Skip systemic mounts during local size calculation

Agent-Logs-Url: https://github.com/sxyazi/yazi/sessions/89d44d10-de98-42c8-bc7b-dc68c41459bb

Co-authored-by: sxyazi <17523360+sxyazi@users.noreply.github.com>

yazi-fs/src/provider/local/calculator.rs

@@ -3,13 +3,19 @@ use std::{collections::VecDeque, future::poll_fn, io, mem, path::{Path, PathBuf}
 use either::Either;
 use tokio::task::JoinHandle;
 
+#[cfg(target_os = "linux")]
+use crate::mounts::Partition;
 use crate::cha::Cha;
 
 type Task = Either<PathBuf, std::fs::ReadDir>;
+#[cfg(target_os = "linux")]
+type SystemicMounts = std::collections::HashSet<PathBuf>;
+#[cfg(not(target_os = "linux"))]
+type SystemicMounts = ();
 
 pub enum SizeCalculator {
-	Idle((VecDeque<Task>, Option<u64>), Cha),
-	Pending(JoinHandle<(VecDeque<Task>, Option<u64>)>, Cha),
+	Idle((VecDeque<Task>, Option<u64>, SystemicMounts), Cha),
+	Pending(JoinHandle<(VecDeque<Task>, Option<u64>, SystemicMounts)>, Cha),
 }
 
 impl SizeCalculator {
@@ -18,12 +24,17 @@ impl SizeCalculator {
 		tokio::task::spawn_blocking(move || {
 			let cha = Cha::new(p.file_name().unwrap_or_default(), std::fs::symlink_metadata(&p)?);
 			if !cha.is_dir() {
-				return Ok(Self::Idle((VecDeque::new(), Some(cha.len)), cha));
+				return Ok(Self::Idle((VecDeque::new(), Some(cha.len), systemic_mounts(&p)), cha));
+			}
+
+			let systemic = systemic_mounts(&p);
+			if is_systemic_mount(&p, &systemic) {
+				return Ok(Self::Idle((VecDeque::new(), Some(0), systemic), cha));
 			}
 
 			let mut buf = VecDeque::from([Either::Right(std::fs::read_dir(&p)?)]);
-			let size = Self::next_chunk(&mut buf);
-			Ok(Self::Idle((buf, size), cha))
+			let size = Self::next_chunk(&mut buf, &systemic);
+			Ok(Self::Idle((buf, size, systemic), cha))
 		})
 		.await?
 	}
@@ -47,7 +58,7 @@ impl SizeCalculator {
 		poll_fn(|cx| {
 			loop {
 				match self {
-					Self::Idle((buf, size), cha) => {
+					Self::Idle((buf, size, systemic), cha) => {
 						if let Some(s) = size.take() {
 							return Poll::Ready(Ok(Some(s)));
 						} else if buf.is_empty() {
@@ -55,10 +66,11 @@ impl SizeCalculator {
 						}
 
 						let mut buf = mem::take(buf);
+						let systemic = mem::take(systemic);
 						*self = Self::Pending(
 							tokio::task::spawn_blocking(move || {
-								let size = Self::next_chunk(&mut buf);
-								(buf, size)
+								let size = Self::next_chunk(&mut buf, &systemic);
+								(buf, size, systemic)
 							}),
 							*cha,
 						);
@@ -72,7 +84,10 @@ impl SizeCalculator {
 		.await
 	}
 
-	fn next_chunk(buf: &mut VecDeque<Either<PathBuf, std::fs::ReadDir>>) -> Option<u64> {
+	fn next_chunk(
+		buf: &mut VecDeque<Either<PathBuf, std::fs::ReadDir>>,
+		systemic: &SystemicMounts,
+	) -> Option<u64> {
 		let (mut i, mut size, now) = (0, 0, Instant::now());
 		macro_rules! pop_and_continue {
 			() => {{
@@ -102,7 +117,10 @@ impl SizeCalculator {
 			let Ok(ent) = next else { continue };
 			let Ok(ft) = ent.file_type() else { continue };
 			if ft.is_dir() {
-				buf.push_back(Either::Left(ent.path()));
+				let path = ent.path();
+				if !is_systemic_mount(&path, systemic) {
+					buf.push_back(Either::Left(path));
+				}
 			} else if let Ok(meta) = ent.metadata() {
 				size += meta.len();
 			}
@@ -110,3 +128,86 @@ impl SizeCalculator {
 		Some(size)
 	}
 }
+
+#[cfg(target_os = "linux")]
+fn systemic_mounts(root: &Path) -> SystemicMounts {
+	systemic_mounts_from(root, &std::fs::read_to_string("/proc/mounts").unwrap_or_default())
+}
+
+#[cfg(not(target_os = "linux"))]
+fn systemic_mounts(_: &Path) -> SystemicMounts {}
+
+#[cfg(target_os = "linux")]
+fn is_systemic_mount(path: &Path, systemic: &SystemicMounts) -> bool { systemic.contains(path) }
+
+#[cfg(not(target_os = "linux"))]
+fn is_systemic_mount(_: &Path, _: &SystemicMounts) -> bool { false }
+
+#[cfg(target_os = "linux")]
+fn systemic_mounts_from(root: &Path, mounts: &str) -> SystemicMounts {
+	mounts
+		.lines()
+		.filter_map(|line| {
+			let mut it = line.split_whitespace();
+			let _src = it.next()?;
+			let dist = unmangle_octal(it.next()?);
+			let fstype = unmangle_octal(it.next()?);
+			let dist = PathBuf::from(dist.as_ref());
+			(Partition { fstype: Some(fstype.into_owned().into()), ..Default::default() }.systemic()
+				&& (dist == root || dist.starts_with(root)))
+			.then_some(dist)
+		})
+		.collect()
+}
+
+#[cfg(target_os = "linux")]
+fn unmangle_octal(s: &str) -> std::borrow::Cow<'_, str> {
+	use yazi_shared::replace_cow;
+
+	let mut s = std::borrow::Cow::Borrowed(s);
+	for (a, b) in
+		[(r"\011", "\t"), (r"\012", "\n"), (r"\040", " "), (r"\043", "#"), (r"\134", r"\")]
+	{
+		s = replace_cow(s, a, b);
+	}
+	s
+}
+
+#[cfg(test)]
+mod tests {
+	use std::{path::Path, sync::OnceLock};
+
+	use super::SizeCalculator;
+
+	#[cfg(target_os = "linux")]
+	use super::systemic_mounts_from;
+
+	fn init() {
+		static INIT: OnceLock<()> = OnceLock::new();
+		INIT.get_or_init(crate::init);
+	}
+
+	#[cfg(target_os = "linux")]
+	#[test]
+	fn systemic_mounts_only_include_systemic_descendants() {
+		let mounts = systemic_mounts_from(
+			Path::new("/"),
+			"rootfs / ext4 rw 0 0\nproc /proc proc rw 0 0\nsysfs /sys sysfs rw 0 0\ntmpfs /tmp tmpfs rw 0 0\n/dev/sda1 /home ext4 rw 0 0\n",
+		);
+
+		assert!(mounts.contains(Path::new("/proc")));
+		assert!(mounts.contains(Path::new("/sys")));
+		assert!(mounts.contains(Path::new("/tmp")));
+		assert!(!mounts.contains(Path::new("/home")));
+	}
+
+	#[cfg(target_os = "linux")]
+	#[tokio::test]
+	async fn proc_size_ignores_systemic_pseudo_files() {
+		init();
+
+		let mut it = SizeCalculator::new(Path::new("/proc")).await.unwrap();
+		assert_eq!(it.next().await.unwrap(), Some(0));
+		assert_eq!(it.next().await.unwrap(), None);
+	}
+}