Move `Alias` to separate alias module

Take all of our Alias code, functions, errors, etc. and move them into
their own module. This removes some clutter from our `main.rs` file and
makes things better organised. Now all the alias code lives in its own
dedicated place.

Update our test file imports to match this change.

Updates to alias code:

* Reordered imports alphabetically
* Made `Alias` public
* Made `AliasSearchError` public
* Made all methods on `Alias` public

3 files changed, 157 insertions, 152 deletions

diff --git a/src/alias.rs b/src/alias.rs
new file mode 100644
index 0000000..8a66db8
--- /dev/null
+++ b/src/alias.rs
@@ -0,0 +1,152 @@
+use std::error::{self, Error};
+use std::fs::{File, OpenOptions};
+use std::fmt;
+use std::io::{self, BufRead, BufReader, Write};
+use std::path::Path;
+
+#[derive(Clone)]
+pub struct Alias {
+    pub alias: String,
+    pub name: String,
+    pub email: String,
+}
+
+impl Alias {
+    pub fn new(email: &str) -> Alias {
+        let mut split: Vec<&str> = email.split_whitespace().collect();
+
+        // Remove "From: "
+        split.remove(0);
+
+        let mut alias = String::new();
+        let mut name = String::new();
+        let mut email = String::new();
+
+        if split.len() == 1 {
+            alias = split[0].to_lowercase().to_string();
+            email = split[0].to_string();
+        } else if split.len() == 2 {
+            alias = split[0].to_lowercase().to_string();
+            name = split[0].to_string();
+            email = split[1].to_string();
+        } else if split.len() > 2 {
+            alias = format!("{}-{}", split[split.len() - 2], split[0]).to_lowercase().to_string();
+            name = split[0..(split.len() - 1)].join(" ");
+            email = split[split.len() - 1].to_string();
+        }
+
+        alias = alias.replace(',', "");
+        alias = alias.replace('\'', "");
+        alias = alias.replace('"', "");
+
+        Alias { alias: alias, name: name, email: email }
+    }
+
+    pub fn to_string(&self) -> String {
+        if self.name.is_empty() {
+            format!("alias {} {}", self.alias, self.email)
+        } else {
+            format!("alias {} {} {}", self.alias, self.name, self.email)
+        }
+    }
+
+    pub fn find_in_file<P: AsRef<Path>>(&self, file: P) -> Result<Vec<String>, AliasSearchError> {
+        let mut matches = Vec::new();
+        let f = try!(File::open(file));
+        let file = BufReader::new(&f);
+        for line in file.lines() {
+            let line = try!(line);
+            let split: Vec<&str> = line.split_whitespace().collect();
+
+            if line.contains(&self.email) {
+                return Err(AliasSearchError::EmailExists)
+            }
+
+            if split[1].starts_with(&self.alias) {
+                matches.push(split[1].to_owned());
+            }
+        }
+
+        if matches.is_empty() {
+            Err(AliasSearchError::NotFound)
+        } else {
+            Ok(matches)
+        }
+    }
+
+    pub fn write_to_file<P: AsRef<Path>>(&mut self, file: P) -> Result<(), AliasSearchError> {
+        let similar_aliases = try!(self.find_in_file(&file));
+        self.update_alias_id(similar_aliases);
+
+        let mut f = try!(OpenOptions::new().append(true).open(file));
+        try!(f.write_all(format!("{}\n", self.to_string()).as_bytes()));
+
+        Ok(())
+    }
+
+    pub fn update_alias_id(&mut self, similar_aliases: Vec<String>) {
+        if !similar_aliases.is_empty() {
+            self.alias = format!("{}-{}", self.alias, similar_aliases.len() + 1);
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum AliasSearchError {
+    NotFound,
+    EmailExists,
+    Io(io::Error),
+}
+
+impl fmt::Display for AliasSearchError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            AliasSearchError::NotFound => writeln!(f, "{}", self.description()),
+            AliasSearchError::EmailExists => writeln!(f, "{}", self.description()),
+            AliasSearchError::Io(ref err) => writeln!(f, "IO error: {}", err),
+        }
+    }
+}
+
+impl error::Error for AliasSearchError {
+    fn description(&self) -> &str {
+        match *self {
+            AliasSearchError::NotFound => "Alias could not be found in aliases file",
+            AliasSearchError::EmailExists => "Email already exists in aliases file",
+            AliasSearchError::Io(ref err) => err.description(),
+        }
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        match *self {
+            AliasSearchError::Io(ref err) => Some(err),
+            _ => None,
+        }
+    }
+}
+
+impl From<io::Error> for AliasSearchError {
+    fn from(err: io::Error) -> AliasSearchError {
+        AliasSearchError::Io(err)
+    }
+}
+
+#[cfg(test)]
+impl PartialEq<AliasSearchError> for AliasSearchError {
+    fn eq(&self, other: &AliasSearchError) -> bool {
+        match *self {
+            AliasSearchError::NotFound => match *other {
+                AliasSearchError::NotFound => true,
+                _ => false,
+            },
+            AliasSearchError::EmailExists => match *other {
+                AliasSearchError::EmailExists => true,
+                _ => false,
+            },
+            AliasSearchError::Io(_) => match *other {
+                AliasSearchError::Io(_) => true,
+                _ => false,
+            },
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 91545bf..0732f6d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,159 +1,12 @@
 use std::env;
-use std::error::{self, Error};
-use std::io::{self, BufRead, BufReader, Write};
-use std::fmt;
-use std::fs::{File, OpenOptions};
-use std::path::Path;
+use std::io::{self, BufRead, Write};
+
+mod alias;
 
 #[cfg(test)]
 mod tests;
 
-#[derive(Clone)]
-struct Alias {
-    alias: String,
-    name: String,
-    email: String,
-}
-
-impl Alias {
-    fn new(email: &str) -> Alias {
-        let mut split: Vec<&str> = email.split_whitespace().collect();
-
-        // Remove "From: "
-        split.remove(0);
-
-        let mut alias = String::new();
-        let mut name = String::new();
-        let mut email = String::new();
-
-        if split.len() == 1 {
-            alias = split[0].to_lowercase().to_string();
-            email = split[0].to_string();
-        } else if split.len() == 2 {
-            alias = split[0].to_lowercase().to_string();
-            name = split[0].to_string();
-            email = split[1].to_string();
-        } else if split.len() > 2 {
-            alias = format!("{}-{}", split[split.len() - 2], split[0]).to_lowercase().to_string();
-            name = split[0..(split.len() - 1)].join(" ");
-            email = split[split.len() - 1].to_string();
-        }
-
-        alias = alias.replace(',', "");
-        alias = alias.replace('\'', "");
-        alias = alias.replace('"', "");
-
-        Alias { alias: alias, name: name, email: email }
-    }
-
-    fn to_string(&self) -> String {
-        if self.name.is_empty() {
-            format!("alias {} {}", self.alias, self.email)
-        } else {
-            format!("alias {} {} {}", self.alias, self.name, self.email)
-        }
-    }
-
-    fn find_in_file<P: AsRef<Path>>(&self, file: P) -> Result<Vec<String>, AliasSearchError> {
-        let mut matches = Vec::new();
-        let f = try!(File::open(file));
-        let file = BufReader::new(&f);
-        for line in file.lines() {
-            let line = try!(line);
-            let split: Vec<&str> = line.split_whitespace().collect();
-
-            if line.contains(&self.email) {
-                return Err(AliasSearchError::EmailExists)
-            }
-
-            if split[1].starts_with(&self.alias) {
-                matches.push(split[1].to_owned());
-            }
-        }
-
-        if matches.is_empty() {
-            Err(AliasSearchError::NotFound)
-        } else {
-            Ok(matches)
-        }
-    }
-
-    fn write_to_file<P: AsRef<Path>>(&mut self, file: P) -> Result<(), AliasSearchError> {
-        let similar_aliases = try!(self.find_in_file(&file));
-        self.update_alias_id(similar_aliases);
-
-        let mut f = try!(OpenOptions::new().append(true).open(file));
-        try!(f.write_all(format!("{}\n", self.to_string()).as_bytes()));
-
-        Ok(())
-    }
-
-    fn update_alias_id(&mut self, similar_aliases: Vec<String>) {
-        if !similar_aliases.is_empty() {
-            self.alias = format!("{}-{}", self.alias, similar_aliases.len() + 1);
-        }
-    }
-}
-
-#[derive(Debug)]
-enum AliasSearchError {
-    NotFound,
-    EmailExists,
-    Io(io::Error),
-}
-
-impl fmt::Display for AliasSearchError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            AliasSearchError::NotFound => writeln!(f, "{}", self.description()),
-            AliasSearchError::EmailExists => writeln!(f, "{}", self.description()),
-            AliasSearchError::Io(ref err) => writeln!(f, "IO error: {}", err),
-        }
-    }
-}
-
-impl error::Error for AliasSearchError {
-    fn description(&self) -> &str {
-        match *self {
-            AliasSearchError::NotFound => "Alias could not be found in aliases file",
-            AliasSearchError::EmailExists => "Email already exists in aliases file",
-            AliasSearchError::Io(ref err) => err.description(),
-        }
-    }
-
-    fn cause(&self) -> Option<&error::Error> {
-        match *self {
-            AliasSearchError::Io(ref err) => Some(err),
-            _ => None,
-        }
-    }
-}
-
-impl From<io::Error> for AliasSearchError {
-    fn from(err: io::Error) -> AliasSearchError {
-        AliasSearchError::Io(err)
-    }
-}
-
-#[cfg(test)]
-impl PartialEq<AliasSearchError> for AliasSearchError {
-    fn eq(&self, other: &AliasSearchError) -> bool {
-        match *self {
-            AliasSearchError::NotFound => match *other {
-                AliasSearchError::NotFound => true,
-                _ => false,
-            },
-            AliasSearchError::EmailExists => match *other {
-                AliasSearchError::EmailExists => true,
-                _ => false,
-            },
-            AliasSearchError::Io(_) => match *other {
-                AliasSearchError::Io(_) => true,
-                _ => false,
-            },
-        }
-    }
-}
+use alias::*;
 
 fn print_usage(program: &str) {
     println!("Usage: {} FILE", program);
diff --git a/src/tests.rs b/src/tests.rs
index 21cf147..708121e 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -1,7 +1,7 @@
 use std::fs::{self, File, OpenOptions};
 use std::io::{Read, Write};
 
-use super::{Alias, AliasSearchError};
+use alias::{Alias, AliasSearchError};
 
 #[test]
 fn new_alias_with_only_email() {