initial commit

alterego/build.rs

@@ -0,0 +1,41 @@
+use std::env;
+
+fn main() {
+    let rev = get_value_from_env("GIT_VERSION")
+        .or_else(|| get_value_from_command("git", &["rev-parse", "--short", "HEAD"]))
+        .unwrap_or_else(|| "unknown".to_owned());
+
+    let branch = get_value_from_env("GIT_BRANCH")
+        .or_else(|| get_value_from_command("git", &["rev-parse", "--abbrev-ref", "HEAD"]))
+        .unwrap_or_else(|| "unknown".to_owned());
+
+    println!("cargo:rustc-env=GIT_REVISION={}", rev);
+    println!("cargo:rustc-env=GIT_BRANCH={}", branch);
+    println!("cargo:rerun-if-env-changed=GIT_REVISION");
+}
+
+fn get_value_from_env(key: &str) -> Option<String> {
+    env::var(key).map_or_else(|_| None, Some)
+}
+
+fn get_value_from_command<I: IntoIterator<Item = S>, S: AsRef<std::ffi::OsStr>>(
+    cmd: &str,
+    args: I,
+) -> Option<String> {
+    std::process::Command::new(cmd)
+        .args(args)
+        .output()
+        .map_or_else(
+            |_| None,
+            |out| {
+                if !out.status.success() {
+                    return None;
+                }
+
+                match std::str::from_utf8(&out.stdout) {
+                    Ok(value) => Some(value.to_owned()),
+                    Err(_) => None,
+                }
+            },
+        )
+}