git_commit_helper/
git.rs

1// ************************************************************************** //
2//                                                                            //
3//                                                        :::      ::::::::   //
4//   git.rs                                             :+:      :+:    :+:   //
5//                                                    +:+ +:+         +:+     //
6//   By: dfine <coding@dfine.tech>                  +#+  +:+       +#+        //
7//                                                +#+#+#+#+#+   +#+           //
8//   Created: 2025/05/10 19:12:46 by dfine             #+#    #+#             //
9//   Updated: 2025/05/10 19:12:48 by dfine            ###   ########.fr       //
10//                                                                            //
11// ************************************************************************** //
12
13use git2::{DiffOptions, Repository};
14use std::error::Error;
15
16/// Returns the staged diff of the current Git repository (i.e., changes staged for commit).
17///
18/// This compares the staged index against the current `HEAD`.
19///
20/// # Arguments
21///
22/// * `repo` - A reference to an open `git2::Repository` instance.
23///
24/// # Returns
25///
26/// A `String` containing the unified diff. If the diff cannot be generated, it returns `"None"`.
27///
28/// # Example
29///
30/// ```
31/// use git_commit_helper::get_staged_diff;
32/// use git2::Repository;
33///
34/// let repo = Repository::discover(".").expect("Not a git repository");
35/// let diff = get_staged_diff(&repo);
36/// println!("{}", diff);
37/// ```
38pub fn get_staged_diff(repo: &Repository) -> String {
39    let index = repo.index().expect("Can't get index");
40    let tree = repo.head().ok().and_then(|head| head.peel_to_tree().ok());
41    let mut diff_opts = DiffOptions::new();
42    let diff = repo
43        .diff_tree_to_index(tree.as_ref(), Some(&index), Some(&mut diff_opts))
44        .expect("Failed to generate diff");
45    let mut buf = Vec::new();
46    if let Err(e) = diff.print(git2::DiffFormat::Patch, |_d, _h, _l| {
47        buf.extend_from_slice(_l.content());
48        true
49    }) {
50        eprintln!("failed to print diff: {}", e);
51        return String::from("None");
52    }
53    String::from_utf8_lossy(&buf).to_string()
54}
55
56/// Returns the messages of the most recent commits (up to 3).
57///
58/// Useful for providing context to an LLM or for generating summaries.
59///
60/// # Arguments
61///
62/// * `repo` - A reference to an open `git2::Repository` instance.
63///
64/// # Returns
65///
66/// A newline-separated string of the latest commit messages. If no commits exist, returns `"None"`.
67///
68/// # Example
69///
70/// ```
71/// use git_commit_helper::get_recent_commit_message;
72/// use git2::Repository;
73///
74/// let repo = Repository::discover(".").expect("Not a git repository");
75/// let messages = get_recent_commit_message(&repo);
76/// println!("{}", messages);
77/// ```
78pub fn get_recent_commit_message(repo: &Repository) -> String {
79    let mut revwalk = repo.revwalk().expect("Failed to get revwalk");
80    if let Err(e) = revwalk.push_head() {
81        eprintln!("Warning: Cannot find HEAD. Possibly no commits yet: {}", e);
82        return String::from("None");
83    };
84    let commits: Vec<String> = revwalk
85        .take(3)
86        .filter_map(|oid| oid.ok())
87        .filter_map(|oid| repo.find_commit(oid).ok())
88        .map(|commit| commit.message().unwrap_or("").trim().replace('"', "\\\""))
89        .collect();
90    commits.join("\n\n")
91}
92
93/// Commits the currently staged changes with the provided commit message.
94///
95/// This function handles both initial and regular commits, constructing the commit tree
96/// and linking to the correct parent if available.
97///
98/// # Arguments
99///
100/// * `repo` - A reference to an open `git2::Repository` instance.
101/// * `message` - The commit message to use.
102///
103/// # Errors
104///
105/// Returns a boxed `Error` if Git operations (e.g., getting the index, writing tree, or committing) fail.
106///
107/// # Example
108///
109/// ```
110/// use git_commit_helper::commit_with_git;
111/// use git2::Repository;
112///
113/// let repo = Repository::discover(".").expect("Not a git repository");
114/// let message = "Add README and initial setup";
115/// if let Err(err) = commit_with_git(&repo, message) {
116///     eprintln!("Commit failed: {}", err);
117/// }
118/// ```
119pub fn commit_with_git(repo: &Repository, message: &str) -> Result<(), Box<dyn Error>> {
120    let sig = repo.signature()?;
121
122    let tree_oid = {
123        let mut index = repo.index()?;
124        let oid = index.write_tree()?;
125        repo.find_tree(oid)?
126    };
127
128    let head = repo.head().ok();
129    let parent_commit = head
130        .as_ref()
131        .and_then(|h| h.target())
132        .and_then(|oid| repo.find_commit(oid).ok());
133
134    let tree = repo.find_tree(tree_oid.id())?;
135
136    let commit_oid = match parent_commit {
137        Some(parent) => repo.commit(Some("HEAD"), &sig, &sig, message, &tree, &[&parent])?,
138        None => repo.commit(Some("HEAD"), &sig, &sig, message, &tree, &[])?,
139    };
140
141    println!("✅ Commit created: {}", commit_oid);
142    Ok(())
143}
git_commit_helper/git.rs

git_commit_helper/
git.rs
