git_index/extension/tree/
decode.rs

1use std::convert::TryInto;
2
3use git_hash::ObjectId;
4
5use crate::{
6    extension::Tree,
7    util::{split_at_byte_exclusive, split_at_pos},
8};
9
10/// A recursive data structure
11pub fn decode(data: &[u8], object_hash: git_hash::Kind) -> Option<Tree> {
12    let (tree, data) = one_recursive(data, object_hash.len_in_bytes())?;
13    assert!(
14        data.is_empty(),
15        "BUG: should fully consume the entire tree extension chunk, got {} left",
16        data.len()
17    );
18    Some(tree)
19}
20
21fn one_recursive(data: &[u8], hash_len: usize) -> Option<(Tree, &[u8])> {
22    let (path, data) = split_at_byte_exclusive(data, 0)?;
23
24    let (entry_count, data) = split_at_byte_exclusive(data, b' ')?;
25    let num_entries: i32 = atoi::atoi(entry_count)?;
26
27    let (subtree_count, data) = split_at_byte_exclusive(data, b'\n')?;
28    let subtree_count: usize = atoi::atoi(subtree_count)?;
29
30    let (id, mut data) = if num_entries >= 0 {
31        let (hash, data) = split_at_pos(data, hash_len)?;
32        (ObjectId::from(hash), data)
33    } else {
34        (
35            ObjectId::null(git_hash::Kind::from_hex_len(hash_len * 2).expect("valid hex_len")),
36            data,
37        )
38    };
39
40    let mut subtrees = Vec::with_capacity(subtree_count);
41    for _ in 0..subtree_count {
42        let (tree, rest) = one_recursive(data, hash_len)?;
43        subtrees.push(tree);
44        data = rest;
45    }
46
47    subtrees.sort_by(|a, b| a.name.cmp(&b.name));
48    let num_trees = subtrees.len();
49    subtrees.dedup_by(|a, b| a.name == b.name);
50    if num_trees != subtrees.len() {
51        return None;
52    }
53
54    Some((
55        Tree {
56            id,
57            num_entries: num_entries.try_into().ok(),
58            name: path.into(),
59            children: subtrees,
60        },
61        data,
62    ))
63}
git_index/extension/tree/decode.rs

git_index/extension/tree/
decode.rs
