Issue 984 (#987)

* WIP: first attempt to fix issue-983

* WIP: bugfixes

* Fixed a problem with displaying empty cell dimensions, one warning

* Another fix: don't allow proxy cells to be selected in the instance properties dialog. This creates a confusing behaviour

* Fixed a few flaws in the cell selection scheme on the instance properties dialog.

* Early warning when trying to build a recursive hierarchy.

* Another fix: avoid too much undo in case of errors thrown during 'apply' followed by 'cancel'

* First attempt to fix issue 984

* Fixed issue-983 solution

* Fixed the modification status of PCell parameters for 'apply to all'

src/lay/lay/layApplication.cc

@@ -1317,6 +1317,20 @@ GuiApplication::notify (QObject *receiver, QEvent *e)
   return ret;
 }
 
+void
+GuiApplication::enter_busy_mode (bool bm)
+{
+  if (mp_mw) {
+    mp_mw->enter_busy_mode (bm);
+  }
+}
+
+bool
+GuiApplication::is_busy () const
+{
+  return mp_mw && mp_mw->is_busy ();
+}
+
 void
 GuiApplication::force_update_app_menu ()
 {
@@ -1484,18 +1498,19 @@ GuiApplication::setup ()
 void
 GuiApplication::process_events_impl (QEventLoop::ProcessEventsFlags flags, bool silent)
 {
+  //  prevent recursive process_events
+  if (is_busy ()) {
+    return;
+  }
+
   if (mp_mw) {
 
-    //  prevent recursive process_events
-    if (mp_mw->is_busy ()) {
-      return;
-    }
+    lay::BusySection busy;
 
     if (silent) {
       tl::DeferredMethodScheduler::enable (false);
     }
 
-    mp_mw->enter_busy_mode (true);
     try {
 #if QT_VERSION < 0x050000
       QApplication::syncX ();
@@ -1507,7 +1522,6 @@ GuiApplication::process_events_impl (QEventLoop::ProcessEventsFlags flags, bool
     } catch (...) {
       //  ignore exceptions
     }
-    mp_mw->enter_busy_mode (false);
 
     if (silent) {
       tl::DeferredMethodScheduler::enable (true);

src/lay/lay/layApplication.h

@@ -25,6 +25,7 @@
 #define HDR_layApplication
 
 #include "layCommon.h"
+#include "layBusy.h"
 
 #include <QApplication>
 #include <QEventLoop>
@@ -366,7 +367,7 @@ private:
  *  @brief The GUI-enabled application class
  */
 class LAY_PUBLIC GuiApplication
-  : public QApplication, public ApplicationBase
+  : public QApplication, public ApplicationBase, public lay::BusyMode
 {
 public:
   GuiApplication (int &argc, char **argv);
@@ -408,6 +409,19 @@ public:
     return mp_mw;
   }
 
+  /**
+   *  @brief Enters busy mode (true) or leaves it (false)
+   *
+   *  Use lay::BusySection to declare a section in "busy" mode. In busy mode, some features are disabled to
+   *  prevent recursion in processing of events.
+   */
+  virtual void enter_busy_mode (bool bm);
+
+  /**
+   *  @brief Gets a value indicating whether busy mode is enabled
+   */
+  virtual bool is_busy () const;
+
   /**
    *  @brief Forces update of the application menu
    *  This function is used for work around a MacOS issue.

src/lay/lay/layMacroEditorDialog.cc

@@ -234,7 +234,7 @@ MacroEditorDialog::MacroEditorDialog (lay::Dispatcher *pr, lym::MacroCollection
     lay::Plugin (pr, true),
     mp_plugin_root (pr),
     mp_root (root),
-    m_first_show (true), m_in_processing (false), m_debugging_on (true),
+    m_first_show (true), m_debugging_on (true),
     mp_run_macro (0),
     md_update_console_text (this, &MacroEditorDialog::update_console_text),
     md_search_edited (this, &MacroEditorDialog::do_search_edited),
@@ -1075,12 +1075,10 @@ void
 MacroEditorDialog::process_events (QEventLoop::ProcessEventsFlags flags)
 {
   if (lay::ApplicationBase::instance ()) {
-    //  disable execution of deferred methods to avoid undesired execution of 
+    //  NOTE: we disable execution of deferred methods to avoid undesired execution of
     //  code while we are inside a Ruby callback through the silent mode
-    bool last_processing = m_in_processing;
-    m_in_processing = true;
+    //  NOTE: process_events will set BusySection::is_busy
     lay::ApplicationBase::instance ()->process_events (flags, true /*silent*/);
-    m_in_processing = last_processing;
   }
 }
 
@@ -1430,7 +1428,7 @@ MacroEditorDialog::eventFilter (QObject *obj, QEvent *event)
     return false;
   }
 
-  if (m_in_processing && (m_in_breakpoint || m_in_exec) && (dynamic_cast <QInputEvent *> (event) != 0 || dynamic_cast <QPaintEvent *> (event) != 0)) {
+  if (lay::BusySection::is_busy () && (m_in_breakpoint || m_in_exec) && (dynamic_cast <QInputEvent *> (event) != 0 || dynamic_cast <QPaintEvent *> (event) != 0)) {
 
     //  In breakpoint or execution mode and while processing the events from the debugger, 
     //  ignore all input or paint events targeted to widgets which are not children of this or the assistant dialog.
@@ -1447,7 +1445,7 @@ MacroEditorDialog::eventFilter (QObject *obj, QEvent *event)
       return true;
     }
 
-  } else if (! m_in_processing && m_in_exec) {
+  } else if (! lay::BusySection::is_busy ()  && m_in_exec) {
 
     //  While no explicit event processing is in progress and we are executing, this is an indication that
     //  "real" events are processed. In that case, we can postpone excplit processing. This avoids interference
@@ -3032,7 +3030,7 @@ MacroEditorDialog::exception_thrown (gsi::Interpreter *interpreter, size_t file_
   }
 
   //  avoid recursive breakpoints and exception catches from the console while in a breakpoint or exception stop
-  if (m_in_processing) {
+  if (lay::BusySection::is_busy ()) {
     return;
   }
 
@@ -3126,7 +3124,7 @@ MacroEditorDialog::trace (gsi::Interpreter *interpreter, size_t file_id, int lin
   }
 
   //  avoid recursive breakpoints and exception catches from the console while in a breakpoint or exception stop
-  if (m_in_processing) {
+  if (lay::BusySection::is_busy ()) {
     return;
   }
 

src/lay/lay/layMacroEditorDialog.h

@@ -301,7 +301,6 @@ private:
   lay::Dispatcher *mp_plugin_root;
   lym::MacroCollection *mp_root;
   bool m_first_show;
-  bool m_in_processing;
   bool m_debugging_on;
   lym::Macro *mp_run_macro;
   std::vector<lym::Macro *> m_macro_templates;

src/laybasic/laybasic/layBusy.cc

@@ -0,0 +1,82 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2022 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+#include "layBusy.h"
+#include "tlThreads.h"
+
+namespace lay
+{
+
+tl::Mutex s_lock;
+
+BusyMode *sp_busy_mode = 0;
+
+// ----------------------------------------------------------------------------------------------------------
+
+BusyMode::BusyMode ()
+{
+  tl::MutexLocker locker (&s_lock);
+  if (sp_busy_mode == 0) {
+    sp_busy_mode = this;
+  }
+}
+
+BusyMode::~BusyMode ()
+{
+  tl::MutexLocker locker (&s_lock);
+  if (sp_busy_mode == this) {
+    sp_busy_mode = 0;
+  }
+}
+
+// ----------------------------------------------------------------------------------------------------------
+
+BusySection::BusySection ()
+{
+  tl::MutexLocker locker (&s_lock);
+  mp_busy_mode = sp_busy_mode;
+  m_previous_mode = false;
+  if (mp_busy_mode) {
+    m_previous_mode = mp_busy_mode->is_busy ();
+    mp_busy_mode->enter_busy_mode (true);
+  }
+}
+
+BusySection::~BusySection ()
+{
+  tl::MutexLocker locker (&s_lock);
+  if (sp_busy_mode == mp_busy_mode && mp_busy_mode) {
+    mp_busy_mode->enter_busy_mode (m_previous_mode);
+  }
+  mp_busy_mode = 0;
+}
+
+bool 
+BusySection::is_busy ()
+{
+  tl::MutexLocker locker (&s_lock);
+  return sp_busy_mode && sp_busy_mode->is_busy ();
+}
+
+// ----------------------------------------------------------------------------------------------------------
+
+}

src/laybasic/laybasic/layBusy.h

@@ -0,0 +1,65 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2022 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+
+#ifndef HDR_layBusy
+#define HDR_layBusy
+
+#include "laybasicCommon.h"
+
+namespace lay
+{
+
+/**
+ *  @brief An interface providing the "busy" methods
+ *
+ *  There must be one provider implementing this interface.
+ */
+class LAYBASIC_PUBLIC BusyMode
+{
+public:
+  BusyMode ();
+  virtual ~BusyMode ();
+
+  virtual bool is_busy () const = 0;
+  virtual void enter_busy_mode (bool bm) = 0;
+};
+
+/**
+ *  @brief A RAII implementation of the busy mode setter
+ */
+class LAYBASIC_PUBLIC BusySection
+{
+public:
+  BusySection ();
+  ~BusySection ();
+
+  static bool is_busy ();
+
+private:
+  bool m_previous_mode;
+  BusyMode *mp_busy_mode;
+};
+
+}
+
+#endif

src/laybasic/laybasic/layHierarchyControlPanel.cc

@@ -42,6 +42,7 @@
 
 #include "dbClipboard.h"
 #include "dbClipboardData.h"
+#include "layBusy.h"
 #include "layHierarchyControlPanel.h"
 #include "layCellTreeModel.h"
 #include "layLayoutView.h"
@@ -146,6 +147,8 @@ HCPCellTreeWidget::startDrag (Qt::DropActions supportedActions)
       return;
     }
 
+    lay::BusySection busy_section; // issue 984
+
     QDrag *drag = new QDrag (this);
     drag->setMimeData(data);
     QPixmap px (1, 1);

src/laybasic/laybasic/layLibrariesView.cc

@@ -44,6 +44,7 @@
 #include "dbClipboardData.h"
 #include "dbLibraryManager.h"
 #include "dbLibrary.h"
+#include "layBusy.h"
 #include "layLibrariesView.h"
 #include "layCellTreeModel.h"
 #include "layLayoutView.h"
@@ -136,6 +137,8 @@ LibraryTreeWidget::startDrag (Qt::DropActions supportedActions)
       return;
     }
 
+    lay::BusySection busy_section; // issue 984
+
     QDrag *drag = new QDrag (this);
     drag->setMimeData(data);
     QPixmap px (1, 1);

src/laybasic/laybasic/laybasic.pro

@@ -102,6 +102,7 @@ SOURCES = \
   layBrowserDialog.cc \
   layBrowserPanel.cc \
   layBrowseShapesForm.cc \
+  layBusy.cc \
   layCanvasPlane.cc \
   layCellSelectionForm.cc \
   layCellTreeModel.cc \
@@ -208,6 +209,7 @@ HEADERS = \
   layBrowser.h \
   layBrowserPanel.h \
   layBrowseShapesForm.h \
+  layBusy.h \
   layCanvasPlane.h \
   layCellSelectionForm.h \
   layCellTreeModel.h \