Implement CPDF_Object::MakeReference method.chromium/3456

Change-Id: I153747ef587a184eaef58ff09dbf8f214c9ddfb3
Reviewed-on: https://pdfium-review.googlesource.com/17230
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Art Snake <art-snake@yandex-team.ru>

8 files changed, 66 insertions, 16 deletions

diff --git a/core/fpdfapi/parser/cpdf_array.cpp b/core/fpdfapi/parser/cpdf_array.cpp
index a5361fbbb9..d53476d1c2 100644
--- a/core/fpdfapi/parser/cpdf_array.cpp
+++ b/core/fpdfapi/parser/cpdf_array.cpp
@@ -191,7 +191,7 @@ void CPDF_Array::ConvertToIndirectObjectAt(size_t i,
     return;
 
   CPDF_Object* pNew = pHolder->AddIndirectObject(std::move(m_Objects[i]));
-  m_Objects[i] = pdfium::MakeUnique<CPDF_Reference>(pHolder, pNew->GetObjNum());
+  m_Objects[i] = pNew->MakeReference(pHolder);
 }
 
 CPDF_Object* CPDF_Array::SetAt(size_t i, std::unique_ptr<CPDF_Object> pObj) {
diff --git a/core/fpdfapi/parser/cpdf_dictionary.cpp b/core/fpdfapi/parser/cpdf_dictionary.cpp
index c6127fa344..071461b756 100644
--- a/core/fpdfapi/parser/cpdf_dictionary.cpp
+++ b/core/fpdfapi/parser/cpdf_dictionary.cpp
@@ -224,7 +224,7 @@ void CPDF_Dictionary::ConvertToIndirectObjectFor(
     return;
 
   CPDF_Object* pObj = pHolder->AddIndirectObject(std::move(it->second));
-  it->second = pdfium::MakeUnique<CPDF_Reference>(pHolder, pObj->GetObjNum());
+  it->second = pObj->MakeReference(pHolder);
 }
 
 std::unique_ptr<CPDF_Object> CPDF_Dictionary::RemoveFor(const ByteString& key) {
diff --git a/core/fpdfapi/parser/cpdf_document.cpp b/core/fpdfapi/parser/cpdf_document.cpp
index 59927bc250..b163cafbbb 100644
--- a/core/fpdfapi/parser/cpdf_document.cpp
+++ b/core/fpdfapi/parser/cpdf_document.cpp
@@ -513,7 +513,7 @@ void CPDF_Document::CreateNewDoc() {
   pPages->SetNewFor<CPDF_Name>("Type", "Pages");
   pPages->SetNewFor<CPDF_Number>("Count", 0);
   pPages->SetNewFor<CPDF_Array>("Kids");
-  m_pRootDict->SetNewFor<CPDF_Reference>("Pages", this, pPages->GetObjNum());
+  m_pRootDict->SetFor("Pages", pPages->MakeReference(this));
   m_pInfoDict = NewIndirect<CPDF_Dictionary>();
 }
 
@@ -545,9 +545,8 @@ bool CPDF_Document::InsertDeletePDFPage(CPDF_Dictionary* pPages,
         continue;
       }
       if (bInsert) {
-        pKidList->InsertNewAt<CPDF_Reference>(i, this, pPageDict->GetObjNum());
-        pPageDict->SetNewFor<CPDF_Reference>("Parent", this,
-                                             pPages->GetObjNum());
+        pKidList->InsertAt(i, pPageDict->MakeReference(this));
+        pPageDict->SetFor("Parent", pPages->MakeReference(this));
       } else {
         pKidList->RemoveAt(i);
       }
@@ -589,9 +588,9 @@ bool CPDF_Document::InsertNewPage(int iPage, CPDF_Dictionary* pPageDict) {
     CPDF_Array* pPagesList = pPages->GetArrayFor("Kids");
     if (!pPagesList)
       pPagesList = pPages->SetNewFor<CPDF_Array>("Kids");
-    pPagesList->AddNew<CPDF_Reference>(this, pPageDict->GetObjNum());
+    pPagesList->Add(pPageDict->MakeReference(this));
     pPages->SetNewFor<CPDF_Number>("Count", nPages + 1);
-    pPageDict->SetNewFor<CPDF_Reference>("Parent", this, pPages->GetObjNum());
+    pPageDict->SetFor("Parent", pPages->MakeReference(this));
     ResetTraversal();
   } else {
     std::set<CPDF_Dictionary*> stack = {pPages};
@@ -647,8 +646,7 @@ size_t CPDF_Document::CalculateEncodingDict(int charset,
     ByteString name = PDF_AdobeNameFromUnicode(pUnicodes[j]);
     pArray->AddNew<CPDF_Name>(name.IsEmpty() ? ".notdef" : name);
   }
-  pBaseDict->SetNewFor<CPDF_Reference>("Encoding", this,
-                                       pEncodingDict->GetObjNum());
+  pBaseDict->SetFor("Encoding", pEncodingDict->MakeReference(this));
   return i;
 }
 
@@ -715,7 +713,7 @@ CPDF_Dictionary* CPDF_Document::ProcessbCJK(
   pCIDSysInfo->SetNewFor<CPDF_Number>("Supplement", supplement);
 
   CPDF_Array* pArray = pBaseDict->SetNewFor<CPDF_Array>("DescendantFonts");
-  pArray->AddNew<CPDF_Reference>(this, pFontDict->GetObjNum());
+  pArray->Add(pFontDict->MakeReference(this));
   return pFontDict;
 }
 
@@ -796,8 +794,7 @@ CPDF_Font* CPDF_Document::AddFont(CFX_Font* pFont, int charset, bool bVert) {
   CPDF_Dictionary* pFontDesc = ToDictionary(AddIndirectObject(
       CalculateFontDesc(this, basefont, flags, italicangle, pFont->GetAscent(),
                         pFont->GetDescent(), std::move(pBBox), nStemV)));
-  pFontDict->SetNewFor<CPDF_Reference>("FontDescriptor", this,
-                                       pFontDesc->GetObjNum());
+  pFontDict->SetFor("FontDescriptor", pFontDesc->MakeReference(this));
   return LoadFont(pBaseDict);
 }
 
@@ -889,9 +886,9 @@ CPDF_Font* CPDF_Document::AddWindowsFont(LOGFONTA* pLogFont,
       CalculateFontDesc(this, basefont, flags, italicangle, ascend, descend,
                         std::move(pBBox), pLogFont->lfWeight / 5);
   pFontDesc->SetNewFor<CPDF_Number>("CapHeight", capheight);
-  pFontDict->SetNewFor<CPDF_Reference>(
-      "FontDescriptor", this,
-      AddIndirectObject(std::move(pFontDesc))->GetObjNum());
+  pFontDict->SetFor(
+      "FontDescriptor",
+      AddIndirectObject(std::move(pFontDesc))->MakeReference(this));
   hFont = SelectObject(hDC, hFont);
   DeleteObject(hFont);
   DeleteDC(hDC);
diff --git a/core/fpdfapi/parser/cpdf_object.cpp b/core/fpdfapi/parser/cpdf_object.cpp
index 8190d3429f..6fedd25242 100644
--- a/core/fpdfapi/parser/cpdf_object.cpp
+++ b/core/fpdfapi/parser/cpdf_object.cpp
@@ -12,6 +12,7 @@
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
 #include "core/fpdfapi/parser/cpdf_indirect_object_holder.h"
 #include "core/fpdfapi/parser/cpdf_parser.h"
+#include "core/fpdfapi/parser/cpdf_reference.h"
 #include "core/fpdfapi/parser/fpdf_parser_decode.h"
 #include "core/fxcrt/fx_string.h"
 #include "third_party/base/logging.h"
@@ -170,3 +171,12 @@ CPDF_String* CPDF_Object::AsString() {
 const CPDF_String* CPDF_Object::AsString() const {
   return nullptr;
 }
+
+std::unique_ptr<CPDF_Object> CPDF_Object::MakeReference(
+    CPDF_IndirectObjectHolder* holder) const {
+  if (IsInline()) {
+    NOTREACHED();
+    return nullptr;
+  }
+  return pdfium::MakeUnique<CPDF_Reference>(holder, GetObjNum());
+}
diff --git a/core/fpdfapi/parser/cpdf_object.h b/core/fpdfapi/parser/cpdf_object.h
index 21eec62b0d..5ff028e9e0 100644
--- a/core/fpdfapi/parser/cpdf_object.h
+++ b/core/fpdfapi/parser/cpdf_object.h
@@ -17,6 +17,7 @@
 class CPDF_Array;
 class CPDF_Boolean;
 class CPDF_Dictionary;
+class CPDF_IndirectObjectHolder;
 class CPDF_Name;
 class CPDF_Null;
 class CPDF_Number;
@@ -106,6 +107,11 @@ class CPDF_Object {
       bool bDirect,
       std::set<const CPDF_Object*>* pVisited) const;
 
+  // Return a reference to itself.
+  // The object must be direct (!IsInlined).
+  virtual std::unique_ptr<CPDF_Object> MakeReference(
+      CPDF_IndirectObjectHolder* holder) const;
+
  protected:
   CPDF_Object() : m_ObjNum(0), m_GenNum(0) {}
 
diff --git a/core/fpdfapi/parser/cpdf_object_unittest.cpp b/core/fpdfapi/parser/cpdf_object_unittest.cpp
index 856dd0ac3b..78a0af7299 100644
--- a/core/fpdfapi/parser/cpdf_object_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_object_unittest.cpp
@@ -393,6 +393,18 @@ TEST_F(PDFObjectsTest, IsTypeAndAsType) {
   }
 }
 
+TEST_F(PDFObjectsTest, MakeReferenceGeneric) {
+  auto original_obj = pdfium::MakeUnique<CPDF_Null>();
+  original_obj->SetObjNum(42);
+  ASSERT_FALSE(original_obj->IsInline());
+
+  auto ref_obj = original_obj->MakeReference(m_ObjHolder.get());
+
+  ASSERT_TRUE(ref_obj->IsReference());
+  EXPECT_EQ(original_obj->GetObjNum(),
+            ToReference(ref_obj.get())->GetRefObjNum());
+}
+
 TEST(PDFArrayTest, GetMatrix) {
   float elems[][6] = {{0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f},
                       {1, 2, 3, 4, 5, 6},
@@ -971,3 +983,18 @@ TEST(PDFDictionaryTest, ExtractObjectOnRemove) {
   extracted_object = dict->RemoveFor("non_exists_object");
   EXPECT_FALSE(extracted_object);
 }
+
+TEST(PDFRefernceTest, MakeReferenceToReference) {
+  auto obj_holder = pdfium::MakeUnique<CPDF_IndirectObjectHolder>();
+  auto original_ref = pdfium::MakeUnique<CPDF_Reference>(obj_holder.get(), 42);
+  original_ref->SetObjNum(1952);
+  ASSERT_FALSE(original_ref->IsInline());
+
+  auto ref_obj = original_ref->MakeReference(obj_holder.get());
+
+  ASSERT_TRUE(ref_obj->IsReference());
+  // We do not allow reference to reference.
+  // New reference should have same RefObjNum.
+  EXPECT_EQ(original_ref->GetRefObjNum(),
+            ToReference(ref_obj.get())->GetRefObjNum());
+}
diff --git a/core/fpdfapi/parser/cpdf_reference.cpp b/core/fpdfapi/parser/cpdf_reference.cpp
index 3f45a96c6b..0f3b7627d6 100644
--- a/core/fpdfapi/parser/cpdf_reference.cpp
+++ b/core/fpdfapi/parser/cpdf_reference.cpp
@@ -103,3 +103,11 @@ bool CPDF_Reference::WriteTo(IFX_ArchiveStream* archive) const {
   return archive->WriteString(" ") && archive->WriteDWord(GetRefObjNum()) &&
          archive->WriteString(" 0 R ");
 }
+
+std::unique_ptr<CPDF_Object> CPDF_Reference::MakeReference(
+    CPDF_IndirectObjectHolder* holder) const {
+  ASSERT(holder == m_pObjList.Get());
+  // Do not allow reference to reference, just create other reference for same
+  // object.
+  return pdfium::MakeUnique<CPDF_Reference>(holder, GetRefObjNum());
+}
diff --git a/core/fpdfapi/parser/cpdf_reference.h b/core/fpdfapi/parser/cpdf_reference.h
index 4cfb5c26e3..d1e0a07e4b 100644
--- a/core/fpdfapi/parser/cpdf_reference.h
+++ b/core/fpdfapi/parser/cpdf_reference.h
@@ -34,6 +34,8 @@ class CPDF_Reference : public CPDF_Object {
   CPDF_Reference* AsReference() override;
   const CPDF_Reference* AsReference() const override;
   bool WriteTo(IFX_ArchiveStream* archive) const override;
+  std::unique_ptr<CPDF_Object> MakeReference(
+      CPDF_IndirectObjectHolder* holder) const override;
 
   CPDF_IndirectObjectHolder* GetObjList() const { return m_pObjList.Get(); }
   uint32_t GetRefObjNum() const { return m_RefObjNum; }