diff --git a/include/qpdf/QPDFObjGen.hh b/include/qpdf/QPDFObjGen.hh
index 3553ff3..5c38665 100644
--- a/include/qpdf/QPDFObjGen.hh
+++ b/include/qpdf/QPDFObjGen.hh
@@ -130,12 +130,6 @@ class QPDFObjGen
         }
 
         QPDF_DLL
-        bool add(QPDFObjectHandle const& oh);
-
-        QPDF_DLL
-        bool add(QPDFObjectHelper const& oh);
-
-        QPDF_DLL
         void
         erase(QPDFObjGen og)
         {
@@ -143,12 +137,6 @@ class QPDFObjGen
                 std::set<QPDFObjGen>::erase(og);
             }
         }
-
-        QPDF_DLL
-        void erase(QPDFObjectHandle const& oh);
-
-        QPDF_DLL
-        void erase(QPDFObjectHelper const& oh);
     };
 
   private:
diff --git a/include/qpdf/QPDFObjectHelper.hh b/include/qpdf/QPDFObjectHelper.hh
index ebd2e80..648b0f7 100644
--- a/include/qpdf/QPDFObjectHelper.hh
+++ b/include/qpdf/QPDFObjectHelper.hh
@@ -31,13 +31,12 @@
 // underlying QPDF objects unless there is a specific comment in a specific helper method that says
 // otherwise. The pattern of using helper objects was introduced to allow creation of higher level
 // helper functions without polluting the public interface of QPDFObjectHandle.
-
-class QPDF_DLL_CLASS QPDFObjectHelper
+class QPDF_DLL_CLASS QPDFObjectHelper: public qpdf::BaseHandle
 {
   public:
     QPDF_DLL
     QPDFObjectHelper(QPDFObjectHandle oh) :
-        oh(oh)
+        qpdf::BaseHandle(oh.getObj())
     {
     }
     QPDF_DLL
@@ -46,17 +45,29 @@ class QPDF_DLL_CLASS QPDFObjectHelper
     QPDFObjectHandle
     getObjectHandle()
     {
-        return this->oh;
+        return {obj};
     }
     QPDF_DLL
     QPDFObjectHandle const
     getObjectHandle() const
     {
-        return this->oh;
+        return {obj};
     }
 
   protected:
-    QPDFObjectHandle oh;
+    QPDF_DLL_PRIVATE
+    QPDFObjectHandle
+    oh()
+    {
+        return {obj};
+    }
+    QPDF_DLL_PRIVATE
+    QPDFObjectHandle const
+    oh() const
+    {
+        return {obj};
+    }
+    QPDFObjectHandle oh_;
 };
 
 #endif // QPDFOBJECTHELPER_HH
diff --git a/libqpdf/CMakeLists.txt b/libqpdf/CMakeLists.txt
index 91344a5..5480f12 100644
--- a/libqpdf/CMakeLists.txt
+++ b/libqpdf/CMakeLists.txt
@@ -76,7 +76,6 @@ set(libqpdf_SOURCES
   QPDFObject.cc
   QPDFObjectHandle.cc
   QPDFObjectHelper.cc
-  QPDFObjGen.cc
   QPDFOutlineDocumentHelper.cc
   QPDFOutlineObjectHelper.cc
   QPDFPageDocumentHelper.cc
diff --git a/libqpdf/QPDFAnnotationObjectHelper.cc b/libqpdf/QPDFAnnotationObjectHelper.cc
index 1878c0e..573273c 100644
--- a/libqpdf/QPDFAnnotationObjectHelper.cc
+++ b/libqpdf/QPDFAnnotationObjectHelper.cc
@@ -13,27 +13,27 @@ QPDFAnnotationObjectHelper::QPDFAnnotationObjectHelper(QPDFObjectHandle oh) :
 std::string
 QPDFAnnotationObjectHelper::getSubtype()
 {
-    return this->oh.getKey("/Subtype").getName();
+    return oh().getKey("/Subtype").getName();
 }
 
 QPDFObjectHandle::Rectangle
 QPDFAnnotationObjectHelper::getRect()
 {
-    return this->oh.getKey("/Rect").getArrayAsRectangle();
+    return oh().getKey("/Rect").getArrayAsRectangle();
 }
 
 QPDFObjectHandle
 QPDFAnnotationObjectHelper::getAppearanceDictionary()
 {
-    return this->oh.getKey("/AP");
+    return oh().getKey("/AP");
 }
 
 std::string
 QPDFAnnotationObjectHelper::getAppearanceState()
 {
-    if (this->oh.getKey("/AS").isName()) {
+    if (oh().getKey("/AS").isName()) {
         QTC::TC("qpdf", "QPDFAnnotationObjectHelper AS present");
-        return this->oh.getKey("/AS").getName();
+        return oh().getKey("/AS").getName();
     }
     QTC::TC("qpdf", "QPDFAnnotationObjectHelper AS absent");
     return "";
@@ -42,7 +42,7 @@ QPDFAnnotationObjectHelper::getAppearanceState()
 int
 QPDFAnnotationObjectHelper::getFlags()
 {
-    QPDFObjectHandle flags_obj = this->oh.getKey("/F");
+    QPDFObjectHandle flags_obj = oh().getKey("/F");
     return flags_obj.isInteger() ? flags_obj.getIntValueAsInt() : 0;
 }
 
@@ -143,7 +143,7 @@ QPDFAnnotationObjectHelper::getPageContentForAppearance(
 
     // 3. Apply the rotation to A as computed above to get the final appearance matrix.
 
-    QPDFObjectHandle rect_obj = this->oh.getKey("/Rect");
+    QPDFObjectHandle rect_obj = oh().getKey("/Rect");
     QPDFObjectHandle as = getAppearanceStream("/N").getDict();
     QPDFObjectHandle bbox_obj = as.getKey("/BBox");
     QPDFObjectHandle matrix_obj = as.getKey("/Matrix");
diff --git a/libqpdf/QPDFEFStreamObjectHelper.cc b/libqpdf/QPDFEFStreamObjectHelper.cc
index b21c898..8728617 100644
--- a/libqpdf/QPDFEFStreamObjectHelper.cc
+++ b/libqpdf/QPDFEFStreamObjectHelper.cc
@@ -16,7 +16,7 @@ QPDFEFStreamObjectHelper::QPDFEFStreamObjectHelper(QPDFObjectHandle oh) :
 QPDFObjectHandle
 QPDFEFStreamObjectHelper::getParam(std::string const& pkey)
 {
-    auto params = this->oh.getDict().getKey("/Params");
+    auto params = oh().getDict().getKey("/Params");
     if (params.isDictionary()) {
         return params.getKey(pkey);
     }
@@ -26,10 +26,9 @@ QPDFEFStreamObjectHelper::getParam(std::string const& pkey)
 void
 QPDFEFStreamObjectHelper::setParam(std::string const& pkey, QPDFObjectHandle const& pval)
 {
-    auto params = this->oh.getDict().getKey("/Params");
+    auto params = oh().getDict().getKey("/Params");
     if (!params.isDictionary()) {
-        params =
-            this->oh.getDict().replaceKeyAndGetNew("/Params", QPDFObjectHandle::newDictionary());
+        params = oh().getDict().replaceKeyAndGetNew("/Params", QPDFObjectHandle::newDictionary());
     }
     params.replaceKey(pkey, pval);
 }
@@ -67,7 +66,7 @@ QPDFEFStreamObjectHelper::getSize()
 std::string
 QPDFEFStreamObjectHelper::getSubtype()
 {
-    auto val = this->oh.getDict().getKey("/Subtype");
+    auto val = oh().getDict().getKey("/Subtype");
     if (val.isName()) {
         auto n = val.getName();
         if (n.length() > 1) {
@@ -124,7 +123,7 @@ QPDFEFStreamObjectHelper::setModDate(std::string const& date)
 QPDFEFStreamObjectHelper&
 QPDFEFStreamObjectHelper::setSubtype(std::string const& subtype)
 {
-    this->oh.getDict().replaceKey("/Subtype", QPDFObjectHandle::newName("/" + subtype));
+    oh().getDict().replaceKey("/Subtype", QPDFObjectHandle::newName("/" + subtype));
     return *this;
 }
 
diff --git a/libqpdf/QPDFFileSpecObjectHelper.cc b/libqpdf/QPDFFileSpecObjectHelper.cc
index eada461..8fac3ba 100644
--- a/libqpdf/QPDFFileSpecObjectHelper.cc
+++ b/libqpdf/QPDFFileSpecObjectHelper.cc
@@ -25,7 +25,7 @@ std::string
 QPDFFileSpecObjectHelper::getDescription()
 {
     std::string result;
-    auto desc = this->oh.getKey("/Desc");
+    auto desc = oh().getKey("/Desc");
     if (desc.isString()) {
         result = desc.getUTF8Value();
     }
@@ -36,7 +36,7 @@ std::string
 QPDFFileSpecObjectHelper::getFilename()
 {
     for (auto const& i: name_keys) {
-        auto k = this->oh.getKey(i);
+        auto k = oh().getKey(i);
         if (k.isString()) {
             return k.getUTF8Value();
         }
@@ -49,7 +49,7 @@ QPDFFileSpecObjectHelper::getFilenames()
 {
     std::map<std::string, std::string> result;
     for (auto const& i: name_keys) {
-        auto k = this->oh.getKey(i);
+        auto k = oh().getKey(i);
         if (k.isString()) {
             result[i] = k.getUTF8Value();
         }
@@ -60,7 +60,7 @@ QPDFFileSpecObjectHelper::getFilenames()
 QPDFObjectHandle
 QPDFFileSpecObjectHelper::getEmbeddedFileStream(std::string const& key)
 {
-    auto ef = this->oh.getKey("/EF");
+    auto ef = oh().getKey("/EF");
     if (!ef.isDictionary()) {
         return QPDFObjectHandle::newNull();
     }
@@ -79,7 +79,7 @@ QPDFFileSpecObjectHelper::getEmbeddedFileStream(std::string const& key)
 QPDFObjectHandle
 QPDFFileSpecObjectHelper::getEmbeddedFileStreams()
 {
-    return this->oh.getKey("/EF");
+    return oh().getKey("/EF");
 }
 
 QPDFFileSpecObjectHelper
@@ -110,7 +110,7 @@ QPDFFileSpecObjectHelper::createFileSpec(
 QPDFFileSpecObjectHelper&
 QPDFFileSpecObjectHelper::setDescription(std::string const& desc)
 {
-    this->oh.replaceKey("/Desc", QPDFObjectHandle::newUnicodeString(desc));
+    oh().replaceKey("/Desc", QPDFObjectHandle::newUnicodeString(desc));
     return *this;
 }
 
@@ -119,13 +119,13 @@ QPDFFileSpecObjectHelper::setFilename(
     std::string const& unicode_name, std::string const& compat_name)
 {
     auto uf = QPDFObjectHandle::newUnicodeString(unicode_name);
-    this->oh.replaceKey("/UF", uf);
+    oh().replaceKey("/UF", uf);
     if (compat_name.empty()) {
         QTC::TC("qpdf", "QPDFFileSpecObjectHelper empty compat_name");
-        this->oh.replaceKey("/F", uf);
+        oh().replaceKey("/F", uf);
     } else {
         QTC::TC("qpdf", "QPDFFileSpecObjectHelper non-empty compat_name");
-        this->oh.replaceKey("/F", QPDFObjectHandle::newString(compat_name));
+        oh().replaceKey("/F", QPDFObjectHandle::newString(compat_name));
     }
     return *this;
 }
diff --git a/libqpdf/QPDFFormFieldObjectHelper.cc b/libqpdf/QPDFFormFieldObjectHelper.cc
index 8e5b2d8..0f9c936 100644
--- a/libqpdf/QPDFFormFieldObjectHelper.cc
+++ b/libqpdf/QPDFFormFieldObjectHelper.cc
@@ -23,19 +23,19 @@ QPDFFormFieldObjectHelper::QPDFFormFieldObjectHelper() :
 bool
 QPDFFormFieldObjectHelper::isNull()
 {
-    return this->oh.isNull();
+    return oh().isNull();
 }
 
 QPDFFormFieldObjectHelper
 QPDFFormFieldObjectHelper::getParent()
 {
-    return this->oh.getKey("/Parent"); // may be null
+    return oh().getKey("/Parent"); // may be null
 }
 
 QPDFFormFieldObjectHelper
 QPDFFormFieldObjectHelper::getTopLevelField(bool* is_different)
 {
-    auto top_field = this->oh;
+    auto top_field = oh();
     QPDFObjGen::set seen;
     while (seen.add(top_field) && !top_field.getKeyIfDict("/Parent").isNull()) {
         top_field = top_field.getKey("/Parent");
@@ -51,7 +51,7 @@ QPDFFormFieldObjectHelper::getFieldFromAcroForm(std::string const& name)
 {
     QPDFObjectHandle result = QPDFObjectHandle::newNull();
     // Fields are supposed to be indirect, so this should work.
-    QPDF* q = this->oh.getOwningQPDF();
+    QPDF* q = oh().getOwningQPDF();
     if (!q) {
         return result;
     }
@@ -65,7 +65,7 @@ QPDFFormFieldObjectHelper::getFieldFromAcroForm(std::string const& name)
 QPDFObjectHandle
 QPDFFormFieldObjectHelper::getInheritableFieldValue(std::string const& name)
 {
-    QPDFObjectHandle node = this->oh;
+    QPDFObjectHandle node = oh();
     if (!node.isDictionary()) {
         return QPDFObjectHandle::newNull();
     }
@@ -116,7 +116,7 @@ std::string
 QPDFFormFieldObjectHelper::getFullyQualifiedName()
 {
     std::string result;
-    QPDFObjectHandle node = this->oh;
+    QPDFObjectHandle node = oh();
     QPDFObjGen::set seen;
     while (!node.isNull() && seen.add(node)) {
         if (node.getKey("/T").isString()) {
@@ -135,8 +135,8 @@ std::string
 QPDFFormFieldObjectHelper::getPartialName()
 {
     std::string result;
-    if (this->oh.getKey("/T").isString()) {
-        result = this->oh.getKey("/T").getUTF8Value();
+    if (oh().getKey("/T").isString()) {
+        result = oh().getKey("/T").getUTF8Value();
     }
     return result;
 }
@@ -144,9 +144,9 @@ QPDFFormFieldObjectHelper::getPartialName()
 std::string
 QPDFFormFieldObjectHelper::getAlternativeName()
 {
-    if (this->oh.getKey("/TU").isString()) {
+    if (oh().getKey("/TU").isString()) {
         QTC::TC("qpdf", "QPDFFormFieldObjectHelper TU present");
-        return this->oh.getKey("/TU").getUTF8Value();
+        return oh().getKey("/TU").getUTF8Value();
     }
     QTC::TC("qpdf", "QPDFFormFieldObjectHelper TU absent");
     return getFullyQualifiedName();
@@ -155,9 +155,9 @@ QPDFFormFieldObjectHelper::getAlternativeName()
 std::string
 QPDFFormFieldObjectHelper::getMappingName()
 {
-    if (this->oh.getKey("/TM").isString()) {
+    if (oh().getKey("/TM").isString()) {
         QTC::TC("qpdf", "QPDFFormFieldObjectHelper TM present");
-        return this->oh.getKey("/TM").getUTF8Value();
+        return oh().getKey("/TM").getUTF8Value();
     }
     QTC::TC("qpdf", "QPDFFormFieldObjectHelper TM absent");
     return getAlternativeName();
@@ -287,13 +287,13 @@ QPDFFormFieldObjectHelper::getChoices()
 void
 QPDFFormFieldObjectHelper::setFieldAttribute(std::string const& key, QPDFObjectHandle value)
 {
-    this->oh.replaceKey(key, value);
+    oh().replaceKey(key, value);
 }
 
 void
 QPDFFormFieldObjectHelper::setFieldAttribute(std::string const& key, std::string const& utf8_value)
 {
-    this->oh.replaceKey(key, QPDFObjectHandle::newUnicodeString(utf8_value));
+    oh().replaceKey(key, QPDFObjectHandle::newUnicodeString(utf8_value));
 }
 
 void
@@ -310,18 +310,18 @@ QPDFFormFieldObjectHelper::setV(QPDFObjectHandle value, bool need_appearances)
                 setCheckBoxValue((name != "/Off"));
             }
             if (!okay) {
-                this->oh.warnIfPossible(
+                oh().warnIfPossible(
                     "ignoring attempt to set a checkbox field to a value whose type is not name");
             }
         } else if (isRadioButton()) {
             if (value.isName()) {
                 setRadioButtonValue(value);
             } else {
-                this->oh.warnIfPossible(
+                oh().warnIfPossible(
                     "ignoring attempt to set a radio button field to an object that is not a name");
             }
         } else if (isPushbutton()) {
-            this->oh.warnIfPossible("ignoring attempt set the value of a pushbutton field");
+            oh().warnIfPossible("ignoring attempt set the value of a pushbutton field");
         }
         return;
     }
@@ -331,7 +331,7 @@ QPDFFormFieldObjectHelper::setV(QPDFObjectHandle value, bool need_appearances)
         setFieldAttribute("/V", value);
     }
     if (need_appearances) {
-        QPDF& qpdf = this->oh.getQPDF(
+        QPDF& qpdf = oh().getQPDF(
             "QPDFFormFieldObjectHelper::setV called with need_appearances = "
             "true on an object that is not associated with an owning QPDF");
         QPDFAcroFormDocumentHelper(qpdf).setNeedAppearances(true);
@@ -355,7 +355,7 @@ QPDFFormFieldObjectHelper::setRadioButtonValue(QPDFObjectHandle name)
     //   its /AP (i.e. its normal appearance stream dictionary), set /AS to name; otherwise, if /Off
     //   is a member, set /AS to /Off.
     // Note that we never turn on /NeedAppearances when setting a radio button field.
-    QPDFObjectHandle parent = this->oh.getKey("/Parent");
+    QPDFObjectHandle parent = oh().getKey("/Parent");
     if (parent.isDictionary() && parent.getKey("/Parent").isNull()) {
         QPDFFormFieldObjectHelper ph(parent);
         if (ph.isRadioButton()) {
@@ -366,9 +366,9 @@ QPDFFormFieldObjectHelper::setRadioButtonValue(QPDFObjectHandle name)
         }
     }
 
-    QPDFObjectHandle kids = this->oh.getKey("/Kids");
+    QPDFObjectHandle kids = oh().getKey("/Kids");
     if (!(isRadioButton() && parent.isNull() && kids.isArray())) {
-        this->oh.warnIfPossible(
+        oh().warnIfPossible(
             "don't know how to set the value"
             " of this field as a radio button");
         return;
@@ -399,7 +399,7 @@ QPDFFormFieldObjectHelper::setRadioButtonValue(QPDFObjectHandle name)
         }
         if (!annot) {
             QTC::TC("qpdf", "QPDFObjectHandle broken radio button");
-            this->oh.warnIfPossible("unable to set the value of this radio button");
+            oh().warnIfPossible("unable to set the value of this radio button");
             continue;
         }
         if (AP.isDictionary() && AP.getKey("/N").isDictionary() &&
@@ -416,12 +416,12 @@ QPDFFormFieldObjectHelper::setRadioButtonValue(QPDFObjectHandle name)
 void
 QPDFFormFieldObjectHelper::setCheckBoxValue(bool value)
 {
-    QPDFObjectHandle AP = this->oh.getKey("/AP");
+    QPDFObjectHandle AP = oh().getKey("/AP");
     QPDFObjectHandle annot;
     if (AP.isNull()) {
         // The widget may be below. If there is more than one, just
         // find the first one.
-        QPDFObjectHandle kids = this->oh.getKey("/Kids");
+        QPDFObjectHandle kids = oh().getKey("/Kids");
         if (kids.isArray()) {
             int nkids = kids.getArrayNItems();
             for (int i = 0; i < nkids; ++i) {
@@ -435,7 +435,7 @@ QPDFFormFieldObjectHelper::setCheckBoxValue(bool value)
             }
         }
     } else {
-        annot = this->oh;
+        annot = oh();
     }
     std::string on_value;
     if (value) {
@@ -462,7 +462,7 @@ QPDFFormFieldObjectHelper::setCheckBoxValue(bool value)
     setFieldAttribute("/V", name);
     if (!annot) {
         QTC::TC("qpdf", "QPDFObjectHandle broken checkbox");
-        this->oh.warnIfPossible("unable to set the value of this checkbox");
+        oh().warnIfPossible("unable to set the value of this checkbox");
         return;
     }
     QTC::TC("qpdf", "QPDFFormFieldObjectHelper set checkbox AS");
@@ -775,7 +775,7 @@ QPDFFormFieldObjectHelper::generateTextAppearance(QPDFAnnotationObjectHelper& ao
             "<< /Resources << /ProcSet [ /PDF /Text ] >>"
             " /Type /XObject /Subtype /Form >>");
         dict.replaceKey("/BBox", QPDFObjectHandle::newFromRectangle(bbox));
-        AS = QPDFObjectHandle::newStream(this->oh.getOwningQPDF(), "/Tx BMC\nEMC\n");
+        AS = QPDFObjectHandle::newStream(oh().getOwningQPDF(), "/Tx BMC\nEMC\n");
         AS.replaceDict(dict);
         QPDFObjectHandle AP = aoh.getAppearanceDictionary();
         if (AP.isNull()) {
diff --git a/libqpdf/QPDFObjGen.cc b/libqpdf/QPDFObjGen.cc
deleted file mode 100644
index 5242f4f..0000000
--- a/libqpdf/QPDFObjGen.cc
+++ /dev/null
@@ -1,53 +0,0 @@
-#include <qpdf/QPDFObjGen.hh>
-
-#include <qpdf/QPDFObjectHandle.hh>
-#include <qpdf/QPDFObjectHelper.hh>
-#include <qpdf/QPDFObject_private.hh>
-
-#include <stdexcept>
-
-bool
-QPDFObjGen::set::add(QPDFObjectHandle const& oh)
-{
-    if (auto* ptr = oh.getObjectPtr()) {
-        return add(ptr->getObjGen());
-    } else {
-        throw std::logic_error(
-            "attempt to retrieve QPDFObjGen from uninitialized QPDFObjectHandle");
-        return false;
-    }
-}
-
-bool
-QPDFObjGen::set::add(QPDFObjectHelper const& helper)
-{
-    if (auto* ptr = helper.getObjectHandle().getObjectPtr()) {
-        return add(ptr->getObjGen());
-    } else {
-        throw std::logic_error(
-            "attempt to retrieve QPDFObjGen from uninitialized QPDFObjectHandle");
-        return false;
-    }
-}
-
-void
-QPDFObjGen::set::erase(QPDFObjectHandle const& oh)
-{
-    if (auto* ptr = oh.getObjectPtr()) {
-        erase(ptr->getObjGen());
-    } else {
-        throw std::logic_error(
-            "attempt to retrieve QPDFObjGen from uninitialized QPDFObjectHandle");
-    }
-}
-
-void
-QPDFObjGen::set::erase(QPDFObjectHelper const& helper)
-{
-    if (auto* ptr = helper.getObjectHandle().getObjectPtr()) {
-        erase(ptr->getObjGen());
-    } else {
-        throw std::logic_error(
-            "attempt to retrieve QPDFObjGen from uninitialized QPDFObjectHandle");
-    }
-}
diff --git a/libqpdf/QPDFOutlineObjectHelper.cc b/libqpdf/QPDFOutlineObjectHelper.cc
index 4da38b8..8d561f8 100644
--- a/libqpdf/QPDFOutlineObjectHelper.cc
+++ b/libqpdf/QPDFOutlineObjectHelper.cc
@@ -9,8 +9,8 @@ QPDFOutlineObjectHelper::Members::Members(QPDFOutlineDocumentHelper& dh) :
 }
 
 QPDFOutlineObjectHelper::QPDFOutlineObjectHelper(
-    QPDFObjectHandle oh, QPDFOutlineDocumentHelper& dh, int depth) :
-    QPDFObjectHelper(oh),
+    QPDFObjectHandle a_oh, QPDFOutlineDocumentHelper& dh, int depth) :
+    QPDFObjectHelper(a_oh),
     m(new Members(dh))
 {
     if (depth > 50) {
@@ -18,13 +18,13 @@ QPDFOutlineObjectHelper::QPDFOutlineObjectHelper(
         // to 1.
         return;
     }
-    if (QPDFOutlineDocumentHelper::Accessor::checkSeen(m->dh, this->oh.getObjGen())) {
+    if (QPDFOutlineDocumentHelper::Accessor::checkSeen(m->dh, a_oh.getObjGen())) {
         QTC::TC("qpdf", "QPDFOutlineObjectHelper loop");
         return;
     }
 
     QPDFObjGen::set children;
-    QPDFObjectHandle cur = oh.getKey("/First");
+    QPDFObjectHandle cur = a_oh.getKey("/First");
     while (!cur.isNull() && cur.isIndirect() && children.add(cur)) {
         QPDFOutlineObjectHelper new_ooh(cur, dh, 1 + depth);
         new_ooh.m->parent = std::make_shared<QPDFOutlineObjectHelper>(*this);
@@ -50,11 +50,11 @@ QPDFOutlineObjectHelper::getDest()
 {
     QPDFObjectHandle dest;
     QPDFObjectHandle A;
-    if (this->oh.hasKey("/Dest")) {
+    if (oh().hasKey("/Dest")) {
         QTC::TC("qpdf", "QPDFOutlineObjectHelper direct dest");
-        dest = this->oh.getKey("/Dest");
+        dest = oh().getKey("/Dest");
     } else if (
-        (A = this->oh.getKey("/A")).isDictionary() && A.getKey("/S").isName() &&
+        (A = oh().getKey("/A")).isDictionary() && A.getKey("/S").isName() &&
         (A.getKey("/S").getName() == "/GoTo") && A.hasKey("/D")) {
         QTC::TC("qpdf", "QPDFOutlineObjectHelper action dest");
         dest = A.getKey("/D");
@@ -85,8 +85,8 @@ int
 QPDFOutlineObjectHelper::getCount()
 {
     int count = 0;
-    if (this->oh.hasKey("/Count")) {
-        count = this->oh.getKey("/Count").getIntValueAsInt();
+    if (oh().hasKey("/Count")) {
+        count = oh().getKey("/Count").getIntValueAsInt();
     }
     return count;
 }
@@ -95,8 +95,8 @@ std::string
 QPDFOutlineObjectHelper::getTitle()
 {
     std::string result;
-    if (this->oh.hasKey("/Title")) {
-        result = this->oh.getKey("/Title").getUTF8Value();
+    if (oh().hasKey("/Title")) {
+        result = oh().getKey("/Title").getUTF8Value();
     }
     return result;
 }
diff --git a/libqpdf/QPDFPageObjectHelper.cc b/libqpdf/QPDFPageObjectHelper.cc
index f474e1c..858b63a 100644
--- a/libqpdf/QPDFPageObjectHelper.cc
+++ b/libqpdf/QPDFPageObjectHelper.cc
@@ -227,9 +227,9 @@ QPDFPageObjectHelper::getAttribute(
     std::function<QPDFObjectHandle()> get_fallback,
     bool copy_if_fallback)
 {
-    const bool is_form_xobject = this->oh.isFormXObject();
+    const bool is_form_xobject = oh().isFormXObject();
     bool inherited = false;
-    auto dict = is_form_xobject ? oh.getDict() : oh;
+    auto dict = is_form_xobject ? oh().getDict() : oh();
     auto result = dict.getKey(name);
 
     if (!is_form_xobject && result.isNull() &&
@@ -324,7 +324,7 @@ QPDFPageObjectHelper::forEachXObject(
     QTC::TC(
         "qpdf",
         "QPDFPageObjectHelper::forEachXObject",
-        recursive ? (this->oh.isFormXObject() ? 0 : 1) : (this->oh.isFormXObject() ? 2 : 3));
+        recursive ? (oh().isFormXObject() ? 0 : 1) : (oh().isFormXObject() ? 2 : 3));
     QPDFObjGen::set seen;
     std::list<QPDFPageObjectHelper> queue;
     queue.push_back(*this);
@@ -402,28 +402,27 @@ QPDFPageObjectHelper::externalizeInlineImages(size_t min_size, bool shallow)
         // Calling mergeResources also ensures that /XObject becomes direct and is not shared with
         // other pages.
         resources.mergeResources("<< /XObject << >> >>"_qpdf);
-        InlineImageTracker iit(this->oh.getOwningQPDF(), min_size, resources);
+        InlineImageTracker iit(oh().getOwningQPDF(), min_size, resources);
         Pl_Buffer b("new page content");
         bool filtered = false;
         try {
             filterContents(&iit, &b);
             filtered = true;
         } catch (std::exception& e) {
-            this->oh.warnIfPossible(
+            oh().warnIfPossible(
                 std::string("Unable to filter content stream: ") + e.what() +
-                "; not attempting to externalize inline images"
-                " from this stream");
+                "; not attempting to externalize inline images from this stream");
         }
         if (filtered && iit.any_images) {
-            if (this->oh.isFormXObject()) {
-                this->oh.replaceStreamData(
+            if (oh().isFormXObject()) {
+                oh().replaceStreamData(
                     b.getBufferSharedPointer(),
                     QPDFObjectHandle::newNull(),
                     QPDFObjectHandle::newNull());
             } else {
-                this->oh.replaceKey(
+                oh().replaceKey(
                     "/Contents",
-                    QPDFObjectHandle::newStream(&this->oh.getQPDF(), b.getBufferSharedPointer()));
+                    QPDFObjectHandle::newStream(&oh().getQPDF(), b.getBufferSharedPointer()));
             }
         }
     } else {
@@ -439,7 +438,7 @@ std::vector<QPDFAnnotationObjectHelper>
 QPDFPageObjectHelper::getAnnotations(std::string const& only_subtype)
 {
     std::vector<QPDFAnnotationObjectHelper> result;
-    QPDFObjectHandle annots = this->oh.getKey("/Annots");
+    QPDFObjectHandle annots = oh().getKey("/Annots");
     if (annots.isArray()) {
         int nannots = annots.getArrayNItems();
         for (int i = 0; i < nannots; ++i) {
@@ -455,25 +454,25 @@ QPDFPageObjectHelper::getAnnotations(std::string const& only_subtype)
 std::vector<QPDFObjectHandle>
 QPDFPageObjectHelper::getPageContents()
 {
-    return this->oh.getPageContents();
+    return oh().getPageContents();
 }
 
 void
 QPDFPageObjectHelper::addPageContents(QPDFObjectHandle contents, bool first)
 {
-    this->oh.addPageContents(contents, first);
+    oh().addPageContents(contents, first);
 }
 
 void
 QPDFPageObjectHelper::rotatePage(int angle, bool relative)
 {
-    this->oh.rotatePage(angle, relative);
+    oh().rotatePage(angle, relative);
 }
 
 void
 QPDFPageObjectHelper::coalesceContentStreams()
 {
-    this->oh.coalesceContentStreams();
+    oh().coalesceContentStreams();
 }
 
 void
@@ -485,10 +484,10 @@ QPDFPageObjectHelper::parsePageContents(QPDFObjectHandle::ParserCallbacks* callb
 void
 QPDFPageObjectHelper::parseContents(QPDFObjectHandle::ParserCallbacks* callbacks)
 {
-    if (this->oh.isFormXObject()) {
-        this->oh.parseAsContents(callbacks);
+    if (oh().isFormXObject()) {
+        oh().parseAsContents(callbacks);
     } else {
-        this->oh.parsePageContents(callbacks);
+        oh().parsePageContents(callbacks);
     }
 }
 
@@ -501,10 +500,10 @@ QPDFPageObjectHelper::filterPageContents(QPDFObjectHandle::TokenFilter* filter, 
 void
 QPDFPageObjectHelper::filterContents(QPDFObjectHandle::TokenFilter* filter, Pipeline* next)
 {
-    if (this->oh.isFormXObject()) {
-        this->oh.filterAsContents(filter, next);
+    if (oh().isFormXObject()) {
+        oh().filterAsContents(filter, next);
     } else {
-        this->oh.filterPageContents(filter, next);
+        oh().filterPageContents(filter, next);
     }
 }
 
@@ -517,10 +516,10 @@ QPDFPageObjectHelper::pipePageContents(Pipeline* p)
 void
 QPDFPageObjectHelper::pipeContents(Pipeline* p)
 {
-    if (this->oh.isFormXObject()) {
-        this->oh.pipeStreamData(p, 0, qpdf_dl_specialized);
+    if (oh().isFormXObject()) {
+        oh().pipeStreamData(p, 0, qpdf_dl_specialized);
     } else {
-        this->oh.pipePageContents(p);
+        oh().pipePageContents(p);
     }
 }
 
@@ -528,10 +527,10 @@ void
 QPDFPageObjectHelper::addContentTokenFilter(
     std::shared_ptr<QPDFObjectHandle::TokenFilter> token_filter)
 {
-    if (this->oh.isFormXObject()) {
-        this->oh.addTokenFilter(token_filter);
+    if (oh().isFormXObject()) {
+        oh().addTokenFilter(token_filter);
     } else {
-        this->oh.addContentTokenFilter(token_filter);
+        oh().addContentTokenFilter(token_filter);
     }
 }
 
@@ -539,30 +538,28 @@ bool
 QPDFPageObjectHelper::removeUnreferencedResourcesHelper(
     QPDFPageObjectHelper ph, std::set<std::string>& unresolved)
 {
-    bool is_page = (!ph.oh.isFormXObject());
+    bool is_page = (!ph.oh().isFormXObject());
     if (!is_page) {
         QTC::TC("qpdf", "QPDFPageObjectHelper filter form xobject");
     }
 
     ResourceFinder rf;
     try {
-        auto q = ph.oh.getOwningQPDF();
+        auto q = ph.oh().getOwningQPDF();
         size_t before_nw = (q ? q->numWarnings() : 0);
         ph.parseContents(&rf);
         size_t after_nw = (q ? q->numWarnings() : 0);
         if (after_nw > before_nw) {
-            ph.oh.warnIfPossible(
+            ph.oh().warnIfPossible(
                 "Bad token found while scanning content stream; "
-                "not attempting to remove unreferenced objects from"
-                " this object");
+                "not attempting to remove unreferenced objects from this object");
             return false;
         }
     } catch (std::exception& e) {
         QTC::TC("qpdf", "QPDFPageObjectHelper bad token finding names");
-        ph.oh.warnIfPossible(
+        ph.oh().warnIfPossible(
             std::string("Unable to parse content stream: ") + e.what() +
-            "; not attempting to remove unreferenced objects"
-            " from this object");
+            "; not attempting to remove unreferenced objects from this object");
         return false;
     }
 
@@ -646,7 +643,7 @@ QPDFPageObjectHelper::removeUnreferencedResources()
                 any_failures = true;
             }
         });
-    if (this->oh.isFormXObject() || (!any_failures)) {
+    if (oh().isFormXObject() || (!any_failures)) {
         removeUnreferencedResourcesHelper(*this, unresolved);
     }
 }
@@ -654,9 +651,8 @@ QPDFPageObjectHelper::removeUnreferencedResources()
 QPDFPageObjectHelper
 QPDFPageObjectHelper::shallowCopyPage()
 {
-    QPDF& qpdf =
-        this->oh.getQPDF("QPDFPageObjectHelper::shallowCopyPage called with a direct object");
-    QPDFObjectHandle new_page = this->oh.shallowCopy();
+    QPDF& qpdf = oh().getQPDF("QPDFPageObjectHelper::shallowCopyPage called with a direct object");
+    QPDFObjectHandle new_page = oh().shallowCopy();
     return {qpdf.makeIndirectObject(new_page)};
 }
 
@@ -707,7 +703,7 @@ QPDFObjectHandle
 QPDFPageObjectHelper::getFormXObjectForPage(bool handle_transformations)
 {
     auto result =
-        this->oh.getQPDF("QPDFPageObjectHelper::getFormXObjectForPage called with a direct object")
+        oh().getQPDF("QPDFPageObjectHelper::getFormXObjectForPage called with a direct object")
             .newStream();
     QPDFObjectHandle newdict = result.getDict();
     newdict.replaceKey("/Type", QPDFObjectHandle::newName("/XObject"));
@@ -716,13 +712,13 @@ QPDFPageObjectHelper::getFormXObjectForPage(bool handle_transformations)
     newdict.replaceKey("/Group", getAttribute("/Group", false).shallowCopy());
     QPDFObjectHandle bbox = getTrimBox(false).shallowCopy();
     if (!bbox.isRectangle()) {
-        this->oh.warnIfPossible(
+        oh().warnIfPossible(
             "bounding box is invalid; form"
             " XObject created from page will not work");
     }
     newdict.replaceKey("/BBox", bbox);
     auto provider =
-        std::shared_ptr<QPDFObjectHandle::StreamDataProvider>(new ContentProvider(this->oh));
+        std::shared_ptr<QPDFObjectHandle::StreamDataProvider>(new ContentProvider(oh()));
     result.replaceStreamData(provider, QPDFObjectHandle::newNull(), QPDFObjectHandle::newNull());
     QPDFObjectHandle rotate_obj = getAttribute("/Rotate", false);
     QPDFObjectHandle scale_obj = getAttribute("/UserUnit", false);
@@ -863,9 +859,8 @@ QPDFPageObjectHelper::placeFormXObject(
 void
 QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
 {
-    QPDF& qpdf =
-        this->oh.getQPDF("QPDFPageObjectHelper::flattenRotation called with a direct object");
-    auto rotate_oh = this->oh.getKey("/Rotate");
+    QPDF& qpdf = oh().getQPDF("QPDFPageObjectHelper::flattenRotation called with a direct object");
+    auto rotate_oh = oh().getKey("/Rotate");
     int rotate = 0;
     if (rotate_oh.isInteger()) {
         rotate = rotate_oh.getIntValueAsInt();
@@ -873,7 +868,7 @@ QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
     if (!((rotate == 90) || (rotate == 180) || (rotate == 270))) {
         return;
     }
-    auto mediabox = this->oh.getKey("/MediaBox");
+    auto mediabox = oh().getKey("/MediaBox");
     if (!mediabox.isRectangle()) {
         return;
     }
@@ -887,7 +882,7 @@ QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
         "/ArtBox",
     };
     for (auto const& boxkey: boxes) {
-        auto box = this->oh.getKey(boxkey);
+        auto box = oh().getKey(boxkey);
         if (!box.isRectangle()) {
             continue;
         }
@@ -930,7 +925,7 @@ QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
             break;
         }
 
-        this->oh.replaceKey(boxkey, QPDFObjectHandle::newFromRectangle(new_rect));
+        oh().replaceKey(boxkey, QPDFObjectHandle::newFromRectangle(new_rect));
     }
 
     // When we rotate the page, pivot about the point 0, 0 and then translate so the page is visible
@@ -962,16 +957,16 @@ QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
         break;
     }
     std::string cm_str = std::string("q\n") + cm.unparse() + " cm\n";
-    this->oh.addPageContents(QPDFObjectHandle::newStream(&qpdf, cm_str), true);
-    this->oh.addPageContents(qpdf.newStream("\nQ\n"), false);
-    this->oh.removeKey("/Rotate");
+    oh().addPageContents(QPDFObjectHandle::newStream(&qpdf, cm_str), true);
+    oh().addPageContents(qpdf.newStream("\nQ\n"), false);
+    oh().removeKey("/Rotate");
     QPDFObjectHandle rotate_obj = getAttribute("/Rotate", false);
     if (!rotate_obj.isNull()) {
         QTC::TC("qpdf", "QPDFPageObjectHelper flatten inherit rotate");
-        this->oh.replaceKey("/Rotate", QPDFObjectHandle::newInteger(0));
+        oh().replaceKey("/Rotate", QPDFObjectHandle::newInteger(0));
     }
 
-    QPDFObjectHandle annots = this->oh.getKey("/Annots");
+    QPDFObjectHandle annots = oh().getKey("/Annots");
     if (annots.isArray()) {
         std::vector<QPDFObjectHandle> new_annots;
         std::vector<QPDFObjectHandle> new_fields;
@@ -986,7 +981,7 @@ QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
         for (auto const& f: new_fields) {
             afdh->addFormField(QPDFFormFieldObjectHelper(f));
         }
-        this->oh.replaceKey("/Annots", QPDFObjectHandle::newArray(new_annots));
+        oh().replaceKey("/Annots", QPDFObjectHandle::newArray(new_annots));
     }
 }
 
@@ -1005,7 +1000,7 @@ QPDFPageObjectHelper::copyAnnotations(
     QPDF& from_qpdf = from_page.getObjectHandle().getQPDF(
         "QPDFPageObjectHelper::copyAnnotations: from page is a direct object");
     QPDF& this_qpdf =
-        this->oh.getQPDF("QPDFPageObjectHelper::copyAnnotations: this page is a direct object");
+        oh().getQPDF("QPDFPageObjectHelper::copyAnnotations: this page is a direct object");
 
     std::vector<QPDFObjectHandle> new_annots;
     std::vector<QPDFObjectHandle> new_fields;
@@ -1032,9 +1027,9 @@ QPDFPageObjectHelper::copyAnnotations(
     afdh->transformAnnotations(
         old_annots, new_annots, new_fields, old_fields, cm, &from_qpdf, from_afdh);
     afdh->addAndRenameFormFields(new_fields);
-    auto annots = this->oh.getKey("/Annots");
+    auto annots = oh().getKey("/Annots");
     if (!annots.isArray()) {
-        annots = this->oh.replaceKeyAndGetNew("/Annots", QPDFObjectHandle::newArray());
+        annots = oh().replaceKeyAndGetNew("/Annots", QPDFObjectHandle::newArray());
     }
     for (auto const& annot: new_annots) {
         annots.appendItem(annot);
diff --git a/qpdf/sizes.cc b/qpdf/sizes.cc
index 6512187..6075712 100644
--- a/qpdf/sizes.cc
+++ b/qpdf/sizes.cc
@@ -109,7 +109,6 @@ main()
     print_size(QPDFNumberTreeObjectHelper);
     print_size(QPDFNumberTreeObjectHelper::iterator);
     print_size(QPDFObjGen);
-    print_size(QPDFObjGen::set);
     print_size(QPDFObjectHandle);
     print_size(QPDFObjectHandle::ParserCallbacks);
     print_size(QPDFObjectHandle::QPDFArrayItems);
@@ -118,6 +117,7 @@ main()
     print_size(QPDFObjectHandle::QPDFDictItems::iterator);
     print_size(QPDFObjectHandle::StreamDataProvider);
     print_size(QPDFObjectHandle::TokenFilter);
+    print_size(QPDFObjectHelper);
     print_size(QPDFOutlineDocumentHelper);
     print_size(QPDFOutlineObjectHelper);
     print_size(QPDFPageDocumentHelper);