feat: display commit info in --version (#558)

This improves --version output for #554.

1 files changed, 50 insertions, 0 deletions

diff --git a/src/version.rs b/src/version.rs
new file mode 100644
index 0000000000..8391e2674c
--- /dev/null
+++ b/src/version.rs
@@ -0,0 +1,50 @@
+use std::fmt;
+
+use lazy_static::lazy_static;
+
+pub struct CommitInfo {
+    pub short_commit_hash: &'static str,
+    pub commit_hash: &'static str,
+    pub commit_date: &'static str,
+}
+
+pub struct VersionInfo {
+    pub version: &'static str,
+    pub commit_info: Option<CommitInfo>,
+}
+
+impl fmt::Display for VersionInfo {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.version)?;
+
+        if let Some(ref ci) = &self.commit_info {
+            write!(f, " ({} {})", ci.short_commit_hash, ci.commit_date)?;
+        }
+        Ok(())
+    }
+}
+
+lazy_static! {
+    pub static ref VERSION: String = version().to_string();
+}
+
+pub const fn version() -> VersionInfo {
+    let version = env!("CARGO_PKG_VERSION");
+    let commit_info = match (
+        option_env!("DFT_COMMIT_SHORT_HASH"),
+        option_env!("DFT_COMMIT_HASH"),
+        option_env!("DFT_COMMIT_DATE"),
+    ) {
+        (Some(short_commit_hash), Some(commit_hash), Some(commit_date)) => Some(CommitInfo {
+            short_commit_hash,
+            commit_hash,
+            commit_date,
+        }),
+        _ => None,
+    };
+
+    VersionInfo {
+        version,
+        commit_info,
+    }
+}