Avoid potential duplicate unique_ptr to CPDF_Document from CPDFXA_Context.

Should FPDFDocumentFromCPDFDocument() be called several times under
XFA, we may WrapUnique() the document several times. So cache a pointer
back from CPDF_Document to CPDFXFA_Context to avoid this.

Because of layering, introduce a placeholder type CPDF_Document::Extension.

This is actually the first step in some larger XFA ownership cleanup, but
makes a nice standalone CL around the one particular issue.

Change-Id: I4be326ddb1a5fae7339e6ed6745dd551b1374b53
Reviewed-on: https://pdfium-review.googlesource.com/31570
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/core/fpdfapi/parser/cpdf_document.h b/core/fpdfapi/parser/cpdf_document.h
index d73dbc1df9..adf4eca75d 100644
--- a/core/fpdfapi/parser/cpdf_document.h
+++ b/core/fpdfapi/parser/cpdf_document.h
@@ -41,9 +41,15 @@ class JBig2_DocumentContext;
 
 class CPDF_Document : public CPDF_IndirectObjectHolder {
  public:
+  // Type from which the XFA extension can subclass itself.
+  class Extension {};
+
   explicit CPDF_Document(std::unique_ptr<CPDF_Parser> pParser);
   ~CPDF_Document() override;
 
+  Extension* GetExtension() const { return m_pExtension.Get(); }
+  void SetExtension(Extension* pExt) { m_pExtension = pExt; }
+
   CPDF_Parser* GetParser() const { return m_pParser.get(); }
   const CPDF_Dictionary* GetRoot() const { return m_pRootDict; }
   CPDF_Dictionary* GetRoot() { return m_pRootDict; }
@@ -153,6 +159,7 @@ class CPDF_Document : public CPDF_IndirectObjectHolder {
   std::unique_ptr<JBig2_DocumentContext> m_pCodecContext;
   std::unique_ptr<CPDF_LinkList> m_pLinksContext;
   std::vector<uint32_t> m_PageList;
+  UnownedPtr<Extension> m_pExtension;
 };
 
 #endif  // CORE_FPDFAPI_PARSER_CPDF_DOCUMENT_H_