use crate::extension::{Tree, tree};
impl Tree {
pub fn write_to(&self, mut out: impl std::io::Write) -> Result<(), std::io::Error> {
fn tree_entry(
out: &mut impl std::io::Write,
tree: &Tree,
buf: &mut itoa::Buffer,
) -> Result<(), std::io::Error> {
let num_entries = match tree.num_entries {
Some(num_entries) => buf.format(num_entries),
None => buf.format(-1),
};
out.write_all(tree.name.as_slice())?;
out.write_all(b"\0")?;
out.write_all(num_entries.as_bytes())?;
out.write_all(b" ")?;
let num_children = buf.format(tree.children.len());
out.write_all(num_children.as_bytes())?;
out.write_all(b"\n")?;
if tree.num_entries.is_some() {
out.write_all(tree.id.as_bytes())?;
}
for child in &tree.children {
tree_entry(out, child, buf)?;
}
Ok(())
}
let signature = tree::SIGNATURE;
let mut entries = Vec::<u8>::new();
let mut num_buf = itoa::Buffer::new();
tree_entry(&mut entries, self, &mut num_buf)?;
out.write_all(&signature)?;
out.write_all(
&u32::try_from(entries.len())
.map_err(|_| std::io::Error::new(std::io::ErrorKind::InvalidData, "tree extension exceeds 4GB"))?
.to_be_bytes(),
)?;
out.write_all(&entries)?;
Ok(())
}
}