From e64965e31be2e3b7059a9b8fe31bb345bddb4e2f Mon Sep 17 00:00:00 2001
From: m-holger <m.holger@qpdf.org>
Date: Thu, 7 Aug 2025 22:30:14 +0100
Subject: [PATCH] Refactor `QPDF`: centralize access to `QPDFAcroFormDocumentHelper` using a dedicated `acroform()` method and update related references for improved performance, consistency and maintainability.

---
 include/qpdf/QPDF.hh                 |  2 ++
 libqpdf/QPDFFormFieldObjectHelper.cc |  3 ++-
 libqpdf/QPDFJob.cc                   |  4 ++--
 libqpdf/QPDFPageDocumentHelper.cc    |  3 ++-
 libqpdf/qpdf/QPDF_private.hh         | 13 +++++++++++++
 5 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index d42b2e6..590257e 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -57,6 +57,7 @@ class BitWriter;
 class BufferInputSource;
 class QPDFLogger;
 class QPDFParser;
+class QPDFAcroFormDocumentHelper;
 
 class QPDF
 {
@@ -792,6 +793,7 @@ class QPDF
     class JobSetter;
 
     inline bool reconstructed_xref() const;
+    inline QPDFAcroFormDocumentHelper& acroform();
 
     // For testing only -- do not add to DLL
     static bool test_json_validators();
diff --git a/libqpdf/QPDFFormFieldObjectHelper.cc b/libqpdf/QPDFFormFieldObjectHelper.cc
index 2f990bc..59d12dc 100644
--- a/libqpdf/QPDFFormFieldObjectHelper.cc
+++ b/libqpdf/QPDFFormFieldObjectHelper.cc
@@ -5,6 +5,7 @@
 #include <qpdf/QPDFAcroFormDocumentHelper.hh>
 #include <qpdf/QPDFAnnotationObjectHelper.hh>
 #include <qpdf/QPDFObjectHandle_private.hh>
+#include <qpdf/QPDF_private.hh>
 #include <qpdf/QTC.hh>
 #include <qpdf/QUtil.hh>
 #include <cstdlib>
@@ -337,7 +338,7 @@ QPDFFormFieldObjectHelper::setV(QPDFObjectHandle value, bool need_appearances)
         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);
+        qpdf.acroform().setNeedAppearances(true);
     }
 }
 
diff --git a/libqpdf/QPDFJob.cc b/libqpdf/QPDFJob.cc
index c6feb31..f9c2e43 100644
--- a/libqpdf/QPDFJob.cc
+++ b/libqpdf/QPDFJob.cc
@@ -1180,7 +1180,7 @@ void
 QPDFJob::doJSONAcroform(Pipeline* p, bool& first, QPDF& pdf)
 {
     JSON j_acroform = JSON::makeDictionary();
-    QPDFAcroFormDocumentHelper afdh(pdf);
+    auto& afdh = pdf.acroform();
     j_acroform.addDictionaryMember("hasacroform", JSON::makeBool(afdh.hasAcroForm()));
     j_acroform.addDictionaryMember("needappearances", JSON::makeBool(afdh.getNeedAppearances()));
     JSON j_fields = j_acroform.addDictionaryMember("fields", JSON::makeArray());
@@ -3013,7 +3013,7 @@ QPDFJob::doSplitPages(QPDF& pdf)
         dh.removeUnreferencedResources();
     }
     QPDFPageLabelDocumentHelper pldh(pdf);
-    QPDFAcroFormDocumentHelper afdh(pdf);
+    auto& afdh = pdf.acroform();
     std::vector<QPDFObjectHandle> const& pages = pdf.getAllPages();
     size_t pageno_len = std::to_string(pages.size()).length();
     size_t num_pages = pages.size();
diff --git a/libqpdf/QPDFPageDocumentHelper.cc b/libqpdf/QPDFPageDocumentHelper.cc
index 12841ac..3d0fbdb 100644
--- a/libqpdf/QPDFPageDocumentHelper.cc
+++ b/libqpdf/QPDFPageDocumentHelper.cc
@@ -1,6 +1,7 @@
 #include <qpdf/QPDFPageDocumentHelper.hh>
 
 #include <qpdf/QPDFAcroFormDocumentHelper.hh>
+#include <qpdf/QPDF_private.hh>
 #include <qpdf/QTC.hh>
 #include <qpdf/QUtil.hh>
 
@@ -55,7 +56,7 @@ QPDFPageDocumentHelper::removePage(QPDFPageObjectHelper page)
 void
 QPDFPageDocumentHelper::flattenAnnotations(int required_flags, int forbidden_flags)
 {
-    QPDFAcroFormDocumentHelper afdh(qpdf);
+    auto& afdh = qpdf.acroform();
     if (afdh.getNeedAppearances()) {
         qpdf.getRoot()
             .getKey("/AcroForm")
diff --git a/libqpdf/qpdf/QPDF_private.hh b/libqpdf/qpdf/QPDF_private.hh
index 55bffce..cd51ec2 100644
--- a/libqpdf/qpdf/QPDF_private.hh
+++ b/libqpdf/qpdf/QPDF_private.hh
@@ -3,6 +3,7 @@
 
 #include <qpdf/QPDF.hh>
 
+#include <qpdf/QPDFAcroFormDocumentHelper.hh>
 #include <qpdf/QPDFObject_private.hh>
 #include <qpdf/QPDFTokenizer_private.hh>
 
@@ -547,6 +548,9 @@ class QPDF::Members
     // Optimization data
     std::map<ObjUser, std::set<QPDFObjGen>> obj_user_to_objects;
     std::map<QPDFObjGen, std::set<ObjUser>> object_to_obj_users;
+
+    // Document Helpers;
+    std::unique_ptr<QPDFAcroFormDocumentHelper> acroform;
 };
 
 // JobSetter class is restricted to QPDFJob.
@@ -569,4 +573,13 @@ QPDF::reconstructed_xref() const
     return m->reconstructed_xref;
 }
 
+inline QPDFAcroFormDocumentHelper&
+QPDF::acroform()
+{
+    if (!m->acroform) {
+        m->acroform = std::make_unique<QPDFAcroFormDocumentHelper>(*this);
+    }
+    return *m->acroform;
+}
+
 #endif // QPDF_PRIVATE_HH
--
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