o Added a Clone() method to InterchangeObject and derivatives

   that allows making a descriptor copy that is not owned by
   any other strucure. The caller must arrange to delete the
   object pointer returned.

 o While implementing the above it became obvious that the
   reference-to-a-pointer-to-the-dictionary idiom that is used
   throughout the lower levels of the MXF library was the
   cause of much more grief than it was originally designed to
   prevent. This was made even more obvious when I replaced all
   of it with simple pointers, which revealed several shadow
   instances of m_Dict that were only reliable while the object
   that held them was valid.

1 files changed, 46 insertions, 12 deletions

diff --git a/src/MXF.cpp b/src/MXF.cpp
index 83954f7..173f97b 100755
--- a/src/MXF.cpp
+++ b/src/MXF.cpp
@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2005-2015, John Hurst
+Copyright (c) 2005-2021, John Hurst
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
@@ -262,13 +262,14 @@ ASDCP::MXF::Partition::PacketList::GetMDObjectsByType(const byte_t* ObjectID, st
 //
 
 
-ASDCP::MXF::Partition::Partition(const Dictionary*& d) :
+ASDCP::MXF::Partition::Partition(const Dictionary* d) :
   m_Dict(d),
   MajorVersion(1), MinorVersion(2),
   KAGSize(1), ThisPartition(0), PreviousPartition(0),
   FooterPartition(0), HeaderByteCount(0), IndexByteCount(0), IndexSID(0),
   BodyOffset(0), BodySID(0)
 {
+  assert(d);
   m_PacketList = new PacketList;
 }
 
@@ -429,7 +430,7 @@ public:
 
 
 //
-ASDCP::MXF::Primer::Primer(const Dictionary*& d) : m_LocalTag(0xff), m_Dict(d) {
+ASDCP::MXF::Primer::Primer(const Dictionary* d) : m_LocalTag(0xff), m_Dict(d) {
   m_UL = m_Dict->ul(MDD_Primer);
 }
 
@@ -595,14 +596,21 @@ ASDCP::MXF::Primer::Dump(FILE* stream)
 //
 
 //
-ASDCP::MXF::Preface::Preface(const Dictionary*& d) :
-  InterchangeObject(d), m_Dict(d), Version(258)
+ASDCP::MXF::Preface::Preface(const Dictionary* d) :
+  InterchangeObject(d), Version(258)
 {
   assert(m_Dict);
   m_UL = m_Dict->Type(MDD_Preface).ul;
   ObjectModelVersion = 0;
 }
 
+ASDCP::MXF::Preface::Preface(const Preface& rhs) : InterchangeObject(rhs.m_Dict)
+{
+  assert(m_Dict);
+  m_UL = rhs.m_UL;
+  Copy(rhs);
+}
+
 //
 void
 ASDCP::MXF::Preface::Copy(const Preface& rhs)
@@ -623,6 +631,13 @@ ASDCP::MXF::Preface::Copy(const Preface& rhs)
 }
 
 //
+ASDCP::MXF::InterchangeObject*
+ASDCP::MXF::Preface::Clone() const
+{
+  return new Preface(*this);
+}
+
+//
 ASDCP::Result_t
 ASDCP::MXF::Preface::InitFromTLVSet(TLVReader& TLVSet)
 {
@@ -725,7 +740,12 @@ ASDCP::MXF::Preface::Dump(FILE* stream)
 //------------------------------------------------------------------------------------------
 //
 
-ASDCP::MXF::OP1aHeader::OP1aHeader(const Dictionary*& d) : Partition(d), m_Dict(d), m_Primer(d), m_Preface(0) {}
+ASDCP::MXF::OP1aHeader::OP1aHeader(const Dictionary* d) :
+  Partition(d), m_Primer(d), m_Preface(0)
+{
+  assert(m_Dict);
+}
+
 ASDCP::MXF::OP1aHeader::~OP1aHeader() {}
 
 //
@@ -1025,8 +1045,8 @@ ASDCP::MXF::OP1aHeader::Dump(FILE* stream)
 //------------------------------------------------------------------------------------------
 //
 
-ASDCP::MXF::OPAtomIndexFooter::OPAtomIndexFooter(const Dictionary*& d) :
-  Partition(d), m_Dict(d),
+ASDCP::MXF::OPAtomIndexFooter::OPAtomIndexFooter(const Dictionary* d) :
+  Partition(d),
   m_CurrentSegment(0), m_BytesPerEditUnit(0), m_BodySID(0),
   m_ECOffset(0), m_Lookup(0)
 {
@@ -1367,6 +1387,11 @@ ASDCP::MXF::OPAtomIndexFooter::PushIndexEntry(const IndexTableSegment::IndexEntr
 //------------------------------------------------------------------------------------------
 //
 
+ASDCP::MXF::InterchangeObject::InterchangeObject(const Dictionary* d) :
+  KLVPacket(), m_Dict(d), m_Lookup(0) {}
+
+ASDCP::MXF::InterchangeObject::~InterchangeObject() {}
+
 //
 void
 ASDCP::MXF::InterchangeObject::Copy(const InterchangeObject& rhs)
@@ -1377,6 +1402,15 @@ ASDCP::MXF::InterchangeObject::Copy(const InterchangeObject& rhs)
 }
 
 //
+ASDCP::MXF::InterchangeObject*
+ASDCP::MXF::InterchangeObject::Clone() const
+{
+  ASDCP::MXF::InterchangeObject* obj = new ASDCP::MXF::InterchangeObject(m_Dict);
+  obj->Copy(*this);
+  return obj;
+}
+
+//
 ASDCP::Result_t
 ASDCP::MXF::InterchangeObject::InitFromTLVSet(TLVReader& TLVSet)
 {
@@ -1540,7 +1574,7 @@ ASDCP::MXF::SetObjectFactory(const ASDCP::UL& label, ASDCP::MXF::MXFObjectFactor
 
 //
 ASDCP::MXF::InterchangeObject*
-ASDCP::MXF::CreateObject(const Dictionary*& Dict, const UL& label)
+ASDCP::MXF::CreateObject(const Dictionary* Dict, const UL& label)
 {
   if ( ! s_TypesInit )
     {
@@ -1595,7 +1629,7 @@ ul_is_an_mca_channel(const ASDCP::UL& ul)
 
 //
 bool
-ASDCP::MXF::decode_mca_string(const std::string& s, const mca_label_map_t& labels, const Dictionary*& dict, const std::string& language,
+ASDCP::MXF::decode_mca_string(const std::string& s, const mca_label_map_t& labels, const Dictionary* dict, const std::string& language,
 			      InterchangeObject_list_t& descriptor_list, ui32_t& channel_count)
 {
   std::string symbol_buf;
@@ -1788,7 +1822,7 @@ ASDCP::MXF::decode_mca_string(const std::string& s, const mca_label_map_t& label
 }
 
 //
-ASDCP::MXF::ASDCP_MCAConfigParser::ASDCP_MCAConfigParser(const Dictionary*& d) : m_Dict(d), m_ChannelCount(0)
+ASDCP::MXF::ASDCP_MCAConfigParser::ASDCP_MCAConfigParser(const Dictionary* d) : m_Dict(d), m_ChannelCount(0)
 {
   typedef mca_label_map_t::value_type pair;
   m_LabelMap.insert(pair("L",     label_traits("Left"                              , true,  m_Dict->ul(MDD_DCAudioChannel_L))));
@@ -1832,7 +1866,7 @@ ASDCP::MXF::ASDCP_MCAConfigParser::DecodeString(const std::string& s, const std:
 }
 
 // ST(L,R),DNS(NSC001,NSC002),-,VIN
-ASDCP::MXF::AS02_MCAConfigParser::AS02_MCAConfigParser(const Dictionary*& d) : ASDCP::MXF::ASDCP_MCAConfigParser(d)
+ASDCP::MXF::AS02_MCAConfigParser::AS02_MCAConfigParser(const Dictionary* d) : ASDCP::MXF::ASDCP_MCAConfigParser(d)
 {
   typedef mca_label_map_t::value_type pair;
   m_LabelMap.insert(pair("M1",    label_traits("Mono One",  true,  m_Dict->ul(MDD_IMFAudioChannel_M1))));