Make conversion between CPDF_Dest and its object explicit.

Precursor to taking a second shot at cleaning up the FPDF_*
APIs.  A FPDF_Dest is a CPDF_Array, and a CPDF_Dest
is a structure holding a FPDF_Dest.  This goes against the
convention that FPDF_ types get cast to CPDF_* types, so we
want to make it clear where objects are getting constructed,
etc.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/984703004

6 files changed, 35 insertions, 41 deletions

diff --git a/core/include/fpdfdoc/fpdf_doc.h b/core/include/fpdfdoc/fpdf_doc.h
index dbcc7f433e..dac215e711 100644
--- a/core/include/fpdfdoc/fpdf_doc.h
+++ b/core/include/fpdfdoc/fpdf_doc.h
@@ -124,28 +124,19 @@ public:
 class CPDF_Dest : public CFX_Object
 {
 public:
+    CPDF_Dest() : m_pObj(nullptr) { }
+    explicit CPDF_Dest(CPDF_Object* pObj) : m_pObj(pObj) { }
 
-    CPDF_Dest(CPDF_Object* pObj = NULL)
-    {
-        m_pObj = pObj;
-    }
-
-    operator CPDF_Object* () const
-    {
-        return m_pObj;
-    }
+    operator bool () const { return m_pObj != NULL; }
+    CPDF_Object* GetObject() const { return m_pObj; }
 
     CFX_ByteString		GetRemoteName();
-
     int					GetPageIndex(CPDF_Document* pDoc);
-
     FX_DWORD			GetPageObjNum();
-
     int					GetZoomMode();
-
     FX_FLOAT			GetParam(int index);
 
-
+protected:
     CPDF_Object*		m_pObj;
 };
 class CPDF_OCContext : public CFX_Object, public IPDF_OCContext
diff --git a/core/src/fpdfdoc/doc_action.cpp b/core/src/fpdfdoc/doc_action.cpp
index 324153563a..ac40335a4c 100644
--- a/core/src/fpdfdoc/doc_action.cpp
+++ b/core/src/fpdfdoc/doc_action.cpp
@@ -7,25 +7,26 @@
 #include "../../include/fpdfdoc/fpdf_doc.h"
 CPDF_Dest CPDF_Action::GetDest(CPDF_Document* pDoc) const
 {
-    if (m_pDict == NULL) {
-        return NULL;
+    if (!m_pDict) {
+        return CPDF_Dest();
     }
     CFX_ByteString type = m_pDict->GetString("S");
     if (type != "GoTo" && type != "GoToR") {
-        return NULL;
+        return CPDF_Dest();
     }
     CPDF_Object* pDest = m_pDict->GetElementValue("D");
-    if (pDest == NULL) {
-        return NULL;
+    if (!pDest) {
+        return CPDF_Dest();
     }
     if (pDest->GetType() == PDFOBJ_STRING || pDest->GetType() == PDFOBJ_NAME) {
         CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
         CFX_ByteStringC name = pDest->GetString();
-        return name_tree.LookupNamedDest(pDoc, name);
-    } else if (pDest->GetType() == PDFOBJ_ARRAY) {
-        return (CPDF_Array*)pDest;
+        return CPDF_Dest(name_tree.LookupNamedDest(pDoc, name));
     }
-    return NULL;
+    if (pDest->GetType() == PDFOBJ_ARRAY) {
+        return CPDF_Dest((CPDF_Array*)pDest);
+    }
+    return CPDF_Dest();
 }
 const FX_CHAR* g_sATypes[] = {"Unknown", "GoTo", "GoToR", "GoToE", "Launch", "Thread", "URI", "Sound", "Movie",
                               "Hide",	"Named", "SubmitForm", "ResetForm", "ImportData", "JavaScript", "SetOCGState",
diff --git a/core/src/fpdfdoc/doc_bookmark.cpp b/core/src/fpdfdoc/doc_bookmark.cpp
index a3a194337e..9814de61bf 100644
--- a/core/src/fpdfdoc/doc_bookmark.cpp
+++ b/core/src/fpdfdoc/doc_bookmark.cpp
@@ -68,20 +68,21 @@ CFX_WideString CPDF_Bookmark::GetTitle() const
 CPDF_Dest CPDF_Bookmark::GetDest(CPDF_Document* pDocument) const
 {
     if (!m_pDict) {
-        return NULL;
+        return CPDF_Dest();
     }
     CPDF_Object* pDest = m_pDict->GetElementValue("Dest");
     if (!pDest) {
-        return NULL;
+        return CPDF_Dest();
     }
     if (pDest->GetType() == PDFOBJ_STRING || pDest->GetType() == PDFOBJ_NAME) {
         CPDF_NameTree name_tree(pDocument, FX_BSTRC("Dests"));
         CFX_ByteStringC name = pDest->GetString();
-        return name_tree.LookupNamedDest(pDocument, name);
-    } else if (pDest->GetType() == PDFOBJ_ARRAY) {
-        return (CPDF_Array*)pDest;
+        return CPDF_Dest(name_tree.LookupNamedDest(pDocument, name));
     }
-    return NULL;
+    if (pDest->GetType() == PDFOBJ_ARRAY) {
+        return CPDF_Dest((CPDF_Array*)pDest);
+    }
+    return CPDF_Dest();
 }
 CPDF_Action CPDF_Bookmark::GetAction() const
 {
diff --git a/core/src/fpdfdoc/doc_link.cpp b/core/src/fpdfdoc/doc_link.cpp
index e7b6be5ca4..b7c640af5e 100644
--- a/core/src/fpdfdoc/doc_link.cpp
+++ b/core/src/fpdfdoc/doc_link.cpp
@@ -90,16 +90,17 @@ CPDF_Dest CPDF_Link::GetDest(CPDF_Document* pDoc)
 {
     CPDF_Object* pDest = m_pDict->GetElementValue("Dest");
     if (pDest == NULL) {
-        return NULL;
+        return CPDF_Dest();
     }
     if (pDest->GetType() == PDFOBJ_STRING || pDest->GetType() == PDFOBJ_NAME) {
         CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
         CFX_ByteStringC name = pDest->GetString();
-        return name_tree.LookupNamedDest(pDoc, name);
-    } else if (pDest->GetType() == PDFOBJ_ARRAY) {
-        return (CPDF_Array*)pDest;
+        return CPDF_Dest(name_tree.LookupNamedDest(pDoc, name));
     }
-    return NULL;
+    if (pDest->GetType() == PDFOBJ_ARRAY) {
+        return CPDF_Dest((CPDF_Array*)pDest);
+    }
+    return CPDF_Dest();
 }
 CPDF_Action CPDF_Link::GetAction()
 {
diff --git a/fpdfsdk/src/fpdfdoc.cpp b/fpdfsdk/src/fpdfdoc.cpp
index f21d5cf938..ab3dd2c5b8 100644
--- a/fpdfsdk/src/fpdfdoc.cpp
+++ b/fpdfsdk/src/fpdfdoc.cpp
@@ -84,12 +84,12 @@ DLLEXPORT FPDF_DEST STDCALL FPDFBookmark_GetDest(FPDF_DOCUMENT document, FPDF_BO
 	CPDF_Document* pDoc = (CPDF_Document*)document;
 	CPDF_Dest dest = bookmark.GetDest(pDoc);
 	if (dest)
-		return dest;
+		return dest.GetObject();
 	// If this bookmark is not directly associated with a dest, we try to get action
 	CPDF_Action action = bookmark.GetAction();
 	if (!action)
 		return NULL;
-	return action.GetDest(pDoc);
+	return action.GetDest(pDoc).GetObject();
 }
 
 DLLEXPORT FPDF_ACTION STDCALL FPDFBookmark_GetAction(FPDF_BOOKMARK pDict)
@@ -129,7 +129,7 @@ DLLEXPORT FPDF_DEST STDCALL FPDFAction_GetDest(FPDF_DOCUMENT document, FPDF_ACTI
 		return NULL;
 	CPDF_Document* pDoc = (CPDF_Document*)document;
 	CPDF_Action action((CPDF_Dictionary*)pDict);
-	return action.GetDest(pDoc);
+	return action.GetDest(pDoc).GetObject();
 }
 
 DLLEXPORT unsigned long STDCALL FPDFAction_GetURIPath(FPDF_DOCUMENT document, FPDF_ACTION pDict,
@@ -155,7 +155,7 @@ DLLEXPORT unsigned long STDCALL FPDFDest_GetPageIndex(FPDF_DOCUMENT document, FP
 	if (!pDict)
 		return 0;
 	CPDF_Document* pDoc = (CPDF_Document*)document;
-	CPDF_Dest dest = (CPDF_Array*)pDict;
+	CPDF_Dest dest((CPDF_Array*)pDict);
 	return dest.GetPageIndex(pDoc);
 }
 
@@ -188,14 +188,14 @@ DLLEXPORT FPDF_DEST STDCALL FPDFLink_GetDest(FPDF_DOCUMENT document, FPDF_LINK p
 		return NULL;
 	CPDF_Link link = (CPDF_Dictionary*)pDict;
 
-	FPDF_DEST dest = link.GetDest(pDoc);
+	FPDF_DEST dest = link.GetDest(pDoc).GetObject();
 	if (dest)
 		return dest;
 	// If this link is not directly associated with a dest, we try to get action
 	CPDF_Action action = link.GetAction();
 	if (!action)
 		return NULL;
-	return action.GetDest(pDoc);
+	return action.GetDest(pDoc).GetObject();
 }
 
 DLLEXPORT FPDF_ACTION STDCALL FPDFLink_GetAction(FPDF_LINK pDict)
diff --git a/fpdfsdk/src/fsdk_actionhandler.cpp b/fpdfsdk/src/fsdk_actionhandler.cpp
index e3fdad393d..fb8bcb2cb7 100644
--- a/fpdfsdk/src/fsdk_actionhandler.cpp
+++ b/fpdfsdk/src/fsdk_actionhandler.cpp
@@ -564,7 +564,7 @@ void CPDFSDK_ActionHandler::DoAction_GoTo(CPDFSDK_Document* pDocument,
 	CPDF_Dest MyDest = action.GetDest(pPDFDocument);
 	int nPageIndex = MyDest.GetPageIndex(pPDFDocument);
 	int nFitType = MyDest.GetZoomMode();
-	const CPDF_Array * pMyArray = (CPDF_Array*)MyDest.m_pObj;
+	const CPDF_Array * pMyArray = (CPDF_Array*)MyDest.GetObject();
 	float* pPosAry = NULL;
 	int sizeOfAry = 0;
 	if (pMyArray != NULL)