gix_index/extension/tree/
decode.rs

1use gix_hash::ObjectId;
2
3use crate::{
4    extension::Tree,
5    util::{split_at_byte_exclusive, split_at_pos},
6};
7
8/// A recursive data structure
9pub fn decode(data: &[u8], object_hash: gix_hash::Kind) -> Option<Tree> {
10    let (tree, data) = one_recursive(data, object_hash.len_in_bytes())?;
11    assert!(
12        data.is_empty(),
13        "BUG: should fully consume the entire tree extension chunk, got {} left",
14        data.len()
15    );
16    Some(tree)
17}
18
19fn one_recursive(data: &[u8], hash_len: usize) -> Option<(Tree, &[u8])> {
20    let (path, data) = split_at_byte_exclusive(data, 0)?;
21
22    let (entry_count, data) = split_at_byte_exclusive(data, b' ')?;
23    let num_entries: i32 = gix_utils::btoi::to_signed(entry_count).ok()?;
24
25    let (subtree_count, data) = split_at_byte_exclusive(data, b'\n')?;
26    let subtree_count: usize = gix_utils::btoi::to_unsigned(subtree_count).ok()?;
27
28    let (id, mut data) = if num_entries >= 0 {
29        let (hash, data) = split_at_pos(data, hash_len)?;
30        (ObjectId::from_bytes_or_panic(hash), data)
31    } else {
32        (
33            ObjectId::null(gix_hash::Kind::from_hex_len(hash_len * 2).expect("valid hex_len")),
34            data,
35        )
36    };
37
38    let mut subtrees = Vec::with_capacity(subtree_count);
39    for _ in 0..subtree_count {
40        let (tree, rest) = one_recursive(data, hash_len)?;
41        subtrees.push(tree);
42        data = rest;
43    }
44
45    subtrees.sort_by(|a, b| a.name.cmp(&b.name));
46    let num_trees = subtrees.len();
47    subtrees.dedup_by(|a, b| a.name == b.name);
48    if num_trees != subtrees.len() {
49        return None;
50    }
51
52    Some((
53        Tree {
54            id,
55            num_entries: num_entries.try_into().ok(),
56            name: path.into(),
57            children: subtrees,
58        },
59        data,
60    ))
61}
gix_index/extension/tree/decode.rs

gix_index/extension/tree/
decode.rs
