Restructure into smaller modules

src/path.rs

@@ -0,0 +1,84 @@
+use std::path::{Path, PathBuf};
+use std::process;
+
+use super::output::*;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn setup() {
+        std::env::set_var("HOME", "/home/test");
+    }
+
+    #[test]
+    fn check_expand_tilde() {
+        setup();
+        assert_eq!(
+            expand_path(Path::new("~/file")),
+            Path::new("/home/test/file")
+        );
+    }
+
+    #[test]
+    fn check_expand_invalid_tilde() {
+        setup();
+        assert_eq!(
+            expand_path(Path::new("/home/~/file")),
+            Path::new("/home/~/file")
+        );
+    }
+
+    #[test]
+    fn check_expand_home() {
+        setup();
+        assert_eq!(
+            expand_path(Path::new("$HOME/file")),
+            Path::new("/home/test/file")
+        );
+        assert_eq!(
+            expand_path(Path::new("${HOME}/file")),
+            Path::new("/home/test/file")
+        );
+    }
+}
+
+pub fn path_as_string(path: &Path) -> String {
+    path.to_path_buf().into_os_string().into_string().unwrap()
+}
+
+pub fn env_home() -> PathBuf {
+    match std::env::var("HOME") {
+        Ok(path) => Path::new(&path).to_path_buf(),
+        Err(e) => {
+            print_error(&format!("Unable to read HOME: {}", e));
+            process::exit(1);
+        }
+    }
+}
+
+pub fn expand_path(path: &Path) -> PathBuf {
+    fn home_dir() -> Option<PathBuf> {
+        Some(env_home())
+    }
+
+    let expanded_path = match shellexpand::full_with_context(
+        &path_as_string(path),
+        home_dir,
+        |name| -> Result<Option<String>, &'static str> {
+            match name {
+                "HOME" => Ok(Some(path_as_string(home_dir().unwrap().as_path()))),
+                _ => Ok(None),
+            }
+        },
+    ) {
+        Ok(std::borrow::Cow::Borrowed(path)) => path.to_owned(),
+        Ok(std::borrow::Cow::Owned(path)) => path,
+        Err(e) => {
+            print_error(&format!("Unable to expand root: {}", e));
+            process::exit(1);
+        }
+    };
+
+    Path::new(&expanded_path).to_path_buf()
+}