Call FPDFAvail_IsFormAvail() before creating form.

pdf/pdfium/pdfium_engine.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 2579 matching lines @@
     return;
   }
 
   if (FPDFDoc_GetPageMode(doc_) == PAGEMODE_USEOUTLINES)
     client_->DocumentHasUnsupportedFeature("Bookmarks");
 
   permissions_ = FPDF_GetDocPermissions(doc_);
   permissions_handler_revision_ = FPDF_GetSecurityHandlerRevision(doc_);
 
   if (!form_) {
-    // Only returns 0 when data isn't available.  If form data is downloaded, or
-    // if this isn't a form, returns positive values.
-    if (!doc_loader_.IsDocumentComplete() &&
-        !FPDFAvail_IsFormAvail(fpdf_availability_, &download_hints_)) {
+    int form_status =
+        FPDFAvail_IsFormAvail(fpdf_availability_, &download_hints_);
+    bool doc_complete = doc_loader_.IsDocumentComplete();
+    // Try again if the data is not available and the document hasn't finished
+    // downloading.
+    if (form_status == PDF_FORM_NOTAVAIL && !doc_complete)
       return;
-    }
 
     form_ = FPDFDOC_InitFormFillEnvironment(
         doc_, static_cast<FPDF_FORMFILLINFO*>(this));
 #ifdef PDF_USE_XFA
     FPDF_LoadXFA(doc_);
 #endif
 
     FPDF_SetFormFieldHighlightColor(form_, 0, kFormHighlightColor);
     FPDF_SetFormFieldHighlightAlpha(form_, kFormHighlightAlpha);
   }
@@ skipping 1383 matching lines @@
     double* height) {
   FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf