From b1d845e708f99f5a77a27b2c0ca088f2f69ea4dd Mon Sep 17 00:00:00 2001
From: m-holger <m.holger@qpdf.org>
Date: Thu, 5 Sep 2024 14:50:38 +0100
Subject: [PATCH] Split QPDF member file into file and file_sp to facilitate aliasing

---
 libqpdf/QPDF.cc              | 19 ++++++++++++-------
 libqpdf/qpdf/QPDF_private.hh |  4 +++-
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index 53f8e71..1d2ffd8 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -198,7 +198,8 @@ QPDF::EncryptionParameters::EncryptionParameters() :
 
 QPDF::Members::Members(QPDF& qpdf) :
     log(QPDFLogger::defaultLogger()),
-    file(new InvalidInputSource()),
+    file_sp(new InvalidInputSource()),
+    file(file_sp.get()),
     encp(new EncryptionParameters),
     xref_table(qpdf)
 {
@@ -272,14 +273,16 @@ QPDF::processMemoryFile(
 void
 QPDF::processInputSource(std::shared_ptr<InputSource> source, char const* password)
 {
-    m->file = source;
+    m->file_sp = source;
+    m->file = source.get();
     parse(password);
 }
 
 void
 QPDF::closeInputSource()
 {
-    m->file = std::shared_ptr<InputSource>(new InvalidInputSource());
+    m->file_sp = std::shared_ptr<InputSource>(new InvalidInputSource());
+    m->file = m->file_sp.get();
 }
 
 void
@@ -412,7 +415,9 @@ QPDF::findHeader()
             // PDF header, all explicit offsets in the file are such that 0 points to the beginning
             // of the header.
             QTC::TC("qpdf", "QPDF global offset");
-            m->file = std::shared_ptr<InputSource>(new OffsetInputSource(m->file, global_offset));
+            m->file_sp =
+                std::shared_ptr<InputSource>(new OffsetInputSource(m->file_sp, global_offset));
+            m->file = m->file_sp.get();
         }
     }
     return valid;
@@ -1541,7 +1546,7 @@ QPDF::readStream(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset)
     } catch (QPDFExc& e) {
         if (m->attempt_recovery) {
             warn(e);
-            length = recoverStreamLength(m->file, og, stream_offset);
+            length = recoverStreamLength(m->file_sp, og, stream_offset);
         } else {
             throw;
         }
@@ -2452,7 +2457,7 @@ QPDF::copyStreamData(QPDFObjectHandle result, QPDFObjectHandle foreign)
     } else {
         auto foreign_stream_data = std::make_shared<ForeignStreamData>(
             foreign_stream_qpdf.m->encp,
-            foreign_stream_qpdf.m->file,
+            foreign_stream_qpdf.m->file_sp,
             foreign.getObjGen(),
             stream->getParsedOffset(),
             stream->getLength(),
@@ -2776,7 +2781,7 @@ QPDF::pipeStreamData(
 {
     return pipeStreamData(
         m->encp,
-        m->file,
+        m->file_sp,
         *this,
         og,
         offset,
diff --git a/libqpdf/qpdf/QPDF_private.hh b/libqpdf/qpdf/QPDF_private.hh
index 06c53e7..658894a 100644
--- a/libqpdf/qpdf/QPDF_private.hh
+++ b/libqpdf/qpdf/QPDF_private.hh
@@ -528,7 +528,9 @@ class QPDF::Members
     std::shared_ptr<QPDFLogger> log;
     unsigned long long unique_id{0};
     QPDFTokenizer tokenizer;
-    std::shared_ptr<InputSource> file;
+    // If file_sp is updated, file must also be updated.
+    std::shared_ptr<InputSource> file_sp;
+    InputSource* file;
     std::string last_object_description;
     bool provided_password_is_hex_key{false};
     bool suppress_warnings{false};
--
libgit2 0.21.4