From 08a92468feea1994f22eeaf9034d19882feeb7c7 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Tue, 8 Aug 2017 16:51:37 +0200
Subject: [PATCH] PVStructure::getSubField() const propagation

---
 src/pv/pvData.h         | 55 ++++++++++++++++++++++++++++++++++++-----
 src/pv/valueBuilder.cpp |  8 +++---
 2 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/src/pv/pvData.h b/src/pv/pvData.h
index 0825e51..cae9031 100644
--- a/src/pv/pvData.h
+++ b/src/pv/pvData.h
@@ -788,13 +788,25 @@ public:
      * @endcode
      */
     template<typename PVT = PVField>
-    FORCE_INLINE std::tr1::shared_ptr<PVT> getSubField(std::string const &fieldName) const
+    FORCE_INLINE std::tr1::shared_ptr<PVT> getSubField(std::string const &fieldName)
     {
         return this->getSubField<PVT>(fieldName.c_str());
     }
 
     template<typename PVT = PVField>
-    std::tr1::shared_ptr<PVT> getSubField(const char *name) const
+    FORCE_INLINE std::tr1::shared_ptr<const PVT> getSubField(std::string const &fieldName) const
+    {
+        return this->getSubField<PVT>(fieldName.c_str());
+    }
+
+    template<typename PVT = PVField>
+    std::tr1::shared_ptr<PVT> getSubField(const char *name)
+    {
+        return std::tr1::dynamic_pointer_cast<PVT>(getSubFieldImpl(name, false));
+    }
+
+    template<typename PVT = PVField>
+    std::tr1::shared_ptr<const PVT> getSubField(const char *name) const
     {
         return std::tr1::dynamic_pointer_cast<PVT>(getSubFieldImpl(name, false));
     }
@@ -805,7 +817,12 @@ public:
      * @return Pointer to the field or null if field does not exist.
      */
     template<typename PVT = PVField>
-    std::tr1::shared_ptr<PVT> getSubField(std::size_t fieldOffset) const
+    std::tr1::shared_ptr<PVT> getSubField(std::size_t fieldOffset)
+    {
+        return std::tr1::dynamic_pointer_cast<PVT>(getSubFieldImpl(fieldOffset, false));
+    }
+    template<typename PVT = PVField>
+    std::tr1::shared_ptr<const PVT> getSubField(std::size_t fieldOffset) const
     {
         return std::tr1::dynamic_pointer_cast<PVT>(getSubFieldImpl(fieldOffset, false));
     }
@@ -820,7 +837,13 @@ public:
      * @endcode
      */
     template<typename PVT = PVField>
-    FORCE_INLINE std::tr1::shared_ptr<PVT> getSubFieldT(std::string const &fieldName) const
+    FORCE_INLINE std::tr1::shared_ptr<PVT> getSubFieldT(std::string const &fieldName)
+    {
+        return this->getSubFieldT<PVT>(fieldName.c_str());
+    }
+
+    template<typename PVT = PVField>
+    FORCE_INLINE std::tr1::shared_ptr<const PVT> getSubFieldT(std::string const &fieldName) const
     {
         return this->getSubFieldT<PVT>(fieldName.c_str());
     }
@@ -830,7 +853,17 @@ private:
 public:
 
     template<typename PVT = PVField>
-    std::tr1::shared_ptr<PVT> getSubFieldT(const char *name) const
+    std::tr1::shared_ptr<PVT> getSubFieldT(const char *name)
+    {
+        std::tr1::shared_ptr<PVT> pvField(std::tr1::dynamic_pointer_cast<PVT>(
+                                              getSubFieldImpl(name, true)));
+        if(!pvField)
+            throwBadFieldType(name);
+        return pvField;
+    }
+
+    template<typename PVT = PVField>
+    std::tr1::shared_ptr<const PVT> getSubFieldT(const char *name) const
     {
         std::tr1::shared_ptr<PVT> pvField(std::tr1::dynamic_pointer_cast<PVT>(
                                               getSubFieldImpl(name, true)));
@@ -850,7 +883,17 @@ public:
      * @throws std::runtime_error if the requested sub-field doesn't exist, or has a different type 
      */
     template<typename PVT = PVField>
-    std::tr1::shared_ptr<PVT> getSubFieldT(std::size_t fieldOffset) const
+    std::tr1::shared_ptr<PVT> getSubFieldT(std::size_t fieldOffset)
+    {
+        std::tr1::shared_ptr<PVT> pvField = std::tr1::dynamic_pointer_cast<PVT>(
+            getSubFieldImpl(fieldOffset, true));
+        if(!pvField)
+            throwBadFieldType(fieldOffset);
+        return pvField;
+    }
+
+    template<typename PVT = PVField>
+    std::tr1::shared_ptr<const PVT> getSubFieldT(std::size_t fieldOffset) const
     {
         std::tr1::shared_ptr<PVT> pvField = std::tr1::dynamic_pointer_cast<PVT>(
             getSubFieldImpl(fieldOffset, true));
diff --git a/src/pv/valueBuilder.cpp b/src/pv/valueBuilder.cpp
index 5df9f30..d2a8ea0 100644
--- a/src/pv/valueBuilder.cpp
+++ b/src/pv/valueBuilder.cpp
@@ -109,16 +109,16 @@ void ValueBuilder::child_struct::fillStruct(ValueBuilder& self, const PVStructur
     const StringArray& field = type->getFieldNames();
     for(StringArray::const_iterator it=field.begin(), end=field.end(); it!=end; ++it)
     {
-        PVFieldPtr sub(val.getSubField(*it));
+        PVField::const_shared_pointer sub(val.getSubField(*it));
         assert(sub);
         FieldConstPtr subtype(sub->getField());
         switch(subtype->getType()) {
         case scalar:
         {
-            PVScalar* subs(static_cast<PVScalar*>(sub.get()));
+            const PVScalar* subs(static_cast<const PVScalar*>(sub.get()));
             ScalarType stype = subs->getScalar()->getScalarType();
             switch(stype) {
-#define STYPE(stype) case pv##stype: { PV ##stype* ptr(static_cast<PV##stype*>(subs)); PV##stype::value_type temp(ptr->get()); self._add(*it, pv##stype, &temp); } break
+#define STYPE(stype) case pv##stype: { const PV ##stype* ptr(static_cast<const PV##stype*>(subs)); PV##stype::value_type temp(ptr->get()); self._add(*it, pv##stype, &temp); } break
             STYPE(Boolean);
             STYPE(Byte);
             STYPE(Short);
@@ -136,7 +136,7 @@ void ValueBuilder::child_struct::fillStruct(ValueBuilder& self, const PVStructur
         }
             break;
         case structure:
-            self._add(*it, *static_cast<PVStructure*>(sub.get()));
+            self._add(*it, *static_cast<const PVStructure*>(sub.get()));
             break;
         default:
             THROW_EXCEPTION2(std::runtime_error, "ValueBuilder can only clone scalar and structure");