Fix some problems @ removing a window.

When we wanted to remove the window idx 0 within the list. the current
index went to usize::max_value always. This add a check for the case when
we have more than one window and removes the window 0.

1 files changed, 14 insertions, 2 deletions

diff --git a/src/desktop.rs b/src/desktop.rs
index 520c196..8bd4a4c 100644
--- a/src/desktop.rs
+++ b/src/desktop.rs
@@ -27,6 +27,14 @@ impl Desktop {
         }
     }
 
+    /// Tells if the current index is valid for indexing the window list.
+    /// 
+    /// This is a precondition that must be valid wherever one index that
+    /// list.
+    fn valid_idx(&self) -> bool {
+        self.cw_idx != usize::max_value()
+    }
+
     pub fn current_window(&self) -> Option<&XWindow> {
         if self.cw_idx < self.window_list.len() {
             self.window_list.get(self.cw_idx)
@@ -63,7 +71,11 @@ impl Desktop {
         
         match pos {
             Some(idx) => { 
-                let new_idx = if idx == 0 { usize::max_value() } else { idx - 1 };
+                let new_idx = if idx == 0 {
+                    if self.window_list.len() == 1 { usize::max_value() } else { 0 }
+                } else {
+                    idx - 1
+                };
                 self.window_list.remove(idx);
                 self.cw_idx = new_idx;
                 self.focus_current_window();
@@ -93,7 +105,7 @@ impl Desktop {
     /// There're 3 posibilities. There's no window, there's one window or there
     /// are more windows.
     pub fn focus_next(&mut self) {
-        if self.window_list.len() > 0 {
+        if self.valid_idx() {
             // Unfocus the current window.
             let prev_win = &self.window_list[self.cw_idx];
             prev_win.unfocus();