[lmi-commits] [5830] Yield to Cancel before calling wxExecute()

[Greg Chicares]

Revision: 5830
          http://svn.sv.gnu.org/viewvc/?view=rev&root=lmi&revision=5830
Author:   chicares
Date:     2013-11-14 14:31:37 +0000 (Thu, 14 Nov 2013)
Log Message:
-----------
Yield to Cancel before calling wxExecute()

Modified Paths:
--------------
    lmi/trunk/ChangeLog
    lmi/trunk/system_command_wx.cpp

Modified: lmi/trunk/ChangeLog
===================================================================
--- lmi/trunk/ChangeLog 2013-11-14 13:17:12 UTC (rev 5829)
+++ lmi/trunk/ChangeLog 2013-11-14 14:31:37 UTC (rev 5830)
@@ -32908,3 +32908,8 @@
 Make do_dawdle() message generic. It's not necessarily only for
 printing.
 
+20131114T1431Z <address@hidden> [542]
+
+  system_command_wx.cpp
+Yield to Cancel before calling wxExecute().
+

Modified: lmi/trunk/system_command_wx.cpp
===================================================================
--- lmi/trunk/system_command_wx.cpp     2013-11-14 13:17:12 UTC (rev 5829)
+++ lmi/trunk/system_command_wx.cpp     2013-11-14 14:31:37 UTC (rev 5830)
@@ -32,11 +32,12 @@
 #include "null_stream.hpp"
 #include "timer.hpp"
 
-#include <wx/app.h> // wxTheApp
+#include <wx/app.h>                     // wxTheApp
+#include <wx/evtloop.h>                 // class wxEventLoopBase
 #include <wx/frame.h>
 #include <wx/utils.h>
 
-#include <cstddef>  // std::size_t
+#include <cstddef>                      // std::size_t
 #include <ostream>
 
 namespace
@@ -74,6 +75,11 @@
 /// exit code and the command itself.
 ///
 /// Show elapsed time on statusbar iff statusbar is available.
+///
+/// Before calling wxExecute(), yield for UI events so that Cancel is
+/// recognized when this function is called from a wxProgressDialog
+/// loop. See the discussion thread starting here:
+///   http://lists.nongnu.org/archive/html/lmi/2013-11/msg00009.html
 
 void concrete_system_command(std::string const& command_line)
 {
@@ -85,13 +91,12 @@
         && dynamic_cast<wxFrame*>(wxTheApp->GetTopWindow())
         && dynamic_cast<wxFrame*>(wxTheApp->GetTopWindow())->GetStatusBar()
         ;
-    std::ostream& statusbar_if_available =
-        b
-        ? status()
-        : null_stream()
-        ;
+    std::ostream& statusbar_if_available = b ? status() : null_stream();
+    statusbar_if_available << "Running..." << std::flush;
 
-    statusbar_if_available << "Running..." << std::flush;
+    wxEventLoopBase* e = wxEventLoopBase::GetActive();
+    e && e->YieldFor(wxEVT_CATEGORY_UI);
+
     wxArrayString output;
     wxArrayString errors;
     long int exit_code = wxExecute(command_line, output, errors);