5 files changed, 32 insertions, 8 deletions
diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
index 1244b12331..859f5b3991 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
@@ -129,7 +129,7 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessGraphics) {
   auto pDoc = pdfium::MakeUnique<CPDF_Document>(nullptr);
   pDoc->CreateNewDoc();
   CPDF_Dictionary* pPageDict = pDoc->CreateNewPage(0);
-  auto pTestPage = pdfium::MakeRetain<CPDF_Page>(pDoc.get(), pPageDict, false);
+  RetainPtr<CPDF_Page> pTestPage = pDoc->GetOrCreatePDFPage(pPageDict);
   CPDF_PageContentGenerator generator(pTestPage.Get());
   std::ostringstream buf;
   TestProcessPath(&generator, &buf, pPathObj.get());
@@ -168,7 +168,7 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessStandardText) {
   auto pDoc = pdfium::MakeUnique<CPDF_Document>(nullptr);
   pDoc->CreateNewDoc();
   CPDF_Dictionary* pPageDict = pDoc->CreateNewPage(0);
-  auto pTestPage = pdfium::MakeRetain<CPDF_Page>(pDoc.get(), pPageDict, false);
+  RetainPtr<CPDF_Page> pTestPage = pDoc->GetOrCreatePDFPage(pPageDict);
   CPDF_PageContentGenerator generator(pTestPage.Get());
   auto pTextObj = pdfium::MakeUnique<CPDF_TextObject>();
   CPDF_Font* pFont = CPDF_Font::GetStockFont(pDoc.get(), "Times-Roman");
@@ -231,7 +231,7 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessText) {
   auto pDoc = pdfium::MakeUnique<CPDF_Document>(nullptr);
   pDoc->CreateNewDoc();
   CPDF_Dictionary* pPageDict = pDoc->CreateNewPage(0);
-  auto pTestPage = pdfium::MakeRetain<CPDF_Page>(pDoc.get(), pPageDict, false);
+  RetainPtr<CPDF_Page> pTestPage = pDoc->GetOrCreatePDFPage(pPageDict);
   CPDF_PageContentGenerator generator(pTestPage.Get());
 
   std::ostringstream buf;
diff --git a/core/fpdfapi/page/cpdf_page.cpp b/core/fpdfapi/page/cpdf_page.cpp
index 7c0a3234c9..c5c85635b2 100644
--- a/core/fpdfapi/page/cpdf_page.cpp
+++ b/core/fpdfapi/page/cpdf_page.cpp
@@ -21,11 +21,11 @@
 
 CPDF_Page::CPDF_Page(CPDF_Document* pDocument,
                      CPDF_Dictionary* pPageDict,
-                     bool bPageCache)
+                     bool bUseRenderCache)
     : CPDF_PageObjectHolder(pDocument, pPageDict),
       m_PageSize(100, 100),
       m_pPDFDocument(pDocument) {
-  if (bPageCache)
+  if (bUseRenderCache)
     m_pPageRender = pdfium::MakeUnique<CPDF_PageRenderCache>(this);
   if (!pPageDict)
     return;
diff --git a/core/fpdfapi/page/cpdf_page.h b/core/fpdfapi/page/cpdf_page.h
index 0bb99b73f1..b94326e47b 100644
--- a/core/fpdfapi/page/cpdf_page.h
+++ b/core/fpdfapi/page/cpdf_page.h
@@ -12,6 +12,7 @@
 #include "core/fpdfapi/page/cpdf_pageobjectholder.h"
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_system.h"
+#include "core/fxcrt/observable.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
 #include "third_party/base/optional.h"
@@ -22,7 +23,9 @@ class CPDF_Object;
 class CPDF_PageRenderCache;
 class CPDF_PageRenderContext;
 
-class CPDF_Page : public Retainable, public CPDF_PageObjectHolder {
+class CPDF_Page : public Retainable,
+                  public Observable<CPDF_Page>,
+                  public CPDF_PageObjectHolder {
  public:
   class View {};  // Caller implements as desired, empty here due to layering.
   class Extension : public Retainable {};  // XFA page parent class, layering.
@@ -66,7 +69,7 @@ class CPDF_Page : public Retainable, public CPDF_PageObjectHolder {
  private:
   CPDF_Page(CPDF_Document* pDocument,
             CPDF_Dictionary* pPageDict,
-            bool bPageCache);
+            bool bUseRenderCache);
   ~CPDF_Page() override;
 
   void StartParse();
diff --git a/core/fpdfapi/parser/cpdf_document.cpp b/core/fpdfapi/parser/cpdf_document.cpp
index 7968d1b019..2e4baabe91 100644
--- a/core/fpdfapi/parser/cpdf_document.cpp
+++ b/core/fpdfapi/parser/cpdf_document.cpp
@@ -602,6 +602,19 @@ bool CPDF_Document::InsertNewPage(int iPage, CPDF_Dictionary* pPageDict) {
   return true;
 }
 
+RetainPtr<CPDF_Page> CPDF_Document::GetOrCreatePDFPage(
+    CPDF_Dictionary* pPageDict) {
+  std::pair<uint32_t, uint32_t> key = {pPageDict->GetObjNum(),
+                                       pPageDict->GetGenNum()};
+  if (m_PageMap[key])
+    return RetainPtr<CPDF_Page>(m_PageMap[key].Get());
+
+  auto pPage = pdfium::MakeRetain<CPDF_Page>(this, pPageDict, true);
+  pPage->ParseContent();
+  m_PageMap[key].Reset(pPage.Get());
+  return pPage;
+}
+
 void CPDF_Document::DeletePage(int iPage) {
   CPDF_Dictionary* pPages = GetPagesDict();
   if (!pPages)
diff --git a/core/fpdfapi/parser/cpdf_document.h b/core/fpdfapi/parser/cpdf_document.h
index c2774b163a..c240e77567 100644
--- a/core/fpdfapi/parser/cpdf_document.h
+++ b/core/fpdfapi/parser/cpdf_document.h
@@ -8,6 +8,7 @@
 #define CORE_FPDFAPI_PARSER_CPDF_DOCUMENT_H_
 
 #include <functional>
+#include <map>
 #include <memory>
 #include <set>
 #include <utility>
@@ -64,6 +65,7 @@ class CPDF_Document : public CPDF_IndirectObjectHolder {
   const CPDF_Dictionary* GetInfo() const { return m_pInfoDict.Get(); }
   CPDF_Dictionary* GetInfo() { return m_pInfoDict.Get(); }
 
+  RetainPtr<CPDF_Page> GetOrCreatePDFPage(CPDF_Dictionary* pPageDict);
   void DeletePage(int iPage);
   int GetPageCount() const;
   bool IsPageLoaded(int iPage) const;
@@ -167,7 +169,13 @@ class CPDF_Document : public CPDF_IndirectObjectHolder {
   std::unique_ptr<CPDF_DocRenderData> m_pDocRender;
   std::unique_ptr<JBig2_DocumentContext> m_pCodecContext;
   std::unique_ptr<CPDF_LinkList> m_pLinksContext;
-  std::vector<uint32_t> m_PageList;  // Page number to page's dict objnum.
+
+  // Page number (index) to page's dict objnum.
+  std::vector<uint32_t> m_PageList;
+
+  // Dict {objnum, gennum} to page mapping.
+  std::map<std::pair<uint32_t, uint32_t>, CPDF_Page::ObservedPtr> m_PageMap;
+
   UnownedPtr<Extension> m_pExtension;
 };