Fix a problem with the new MythSignalingTimer consuming all memory an…

…d causing

both MythFrontend and MythWelcome to become unresponsive and eventually to be
killed by the OOM killer.

The problem is triggered when the main UI thread is stopped waiting for another
external process to finish, e.g. when using an external player or when starting
the FE from MythWelcome. Because the timer is run in its own thread it
continues to emit the timeout signals which just get queued up waiting to be
handled.

This patch just start/stops the timer when SetDrawEnabled(true/false) is
called and changes myth_system() to disable drawing when an external process is
running and re-enables it when it finishes.


git-svn-id: http://svn.mythtv.org/svn/trunk@23575 7dbf422c-18fa-0310-86e9-fd20926502f2

mythtv/libs/libmythui/mythmainwindow.cpp

@@ -1058,6 +1058,11 @@ void MythMainWindow::SetDrawEnabled(bool enable)
     setUpdatesEnabled(enable);
     d->m_drawEnabled = enable;
 
+    if (enable)
+        d->drawTimer->start(1000 / 70);
+    else
+        d->drawTimer->stop();
+
     // TODO FIXME
     // Sleep 50 ms to give any in progress draw a chance to finish.
     // This should be replaced with something sane after MythTV 0.22

mythtv/libs/libmythui/mythsystem.cpp

@@ -58,6 +58,9 @@ uint myth_system(const QString &command, int flags)
     bool ready_to_lock = HasMythMainWindow();
 
     (void)ready_to_lock; /* Kill warning */
+
+    uint result = GENERIC_EXIT_NOT_OK;
+
 #ifdef USE_LIRC
     bool lirc_lock_flag = !(flags & MYTH_SYSTEM_DONT_BLOCK_LIRC);
     LircEventLock lirc_lock(lirc_lock_flag && ready_to_lock);
@@ -75,6 +78,9 @@ uint myth_system(const QString &command, int flags)
     flags |= MYTH_SYSTEM_DONT_BLOCK_PARENT;
 #endif
 
+    if (ready_to_lock && !(flags & MYTH_SYSTEM_DONT_BLOCK_PARENT))
+        GetMythMainWindow()->SetDrawEnabled(false);
+
     QString LOC_ERR = QString("myth_system('%1'): Error: ").arg(command);
 
 #ifndef USING_MINGW
@@ -85,7 +91,7 @@ uint myth_system(const QString &command, int flags)
         /* Fork failed */
         VERBOSE(VB_IMPORTANT, (LOC_ERR + "fork() failed because %1")
                 .arg(strerror(errno)));
-        return GENERIC_EXIT_NOT_OK;
+        result = GENERIC_EXIT_NOT_OK;
     }
     else if (child == 0)
     {
@@ -141,14 +147,18 @@ uint myth_system(const QString &command, int flags)
                     VERBOSE(VB_IMPORTANT,
                             (LOC_ERR + "waitpid() failed because %1")
                             .arg(strerror(errno)));
-                    return GENERIC_EXIT_NOT_OK;
+                    result = GENERIC_EXIT_NOT_OK;
+                    break;
                 }
 
                 qApp->processEvents();
 
 
                 if (res > 0)
-                    return WEXITSTATUS(status);
+                {
+                    result = WEXITSTATUS(status);
+                    break;
+                }
 
                 usleep(100000);
             }
@@ -159,9 +169,10 @@ uint myth_system(const QString &command, int flags)
             {
                 VERBOSE(VB_IMPORTANT, (LOC_ERR + "waitpid() failed because %1")
                         .arg(strerror(errno)));
-                return GENERIC_EXIT_NOT_OK;
+                result = GENERIC_EXIT_NOT_OK;
             }
-            return WEXITSTATUS(status);
+            else
+                result = WEXITSTATUS(status);
         }
     }
 
@@ -196,6 +207,10 @@ uint myth_system(const QString &command, int flags)
         return exitcode;
     }
 #endif
-    return GENERIC_EXIT_NOT_OK;
+
+    if (ready_to_lock && !(flags & MYTH_SYSTEM_DONT_BLOCK_PARENT))
+        GetMythMainWindow()->SetDrawEnabled(true);
+
+    return result;
 }