refactor code

Signed-off-by: Saurav Sharma <appdroiddeveloper@gmail.com>

src/hyperfine/app.rs

@@ -80,10 +80,11 @@ fn build_app() -> App<'static, 'static> {
                 .number_of_values(1)
                 .value_name("CMD")
                 .help(
-                    "Execute CMD before each timing run. For example, this is \
-                     useful for clearing disk caches. This can be mentioned \
-                     out multiple time for each command or only one time for \
-                     all command.",
+                    "Execute CMD before each timing run. This is useful for \
+                     clearing disk caches, for example. \nThe --prepare option can \
+                     be specified once for all commands or multiple times, once for \
+                     each command. In the latter case, each preparation command will \
+                     be run prior to the corresponding benchmark command.",
                 ),
         )
         .arg(

src/hyperfine/benchmark.rs

@@ -234,14 +234,19 @@ pub fn run_benchmark(
     );
 
     // Run init command
-    let mut prepare_cmd = None;
-    if let Some(values) = &options.preparation_command {
-        if values.len() == 1 {
-            prepare_cmd = Some(new_command_from_get_parameter(cmd, &values[0]));
-        } else {
-            prepare_cmd = Some(new_command_from_get_parameter(cmd, &values[num]));
+    let prepare_cmd = options.preparation_command.as_ref().map(|values| {
+        let corresponding_prepare_cmd = match values.len() {
+            1 => &values[0],
+            _ => &values[num],
+        };
+        match cmd.get_parameter() {
+            Some((param, value)) => {
+                Command::new_parametrized(corresponding_prepare_cmd, param, value)
+            }
+            None => Command::new(corresponding_prepare_cmd),
         }
-    };
+    });
+
     let prepare_res = run_preparation_command(&options.shell, &prepare_cmd, options.show_output)?;
 
     // Initial timing run
@@ -405,14 +410,3 @@ pub fn run_benchmark(
         cmd.get_parameter().map(|p| p.1),
     ))
 }
-
-// Get out new Command from a Command and preparation command
-fn new_command_from_get_parameter<'a>(
-    cmd: &Command<'a>,
-    preparation_command: &'a str,
-) -> Command<'a> {
-    match cmd.get_parameter() {
-        Some((param, value)) => Command::new_parametrized(preparation_command, param, value),
-        None => Command::new(preparation_command),
-    }
-}

src/main.rs

@@ -123,11 +123,9 @@ fn build_hyperfine_options(matches: &ArgMatches<'_>) -> Result<HyperfineOptions,
         (None, None) => {}
     };
 
-    if let Some(values) = matches.values_of("prepare") {
-        options.preparation_command = Some(values.map(String::from).collect::<Vec<String>>());
-    } else {
-        options.preparation_command = None;
-    }
+    options.preparation_command = matches
+        .values_of("prepare")
+        .map(|values| values.map(String::from).collect::<Vec<String>>());
 
     options.cleanup_command = matches.value_of("cleanup").map(String::from);