Refactored the username mask concept behind a struct.

src/greeter.rs

@@ -27,7 +27,7 @@ use crate::{
   },
   power::PowerOption,
   ui::{
-    common::menu::Menu,
+    common::{masked::MaskedString, menu::Menu},
     power::Power,
     sessions::{Session, SessionSource, SessionType},
     users::User,
@@ -124,10 +124,8 @@ pub struct Greeter {
   pub user_menu: bool,
   // Menu for user selection.
   pub users: Menu<User>,
-  // Current username.
-  pub username: String,
-  // Value to display in place of the username (e.g. full name of the user).
-  pub username_mask: Option<String>,
+  // Current username. Masked to display the full name if available.
+  pub username: MaskedString,
   // Prompt that should be displayed to ask for entry.
   pub prompt: Option<String>,
 
@@ -194,8 +192,7 @@ impl Greeter {
     // If we should remember the last logged-in user.
     if greeter.remember {
       if let Some(username) = get_last_user_username() {
-        greeter.username = username.clone();
-        greeter.username_mask = get_last_user_name();
+        greeter.username = MaskedString::from(username.clone(), get_last_user_name());
 
         // If, on top of that, we should remember their last session.
         if greeter.remember_user_session {
@@ -237,7 +234,6 @@ impl Greeter {
 
     if !soft {
       self.username.zeroize();
-      self.username_mask.zeroize();
     }
 
     if scrub_message {

src/info.rs

@@ -13,6 +13,7 @@ use nix::sys::utsname;
 
 use crate::{
   ui::{
+    common::masked::MaskedString,
     sessions::{Session, SessionType},
     users::User,
   },
@@ -101,10 +102,10 @@ pub fn get_last_user_name() -> Option<String> {
   }
 }
 
-pub fn write_last_username(username: &str, name: Option<&str>) {
-  let _ = fs::write(LAST_USER_USERNAME, username);
+pub fn write_last_username(username: &MaskedString) {
+  let _ = fs::write(LAST_USER_USERNAME, username.value.clone());
 
-  if let Some(name) = name {
+  if let Some(ref name) = username.mask {
     let _ = fs::write(LAST_USER_NAME, name);
   } else {
     let _ = fs::remove_file(LAST_USER_NAME);

src/ipc.rs

@@ -104,19 +104,19 @@ impl Ipc {
       Response::Success => {
         if greeter.done {
           if greeter.remember {
-            write_last_username(&greeter.username, greeter.username_mask.as_deref());
+            write_last_username(&greeter.username);
 
             if greeter.remember_user_session {
               match greeter.session_source {
                 SessionSource::Command(ref command) => {
-                  write_last_user_session(&greeter.username, command);
-                  delete_last_user_session_path(&greeter.username);
+                  write_last_user_session(&greeter.username.value, command);
+                  delete_last_user_session_path(&greeter.username.value);
                 }
 
                 SessionSource::Session(index) => {
                   if let Some(Session { path: Some(session_path), .. }) = greeter.sessions.options.get(index) {
-                    write_last_user_session_path(&greeter.username, session_path);
-                    delete_last_user_session(&greeter.username);
+                    write_last_user_session_path(&greeter.username.value, session_path);
+                    delete_last_user_session(&greeter.username.value);
                   }
                 }
 
@@ -161,7 +161,11 @@ impl Ipc {
         match error_type {
           ErrorType::AuthError => {
             greeter.message = Some(fl!("failed"));
-            self.send(Request::CreateSession { username: greeter.username.clone() }).await;
+            self
+              .send(Request::CreateSession {
+                username: greeter.username.value.clone(),
+              })
+              .await;
             greeter.reset(true).await;
           }
 

src/keyboard.rs

@@ -9,6 +9,7 @@ use crate::{
   ipc::Ipc,
   power::power,
   ui::{
+    common::masked::MaskedString,
     sessions::{Session, SessionSource},
     users::User,
   },
@@ -31,7 +32,7 @@ pub async fn handle(greeter: Arc<RwLock<Greeter>>, input: KeyEvent, ipc: Ipc) ->
       modifiers: KeyModifiers::CONTROL,
       ..
     } => match greeter.mode {
-      Mode::Username => greeter.username = String::new(),
+      Mode::Username => greeter.username = MaskedString::default(),
       Mode::Password => greeter.buffer = String::new(),
       Mode::Command => greeter.buffer = String::new(),
       _ => {}
@@ -163,7 +164,7 @@ pub async fn handle(greeter: Arc<RwLock<Greeter>>, input: KeyEvent, ipc: Ipc) ->
     } => {
       let value = {
         match greeter.mode {
-          Mode::Username => &greeter.username,
+          Mode::Username => &greeter.username.value,
           _ => &greeter.buffer,
         }
       };
@@ -180,13 +181,13 @@ pub async fn handle(greeter: Arc<RwLock<Greeter>>, input: KeyEvent, ipc: Ipc) ->
 
     // Tab should validate the username entry (same as Enter).
     KeyEvent { code: KeyCode::Tab, .. } => match greeter.mode {
-      Mode::Username if !greeter.username.is_empty() => validate_username(&mut greeter, &ipc).await,
+      Mode::Username if !greeter.username.value.is_empty() => validate_username(&mut greeter, &ipc).await,
       _ => {}
     },
 
     // Enter validates the current entry, depending on the active mode.
     KeyEvent { code: KeyCode::Enter, .. } => match greeter.mode {
-      Mode::Username if !greeter.username.is_empty() => validate_username(&mut greeter, &ipc).await,
+      Mode::Username if !greeter.username.value.is_empty() => validate_username(&mut greeter, &ipc).await,
 
       Mode::Username if greeter.user_menu => {
         greeter.previous_mode = match greeter.mode {
@@ -230,8 +231,7 @@ pub async fn handle(greeter: Arc<RwLock<Greeter>>, input: KeyEvent, ipc: Ipc) ->
         let username = greeter.users.options.get(greeter.users.selected).cloned();
 
         if let Some(User { username, name }) = username {
-          greeter.username = username;
-          greeter.username_mask = name;
+          greeter.username = MaskedString::from(username, name);
         }
 
         validate_username(&mut greeter, &ipc).await;
@@ -287,7 +287,7 @@ pub async fn handle(greeter: Arc<RwLock<Greeter>>, input: KeyEvent, ipc: Ipc) ->
 // current mode and the position of the cursor.
 async fn insert_key(greeter: &mut Greeter, c: char) {
   let value = match greeter.mode {
-    Mode::Username => &greeter.username,
+    Mode::Username => &greeter.username.value,
     Mode::Password => &greeter.buffer,
     Mode::Command => &greeter.buffer,
     Mode::Users | Mode::Sessions | Mode::Power | Mode::Processing => return,
@@ -301,7 +301,7 @@ async fn insert_key(greeter: &mut Greeter, c: char) {
   let mode = greeter.mode;
 
   match mode {
-    Mode::Username => greeter.username = value,
+    Mode::Username => greeter.username.value = value,
     Mode::Password => greeter.buffer = value,
     Mode::Command => greeter.buffer = value,
     _ => {}
@@ -313,7 +313,7 @@ async fn insert_key(greeter: &mut Greeter, c: char) {
 // of the cursor.
 async fn delete_key(greeter: &mut Greeter, key: KeyCode) {
   let value = match greeter.mode {
-    Mode::Username => &greeter.username,
+    Mode::Username => &greeter.username.value,
     Mode::Password => &greeter.buffer,
     Mode::Command => &greeter.buffer,
     Mode::Users | Mode::Sessions | Mode::Power | Mode::Processing => return,
@@ -332,7 +332,7 @@ async fn delete_key(greeter: &mut Greeter, key: KeyCode) {
     let value = left.chain(right).collect();
 
     match greeter.mode {
-      Mode::Username => greeter.username = value,
+      Mode::Username => greeter.username.value = value,
       Mode::Password => greeter.buffer = value,
       Mode::Command => greeter.buffer = value,
       Mode::Users | Mode::Sessions | Mode::Power | Mode::Processing => return,
@@ -349,18 +349,22 @@ async fn validate_username(greeter: &mut Greeter, ipc: &Ipc) {
   greeter.working = true;
   greeter.message = None;
 
-  ipc.send(Request::CreateSession { username: greeter.username.clone() }).await;
+  ipc
+    .send(Request::CreateSession {
+      username: greeter.username.value.clone(),
+    })
+    .await;
   greeter.buffer = String::new();
 
   if greeter.remember_user_session {
-    if let Ok(last_session) = get_last_user_session_path(&greeter.username) {
+    if let Ok(last_session) = get_last_user_session_path(&greeter.username.value) {
       if let Some(last_session) = Session::from_path(greeter, last_session).cloned() {
         greeter.sessions.selected = greeter.sessions.options.iter().position(|sess| sess.path == last_session.path).unwrap_or(0);
         greeter.session_source = SessionSource::Session(greeter.sessions.selected);
       }
     }
 
-    if let Ok(command) = get_last_user_session(&greeter.username) {
+    if let Ok(command) = get_last_user_session(&greeter.username.value) {
       greeter.session_source = SessionSource::Command(command);
     }
   }
@@ -374,7 +378,11 @@ mod test {
   use tokio::sync::RwLock;
 
   use super::handle;
-  use crate::{ipc::Ipc, ui::sessions::SessionSource, Greeter, Mode};
+  use crate::{
+    ipc::Ipc,
+    ui::{common::masked::MaskedString, sessions::SessionSource},
+    Greeter, Mode,
+  };
 
   #[tokio::test]
   async fn ctrl_u() {
@@ -383,7 +391,7 @@ mod test {
     {
       let mut greeter = greeter.write().await;
       greeter.mode = Mode::Username;
-      greeter.username = "apognu".to_string();
+      greeter.username = MaskedString::from("apognu".to_string(), None);
     }
 
     let result = handle(greeter.clone(), KeyEvent::new(KeyCode::Char('u'), KeyModifiers::CONTROL), Ipc::new()).await;
@@ -392,7 +400,7 @@ mod test {
       let status = greeter.read().await;
 
       assert!(matches!(result, Ok(_)));
-      assert_eq!(status.username, "".to_string());
+      assert_eq!(status.username.value, "".to_string());
     }
 
     {

src/main.rs

@@ -54,8 +54,12 @@ async fn run() -> Result<(), Box<dyn Error>> {
   let mut events = Events::new().await;
   let ipc = Ipc::new();
 
-  if greeter.remember && !greeter.username.is_empty() {
-    ipc.send(Request::CreateSession { username: greeter.username.clone() }).await;
+  if greeter.remember && !greeter.username.value.is_empty() {
+    ipc
+      .send(Request::CreateSession {
+        username: greeter.username.value.clone(),
+      })
+      .await;
   }
 
   let greeter = Arc::new(RwLock::new(greeter));

src/ui/common/masked.rs

@@ -0,0 +1,49 @@
+use zeroize::Zeroize;
+
+#[derive(Default)]
+pub struct MaskedString {
+  pub value: String,
+  pub mask: Option<String>,
+}
+
+impl MaskedString {
+  pub fn from(value: String, mask: Option<String>) -> MaskedString {
+    MaskedString { value, mask }
+  }
+
+  pub fn get(&self) -> &str {
+    match self.mask {
+      Some(ref mask) => mask,
+      None => &self.value,
+    }
+  }
+
+  pub fn zeroize(&mut self) {
+    self.value.zeroize();
+
+    if let Some(ref mut mask) = self.mask {
+      mask.zeroize();
+    }
+
+    self.mask = None;
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::MaskedString;
+
+  #[test]
+  fn get_value_when_unmasked() {
+    let masked = MaskedString::from("value".to_string(), None);
+
+    assert_eq!(masked.get(), "value");
+  }
+
+  #[test]
+  fn get_mask_when_masked() {
+    let masked = MaskedString::from("value".to_string(), Some("mask".to_string()));
+
+    assert_eq!(masked.get(), "mask");
+  }
+}

src/ui/common/mod.rs

@@ -1 +1,2 @@
+pub mod masked;
 pub mod menu;

src/ui/prompt.rs

@@ -53,7 +53,7 @@ pub fn draw(greeter: &mut Greeter, f: &mut Frame) -> Result<(u16, u16), Box<dyn
     f.render_widget(greeting_label, chunks[GREETING_INDEX]);
   }
 
-  let username_label = if greeter.user_menu && greeter.username.is_empty() {
+  let username_label = if greeter.user_menu && greeter.username.value.is_empty() {
     let prompt_text = Span::from(fl!("select_user"));
 
     Paragraph::new(prompt_text).alignment(Alignment::Center)
@@ -63,7 +63,7 @@ pub fn draw(greeter: &mut Greeter, f: &mut Frame) -> Result<(u16, u16), Box<dyn
     Paragraph::new(username_text)
   };
 
-  let username = greeter.username_mask.as_deref().unwrap_or_else(|| greeter.username.as_ref());
+  let username = greeter.username.get();
   let username_value_text = Span::from(username);
   let username_value = Paragraph::new(username_value_text);
 
@@ -71,7 +71,7 @@ pub fn draw(greeter: &mut Greeter, f: &mut Frame) -> Result<(u16, u16), Box<dyn
     Mode::Username | Mode::Password => {
       f.render_widget(username_label, chunks[USERNAME_INDEX]);
 
-      if !greeter.user_menu || !greeter.username.is_empty() {
+      if !greeter.user_menu || !greeter.username.value.is_empty() {
         f.render_widget(
           username_value,
           Rect::new(
@@ -124,7 +124,7 @@ pub fn draw(greeter: &mut Greeter, f: &mut Frame) -> Result<(u16, u16), Box<dyn
 
   match greeter.mode {
     Mode::Username => {
-      let username_length = greeter.username.chars().count();
+      let username_length = greeter.username.get().chars().count();
       let offset = get_cursor_offset(greeter, username_length);
 
       Ok((2 + cursor.x + fl!("username").chars().count() as u16 + offset as u16, USERNAME_INDEX as u16 + cursor.y))

src/ui/util.rs

@@ -12,7 +12,7 @@ pub fn titleize(message: &str) -> String {
 pub fn should_hide_cursor(greeter: &Greeter) -> bool {
   greeter.working
     || greeter.done
-    || (greeter.user_menu && greeter.mode == Mode::Username && greeter.username.is_empty())
+    || (greeter.user_menu && greeter.mode == Mode::Username && greeter.username.value.is_empty())
     || (greeter.mode == Mode::Password && greeter.prompt.is_none())
     || greeter.mode == Mode::Users
     || greeter.mode == Mode::Sessions