From 523e9a1a07425cf0ba22a171933f79b0bed7cdc4 Mon Sep 17 00:00:00 2001
From: Bill Somerville <bill@classdesign.com>
Date: Sat, 14 Mar 2020 00:01:54 +0000
Subject: [PATCH] Enhanced process control for jt9 executable

The wsjtx  process creates control  files .start, .stop, or  .quit and
the jt9  process deletes  them.  This  is intended  to avoid  any race
conditions that get the processes out of sync.
---
 lib/jt9a.f90           | 26 +++++++++++++++-----------
 widgets/mainwindow.cpp | 37 ++++++-------------------------------
 widgets/mainwindow.h   |  1 -
 3 files changed, 21 insertions(+), 43 deletions(-)

diff --git a/lib/jt9a.f90 b/lib/jt9a.f90
index 3ca567b81..f316a8226 100644
--- a/lib/jt9a.f90
+++ b/lib/jt9a.f90
@@ -18,12 +18,11 @@ subroutine jt9a()
   integer*1 attach_jt9
 !  integer*1 lock_jt9,unlock_jt9
   integer size_jt9
-  integer itime(8)
 ! Multiple instances:
   character*80 mykey
+  integer :: lun, stat
   type(dec_data), pointer :: shared_data
   type(params_block) :: local_params
-  logical fileExists
   volatile shared_data
 
 ! Multiple instances:
@@ -39,17 +38,19 @@ subroutine jt9a()
   i0 = len(mykey)
   i0=setkey_jt9(trim(mykey))
   i1=attach_jt9()
-  msdelay=1
+  msdelay=100
 
-! Wait here until the .lock file is removed by GUI
-10 inquire(file=trim(temp_dir)//'/.lock',exist=fileExists)
-  if(fileExists) then
+! Wait here until the .start file is created by GUI
+10 open(newunit=lun,file=trim(temp_dir)//'/.start',iostat=stat,status='old')
+  if(stat.ne.0) then
      call sleep_msec(msdelay)
      go to 10
   endif
+  close(unit=lun,status='delete')
 
-  inquire(file=trim(temp_dir)//'/.quit',exist=fileExists)
-  if(fileExists) then
+  open(newunit=lun,file=trim(temp_dir)//'/.quit',iostat=stat,status='old')
+  if(stat.eq.0) then
+     close(unit=lun,status='delete')
      i1=detach_jt9()
      go to 999
   endif
@@ -83,9 +84,12 @@ subroutine jt9a()
   call multimode_decoder(shared_data%ss,shared_data%id2,local_params,12000)
   call timer('decoder ',1)
 
-! Wait here until GUI routine decodeDone() has re-created the .lock file
-100 inquire(file=trim(temp_dir)//'/.lock',exist=fileExists)
-  if(fileExists) go to 10
+! Wait here until GUI routine decodeDone() has re-created the .start file
+100 open(newunit=lun,file=trim(temp_dir)//'/.stop',iostat=stat,status='old')
+  if(stat.eq.0) then
+     close(unit=lun,status='delete')
+     go to 10
+  endif
   call sleep_msec(msdelay)
   go to 100
 
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 8c3905d98..8622a5213 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -1041,8 +1041,8 @@ void MainWindow::on_the_minute ()
 
 void MainWindow::pause_jt9 ()
 {
-  // Create .lock so jt9 will wait
-  QFile l {m_config.temp_dir ().absoluteFilePath (".lock")};
+  // Create .stop so jt9 will wait
+  QFile l {m_config.temp_dir ().absoluteFilePath (".stop")};
   if (!l.open(QFile::ReadWrite))
     {
       MessageBox::warning_message (this, tr ("Error creating \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ()));
@@ -1051,21 +1051,11 @@ void MainWindow::pause_jt9 ()
 
 void MainWindow::release_jt9 ()
 {
-  // Remove .lock so jt9 will continue
-  QFile l {m_config.temp_dir ().absoluteFilePath (".lock")};
-  while (l.exists ())
+  // Create .start so jt9 will continue
+  QFile l {m_config.temp_dir ().absoluteFilePath (".start")};
+  if (!l.open(QFile::ReadWrite))
     {
-      if (!l.remove ())
-        {
-          if (MessageBox::Cancel == MessageBox::query_message (this
-                                                               , tr ("IPC Error")
-                                                               , tr ("Error removing \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ())
-                                                               , QString {}
-                                                               , MessageBox::Retry | MessageBox::Cancel))
-            {
-              break;
-            }
-        }
+      MessageBox::warning_message (this, tr ("Error creating \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ()));
     }
 }
 
@@ -1108,21 +1098,6 @@ void MainWindow::stop_jt9 ()
     }
 }
 
-void MainWindow::cleanup_jt9 ()
-{
-  // Remove .quit as no longer needed
-  QFile l {m_config.temp_dir ().absoluteFilePath (".lock")};
-  while (l.exists ())
-    {
-      if (!l.remove ())
-        {
-          MessageBox::query_message (this
-                                     , tr ("Error removing \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ())
-                                     , tr ("Click OK to retry"));
-        }
-    }
-}
-
 //--------------------------------------------------- MainWindow destructor
 MainWindow::~MainWindow()
 {
diff --git a/widgets/mainwindow.h b/widgets/mainwindow.h
index 675e25a4a..c1f99df74 100644
--- a/widgets/mainwindow.h
+++ b/widgets/mainwindow.h
@@ -774,7 +774,6 @@ private:
   void pause_jt9 ();
   void release_jt9 ();
   void stop_jt9 ();
-  void cleanup_jt9 ();
 };
 
 extern int killbyname(const char* progName);