAD"]).output()?.stdout)?;
+  let commit = String::from_utf8(Command::new("git").args(&["rev-parse", "--short", "HEAD"]).output()?.stdout)?;
+  let version = format!("{}.r{}.{}", tag.trim(), count.trim(), commit.trim());
+
+  match version.as_str() {
+    "0.0.0.r." => Err("could not retrieve version".into()),
+    version => Ok(version.to_string()),
+  }
+}

src/config.rs

@@ -124,6 +124,7 @@ impl Greeter {
     let mut opts = Options::new();
 
     opts.optflag("h", "help", "show this usage information");
+    opts.optflag("v", "version", "print version information");
     opts.optopt("c", "cmd", "command to run", "COMMAND");
     opts.optopt("w", "width", "width of the main prompt (default: 80)", "WIDTH");
     opts.optflag("i", "issue", "show the host's issue file");
@@ -146,6 +147,10 @@ impl Greeter {
       print_usage(opts);
       std::process::exit(0);
     }
+    if self.config().opt_present("version") {
+      print_version();
+      std::process::exit(0);
+    }
 
     let socket = env::var("GREETD_SOCK");
     if socket.is_err() {
@@ -180,3 +185,9 @@ impl Greeter {
 fn print_usage(opts: Options) {
   eprint!("{}", opts.usage("Usage: tuigreet [OPTIONS]"));
 }
+
+fn print_version() {
+  println!("tuigreet {} ({})", env!("VERSION"), env!("TARGET"));
+  println!("Copyright (C) 2020 Antoine POPINEAU <https://github.com/apognu/tuigreet>.");
+  println!("Licensed under GPLv3 (GNU GPL version 3 or later).");
+}