Add config.rs which I forgot for the last commit

Closes #73

Author: nrc

src/config.rs

@@ -0,0 +1,42 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+extern crate toml;
+
+#[derive(RustcDecodable)]
+pub struct Config {
+    pub max_width: usize,
+    pub ideal_width: usize,
+    pub leeway: usize,
+    pub tab_spaces: usize,
+    pub newline_style: ::NewlineStyle,
+    pub fn_brace_style: ::BraceStyle,
+    pub fn_return_indent: ::ReturnIndent,
+}
+
+impl Config {
+    fn from_toml(toml: &str) -> Config {
+        println!("About to parse: {}", toml);
+        let parsed = toml.parse().unwrap();
+        toml::decode(parsed).unwrap()
+    }
+}
+
+pub fn set_config(toml: &str) {
+    unsafe {
+        ::CONFIG = Some(Config::from_toml(toml));
+    }
+}
+
+macro_rules! config {
+    ($name: ident) => {
+        unsafe { ::CONFIG.as_ref().unwrap().$name }
+    };
+}

src/lib.rs

@@ -267,7 +267,6 @@ impl<'a> CompilerCalls<'a> for RustFmtCalls {
             changes.append_newlines();
             fmt_lines(&mut changes);
 
-            // FIXME(#5) Should be user specified whether to show or replace.
             let result = changes.write_all_files(write_mode);
 
             match result {