From 0d855614813efe1492ad32d9c303ea3c00a3c18c Mon Sep 17 00:00:00 2001
From: Sinisa Veseli <sveseli@aps.anl.gov>
Date: Mon, 14 Mar 2022 09:17:33 -0500
Subject: [PATCH] this resolves issue with monitor overrun counter; master
 field listeners will be called only once, before calling listeners for the
 first subfield

---
 src/database/pvRecord.cpp | 23 ++++++++++++++++++++++-
 src/pv/pvDatabase.h       |  1 +
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/database/pvRecord.cpp b/src/database/pvRecord.cpp
index d343b6c..5357fc8 100644
--- a/src/database/pvRecord.cpp
+++ b/src/database/pvRecord.cpp
@@ -332,6 +332,7 @@ PVRecordField::PVRecordField(
     PVRecordPtr const & pvRecord)
 :  pvField(pvField),
    isStructure(pvField->getField()->getType()==structure ? true : false),
+   master(),
    parent(parent),
    pvRecord(pvRecord)
 {
@@ -420,12 +421,16 @@ void PVRecordField::postParent(PVRecordFieldPtr const & subField)
     PVRecordStructurePtr parent(this->parent.lock());
     if(parent) {
         parent->postParent(subField);
-        parent->callListener();
     }
 }
 
 void PVRecordField::postSubField()
 {
+    // Master field pointer will be set in only one subfield
+    PVRecordStructurePtr master(this->master.lock());
+    if(master) {
+        master->callListener();
+    }
     callListener();
     if(isStructure) {
         PVRecordStructurePtr pvrs =
@@ -468,6 +473,11 @@ void PVRecordStructure::init()
     PVRecordStructurePtr self =
         static_pointer_cast<PVRecordStructure>(shared_from_this());
     PVRecordPtr pvRecord = getPVRecord();
+    static bool masterFieldCallbackSet = false;
+    bool isMasterField = (!getFullFieldName().size());
+    if (isMasterField) {
+        masterFieldCallbackSet = false;
+    }
     for(size_t i=0; i<numFields; i++) {
         PVFieldPtr pvField = pvFields[i];
         if(pvField->getField()->getType()==structure) {
@@ -481,6 +491,17 @@ void PVRecordStructure::init()
                 new PVRecordField(pvField,self,pvRecord));
              pvRecordFields->push_back(pvRecordField);
              pvRecordField->init();
+             // Master field listeners will be called before
+             // calling listeners for the first subfield
+             if (!masterFieldCallbackSet) {
+                 masterFieldCallbackSet = true;
+                 // Find master field
+                 PVRecordStructurePtr p = pvRecordField->parent.lock();
+                 while (p) {
+                     pvRecordField->master = p;
+                     p = p->parent.lock();
+                 }
+             }
         }
     }
 }
diff --git a/src/pv/pvDatabase.h b/src/pv/pvDatabase.h
index a072466..3142373 100644
--- a/src/pv/pvDatabase.h
+++ b/src/pv/pvDatabase.h
@@ -376,6 +376,7 @@ private:
     std::list<PVListenerWPtr> pvListenerList;
     epics::pvData::PVField::weak_pointer pvField;
     bool isStructure;
+    PVRecordStructureWPtr master;
     PVRecordStructureWPtr parent;
     PVRecordWPtr pvRecord;
     std::string fullName;