gix_index/extension/tree/
decode.rs

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

gix_index/extension/tree/
decode.rs
