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stratum/domain/
mfile.rs

1use git2::{Delta, Diff, DiffDelta, Patch};
2use std::{path::Path, sync::OnceLock};
3
4use crate::Error;
5
6/// A file that was touched in a commit
7pub struct ModifiedFile<'c> {
8    cache: OnceLock<Option<Patch<'c>>>,
9    diff: &'c Diff<'c>,
10    n: usize,
11}
12
13impl<'c> ModifiedFile<'c> {
14    /// Instantiate the modified file object from a git diff.
15    ///
16    /// As a single diff can have > 1 modified/touched file, a single unsigned
17    /// integer is provided to specify the delta and/or patch that this file
18    /// looks to represent. Hence, the struct will normally be instantiated via
19    /// iterating over the diff deltas as they are readily avaliable.
20    pub fn new(diff: &'c Diff<'_>, n: usize) -> Self {
21        ModifiedFile {
22            cache: OnceLock::new(),
23            diff,
24            n,
25        }
26    }
27
28    /// Return the path of the old file in the diff
29    pub fn old_path(&self) -> Option<&Path> {
30        self.delta()?.old_file().path()
31    }
32
33    /// Return the path of the new file in the diff
34    pub fn new_file(&self) -> Option<&Path> {
35        self.delta()?.new_file().path()
36    }
37
38    /// Return the file status of the given patch
39    //TODO: Should this return a custom type?? Probably
40    pub fn status(&self) -> Option<Delta> {
41        Some(self.delta()?.status())
42    }
43
44    /// Return the delta associated with the index
45    fn delta(&self) -> Option<DiffDelta<'_>> {
46        self.diff.get_delta(self.n)
47    }
48
49    /// Return the patch given the diff, caching it within the struct
50    //TODO: https://github.com/segfault-merchant/git-stratum/issues/32
51    #[allow(dead_code)]
52    fn patch(&self) -> Result<Option<&Patch<'_>>, Error> {
53        let patch = Patch::from_diff(self.diff, self.n)?;
54        Ok(self.cache.get_or_init(|| patch).as_ref())
55    }
56}
57
58#[cfg(test)]
59mod test {
60    use super::*;
61    use crate::common::init_repo;
62
63    fn mfile_fixture<F, R>(f: F) -> R
64    where
65        F: FnOnce(&git2::Diff, &ModifiedFile) -> R,
66    {
67        let repo = init_repo();
68
69        let c1 = repo
70            .head()
71            .expect("Failed to fetch HEAD")
72            .peel_to_commit()
73            .expect("Failed to peel HEAD to commit");
74        let c2 = c1.parent(0).expect("Couldn't get parent");
75
76        let diff = repo
77            .diff_tree_to_tree(
78                Some(&c2.tree().expect("Failed to get tree")),
79                Some(&c1.tree().expect("Failed to get tree")),
80                None,
81            )
82            .expect("Failed to make diff");
83
84        let mfile = ModifiedFile::new(&diff, 0);
85
86        f(&diff, &mfile)
87    }
88
89    #[test]
90    fn test_old_path() {
91        mfile_fixture(|_, mfile| {
92            // use mfile here
93            assert_eq!(mfile.old_path().unwrap(), "file.txt");
94        });
95    }
96
97    #[test]
98    fn test_new_path() {
99        mfile_fixture(|_, mfile| {
100            // use mfile here
101            assert_eq!(mfile.new_file().unwrap(), "file.txt");
102        });
103    }
104
105    #[test]
106    fn test_delta() {
107        mfile_fixture(|_, mfile| {
108            // use mfile here
109            assert_eq!(mfile.new_file().unwrap(), "file.txt");
110        });
111    }
112}