Fix receiving page, if it have not obj num.

core/fpdfapi/parser/cpdf_document_unittest.cpp

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/fpdfapi/parser/cpdf_document.h"
 
 #include <memory>
 
 #include "core/fpdfapi/cpdf_modulemgr.h"
 #include "core/fpdfapi/parser/cpdf_array.h"
@@ skipping 58 matching lines @@
     m_pOwnedRootDict.reset(new CPDF_Dictionary());
     m_pOwnedRootDict->SetReferenceFor("Pages", this, pagesDict->GetObjNum());
     m_pRootDict = m_pOwnedRootDict.get();
     m_PageList.SetSize(7);
   }
 
  private:
   std::unique_ptr<CPDF_Dictionary> m_pOwnedRootDict;
 };
 
+class CPDF_TestDocumentWithPageWithoutPageNum : public CPDF_Document {
+ public:
+  CPDF_TestDocumentWithPageWithoutPageNum() : CPDF_Document(nullptr) {
+    // Set up test
+    CPDF_Array* allPages = new CPDF_Array();
+    allPages->AddReference(this, AddIndirectObject(CreateNumberedPage(0)));
+    allPages->AddReference(this, AddIndirectObject(CreateNumberedPage(1)));
+    // Page without pageNum.
+    allPages->Add(CreateNumberedPage(2));
+    CPDF_Dictionary* pagesDict = CreatePageTreeNode(allPages, this, 3);
+
+    m_pOwnedRootDict.reset(new CPDF_Dictionary());
+    m_pOwnedRootDict->SetReferenceFor("Pages", this, pagesDict->GetObjNum());
+    m_pRootDict = m_pOwnedRootDict.get();
+    m_PageList.SetSize(3);
+  }
+
+ private:
+  std::unique_ptr<CPDF_Dictionary> m_pOwnedRootDict;
+};
+
 class TestLinearized : public CPDF_LinearizedHeader {
  public:
   explicit TestLinearized(CPDF_Dictionary* dict)
       : CPDF_LinearizedHeader(dict) {}
 };
 }  // namespace
 
 class cpdf_document_test : public testing::Test {
  public:
   void SetUp() override {
     CPDF_ModuleMgr* module_mgr = CPDF_ModuleMgr::Get();
     module_mgr->InitPageModule();
   }
   void TearDown() override {}
 };
 
 TEST_F(cpdf_document_test, GetPages) {
   std::unique_ptr<CPDF_TestDocumentForPages> document =
       pdfium::MakeUnique<CPDF_TestDocumentForPages>();
   for (int i = 0; i < 7; i++) {
     CPDF_Dictionary* page = document->GetPage(i);
     ASSERT_TRUE(page);
     ASSERT_TRUE(page->KeyExist("PageNumbering"));
     EXPECT_EQ(i, page->GetIntegerFor("PageNumbering"));
   }
   CPDF_Dictionary* page = document->GetPage(7);
   EXPECT_FALSE(page);
 }
 
+TEST_F(cpdf_document_test, GetPageWithoutObjNumTwice) {
+  std::unique_ptr<CPDF_TestDocumentWithPageWithoutPageNum> document =
+      pdfium::MakeUnique<CPDF_TestDocumentWithPageWithoutPageNum>();
+  const CPDF_Dictionary* page = document->GetPage(2);
+  ASSERT_TRUE(page);
+  // This is page without obj num.
+  ASSERT_EQ(0ul, page->GetObjNum());
+  const CPDF_Dictionary* second_call_page = document->GetPage(2);
+  EXPECT_TRUE(second_call_page);
+  EXPECT_EQ(page, second_call_page);
+}
+
 TEST_F(cpdf_document_test, GetPagesReverseOrder) {
   std::unique_ptr<CPDF_TestDocumentForPages> document =
       pdfium::MakeUnique<CPDF_TestDocumentForPages>();
   for (int i = 6; i >= 0; i--) {
     CPDF_Dictionary* page = document->GetPage(i);
     ASSERT_TRUE(page);
     ASSERT_TRUE(page->KeyExist("PageNumbering"));
     EXPECT_EQ(i, page->GetIntegerFor("PageNumbering"));
   }
   CPDF_Dictionary* page = document->GetPage(7);
@@ skipping 40 matching lines @@
   const int test_page_num = 33;
 
   EXPECT_FALSE(document.IsPageLoaded(test_page_num));
   EXPECT_EQ(nullptr, document.GetPage(test_page_num));
 
   document.SetPageObjNum(test_page_num, obj_num);
 
   EXPECT_TRUE(document.IsPageLoaded(test_page_num));
   EXPECT_EQ(page_stub, document.GetPage(test_page_num));
 }