feat(builtins): implement times builtin (#309)

brush-core/Cargo.toml

@@ -57,6 +57,7 @@ command-fds = "0.3.0"
 nix = { version = "0.29.0", features = [
     "fs",
     "process",
+    "resource",
     "signal",
     "term",
     "user",

brush-core/src/builtins.rs

@@ -50,6 +50,8 @@ mod set;
 mod shift;
 mod shopt;
 mod test;
+#[cfg(unix)]
+mod times;
 mod trap;
 mod true_;
 mod type_;

brush-core/src/builtins/factory.rs

@@ -219,10 +219,8 @@ pub(crate) fn get_default_builtins(
         "readonly".into(),
         special_decl_builtin::<declare::DeclareCommand>(),
     );
-    m.insert(
-        "times".into(),
-        special_builtin::<unimp::UnimplementedCommand>(),
-    );
+    #[cfg(unix)]
+    m.insert("times".into(), special_builtin::<times::TimesCommand>());
 
     //
     // Non-special builtins

brush-core/src/builtins/times.rs

@@ -0,0 +1,76 @@
+use clap::Parser;
+use std::io::Write;
+
+use crate::{builtins, commands, error};
+
+/// Report on usage time.
+#[derive(Parser)]
+pub(crate) struct TimesCommand {}
+
+impl builtins::Command for TimesCommand {
+    async fn execute(
+        &self,
+        context: commands::ExecutionContext<'_>,
+    ) -> Result<builtins::ExitCode, error::Error> {
+        let self_usage = nix::sys::resource::getrusage(nix::sys::resource::UsageWho::RUSAGE_SELF)?;
+
+        writeln!(
+            context.stdout(),
+            "{} {}",
+            format_time(self_usage.user_time()),
+            format_time(self_usage.system_time()),
+        )?;
+
+        let children_usage =
+            nix::sys::resource::getrusage(nix::sys::resource::UsageWho::RUSAGE_CHILDREN)?;
+
+        writeln!(
+            context.stdout(),
+            "{} {}",
+            format_time(children_usage.user_time()),
+            format_time(children_usage.system_time()),
+        )?;
+
+        Ok(builtins::ExitCode::Success)
+    }
+}
+
+fn format_time(time: nix::sys::time::TimeVal) -> String {
+    #[allow(clippy::cast_sign_loss)]
+    #[allow(clippy::cast_possible_truncation)]
+    let duration = std::time::Duration::new(time.tv_sec() as u64, time.tv_usec() as u32 * 1000);
+    let minutes = duration.as_secs() / 60;
+    let seconds = duration.as_secs() % 60;
+    let millis = duration.subsec_millis();
+    format!("{minutes}m{seconds}.{millis:03}s")
+}
+
+#[cfg(test)]
+mod tests {
+    use nix::sys::time::TimeValLike;
+
+    use super::*;
+
+    #[test]
+    fn test_format_time() {
+        fn ms_to_timeval(ms: i64) -> nix::sys::time::TimeVal {
+            nix::sys::time::TimeVal::milliseconds(ms)
+        }
+
+        fn us_to_timeval(us: i64) -> nix::sys::time::TimeVal {
+            nix::sys::time::TimeVal::microseconds(us)
+        }
+
+        assert_eq!(format_time(ms_to_timeval(0)), "0m0.000s");
+        assert_eq!(format_time(ms_to_timeval(1)), "0m0.001s");
+        assert_eq!(format_time(ms_to_timeval(123)), "0m0.123s");
+        assert_eq!(format_time(ms_to_timeval(1234)), "0m1.234s");
+        assert_eq!(format_time(ms_to_timeval(12345)), "0m12.345s");
+        assert_eq!(format_time(ms_to_timeval(123456)), "2m3.456s");
+        assert_eq!(format_time(ms_to_timeval(1234567)), "20m34.567s");
+
+        assert_eq!(format_time(us_to_timeval(1)), "0m0.000s");
+        assert_eq!(format_time(us_to_timeval(999)), "0m0.000s");
+        assert_eq!(format_time(us_to_timeval(1000)), "0m0.001s");
+    }
+}

brush-shell/tests/cases/builtins/times.yaml

@@ -0,0 +1,6 @@
+name: "Builtins: times"
+cases:
+  - name: "Basic usage"
+    ignore_stdout: true
+    stdin: |
+      times