1 files changed, 89 insertions, 0 deletions
diff --git a/src/git.rs b/src/git.rs
new file mode 100644
index 0000000..89e84db
--- /dev/null
+++ b/src/git.rs
@@ -0,0 +1,89 @@
+use crate::error::SiteError;
+use regex::Regex;
+use std::collections::HashMap;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+pub fn git(args: &[&str], cwd: &Path) -> Result<String, SiteError> {
+    assert!(!args.is_empty());
+    let output = Command::new("git")
+        .args(args)
+        .current_dir(cwd)
+        .output()
+        .map_err(|e| SiteError::GitInvoke(args[0].into(), cwd.into(), e))?;
+    if output.status.success() {
+        Ok(String::from_utf8_lossy(&output.stdout).into())
+    } else {
+        let stderr = String::from_utf8_lossy(&output.stderr).into();
+        Err(SiteError::GitError(args[0].into(), cwd.into(), stderr))
+    }
+}
+
+pub fn git_whatchanged(cwd: &Path) -> Result<HashMap<PathBuf, SystemTime>, SiteError> {
+    let mut files = HashMap::new();
+    if cwd.join(".git").is_dir() {
+        let output = git(&["whatchanged", "--pretty=format:%ad", "--date=unix"], cwd)?;
+        let timepat = Regex::new(r#"^(?P<secs>\d+)$"#).expect("regex compilation");
+        let filepat = Regex::new(r#"^:\S+ \S+ \S+ \S+ (?P<flag>\S)\t(?P<filename>\S+)$"#)
+            .expect("regex compilation");
+        let mut mtime = None;
+
+        for line in output.lines() {
+            if let Some(caps) = timepat.captures(line) {
+                let secs = caps.name("secs").unwrap().as_str();
+                let timestamp = secs
+                    .parse::<u64>()
+                    .map_err(|e| SiteError::ParseUnixTimestamp(secs.into(), e))?;
+                mtime = Some(UNIX_EPOCH + Duration::new(timestamp, 0));
+            } else if let Some(caps) = filepat.captures(line) {
+                let flag = caps.name("flag").unwrap().as_str();
+                let filename = PathBuf::from(caps.name("filename").unwrap().as_str());
+                if (flag == "M" || flag == "A") && !files.contains_key(&filename) {
+                    assert!(mtime.is_some());
+                    files.insert(filename, mtime.unwrap());
+                }
+            } else if line.trim().is_empty() {
+                mtime = None;
+            }
+        }
+    }
+    Ok(files)
+}
+
+pub fn git_dirty(cwd: &Path) -> Result<Vec<PathBuf>, SiteError> {
+    let mut dirty = vec![];
+    if cwd.join(".git").is_dir() {
+        let output = git(&["status", "--short"], cwd)?;
+
+        let pat = Regex::new(r#"^.(?P<status>.) (?P<filename>\S.+)$"#).expect("regex compilation");
+        for line in output.lines() {
+            if let Some(caps) = pat.captures(line) {
+                let status = GitStatus::from(caps.name("status").unwrap().as_str());
+                let filename = caps.name("filename").unwrap().as_str();
+                if status == GitStatus::Dirty {
+                    dirty.push(filename.into());
+                }
+            }
+        }
+    }
+
+    Ok(dirty)
+}
+
+#[derive(Debug, Eq, PartialEq)]
+pub enum GitStatus {
+    Clean,
+    Dirty,
+    Unknown,
+}
+
+impl From<&str> for GitStatus {
+    fn from(status: &str) -> Self {
+        match status {
+            "M" => Self::Dirty,
+            "?" => Self::Unknown,
+            _ => Self::Clean,
+        }
+    }
+}