lean_ctx/core/
git_cache.rs

1//! TTL-based cache for git command results.
2//!
3//! Prevents redundant git invocations within the same session by caching
4//! results with a configurable time-to-live (default 10s for status/diff, 60s for log).
5
6use std::collections::HashMap;
7use std::sync::Mutex;
8use std::time::{Duration, Instant};
9
10static CACHE: std::sync::LazyLock<Mutex<GitCache>> =
11    std::sync::LazyLock::new(|| Mutex::new(GitCache::new()));
12
13struct CacheEntry {
14    output: String,
15    inserted: Instant,
16    ttl: Duration,
17}
18
19struct GitCache {
20    entries: HashMap<String, CacheEntry>,
21}
22
23impl GitCache {
24    fn new() -> Self {
25        Self {
26            entries: HashMap::new(),
27        }
28    }
29
30    fn get(&self, key: &str) -> Option<&str> {
31        let now = Instant::now();
32        if let Some(entry) = self.entries.get(key) {
33            if now.duration_since(entry.inserted) < entry.ttl {
34                return Some(&entry.output);
35            }
36        }
37        None
38    }
39
40    fn prune_expired(&mut self) {
41        let now = Instant::now();
42        self.entries
43            .retain(|_, e| now.duration_since(e.inserted) < e.ttl);
44    }
45
46    fn insert(&mut self, key: String, output: String, ttl: Duration) {
47        if self.entries.len() > 100 {
48            self.prune_expired();
49        }
50        self.entries.insert(
51            key,
52            CacheEntry {
53                output,
54                inserted: Instant::now(),
55                ttl,
56            },
57        );
58    }
59}
60
61/// Run a git command with TTL caching. Returns cached result if available.
62pub fn git_cached(args: &[&str], cwd: &str, ttl: Duration) -> Option<String> {
63    let key = format!("{cwd}:{}", args.join(" "));
64
65    if let Ok(cache) = CACHE.lock() {
66        if let Some(cached) = cache.get(&key) {
67            return Some(cached.to_string());
68        }
69    }
70
71    let output = std::process::Command::new("git")
72        .args(args)
73        .current_dir(cwd)
74        .output()
75        .ok()?;
76
77    if !output.status.success() {
78        return None;
79    }
80
81    let result = String::from_utf8_lossy(&output.stdout).to_string();
82
83    if let Ok(mut cache) = CACHE.lock() {
84        cache.insert(key, result.clone(), ttl);
85    }
86
87    Some(result)
88}
89
90/// Short-TTL (10s) for frequently-changing git data (status, diff).
91pub fn git_status_cached(cwd: &str) -> Option<String> {
92    git_cached(&["status", "--porcelain"], cwd, Duration::from_secs(10))
93}
94
95/// Short-TTL (10s) for git diff.
96pub fn git_diff_cached(args: &[&str], cwd: &str) -> Option<String> {
97    let mut full_args = vec!["diff"];
98    full_args.extend_from_slice(args);
99    git_cached(&full_args, cwd, Duration::from_secs(10))
100}
101
102/// Longer-TTL (60s) for git log (rarely changes within a session).
103pub fn git_log_cached(args: &[&str], cwd: &str) -> Option<String> {
104    let mut full_args = vec!["log"];
105    full_args.extend_from_slice(args);
106    git_cached(&full_args, cwd, Duration::from_mins(1))
107}
108
109/// Invalidate all cached entries for a given directory.
110pub fn invalidate(cwd: &str) {
111    if let Ok(mut cache) = CACHE.lock() {
112        cache.entries.retain(|k, _| !k.starts_with(cwd));
113    }
114}
115
116#[cfg(test)]
117mod tests {
118    use super::*;
119
120    #[test]
121    fn cache_insert_and_retrieve() {
122        let mut cache = GitCache::new();
123        cache.insert(
124            "test:key".to_string(),
125            "output".to_string(),
126            Duration::from_mins(1),
127        );
128        assert_eq!(cache.get("test:key"), Some("output"));
129    }
130
131    #[test]
132    fn cache_miss_on_unknown_key() {
133        let cache = GitCache::new();
134        assert_eq!(cache.get("unknown"), None);
135    }
136
137    #[test]
138    fn cache_evicts_when_full() {
139        let mut cache = GitCache::new();
140        for i in 0..105 {
141            cache.insert(
142                format!("key:{i}"),
143                "val".to_string(),
144                Duration::from_mins(1),
145            );
146        }
147        assert!(cache.entries.len() <= 105);
148    }
149}
lean_ctx/core/git_cache.rs

lean_ctx/core/
git_cache.rs
