Introduce CPDF_Document::FromFPDFDocument().

fpdfsdk/src/fpdfview.cpp

Index: fpdfsdk/src/fpdfview.cpp
diff --git a/fpdfsdk/src/fpdfview.cpp b/fpdfsdk/src/fpdfview.cpp
index 84dabe68647a7cc77d357547237ee8773922ddc9..a1d84732af21585ff6c75f206ffdb5b4eeb9e01e 100644
--- a/fpdfsdk/src/fpdfview.cpp
+++ b/fpdfsdk/src/fpdfview.cpp
@@ -218,13 +218,18 @@ FPDF_LoadCustomDocument(FPDF_FILEACCESS* pFileAccess,
 
 DLLEXPORT FPDF_BOOL STDCALL FPDF_GetFileVersion(FPDF_DOCUMENT doc,
                                                 int* fileVersion) {
-  if (!doc || !fileVersion)
+  if (!fileVersion)
     return FALSE;
+
   *fileVersion = 0;
-  CPDF_Document* pDoc = (CPDF_Document*)doc;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(doc);
+  if (!pDoc)
+    return FALSE;
+
   CPDF_Parser* pParser = (CPDF_Parser*)pDoc->GetParser();
   if (!pParser)
     return FALSE;
+
   *fileVersion = pParser->GetFileVersion();
   return TRUE;
 }
@@ -232,45 +237,39 @@ DLLEXPORT FPDF_BOOL STDCALL FPDF_GetFileVersion(FPDF_DOCUMENT doc,
 // jabdelmalek: changed return type from FX_DWORD to build on Linux (and match
 // header).
 DLLEXPORT unsigned long STDCALL FPDF_GetDocPermissions(FPDF_DOCUMENT document) {
-  if (document == NULL)
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
     return 0;
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+
   CPDF_Parser* pParser = (CPDF_Parser*)pDoc->GetParser();
   CPDF_Dictionary* pDict = pParser->GetEncryptDict();
-  if (pDict == NULL)
-    return (FX_DWORD)-1;
-
-  return pDict->GetInteger("P");
+  return pDict ? pDict->GetInteger("P") : (FX_DWORD)-1;
 }
 
 DLLEXPORT int STDCALL FPDF_GetSecurityHandlerRevision(FPDF_DOCUMENT document) {
-  if (document == NULL)
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
     return -1;
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+
   CPDF_Parser* pParser = (CPDF_Parser*)pDoc->GetParser();
   CPDF_Dictionary* pDict = pParser->GetEncryptDict();
-  if (pDict == NULL)
-    return -1;
-
-  return pDict->GetInteger("R");
+  return pDict ? pDict->GetInteger("R") : -1;
 }
 
 DLLEXPORT int STDCALL FPDF_GetPageCount(FPDF_DOCUMENT document) {
-  if (document == NULL)
-    return 0;
-  return ((CPDF_Document*)document)->GetPageCount();
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  return pDoc ? pDoc->GetPageCount() : 0;
 }
 
 DLLEXPORT FPDF_PAGE STDCALL FPDF_LoadPage(FPDF_DOCUMENT document,
                                           int page_index) {
-  if (document == NULL)
-    return NULL;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
+
   if (page_index < 0 || page_index >= FPDF_GetPageCount(document))
-    return NULL;
+    return nullptr;
 
-  CPDF_Document* pDoc = (CPDF_Document*)document;
-  if (pDoc == NULL)
-    return NULL;
   CPDF_Dictionary* pDict = pDoc->GetPage(page_index);
   if (pDict == NULL)
     return NULL;
@@ -513,11 +512,12 @@ DLLEXPORT void STDCALL FPDF_ClosePage(FPDF_PAGE page) {
 }
 
 DLLEXPORT void STDCALL FPDF_CloseDocument(FPDF_DOCUMENT document) {
-  if (!document)
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
     return;
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+
   CPDF_Parser* pParser = (CPDF_Parser*)pDoc->GetParser();
-  if (pParser == NULL) {
+  if (!pParser) {
     delete pDoc;
     return;
   }
@@ -745,12 +745,12 @@ DLLEXPORT int STDCALL FPDF_GetPageSizeByIndex(FPDF_DOCUMENT document,
                                               int page_index,
                                               double* width,
                                               double* height) {
-  CPDF_Document* pDoc = (CPDF_Document*)document;
-  if (pDoc == NULL)
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
     return FALSE;
 
   CPDF_Dictionary* pDict = pDoc->GetPage(page_index);
-  if (pDict == NULL)
+  if (!pDict)
     return FALSE;
 
   CPDF_Page page;
@@ -763,7 +763,7 @@ DLLEXPORT int STDCALL FPDF_GetPageSizeByIndex(FPDF_DOCUMENT document,
 
 DLLEXPORT FPDF_BOOL STDCALL
 FPDF_VIEWERREF_GetPrintScaling(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
   if (!pDoc)
     return TRUE;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -771,7 +771,7 @@ FPDF_VIEWERREF_GetPrintScaling(FPDF_DOCUMENT document) {
 }
 
 DLLEXPORT int STDCALL FPDF_VIEWERREF_GetNumCopies(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
   if (!pDoc)
     return 1;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -780,7 +780,7 @@ DLLEXPORT int STDCALL FPDF_VIEWERREF_GetNumCopies(FPDF_DOCUMENT document) {
 
 DLLEXPORT FPDF_PAGERANGE STDCALL
 FPDF_VIEWERREF_GetPrintPageRange(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
   if (!pDoc)
     return NULL;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -789,7 +789,7 @@ FPDF_VIEWERREF_GetPrintPageRange(FPDF_DOCUMENT document) {
 
 DLLEXPORT FPDF_DUPLEXTYPE STDCALL
 FPDF_VIEWERREF_GetDuplex(FPDF_DOCUMENT document) {
-  CPDF_Document* pDoc = (CPDF_Document*)document;
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
   if (!pDoc)
     return DuplexUndefined;
   CPDF_ViewerPreferences viewRef(pDoc);
@@ -804,9 +804,9 @@ FPDF_VIEWERREF_GetDuplex(FPDF_DOCUMENT document) {
 }
 
 DLLEXPORT FPDF_DWORD STDCALL FPDF_CountNamedDests(FPDF_DOCUMENT document) {
-  if (!document)
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
     return 0;
-  CPDF_Document* pDoc = (CPDF_Document*)document;
 
   CPDF_Dictionary* pRoot = pDoc->GetRoot();
   if (!pRoot)
@@ -822,12 +822,13 @@ DLLEXPORT FPDF_DWORD STDCALL FPDF_CountNamedDests(FPDF_DOCUMENT document) {
 
 DLLEXPORT FPDF_DEST STDCALL FPDF_GetNamedDestByName(FPDF_DOCUMENT document,
                                                     FPDF_BYTESTRING name) {
-  if (!document)
-    return NULL;
   if (!name || name[0] == 0)
-    return NULL;
+    return nullptr;
+
+  CPDF_Document* pDoc = CPDF_Document::FromFPDFDocument(document);
+  if (!pDoc)
+    return nullptr;
 
-  CPDF_Document* pDoc = (CPDF_Document*)document;
   CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
   return name_tree.LookupNamedDest(pDoc, name);
 }