/// <summary>
/// Gets called when the external process writes to the error pipe.
/// </summary>
/// <param name="result"></param>
/// <param name="data"></param>
protected virtual void OnErrorReceived(ProcessResult result, string data)
{
result.Errors.Add(data);
}
/// <summary>
/// Implements executing an external process with overridable functions.
/// </summary>
/// <param name="setup"></param>
/// <param name="timeout"></param>
/// <returns></returns>
public ProcessResult Execute(ProcessSetup setup, int timeout = 30000)
{
var result = new ProcessResult()
{
Output = new List <string>(),
Errors = new List <string>()
};
using (var process = new Process())
{
if (!this.OnSetupProcess(process, setup))
{
// handle erros.
result.Errors.Add("OnSetupProcess returned false");
return(result);
}
// we assume user has handled setup correctly.
process.OutputDataReceived += (sender, args) =>
{
//TODO: should we just give user all output or filter?
if (args.Data != null)
{
OnOutputReceived(result, args.Data);
}
};
process.StartInfo.RedirectStandardOutput = true;
process.ErrorDataReceived += (sender, args) =>
{
if (args.Data != null)
{
OnErrorReceived(result, args.Data);
}
};
process.StartInfo.RedirectStandardError = true;
// try to start process.
try
{
result.WasStarted = process.Start();
}
catch (Exception e)
{
// Usually it occurs when an executable file is not found or is not executable
// or requires admin privileges.
result.Errors.Add(e.Message);
return(result);
}
// start listening on readlines.
process.BeginOutputReadLine();
process.BeginErrorReadLine();
var flagExitedBeforeTimeout = process.WaitForExit(timeout);
if (flagExitedBeforeTimeout)
{
process.WaitForExit(); // wait more to ensure events are processed.
result.HasCompleted = true;
result.ExitCode = process.ExitCode;
}
else
{
// kill process.
try
{
process.Kill();
}
catch { } // ignore error.
}
//TODO: should we indicate to user that process was killed?
return(result);
}
}
/// <summary>
/// Gets called when the external process writes to the output pipe.
/// </summary>
/// <param name="result"></param>
/// <param name="data"></param>
protected virtual void OnOutputReceived(ProcessResult result, string data)
{
//TODO: this function might need more context parameters than result and string data...
result.Output.Add(data);
}
/// <summary>
/// Implements executing an external process async with overridable functions.
/// </summary>
/// <param name="setup"></param>
/// <param name="cancel"></param>
/// <returns></returns>
public async Task <ProcessResult> ExecuteAsync(ProcessSetup setup, CancellationToken cancel = default)
{
var result = new ProcessResult()
{
Output = new List <string>(),
Errors = new List <string>()
};
using (var process = new Process())
{
if (!OnSetupProcess(process, setup))
{
// handle erros.
result.Errors.Add("OnSetupProcess returned false");
return(result);
}
// we assume user has handled setup correctly.
// setup output event handling.
var outputCloseEvent = new TaskCompletionSource <bool>();
process.OutputDataReceived += (sender, args) =>
{
if (args.Data == null)
{
outputCloseEvent.SetResult(true);
}
else
{
OnOutputReceived(result, args.Data);
}
};
process.StartInfo.RedirectStandardOutput = true;
// setup error event listening.
var errorCloseEvent = new TaskCompletionSource <bool>();
process.ErrorDataReceived += (sender, args) =>
{
if (args.Data == null)
{
errorCloseEvent.SetResult(true);
}
else
{
OnErrorReceived(result, args.Data);
}
};
process.StartInfo.RedirectStandardError = true;
// setup exit event listening.
var exitCloseEvent = new TaskCompletionSource <bool>();
process.Exited += (sender, args) =>
{
exitCloseEvent.SetResult(true);
};
process.EnableRaisingEvents = true;
// try to start process.
try
{
result.WasStarted = process.Start();
}
catch (Exception e)
{
// Usually it occurs when an executable file is not found or is not executable
// or requires admin privileges.
result.Errors.Add(e.Message);
return(result);
}
// start listening on readlines.
process.BeginOutputReadLine();
process.BeginErrorReadLine();
//TODO: find out how to await a cancellation token.
/*
* There are now 2 types of tasks.
* * Those that should all be finished.
* * Those that can be either.
*
* So wrap the event tasks into one taskProcess which awaits all.
* Then create a task which handles waiting and cancellation.
*
* At last, wait for which finished first.
*/
// wrap all the event task into one task.
var taskProcess = Task.WhenAll(exitCloseEvent.Task, outputCloseEvent.Task, errorCloseEvent.Task);
// create a task for handling waiting for exit or cancellation whichever happens first.
var taskWaitForExit = OnWaitForExitAsync(process, cancel);
// this awaits any of event tasks and exit task.
// when any is finished it waits for result from exit task anyway.
if (await Task.WhenAny(taskProcess, taskWaitForExit) == taskProcess && taskWaitForExit.Result)
{
result.ExitCode = process.ExitCode;
result.HasCompleted = true;
}
else
{
// process canceled. kill it...
try
{
process.Kill();
}
catch { } // ignore error.
}
return(result);
}
}
