From 4a19bef2ac55491d9ed43b78fcf43bea3047c5e8 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Mon, 27 Nov 2023 13:18:04 -0800
Subject: [PATCH] Handle external simulator output gracefully

On Windows, ngspice doesn't output messages to stdout or stderr, it
starts the gui which causes KiCad to hang until ngspice is terminated.
We want to handle immediate responses but not get hung by the external
process.  Passing a process class to wxExecute allows us to detach the
process (it will terminate and free itself) while still handling the
immediate output and errors

Fixes https://gitlab.com/kicad/code/kicad/-/issues/15446
---
 eeschema/dialogs/dialog_export_netlist.cpp | 80 ++++++++++++++--------
 1 file changed, 51 insertions(+), 29 deletions(-)

diff --git a/eeschema/dialogs/dialog_export_netlist.cpp b/eeschema/dialogs/dialog_export_netlist.cpp
index 927e3f5352..7ce0d0f865 100644
--- a/eeschema/dialogs/dialog_export_netlist.cpp
+++ b/eeschema/dialogs/dialog_export_netlist.cpp
@@ -52,6 +52,7 @@
 #include <wx/filedlg.h>
 #include <wx/msgdlg.h>
 #include <wx/regex.h>
+#include <wx/txtstrm.h>
 
 
 
@@ -565,47 +566,68 @@ bool DIALOG_EXPORT_NETLIST::TransferDataFromWindow()
 
         if( !commandLine.IsEmpty() )
         {
-            wxArrayString output;
-            wxArrayString errors;
-            wxExecute( commandLine, output, errors, wxEXEC_ASYNC );
+            wxProcess* process = new wxProcess( GetEventHandler(), wxID_ANY );
+            process->Redirect();
+            wxExecute( commandLine, wxEXEC_ASYNC, process );
 
             reporter.ReportHead( commandLine, RPT_SEVERITY_ACTION );
+            process->Activate();
 
-            if( output.GetCount() )
+            sleep( 1 ); // give the process time to start and output any data or errors
+
+            if( process->IsInputAvailable() )
             {
-                for( unsigned ii = 0; ii < output.GetCount(); ii++ )
-                    reporter.Report( output[ii], RPT_SEVERITY_INFO );
+                wxInputStream* in = process->GetInputStream();
+                wxTextInputStream textstream( *in );
+
+                while( in->CanRead() )
+                {
+                    wxString line = textstream.ReadLine();
+
+                    if( !line.IsEmpty() )
+                        reporter.Report( line, RPT_SEVERITY_INFO );
+                }
             }
 
-            if( errors.GetCount() )
+            if( process->IsErrorAvailable() )
             {
-                for( unsigned ii = 0; ii < errors.GetCount(); ii++ )
-                {
-                    // wxExecute returns -1 for all error conditions, so we've no choice but
-                    // to scrape the stderr messages for the error code(s).
+                wxInputStream* err = process->GetErrorStream();
+                wxTextInputStream textstream( *err );
 
-                    if( errors[ii].EndsWith( wxS( "failed with error 2!" ) ) )      // ENOENT
+                while( err->CanRead() )
+                {
+                    wxString line = textstream.ReadLine();
+
+                    if( !line.IsEmpty() )
                     {
-                        reporter.Report( _( "external simulator not found" ), RPT_SEVERITY_ERROR );
-                        reporter.Report( _( "Note: command line is usually: "
-                                            "<tt>&lt;path to SPICE binary&gt; \"%I\"</tt>" ),
-                                         RPT_SEVERITY_INFO );
-                    }
-                    else if( errors[ii].EndsWith( wxS( "failed with error 8!" ) ) ) // ENOEXEC
-                    {
-                        reporter.Report( _( "external simulator has the wrong format or "
-                                            "architecture" ), RPT_SEVERITY_ERROR );
-                    }
-                    else if( errors[ii].EndsWith( "failed with error 13!" ) ) // EACCES
-                    {
-                        reporter.Report( _( "permission denied" ), RPT_SEVERITY_ERROR );
-                    }
-                    else
-                    {
-                        reporter.Report( errors[ii], RPT_SEVERITY_ERROR );
+                        if( line.EndsWith( wxS( "failed with error 2!" ) ) )      // ENOENT
+                        {
+                            reporter.Report( _( "external simulator not found" ), RPT_SEVERITY_ERROR );
+                            reporter.Report( _( "Note: command line is usually: "
+                                                "<tt>&lt;path to SPICE binary&gt; \"%I\"</tt>" ),
+                                            RPT_SEVERITY_INFO );
+                        }
+                        else if( line.EndsWith( wxS( "failed with error 8!" ) ) ) // ENOEXEC
+                        {
+                            reporter.Report( _( "external simulator has the wrong format or "
+                                                "architecture" ), RPT_SEVERITY_ERROR );
+                        }
+                        else if( line.EndsWith( "failed with error 13!" ) ) // EACCES
+                        {
+                            reporter.Report( _( "permission denied" ), RPT_SEVERITY_ERROR );
+                        }
+                        else
+                        {
+                            reporter.Report( line, RPT_SEVERITY_ERROR );
+                        }
                     }
                 }
             }
+
+            process->CloseOutput();
+            process->Detach();
+
+            // Do not delete process, it will delete itself when it terminates
         }
     }