Make time elapsed only show up initially

src/benchmark/mod.rs

@@ -14,7 +14,9 @@ use crate::options::{
 };
 use crate::outlier_detection::OUTLIER_THRESHOLD;
 use crate::output::console_writeln;
-use crate::output::progress_bar::get_progress_bar;
+use crate::output::progress_bar::{
+    get_progress_bar, replace_message_template, reset_progress_template,
+};
 use crate::output::warnings::{OutlierWarningOptions, Warnings};
 use crate::parameter::ParameterNameAndValue;
 use crate::quantity::{const_time_from_seconds, ratio, FormatQuantity, Time, Zero};
@@ -242,11 +244,13 @@ impl<'a> Benchmark<'a> {
 
         // Set up progress bar (and spinner for initial measurement)
         let progress_bar = if self.options.output_style != OutputStyleOption::Disabled {
-            Some(get_progress_bar(
+            let temp_bar = get_progress_bar(
                 self.options.run_bounds.min,
-                "Initial time measurement",
+                "Initial time measurement:",
                 self.options.output_style,
-            ))
+            );
+            let template = format!("{{msg}} {{elapsed:<{}}}", 30 - temp_bar.message().len() - 1,);
+            Some(replace_message_template(temp_bar, &template))
         } else {
             None
         };
@@ -298,6 +302,7 @@ impl<'a> Benchmark<'a> {
         all_succeeded = all_succeeded && success;
 
         // Re-configure the progress bar
+        let progress_bar = progress_bar.map(reset_progress_template);
         if let Some(bar) = progress_bar.as_ref() {
             bar.set_length(count)
         }

src/output/progress_bar.rs

@@ -9,13 +9,42 @@ const TICK_SETTINGS: (&str, u64) = ("⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏ ", 80);
 #[cfg(windows)]
 const TICK_SETTINGS: (&str, u64) = (r"+-x| ", 200);
 
+const DEFAULT_MESSAGE_TEMPLATE: &str = "{msg:<30}";
+
+fn create_progress_template(msg_template: &str) -> String {
+    format!(
+        " {{spinner}} {} {{wide_bar}} ETA {{eta_precise}} ",
+        msg_template
+    )
+}
+
+/// Replace the usual `message` in a progress bar with the result of evaluating `template`.
+/// The `template` may contain a `ProgressBar`'s templated fields.
+#[must_use]
+pub fn replace_message_template(bar: ProgressBar, template: &str) -> ProgressBar {
+    let old_style = bar.style();
+    let new_template = create_progress_template(template);
+    let new_style = old_style
+        .template(&new_template)
+        .expect("no template error");
+    bar.with_style(new_style)
+}
+
+/// Reset a progress bar's template to the default.
+/// This is useful after calling `replace_message_template()`.
+#[must_use]
+pub fn reset_progress_template(bar: ProgressBar) -> ProgressBar {
+    replace_message_template(bar, DEFAULT_MESSAGE_TEMPLATE)
+}
+
 /// Return a pre-configured progress bar
 pub fn get_progress_bar(length: u64, msg: &str, option: OutputStyleOption) -> ProgressBar {
+    let template = create_progress_template(DEFAULT_MESSAGE_TEMPLATE);
     let progressbar_style = match option {
         OutputStyleOption::Basic | OutputStyleOption::Color => ProgressStyle::default_bar(),
         _ => ProgressStyle::default_spinner()
             .tick_chars(TICK_SETTINGS.0)
-            .template(" {spinner} {msg:<30} {wide_bar} Time: {elapsed} ETA {eta_precise} ")
+            .template(&template)
             .expect("no template error"),
     };