From 4f7b7c80a5d4f9068fb5bca133972fd39ee51e6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Le=CC=81o=20Testard?= <leo.testard@gmail.com>
Date: Tue, 22 Oct 2013 20:25:38 +0200
Subject: [PATCH] Add env util

---
 env/env.rs | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 env/env.rs

diff --git a/env/env.rs b/env/env.rs
new file mode 100644
index 000000000..1479d9ee6
--- /dev/null
+++ b/env/env.rs
@@ -0,0 +1,141 @@
+struct options {
+    ignore_env: bool,
+    null: bool,
+    unsets: ~[~str],
+    sets: ~[(~str, ~str)],
+    program: ~[~str]
+}
+
+fn usage(prog: &str) {
+    println!("Usage: {:s} [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]", prog);
+    println!("Sets each NAME as VALUE in the environment, then run COMMAND\n");
+    println!("Possible options are:");
+    println!("  -i, --ignore-environment  starts with an empty environment");
+    println!("  -0, --null end each line with a 0 byte instead of a \\\\n\n");
+}
+
+fn version() {
+    println!("env (Rust Coreutils) 1.0");
+}
+
+fn print_env(null: bool) {
+    println!("env!")
+}
+
+fn main() {
+    let args = std::os::args();
+    let prog = args[0].as_slice();
+
+    // to handle arguments the same way than GNU env, we can't use getopts
+    // and have to do this:
+
+    let mut opts = ~options {
+        ignore_env: false,
+        null: false,
+        unsets: ~[],
+        sets: ~[],
+        program: ~[]
+    };
+
+    let mut wait_cmd = false;
+    let mut iter = args.iter();
+    iter.next(); // skip program
+
+    for opt in iter {
+        if wait_cmd {
+            // we still accept NAME=VAL here but not other options
+            let mut sp = opt.splitn_iter('=', 1);
+            let name = sp.next();
+            let value = sp.next();
+
+            match (name, value) {
+                (Some(n), Some(v)) => { 
+                    opts.sets.push((n.into_owned(), v.into_owned())); 
+                }
+                _ => {
+                    // read the program now
+                    opts.program.push(opt.to_owned());
+                    break;
+                }
+            }
+        }
+
+        else {
+            if opt.starts_with("--") {
+                match *opt {
+                    ~"--help" => { usage(prog); return }
+                    ~"--version" => { version(); return }
+
+                    ~"--ignore-environment" => {
+                        opts.ignore_env = true; 
+                    }
+
+                    ~"--null" => {
+                        opts.null = true;
+                    }
+                            
+                    _ => {
+                        println!("{:s}: invalid option \"{:s}\"", prog, *opt);
+                        println!("Type \"{:s} --help\" for detailed informations", prog);
+                        return
+                    }
+                }
+            }
+
+            else {
+                match *opt {
+                    ~"-" => {
+                        // implies -i and stop parsing opts
+                        wait_cmd = true;
+                        opts.ignore_env = true;
+                    }
+
+                    _ => {
+                        // is it a NAME=VALUE like opt ?
+                        let mut sp = opt.splitn_iter('=', 1);
+                        let name = sp.next();
+                        let value = sp.next();
+
+                        match (name, value) {
+                            (Some(n), Some(v)) => { 
+                                // yes
+                                opts.sets.push((n.into_owned(), v.into_owned())); 
+                                wait_cmd = true;
+                            }
+                            // no, its a program-like opt
+                            _ => {
+                                opts.program.push(opt.to_owned());
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    // read program arguments now
+    for opt in iter {
+        opts.program.push(opt.to_owned());
+    }
+
+    let env = std::os::env();
+
+    if opts.ignore_env {
+        for &(ref name, _) in env.iter() {
+            std::os::unsetenv(name.as_slice())
+        }
+    }
+
+    for &(ref name, ref val) in opts.sets.iter() {
+        std::os::setenv(name.as_slice(), val.as_slice())
+    }
+
+    match opts.program {
+        [ref prog, ..args] => { 
+            let status = std::run::process_status(prog.as_slice(), args);
+            std::os::set_exit_status(status)
+        }
+        [] => { print_env(opts.null); }
+    }
+}