Add multiple --prepare support

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

src/hyperfine/app.rs

@@ -76,10 +76,14 @@ fn build_app() -> App<'static, 'static> {
                 .long("prepare")
                 .short("p")
                 .takes_value(true)
+                .multiple(true)
+                .number_of_values(1)
                 .value_name("CMD")
                 .help(
-                    "Execute CMD before each timing run. This is useful for \
-                     clearing disk caches, for example.",
+                    "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.",
                 ),
         )
         .arg(

src/hyperfine/benchmark.rs

@@ -234,13 +234,17 @@ pub fn run_benchmark(
     );
 
     // Run init command
-    let prepare_cmd = options
-        .preparation_command
-        .as_ref()
-        .map(|preparation_command| match cmd.get_parameter() {
-            Some((param, value)) => Command::new_parametrized(preparation_command, param, value),
-            None => Command::new(preparation_command),
-        });
+    let mut prepare_cmd = None;
+    if let Some(values) = &options.preparation_command {
+        if num >= values.len() {
+            prepare_cmd = Some(new_command_from_get_parameter(
+                cmd,
+                &values[values.len() - 1],
+            ));
+        } else {
+            prepare_cmd = Some(new_command_from_get_parameter(cmd, &values[num]));
+        }
+    };
     let prepare_res = run_preparation_command(&options.shell, &prepare_cmd, options.show_output)?;
 
     // Initial timing run
@@ -404,3 +408,14 @@ 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/hyperfine/timer/windows_timer.rs

@@ -65,7 +65,8 @@ fn get_cpu_times(handle: RawHandle) -> CPUTimes {
             // Extract times as laid out here: https://support.microsoft.com/en-us/help/188768/info-working-with-the-filetime-structure
             // Both user_time and kernel_time are spans that the proces spent in either.
             let user: i64 = (((user_time.dwHighDateTime as i64) << 32)
-                + user_time.dwLowDateTime as i64) / HUNDRED_NS_PER_MS;
+                + user_time.dwLowDateTime as i64)
+                / HUNDRED_NS_PER_MS;
             let kernel: i64 = (((kernel_time.dwHighDateTime as i64) << 32)
                 + kernel_time.dwLowDateTime as i64)
                 / HUNDRED_NS_PER_MS;

src/hyperfine/types.rs

@@ -145,7 +145,7 @@ pub struct HyperfineOptions {
     pub failure_action: CmdFailureAction,
 
     /// Command to run before each timing run
-    pub preparation_command: Option<String>,
+    pub preparation_command: Option<Vec<String>>,
 
     /// Command to run after each benchmark
     pub cleanup_command: Option<String>,

src/main.rs

@@ -113,7 +113,11 @@ fn build_hyperfine_options(matches: &ArgMatches<'_>) -> Result<HyperfineOptions,
         (None, None) => {}
     };
 
-    options.preparation_command = matches.value_of("prepare").map(String::from);
+    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.cleanup_command = matches.value_of("cleanup").map(String::from);