Cleanup CXFA_Node ownership

Currently a CXFA_Node can be owned by the CXFA_Document root pointer,
the CXFA_Document Purge list or as a child of another CXFA_Node. This
makes it hard to know who currently owns what.

This CL moves all ownership of nodes into a CXFA_NodeOwner class which
CXFA_Document subclasses. The node owner always owns all nodes and is
responsible for cleaning them up upon destruction. The destruction order
is not guarenteed to be in tree order as nodes can be inserted and moved
around the tree.

Change-Id: I6b202b8e844999ba835093dcdd1a808938b6d9a8
Reviewed-on: https://pdfium-review.googlesource.com/26434
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

1 files changed, 5 insertions, 31 deletions

diff --git a/xfa/fxfa/parser/cxfa_document.cpp b/xfa/fxfa/parser/cxfa_document.cpp
index 434d6cbfde..a21d3f974c 100644
--- a/xfa/fxfa/parser/cxfa_document.cpp
+++ b/xfa/fxfa/parser/cxfa_document.cpp
@@ -6,6 +6,8 @@
 
 #include "xfa/fxfa/parser/cxfa_document.h"
 
+#include <set>
+
 #include "core/fxcrt/fx_extension.h"
 #include "fxjs/cfxjse_engine.h"
 #include "xfa/fxfa/cxfa_ffnotify.h"
@@ -87,7 +89,8 @@ void MergeNode(CXFA_Document* pDocument,
 }  // namespace
 
 CXFA_Document::CXFA_Document(CXFA_DocumentParser* pParser)
-    : m_pParser(pParser),
+    : CXFA_NodeOwner(),
+      m_pParser(pParser),
       m_pRootNode(nullptr),
       m_eCurVersionMode(XFA_VERSION_DEFAULT),
       m_dwDocFlags(0) {
@@ -98,12 +101,6 @@ CXFA_Document::~CXFA_Document() {
   // Remove all the bindings before freeing the node as the ownership is wonky.
   if (m_pRootNode)
     m_pRootNode->ReleaseBindingNodes();
-
-  delete m_pRootNode;
-
-  for (CXFA_Node* pNode : m_PurgeNodes)
-    delete pNode;
-  m_PurgeNodes.clear();
 }
 
 CXFA_LayoutProcessor* CXFA_Document::GetLayoutProcessor() {
@@ -128,14 +125,6 @@ void CXFA_Document::ClearLayoutData() {
   m_pScriptSignature.reset();
 }
 
-void CXFA_Document::SetRoot(CXFA_Node* pNewRoot) {
-  if (m_pRootNode)
-    AddPurgeNode(m_pRootNode);
-
-  m_pRootNode = pNewRoot;
-  RemovePurgeNode(pNewRoot);
-}
-
 CFX_XMLDoc* CXFA_Document::GetXMLDoc() const {
   return m_pParser->GetXMLDoc();
 }
@@ -221,22 +210,7 @@ CXFA_Node* CXFA_Document::CreateNode(XFA_PacketType packet,
                                      XFA_Element eElement) {
   if (eElement == XFA_Element::Unknown)
     return nullptr;
-
-  std::unique_ptr<CXFA_Node> pNode = CXFA_Node::Create(this, eElement, packet);
-  if (!pNode)
-    return nullptr;
-
-  // TODO(dsinclair): AddPrugeNode should take ownership of the pointer.
-  AddPurgeNode(pNode.get());
-  return pNode.release();
-}
-
-void CXFA_Document::AddPurgeNode(CXFA_Node* pNode) {
-  m_PurgeNodes.insert(pNode);
-}
-
-bool CXFA_Document::RemovePurgeNode(CXFA_Node* pNode) {
-  return !!m_PurgeNodes.erase(pNode);
+  return AddOwnedNode(CXFA_Node::Create(this, eElement, packet));
 }
 
 void CXFA_Document::SetFlag(uint32_t dwFlag, bool bOn) {