From 81510829f126c6c050b414f9992b9c8cb24dc832 Mon Sep 17 00:00:00 2001
From: m-holger <m.holger@qpdf.org>
Date: Sat, 30 Aug 2025 12:10:35 +0100
Subject: [PATCH] Enhance `QPDFAcroFormDocumentHelper` with `get()` for shared access and `validate()` for re-validation and repair of AcroForm structure.

---
 include/qpdf/QPDFAcroFormDocumentHelper.hh | 15 +++++++++++++++
 libqpdf/QPDFAcroFormDocumentHelper.cc      | 14 ++++++++++++++
 2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/include/qpdf/QPDFAcroFormDocumentHelper.hh b/include/qpdf/QPDFAcroFormDocumentHelper.hh
index db75226..6094ed7 100644
--- a/include/qpdf/QPDFAcroFormDocumentHelper.hh
+++ b/include/qpdf/QPDFAcroFormDocumentHelper.hh
@@ -68,6 +68,21 @@
 class QPDFAcroFormDocumentHelper: public QPDFDocumentHelper
 {
   public:
+    // Get a shared document helper for a given QPDF object.
+    //
+    // Retrieving a document helper for a QPDF object rather than creating a new one avoids repeated
+    // validation of the Acroform structure, which can be expensive.
+    QPDF_DLL
+    static QPDFAcroFormDocumentHelper& get(QPDF& qpdf);
+
+    // Re-validate the AcroForm structure. This is useful if you have modified the structure of the
+    // AcroForm dictionary in a way that would invalidate the cache.
+    //
+    // If repair is true, the document will be repaired if possible if the validation encounters
+    // errors.
+    QPDF_DLL
+    void validate(bool repair = true);
+
     QPDF_DLL
     QPDFAcroFormDocumentHelper(QPDF&);
 
diff --git a/libqpdf/QPDFAcroFormDocumentHelper.cc b/libqpdf/QPDFAcroFormDocumentHelper.cc
index 9ed850b..6974133 100644
--- a/libqpdf/QPDFAcroFormDocumentHelper.cc
+++ b/libqpdf/QPDFAcroFormDocumentHelper.cc
@@ -3,6 +3,7 @@
 #include <qpdf/Pl_Buffer.hh>
 #include <qpdf/QPDFObjectHandle_private.hh>
 #include <qpdf/QPDFPageDocumentHelper.hh>
+#include <qpdf/QPDF_private.hh>
 #include <qpdf/QTC.hh>
 #include <qpdf/QUtil.hh>
 #include <qpdf/ResourceFinder.hh>
@@ -21,6 +22,19 @@ QPDFAcroFormDocumentHelper::QPDFAcroFormDocumentHelper(QPDF& qpdf) :
     analyze();
 }
 
+QPDFAcroFormDocumentHelper&
+QPDFAcroFormDocumentHelper::get(QPDF& qpdf)
+{
+    return qpdf.acroform();
+}
+
+void
+QPDFAcroFormDocumentHelper::validate(bool repair)
+{
+    invalidateCache();
+    analyze();
+}
+
 void
 QPDFAcroFormDocumentHelper::invalidateCache()
 {
--
libgit2 0.21.4