Refactor the runtime settings into a struct (#1)

This makes more sense than having a lot of parameters. Making this change makes it possible to do a lot of other nice changes, will probably continue doing one of these as soon as I get this reviewed. :)

src/main.rs

@@ -2,31 +2,39 @@ use std::env;
 use std::process::Command;
 use std::process::exit;
 
-pub fn get_commits(dir: &str, from_revision: &str, to_revision: &str) {
-    let range = format!("{}..{}", from_revision, to_revision);
-
-    let output = Command::new("git")
-            .arg("log")
-            .arg("--oneline")
-            .arg(&range)
-            .current_dir(dir)
-            .output().unwrap_or_else(|e| panic!("Failed to run 'git log' with error: {}", e));
-
-    let stdout_output = String::from_utf8_lossy(&output.stdout);
-    let lines = stdout_output
-            .split('\n')
-            .collect::<Vec<_>>();
-    let mut lines_iterator = lines.iter();
-
-    print!("## {}\n\n", to_revision);
-
-    loop {
-        match lines_iterator.next() {
-            Some(line) => {
-                if line.is_empty() { return; }
-                println!("* {}", line)
-            },
-            None => break
+struct Settings<'a> {
+    repository_path: &'a str,
+    from_revision: &'a str,
+    to_revision: &'a str
+}
+
+impl<'a> Settings<'a> {
+    pub fn get_commits(self) {
+        let range = format!("{}..{}", self.from_revision, self.to_revision);
+
+        let output = Command::new("git")
+                .arg("log")
+                .arg("--oneline")
+                .arg(&range)
+                .current_dir(self.repository_path)
+                .output().unwrap_or_else(|e| panic!("Failed to run 'git log' with error: {}", e));
+
+        let stdout_output = String::from_utf8_lossy(&output.stdout);
+        let lines = stdout_output
+                .split('\n')
+                .collect::<Vec<_>>();
+        let mut lines_iterator = lines.iter();
+
+        print!("## {}\n\n", self.to_revision);
+
+        loop {
+            match lines_iterator.next() {
+                Some(line) => {
+                    if line.is_empty() { return; }
+                    println!("* {}", line)
+                },
+                None => break
+            }
         }
     }
 }
@@ -35,7 +43,12 @@ fn main() {
     let args: Vec<_> = env::args().collect();
 
     if args.len() == 4 {
-        get_commits(&args[1], &args[2], &args[3]);
+        let settings = Settings {
+            repository_path: &args[1],
+            from_revision: &args[2],
+            to_revision: &args[3]
+        };
+        settings.get_commits();
     }
     else {
         println!("Usage: {} <path> <from_revision> <to_revision>\n", args[0]);