PerformanceTimer.fsx

namespace SafeAlert.Fircosoft.Net.Diagnostics

open System.Collections.Generic
open System.Diagnostics
open System
open System.Text

/// <summary>
/// Allows ad-hoc timing of any delegate method, or more robust parallel timing of multiple named tasks.
/// </summary>
type PerformanceTimer() =
    // Dictionary of named watches.
    let watches = new Dictionary<string, Stopwatch>();

    /// Dictionary of named watches
    member x.Watches = watches

    /// Starts a timer with a given name
    member x.StartTimer(name: string) =
        match watches.TryGetValue(name) with
        | true, w -> w.Restart()
        | _ -> watches.Add(name, Stopwatch.StartNew())

    /// Stops a named timer (if one exists) and returns the time elapsed.
    member x.StopTimer(name: string) = 
        match watches.TryGetValue(name) with
        | true, w ->
            w.Stop()
            w.Elapsed
        | _ -> TimeSpan.Zero

    /// Stops all timers
    member x.StopAllTimers() =
        for watch in watches do
            watch.Value.Stop()

    /// Clears all timers from the report
    member x.ClearAllTimers() = 
        watches.Clear()

    /// Dumps a report of all timers and their elapsed times.
    member x.GetReport(showMilliseconds : bool) =
        let sb = new StringBuilder()
        watches
        |> Seq.iteri (fun i watch ->
            match watch.Value.IsRunning, showMilliseconds with
            | true, true   -> sb.AppendFormat("{0}: {1:0.00}ms (In Progress)", watch.Key, watch.Value.Elapsed.TotalMilliseconds) |> ignore
            | true, false  -> sb.AppendFormat("{0}: {1} (In Progress)", watch.Value.Elapsed, watch.Key) |> ignore
            | false, true  -> sb.AppendFormat("{0}: {1:0.00}ms", watch.Key, watch.Value.Elapsed.TotalMilliseconds) |> ignore
            | false, false -> sb.AppendFormat("{0}: {1}", watch.Value.Elapsed, watch.Key) |> ignore

            if (not <| (i = watches.Count - 1)) 
                then sb.Append("\r\n") |> ignore )
        sb.ToString()
    
    /// Executes the given delegate and returns the elapsed time
    member x.TimedAction(action : Action) =
        let sw = Stopwatch.StartNew()
        action.Invoke()
        sw.Stop()
        sw.Elapsed