From c0cd72a3eef996e597ba82b784de029ec6d88707 Mon Sep 17 00:00:00 2001
From: m-holger <m-holger@kubitscheck.org>
Date: Wed, 10 Aug 2022 13:16:06 +0100
Subject: [PATCH] Add private methods QPDF::isCached and QPDF::isUnresolved

---
 include/qpdf/QPDF.hh        |  2 ++
 include/qpdf/QPDFObject.hh  |  6 +++++-
 libqpdf/QPDF.cc             | 23 +++++++++++++++++------
 libqpdf/QPDFObjectHandle.cc |  2 +-
 4 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index 701c5e55..ee265cec 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -1175,6 +1175,8 @@ class QPDF
     QPDFObjectHandle reserveStream(QPDFObjGen const& og);
     QPDFObjectHandle
     newIndirect(QPDFObjGen const&, std::shared_ptr<QPDFObject> const&);
+    bool isCached(QPDFObjGen const& og);
+    bool isUnresolved(QPDFObjGen const& og);
 
     // Calls finish() on the pipeline when done but does not delete it
     bool pipeStreamData(
diff --git a/include/qpdf/QPDFObject.hh b/include/qpdf/QPDFObject.hh
index a1930168..198488dd 100644
--- a/include/qpdf/QPDFObject.hh
+++ b/include/qpdf/QPDFObject.hh
@@ -134,7 +134,11 @@ class QPDFObject
         value = o->value;
         o->value = v;
     }
-
+    bool
+    isUnresolved()
+    {
+        return value->type_code == ::ot_unresolved;
+    }
     template <typename T>
     T*
     as()
diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index 000dab5d..d877c14a 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -1425,8 +1425,7 @@ QPDF::fixDanglingReferences(bool force)
         for (auto sub: to_check) {
             if (sub.isIndirect()) {
                 if (sub.getOwningQPDF() == this) {
-                    QPDFObjGen og(sub.getObjGen());
-                    if (this->m->obj_cache.count(og) == 0) {
+                    if (!isCached(sub.getObjGen())) {
                         QTC::TC("qpdf", "QPDF detected dangling ref");
                         queue.push_back(sub);
                     }
@@ -1886,7 +1885,7 @@ QPDF::readObjectAtOffset(
             "expected endobj");
     }
 
-    if (!this->m->obj_cache.count(og)) {
+    if (!isCached(og)) {
         // Store the object in the cache here so it gets cached
         // whether we first know the offset or whether we first know
         // the object ID and generation (in which we case we would get
@@ -1947,7 +1946,7 @@ QPDF::resolve(QPDFObjGen const& og)
     }
     ResolveRecorder rr(this, og);
 
-    if ((!this->m->obj_cache.count(og)) && this->m->xref_table.count(og)) {
+    if ((!isCached(og)) && this->m->xref_table.count(og)) {
         QPDFXRefEntry const& entry = this->m->xref_table[og];
         try {
             switch (entry.getType()) {
@@ -1985,7 +1984,7 @@ QPDF::resolve(QPDFObjGen const& og)
                  ": error reading object: " + e.what()));
         }
     }
-    if (this->m->obj_cache.count(og) == 0) {
+    if (!isCached(og)) {
         // PDF spec says unknown objects resolve to the null object.
         QTC::TC("qpdf", "QPDF resolve failure to null");
         QPDFObjectHandle oh = QPDFObjectHandle::newNull();
@@ -2112,6 +2111,18 @@ QPDF::newIndirect(QPDFObjGen const& og, std::shared_ptr<QPDFObject> const& obj)
     return QPDFObjectHandle::Factory::newIndirect(this, og, obj);
 }
 
+bool
+QPDF::isCached(QPDFObjGen const& og)
+{
+    return m->obj_cache.count(og) != 0;
+}
+
+bool
+QPDF::isUnresolved(QPDFObjGen const& og)
+{
+    return !isCached(og) || m->obj_cache[og].object->isUnresolved();
+}
+
 QPDFObjectHandle
 QPDF::makeIndirectObject(QPDFObjectHandle oh)
 {
@@ -2129,7 +2140,7 @@ QPDF::makeIndirectObject(QPDFObjectHandle oh)
 QPDFObjectHandle
 QPDF::reserveObjectIfNotExists(QPDFObjGen const& og)
 {
-    if ((!m->obj_cache.count(og)) && (!m->xref_table.count(og))) {
+    if (!isCached(og) && !m->xref_table.count(og)) {
         resolve(og);
         m->obj_cache[og].object = QPDF_Reserved::create();
         return newIndirect(og, m->obj_cache[og].object);
diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index c8611e07..aae06529 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -2609,7 +2609,7 @@ QPDFObjectHandle::dereference()
     if (!isInitialized()) {
         return false;
     }
-    if (this->obj->getTypeCode() == QPDFObject::ot_unresolved) {
+    if (this->obj->isUnresolved()) {
         this->obj = QPDF::Resolver::resolve(this->qpdf, getObjGen());
     }
     return true;