Add type cast definitions for CPDF_Reference.

This Cl adds ToReference, CPDF_Object::AsReference and CPDF_Object::IsReference
and updates the src to use them as needed.

BUG=pdfium:201
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1420973002 .

1 files changed, 58 insertions, 77 deletions

diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index b2f7eb6d7e..71cd8443d5 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -258,11 +258,9 @@ FX_DWORD CPDF_Parser::StartParse(IFX_FileRead* pFileAccess,
   }
   if (m_pSecurityHandler && !m_pSecurityHandler->IsMetadataEncrypted()) {
     CPDF_Reference* pMetadata =
-        (CPDF_Reference*)m_pDocument->GetRoot()->GetElement(
-            FX_BSTRC("Metadata"));
-    if (pMetadata && pMetadata->GetType() == PDFOBJ_REFERENCE) {
+        ToReference(m_pDocument->GetRoot()->GetElement(FX_BSTRC("Metadata")));
+    if (pMetadata)
       m_Syntax.m_MetadataObjnum = pMetadata->GetRefObjNum();
-    }
   }
   return PDFPARSE_ERROR_SUCCESS;
 }
@@ -276,12 +274,10 @@ FX_DWORD CPDF_Parser::SetEncryptHandler() {
   if (pEncryptObj) {
     if (CPDF_Dictionary* pEncryptDict = pEncryptObj->AsDictionary()) {
       SetEncryptDictionary(pEncryptDict);
-    } else if (pEncryptObj->GetType() == PDFOBJ_REFERENCE) {
-      pEncryptObj = m_pDocument->GetIndirectObject(
-          ((CPDF_Reference*)pEncryptObj)->GetRefObjNum());
-      if (pEncryptObj) {
+    } else if (CPDF_Reference* pRef = pEncryptObj->AsReference()) {
+      pEncryptObj = m_pDocument->GetIndirectObject(pRef->GetRefObjNum());
+      if (pEncryptObj)
         SetEncryptDictionary(pEncryptObj->GetDict());
-      }
     }
   }
   if (m_bForceUseSecurityHandler) {
@@ -840,12 +836,12 @@ FX_BOOL CPDF_Parser::RebuildCrossRef() {
                     if (m_pTrailer) {
                       CPDF_Object* pRoot =
                           pTrailer->GetElement(FX_BSTRC("Root"));
-                      if (pRoot == NULL ||
-                          (pRoot->GetType() == PDFOBJ_REFERENCE &&
+                      CPDF_Reference* pRef = ToReference(pRoot);
+                      if (!pRoot ||
+                          (pRef &&
                            (FX_DWORD)m_CrossRef.GetSize() >
-                               ((CPDF_Reference*)pRoot)->GetRefObjNum() &&
-                           m_CrossRef.GetAt(((CPDF_Reference*)pRoot)
-                                                ->GetRefObjNum()) != 0)) {
+                               pRef->GetRefObjNum() &&
+                           m_CrossRef.GetAt(pRef->GetRefObjNum()) != 0)) {
                         FX_POSITION pos = pTrailer->GetStartPos();
                         while (pos) {
                           CFX_ByteString key;
@@ -1129,27 +1125,21 @@ CPDF_Array* CPDF_Parser::GetIDArray() {
   if (!pID)
     return nullptr;
 
-  if (pID->GetType() == PDFOBJ_REFERENCE) {
-    pID = ParseIndirectObject(NULL, ((CPDF_Reference*)pID)->GetRefObjNum());
+  if (CPDF_Reference* pRef = pID->AsReference()) {
+    pID = ParseIndirectObject(nullptr, pRef->GetRefObjNum());
     m_pTrailer->SetAt(FX_BSTRC("ID"), pID);
   }
   return ToArray(pID);
 }
 FX_DWORD CPDF_Parser::GetRootObjNum() {
-  CPDF_Object* pRef =
-      m_pTrailer ? m_pTrailer->GetElement(FX_BSTRC("Root")) : NULL;
-  if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
-    return 0;
-  }
-  return ((CPDF_Reference*)pRef)->GetRefObjNum();
+  CPDF_Reference* pRef = ToReference(
+      m_pTrailer ? m_pTrailer->GetElement(FX_BSTRC("Root")) : nullptr);
+  return pRef ? pRef->GetRefObjNum() : 0;
 }
 FX_DWORD CPDF_Parser::GetInfoObjNum() {
-  CPDF_Object* pRef =
-      m_pTrailer ? m_pTrailer->GetElement(FX_BSTRC("Info")) : NULL;
-  if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
-    return 0;
-  }
-  return ((CPDF_Reference*)pRef)->GetRefObjNum();
+  CPDF_Reference* pRef = ToReference(
+      m_pTrailer ? m_pTrailer->GetElement(FX_BSTRC("Info")) : nullptr);
+  return pRef ? pRef->GetRefObjNum() : 0;
 }
 FX_BOOL CPDF_Parser::IsFormStream(FX_DWORD objnum, FX_BOOL& bForm) {
   bForm = FALSE;
@@ -1617,11 +1607,9 @@ FX_DWORD CPDF_Parser::StartAsynParse(IFX_FileRead* pFileAccess,
     }
   }
   if (m_pSecurityHandler && m_pSecurityHandler->IsMetadataEncrypted()) {
-    CPDF_Object* pMetadata =
-        m_pDocument->GetRoot()->GetElement(FX_BSTRC("Metadata"));
-    if (pMetadata && pMetadata->GetType() == PDFOBJ_REFERENCE) {
-      m_Syntax.m_MetadataObjnum = ((CPDF_Reference*)pMetadata)->GetRefObjNum();
-    }
+    if (CPDF_Reference* pMetadata = ToReference(
+            m_pDocument->GetRoot()->GetElement(FX_BSTRC("Metadata"))))
+      m_Syntax.m_MetadataObjnum = pMetadata->GetRefObjNum();
   }
   return PDFPARSE_ERROR_SUCCESS;
 }
@@ -2374,11 +2362,13 @@ CPDF_Stream* CPDF_SyntaxParser::ReadStream(CPDF_Dictionary* pDict,
                                            FX_DWORD gennum) {
   CPDF_Object* pLenObj = pDict->GetElement(FX_BSTRC("Length"));
   FX_FILESIZE len = -1;
-  if (pLenObj && ((pLenObj->GetType() != PDFOBJ_REFERENCE) ||
-                  ((((CPDF_Reference*)pLenObj)->GetObjList()) &&
-                   ((CPDF_Reference*)pLenObj)->GetRefObjNum() != objnum))) {
+  CPDF_Reference* pLenObjRef = ToReference(pLenObj);
+
+  bool differingObjNum = pLenObjRef && pLenObjRef->GetObjList() &&
+                         pLenObjRef->GetRefObjNum() != objnum;
+  if (pLenObj && differingObjNum)
     len = pLenObj->GetInteger();
-  }
+
   // Locate the start of stream.
   ToNextLine();
   FX_FILESIZE streamStartPos = m_Pos;
@@ -3064,7 +3054,7 @@ FX_BOOL CPDF_DataAvail::IsObjectsAvail(CFX_PtrArray& obj_array,
         }
       } break;
       case PDFOBJ_REFERENCE: {
-        CPDF_Reference* pRef = (CPDF_Reference*)pObj;
+        CPDF_Reference* pRef = pObj->AsReference();
         FX_DWORD dwNum = pRef->GetRefObjNum();
         FX_FILESIZE offset;
         FX_DWORD original_size = GetObjectSize(dwNum, offset);
@@ -3106,13 +3096,10 @@ FX_BOOL CPDF_DataAvail::IsObjectsAvail(CFX_PtrArray& obj_array,
     int32_t iSize = new_obj_array.GetSize();
     for (i = 0; i < iSize; ++i) {
       CPDF_Object* pObj = (CPDF_Object*)new_obj_array[i];
-      int32_t type = pObj->GetType();
-      if (type == PDFOBJ_REFERENCE) {
-        CPDF_Reference* pRef = (CPDF_Reference*)pObj;
+      if (CPDF_Reference* pRef = pObj->AsReference()) {
         FX_DWORD dwNum = pRef->GetRefObjNum();
-        if (!m_objnum_array.Find(dwNum)) {
+        if (!m_objnum_array.Find(dwNum))
           ret_array.Add(pObj);
-        }
       } else {
         ret_array.Add(pObj);
       }
@@ -3380,37 +3367,37 @@ FX_BOOL CPDF_DataAvail::CheckRoot(IFX_DownloadHints* pHints) {
     m_docStatus = PDF_DATAAVAIL_ERROR;
     return FALSE;
   }
-  CPDF_Reference* pRef = (CPDF_Reference*)pDict->GetElement(FX_BSTRC("Pages"));
-  if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
+  CPDF_Reference* pRef = ToReference(pDict->GetElement(FX_BSTRC("Pages")));
+  if (!pRef) {
     m_docStatus = PDF_DATAAVAIL_ERROR;
     return FALSE;
   }
+
   m_PagesObjNum = pRef->GetRefObjNum();
   CPDF_Reference* pAcroFormRef =
-      (CPDF_Reference*)m_pRoot->GetDict()->GetElement(FX_BSTRC("AcroForm"));
-  if (pAcroFormRef && pAcroFormRef->GetType() == PDFOBJ_REFERENCE) {
+      ToReference(m_pRoot->GetDict()->GetElement(FX_BSTRC("AcroForm")));
+  if (pAcroFormRef) {
     m_bHaveAcroForm = TRUE;
     m_dwAcroFormObjNum = pAcroFormRef->GetRefObjNum();
   }
+
   if (m_dwInfoObjNum) {
     m_docStatus = PDF_DATAAVAIL_INFO;
   } else {
-    if (m_bHaveAcroForm) {
-      m_docStatus = PDF_DATAAVAIL_ACROFORM;
-    } else {
-      m_docStatus = PDF_DATAAVAIL_PAGETREE;
-    }
+    m_docStatus =
+        m_bHaveAcroForm ? PDF_DATAAVAIL_ACROFORM : PDF_DATAAVAIL_PAGETREE;
   }
   return TRUE;
 }
 FX_BOOL CPDF_DataAvail::PreparePageItem() {
   CPDF_Dictionary* pRoot = m_pDocument->GetRoot();
   CPDF_Reference* pRef =
-      pRoot ? (CPDF_Reference*)pRoot->GetElement(FX_BSTRC("Pages")) : NULL;
-  if (pRef == NULL || pRef->GetType() != PDFOBJ_REFERENCE) {
+      ToReference(pRoot ? pRoot->GetElement(FX_BSTRC("Pages")) : nullptr);
+  if (!pRef) {
     m_docStatus = PDF_DATAAVAIL_ERROR;
     return FALSE;
   }
+
   m_PagesObjNum = pRef->GetRefObjNum();
   m_pCurrentParser = (CPDF_Parser*)m_pDocument->GetParser();
   m_docStatus = PDF_DATAAVAIL_PAGETREE;
@@ -3443,12 +3430,9 @@ FX_BOOL CPDF_DataAvail::CheckPage(IFX_DownloadHints* pHints) {
       CPDF_Array* pArray = pObj->GetArray();
       if (pArray) {
         int32_t iSize = pArray->GetCount();
-        CPDF_Object* pItem = NULL;
         for (int32_t j = 0; j < iSize; ++j) {
-          pItem = pArray->GetElement(j);
-          if (pItem && pItem->GetType() == PDFOBJ_REFERENCE) {
-            UnavailObjList.Add(((CPDF_Reference*)pItem)->GetRefObjNum());
-          }
+          if (CPDF_Reference* pRef = ToReference(pArray->GetElement(j)))
+            UnavailObjList.Add(pRef->GetRefObjNum());
         }
       }
     }
@@ -3503,17 +3487,14 @@ FX_BOOL CPDF_DataAvail::GetPageKids(CPDF_Parser* pParser, CPDF_Object* pPages) {
     return TRUE;
   }
   switch (pKids->GetType()) {
-    case PDFOBJ_REFERENCE: {
-      CPDF_Reference* pKid = (CPDF_Reference*)pKids;
-      m_PageObjList.Add(pKid->GetRefObjNum());
-    } break;
+    case PDFOBJ_REFERENCE:
+      m_PageObjList.Add(pKids->AsReference()->GetRefObjNum());
+      break;
     case PDFOBJ_ARRAY: {
       CPDF_Array* pKidsArray = pKids->AsArray();
       for (FX_DWORD i = 0; i < pKidsArray->GetCount(); ++i) {
-        CPDF_Object* pKid = (CPDF_Object*)pKidsArray->GetElement(i);
-        if (pKid && pKid->GetType() == PDFOBJ_REFERENCE) {
-          m_PageObjList.Add(((CPDF_Reference*)pKid)->GetRefObjNum());
-        }
+        if (CPDF_Reference* pRef = ToReference(pKidsArray->GetElement(i)))
+          m_PageObjList.Add(pRef->GetRefObjNum());
       }
     } break;
     default:
@@ -4012,7 +3993,7 @@ FX_BOOL CPDF_DataAvail::CheckTrailer(IFX_DownloadHints* pHints) {
 
     CPDF_Dictionary* pTrailerDict = pTrailer->GetDict();
     CPDF_Object* pEncrypt = pTrailerDict->GetElement("Encrypt");
-    if (pEncrypt && pEncrypt->GetType() == PDFOBJ_REFERENCE) {
+    if (ToReference(pEncrypt)) {
       m_docStatus = PDF_DATAAVAIL_LOADALLFILE;
       return TRUE;
     }
@@ -4091,13 +4072,13 @@ FX_BOOL CPDF_DataAvail::CheckArrayPageNode(FX_DWORD dwPageNo,
 
   pPageNode->m_type = PDF_PAGENODE_PAGES;
   for (FX_DWORD i = 0; i < pArray->GetCount(); ++i) {
-    CPDF_Object* pKid = (CPDF_Object*)pArray->GetElement(i);
-    if (!pKid || pKid->GetType() != PDFOBJ_REFERENCE) {
+    CPDF_Reference* pKid = ToReference(pArray->GetElement(i));
+    if (!pKid)
       continue;
-    }
+
     CPDF_PageNode* pNode = new CPDF_PageNode();
     pPageNode->m_childNode.Add(pNode);
-    pNode->m_dwPageNo = ((CPDF_Reference*)pKid)->GetRefObjNum();
+    pNode->m_dwPageNo = pKid->GetRefObjNum();
   }
   pPages->Release();
   return TRUE;
@@ -4141,7 +4122,7 @@ FX_BOOL CPDF_DataAvail::CheckUnkownPageNode(FX_DWORD dwPageNo,
     }
     switch (pKids->GetType()) {
       case PDFOBJ_REFERENCE: {
-        CPDF_Reference* pKid = (CPDF_Reference*)pKids;
+        CPDF_Reference* pKid = pKids->AsReference();
         CPDF_PageNode* pNode = new CPDF_PageNode();
         pPageNode->m_childNode.Add(pNode);
         pNode->m_dwPageNo = pKid->GetRefObjNum();
@@ -4149,13 +4130,13 @@ FX_BOOL CPDF_DataAvail::CheckUnkownPageNode(FX_DWORD dwPageNo,
       case PDFOBJ_ARRAY: {
         CPDF_Array* pKidsArray = pKids->AsArray();
         for (FX_DWORD i = 0; i < pKidsArray->GetCount(); ++i) {
-          CPDF_Object* pKid = (CPDF_Object*)pKidsArray->GetElement(i);
-          if (!pKid || pKid->GetType() != PDFOBJ_REFERENCE) {
+          CPDF_Reference* pKid = ToReference(pKidsArray->GetElement(i));
+          if (!pKid)
             continue;
-          }
+
           CPDF_PageNode* pNode = new CPDF_PageNode();
           pPageNode->m_childNode.Add(pNode);
-          pNode->m_dwPageNo = ((CPDF_Reference*)pKid)->GetRefObjNum();
+          pNode->m_dwPageNo = pKid->GetRefObjNum();
         }
       } break;
       default: