simplify the code

app/src/app.rs

@@ -119,9 +119,9 @@ impl App {
 		let manager = &mut self.cx.manager;
 		let tasks = &mut self.cx.tasks;
 		match event {
-			Event::Cd(url, backstack_push) => {
+			Event::Cd(url) => {
 				futures::executor::block_on(async {
-					manager.active_mut().cd(expand_url(url), backstack_push).await;
+					manager.active_mut().cd(expand_url(url)).await;
 				});
 			}
 			Event::Refresh => {

app/src/executor.rs

@@ -78,7 +78,7 @@ impl Executor {
 				if exec.named.contains_key("interactive") {
 					cx.manager.active_mut().cd_interactive(url)
 				} else {
-					emit!(Cd(url, true));
+					emit!(Cd(url));
 					false
 				}
 			}

core/src/event.rs

@@ -21,7 +21,7 @@ pub enum Event {
 	Call(Vec<Exec>, KeymapLayer),
 
 	// Manager
-	Cd(Url, bool),
+	Cd(Url),
 	Refresh,
 	Files(FilesOp),
 	Pages(usize),
@@ -71,8 +71,8 @@ macro_rules! emit {
 		$crate::Event::Call($exec, $layer).emit();
 	};
 
-	(Cd($url:expr, $backstack_push:expr)) => {
+	(Cd($url:expr)) => {
-		$crate::Event::Cd($url, $backstack_push).emit();
+		$crate::Event::Cd($url).emit();
 	};
 	(Files($op:expr)) => {
 		$crate::Event::Files($op).emit();

core/src/manager/backstack.rs

@@ -1,36 +1,51 @@
-pub struct BackStack<T> {
+pub struct BackStack<T: Eq> {
-	current: usize,
+	cursor: usize,
 	stack:  Vec<T>,
 }
 
-impl<T> BackStack<T> {
+impl<T: Eq> BackStack<T> {
-	pub fn new(item: T) -> Self { Self { current: 0, stack: vec![item] } }
+	pub fn new(item: T) -> Self { Self { cursor: 0, stack: vec![item] } }
+
+	pub fn push(&mut self, item: T) {
+		if self.stack[self.cursor] == item {
+			return;
+		}
+
+		self.cursor += 1;
+		if self.cursor == self.stack.len() {
+			self.stack.push(item);
+		} else {
+			self.stack[self.cursor] = item;
+			self.stack.truncate(self.cursor + 1);
+		}
+
+		// Only keep 30 items before the cursor, the cleanup threshold is 60
+		if self.stack.len() > 60 {
+			let start = self.cursor.saturating_sub(30);
+			self.stack.drain(..start);
+			self.cursor -= start;
+		}
+	}
+
+	#[inline]
+	#[cfg(test)]
+	pub fn current(&self) -> &T { &self.stack[self.cursor] }
 
 	pub fn shift_backward(&mut self) -> Option<&T> {
-		if self.current > 0 {
+		if self.cursor > 0 {
-			self.current -= 1;
+			self.cursor -= 1;
-			Some(&self.stack[self.current])
+			Some(&self.stack[self.cursor])
 		} else {
 			None
 		}
 	}
 
 	pub fn shift_forward(&mut self) -> Option<&T> {
-		if self.current + 1 == self.stack.len() {
+		if self.cursor + 1 == self.stack.len() {
 			None
 		} else {
-			self.current += 1;
+			self.cursor += 1;
-			Some(&self.stack[self.current])
+			Some(&self.stack[self.cursor])
-		}
-	}
-
-	pub fn push(&mut self, item: T) {
-		self.current += 1;
-		if self.current == self.stack.len() {
-			self.stack.push(item);
-		} else {
-			self.stack[self.current] = item;
-			self.stack.truncate(self.current + 1);
 		}
 	}
 }
@@ -39,22 +54,20 @@ impl<T> BackStack<T> {
 mod tests {
 	use super::*;
 
-	fn get_current<T>(backstack: &BackStack<T>) -> &T { &backstack.stack[backstack.current] }
-
 	#[test]
 	fn test_backstack() {
-		let mut backstack = BackStack::<i32>::new(1);
+		let mut backstack = BackStack::<u32>::new(1);
-		assert_eq!(get_current(&backstack), &1);
+		assert_eq!(backstack.current(), &1);
 
 		backstack.push(2);
 		backstack.push(3);
-		assert_eq!(get_current(&backstack), &3);
+		assert_eq!(backstack.current(), &3);
 
 		assert_eq!(backstack.shift_backward(), Some(&2));
 		assert_eq!(backstack.shift_backward(), Some(&1));
 		assert_eq!(backstack.shift_backward(), None);
 		assert_eq!(backstack.shift_backward(), None);
-		assert_eq!(get_current(&backstack), &1);
+		assert_eq!(backstack.current(), &1);
 		assert_eq!(backstack.shift_forward(), Some(&2));
 		assert_eq!(backstack.shift_forward(), Some(&3));
 		assert_eq!(backstack.shift_forward(), None);
@@ -62,7 +75,7 @@ mod tests {
 		backstack.shift_backward();
 		backstack.push(4);
 
-		assert_eq!(get_current(&backstack), &4);
+		assert_eq!(backstack.current(), &4);
 		assert_eq!(backstack.shift_forward(), None);
 		assert_eq!(backstack.shift_backward(), Some(&2));
 	}

core/src/manager/tab.rs

@@ -89,7 +89,8 @@ impl Tab {
 		true
 	}
 
-	pub async fn cd(&mut self, mut target: Url, backstack_push: bool) -> bool {
+	// TODO: change to sync, and remove `Event::Cd`
+	pub async fn cd(&mut self, mut target: Url) -> bool {
 		let Ok(file) = File::from(target.clone()).await else {
 			return false;
 		};
@@ -111,14 +112,11 @@ impl Tab {
 			self.history.insert(rep.cwd.clone(), rep);
 		}
 
-		if backstack_push {
-			self.backstack.push(target.clone());
-		}
-
 		let rep = self.history_new(&target);
 		let rep = mem::replace(&mut self.current, rep);
 		if rep.cwd.is_regular() {
 			self.history.insert(rep.cwd.clone(), rep);
+			self.backstack.push(target.clone());
 		}
 
 		if let Some(parent) = target.parent_url() {
@@ -138,7 +136,7 @@ impl Tab {
 				emit!(Input(InputOpt::top("Change directory:").with_value(target.to_string_lossy())));
 
 			if let Some(Ok(s)) = result.recv().await {
-				emit!(Cd(Url::from(s), true));
+				emit!(Cd(Url::from(s)));
 			}
 		});
 		false
@@ -156,6 +154,7 @@ impl Tab {
 		let rep = mem::replace(&mut self.current, rep);
 		if rep.cwd.is_regular() {
 			self.history.insert(rep.cwd.clone(), rep);
+			self.backstack.push(self.current.cwd.clone());
 		}
 
 		if let Some(rep) = self.parent.take() {
@@ -163,8 +162,6 @@ impl Tab {
 		}
 		self.parent = Some(self.history_new(&hovered.parent().unwrap()));
 
-		self.backstack.push(self.current.cwd.clone());
-
 		emit!(Refresh);
 		true
 	}
@@ -193,24 +190,23 @@ impl Tab {
 		let rep = mem::replace(&mut self.current, rep);
 		if rep.cwd.is_regular() {
 			self.history.insert(rep.cwd.clone(), rep);
-		}
-
 			self.backstack.push(self.current.cwd.clone());
+		}
 
 		emit!(Refresh);
 		true
 	}
 
 	pub fn back(&mut self) -> bool {
-		if let Some(url) = self.backstack.shift_backward() {
+		if let Some(url) = self.backstack.shift_backward().cloned() {
-			emit!(Cd(url.clone(), false));
+			futures::executor::block_on(self.cd(url));
 		}
 		false
 	}
 
 	pub fn forward(&mut self) -> bool {
-		if let Some(url) = self.backstack.shift_forward() {
+		if let Some(url) = self.backstack.shift_forward().cloned() {
-			emit!(Cd(url.clone(), false));
+			futures::executor::block_on(self.cd(url));
 		}
 		false
 	}
@@ -327,7 +323,7 @@ impl Tab {
 			let mut first = true;
 			while let Some(chunk) = rx.next().await {
 				if first {
-					emit!(Cd(cwd.clone(), true));
+					emit!(Cd(cwd.clone()));
 					first = false;
 				}
 				emit!(Files(FilesOp::Part(cwd.clone(), ticket, chunk)));
@@ -363,7 +359,7 @@ impl Tab {
 				if global { external::fzf(FzfOpt { cwd }) } else { external::zoxide(ZoxideOpt { cwd }) }?;
 
 			if let Ok(target) = rx.await? {
-				emit!(Cd(target, true));
+				emit!(Cd(target));
 			}
 			Ok::<(), Error>(())
 		});

cspell.json

@@ -1 +1 @@
-{"language":"en","words":["Punct","KEYMAP","splitn","crossterm","YAZI","unar","peekable","ratatui","syntect","pbpaste","pbcopy","ffmpegthumbnailer","oneshot","Posix","Lsar","XADDOS","zoxide","cands","Deque","precache","imageops","IFBLK","IFCHR","IFDIR","IFIFO","IFLNK","IFMT","IFSOCK","IRGRP","IROTH","IRUSR","ISGID","ISUID","ISVTX","IWGRP","IWOTH","IWUSR","IXGRP","IXOTH","IXUSR","libc","winsize","TIOCGWINSZ","xpixel","ypixel","ioerr","appender","Catppuccin","macchiato","gitmodules","Dotfiles","bashprofile","vimrc","flac","webp","exiftool","mediainfo","ripgrep","nvim","indexmap","indexmap","unwatch","canonicalize","serde","fsevent","Ueberzug","iterm","wezterm","sixel","chafa","ueberzugpp","️ Überzug","️ Überzug","Konsole","Alacritty","Überzug","pkgs","paru","unarchiver","pdftoppm","poppler","prebuild","singlefile","jpegopt","EXIF","rustfmt","mktemp","nanos","xclip","xsel","natord","Mintty","nixos","nixpkgs","SIGTSTP","SIGCONT","SIGCONT"],"version":"0.2","flagWords":[]}
+{"version":"0.2","words":["Punct","KEYMAP","splitn","crossterm","YAZI","unar","peekable","ratatui","syntect","pbpaste","pbcopy","ffmpegthumbnailer","oneshot","Posix","Lsar","XADDOS","zoxide","cands","Deque","precache","imageops","IFBLK","IFCHR","IFDIR","IFIFO","IFLNK","IFMT","IFSOCK","IRGRP","IROTH","IRUSR","ISGID","ISUID","ISVTX","IWGRP","IWOTH","IWUSR","IXGRP","IXOTH","IXUSR","libc","winsize","TIOCGWINSZ","xpixel","ypixel","ioerr","appender","Catppuccin","macchiato","gitmodules","Dotfiles","bashprofile","vimrc","flac","webp","exiftool","mediainfo","ripgrep","nvim","indexmap","indexmap","unwatch","canonicalize","serde","fsevent","Ueberzug","iterm","wezterm","sixel","chafa","ueberzugpp","️ Überzug","️ Überzug","Konsole","Alacritty","Überzug","pkgs","paru","unarchiver","pdftoppm","poppler","prebuild","singlefile","jpegopt","EXIF","rustfmt","mktemp","nanos","xclip","xsel","natord","Mintty","nixos","nixpkgs","SIGTSTP","SIGCONT","SIGCONT","backstack"],"flagWords":[],"language":"en"}