1 files changed, 53 insertions, 0 deletions
diff --git a/tvix/castore/src/fs/file_attr.rs b/tvix/castore/src/fs/file_attr.rs
new file mode 100644
index 000000000000..ad41f036a253
--- /dev/null
+++ b/tvix/castore/src/fs/file_attr.rs
@@ -0,0 +1,53 @@
+#![allow(clippy::unnecessary_cast)] // libc::S_IFDIR is u32 on Linux and u16 on MacOS
+use super::inodes::{DirectoryInodeData, InodeData};
+use fuse_backend_rs::abi::fuse_abi::Attr;
+
+/// The [Attr] describing the root
+pub const ROOT_FILE_ATTR: Attr = Attr {
+    ino: fuse_backend_rs::api::filesystem::ROOT_ID,
+    size: 0,
+    blksize: 1024,
+    blocks: 0,
+    mode: libc::S_IFDIR as u32 | 0o555,
+    atime: 0,
+    mtime: 0,
+    ctime: 0,
+    atimensec: 0,
+    mtimensec: 0,
+    ctimensec: 0,
+    nlink: 0,
+    uid: 0,
+    gid: 0,
+    rdev: 0,
+    flags: 0,
+    #[cfg(target_os = "macos")]
+    crtime: 0,
+    #[cfg(target_os = "macos")]
+    crtimensec: 0,
+    #[cfg(target_os = "macos")]
+    padding: 0,
+};
+
+/// for given &Node and inode, construct an [Attr]
+pub fn gen_file_attr(inode_data: &InodeData, inode: u64) -> Attr {
+    Attr {
+        ino: inode,
+        // FUTUREWORK: play with this numbers, as it affects read sizes for client applications.
+        blocks: 1024,
+        size: match inode_data {
+            InodeData::Regular(_, size, _) => *size as u64,
+            InodeData::Symlink(target) => target.len() as u64,
+            InodeData::Directory(DirectoryInodeData::Sparse(_, size)) => *size as u64,
+            InodeData::Directory(DirectoryInodeData::Populated(_, ref children)) => {
+                children.len() as u64
+            }
+        },
+        mode: match inode_data {
+            InodeData::Regular(_, _, false) => libc::S_IFREG as u32 | 0o444, // no-executable files
+            InodeData::Regular(_, _, true) => libc::S_IFREG as u32 | 0o555,  // executable files
+            InodeData::Symlink(_) => libc::S_IFLNK as u32 | 0o444,
+            InodeData::Directory(_) => libc::S_IFDIR as u32 | 0o555,
+        },
+        ..Default::default()
+    }
+}