From 4ff837f099c4594fbb95463ebfd6199051d0fa30 Mon Sep 17 00:00:00 2001
From: m-holger <m-holger@kubitscheck.org>
Date: Wed, 9 Feb 2022 13:54:33 +0000
Subject: [PATCH] Fix tests for Form XObjects

Remove test for type == /XObject in QPDFObjectHandle::isFormXObject
as type value is optional (as per spec 8.10.2).

Replace code to test for /Form in QPDFJob::shouldRemoveUnreferencedResources
with a call to isFormXObject.
---
 libqpdf/QPDFJob.cc          | 8 +-------
 libqpdf/QPDFObjectHandle.cc | 2 +-
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/libqpdf/QPDFJob.cc b/libqpdf/QPDFJob.cc
index e95d08ad..c23b950b 100644
--- a/libqpdf/QPDFJob.cc
+++ b/libqpdf/QPDFJob.cc
@@ -2743,13 +2743,7 @@ QPDFJob::shouldRemoveUnreferencedResources(QPDF& pdf)
                 for (auto const& k: xobject.getKeys())
                 {
                     QPDFObjectHandle xobj = xobject.getKey(k);
-                    if (xobj.isStream() &&
-                        xobj.getDict().getKey("/Type").isName() &&
-                        ("/XObject" ==
-                         xobj.getDict().getKey("/Type").getName()) &&
-                        xobj.getDict().getKey("/Subtype").isName() &&
-                        ("/Form" ==
-                         xobj.getDict().getKey("/Subtype").getName()))
+                    if (xobj.isFormXObject())
                     {
                         queue.push_back(xobj);
                     }
diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index c2917157..745de6c9 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -3406,7 +3406,7 @@ QPDFObjectHandle::isPagesObject()
 bool
 QPDFObjectHandle::isFormXObject()
 {
-    return isStreamOfType("/XObject", "/Form");
+    return isStreamOfType("", "/Form");
 }
 
 bool