Merge to XFA: Support linearized loading

fpdfsdk/src/fpdf_dataavail.cpp

Index: fpdfsdk/src/fpdf_dataavail.cpp
diff --git a/fpdfsdk/src/fpdf_dataavail.cpp b/fpdfsdk/src/fpdf_dataavail.cpp
index 4d96a7ca262c7d2335e1f76a372464b194596a3f..b8eca303154a7220a415acf0a3e32929ed373d3a 100644
--- a/fpdfsdk/src/fpdf_dataavail.cpp
+++ b/fpdfsdk/src/fpdf_dataavail.cpp
@@ -90,10 +90,10 @@ DLLEXPORT void STDCALL FPDFAvail_Destroy(FPDF_AVAIL avail) {
   delete (CFPDF_DataAvail*)avail;
 }
 
-DLLEXPORT int STDCALL FPDFAvail_IsDocAvail(FPDF_AVAIL avail,
-                                           FX_DOWNLOADHINTS* hints) {
-  if (avail == NULL || hints == NULL)
-    return 0;
+DLLEXPORT int STDCALL
+FPDFAvail_IsDocAvail(FPDF_AVAIL avail, FX_DOWNLOADHINTS* hints) {
+  if (!avail || !hints)
+    return PDF_DATA_ERROR;
   CFPDF_DownloadHintsWrap hints_wrap(hints);
   return ((CFPDF_DataAvail*)avail)->m_pDataAvail->IsDocAvail(&hints_wrap);
 }
@@ -125,8 +125,8 @@ DLLEXPORT int STDCALL FPDFAvail_GetFirstPageNum(FPDF_DOCUMENT doc) {
 DLLEXPORT int STDCALL FPDFAvail_IsPageAvail(FPDF_AVAIL avail,
                                             int page_index,
                                             FX_DOWNLOADHINTS* hints) {
-  if (avail == NULL || hints == NULL)
-    return 0;
+  if (!avail || !hints)
+    return PDF_DATA_ERROR;
   CFPDF_DownloadHintsWrap hints_wrap(hints);
   return ((CFPDF_DataAvail*)avail)
       ->m_pDataAvail->IsPageAvail(page_index, &hints_wrap);
@@ -134,14 +134,14 @@ DLLEXPORT int STDCALL FPDFAvail_IsPageAvail(FPDF_AVAIL avail,
 
 DLLEXPORT int STDCALL FPDFAvail_IsFormAvail(FPDF_AVAIL avail,
                                             FX_DOWNLOADHINTS* hints) {
-  if (avail == NULL || hints == NULL)
-    return -1;
+  if (!avail || !hints)
+    return PDF_FORM_ERROR;
   CFPDF_DownloadHintsWrap hints_wrap(hints);
   return ((CFPDF_DataAvail*)avail)->m_pDataAvail->IsFormAvail(&hints_wrap);
 }
 
-DLLEXPORT FPDF_BOOL STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail) {
-  if (avail == NULL)
-    return -1;
+DLLEXPORT int STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail) {
+  if (!avail)
+    return PDF_LINEARIZATION_UNKNOWN;
   return ((CFPDF_DataAvail*)avail)->m_pDataAvail->IsLinearizedPDF();
 }