Look for config file specified on command line.

src/config.rs

@@ -1,5 +1,5 @@
 use std::error::Error;
-use std::path::PathBuf;
+use std::path::{PathBuf, Path};
 use std::convert::From;
 use std::fs::metadata;
 use std::mem::swap;
@@ -42,7 +42,7 @@ impl Default for SpotifydConfig {
     }
 }
 
-fn get_config_file() -> Result<PathBuf, Box<Error>> {
+pub fn get_config_file() -> Result<PathBuf, Box<Error>> {
     let etc_conf = format!("/etc/{}", CONFIG_FILE);
     let xdg_dirs = try!(xdg::BaseDirectories::with_prefix("spotifyd"));
     xdg_dirs.find_config_file(CONFIG_FILE)
@@ -64,12 +64,12 @@ fn update<T>(r: &mut T, val: Option<T>) {
     }
 }
 
-pub fn get_config() -> SpotifydConfig {
+pub fn get_config<P: AsRef<Path>>(config_path: Option<P>) -> SpotifydConfig {
     let mut config = SpotifydConfig::default();
 
-    let config_path = match get_config_file() {
-        Ok(c) => c,
-        Err(_) => {
+    let config_path = match config_path {
+        Some(c) => c,
+        None => {
             info!("Couldn't find config file, continuing with default configuration.");
             return config;
         }

src/main.rs

@@ -17,6 +17,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
 use std::convert::From;
 use std::error::Error;
+use std::path::PathBuf;
 
 use librespot::spirc::SpircManager;
 use librespot::session::Session;
@@ -94,7 +95,10 @@ fn main() {
                });
     }));
 
-    let config = config::get_config();
+    let config_file = matches.opt_str("config")
+        .map(|s| PathBuf::from(s))
+        .or_else(|| config::get_config_file().ok());
+    let config = config::get_config(config_file);
 
     let cache = config.cache;
     let backend = config.backend;