Handle overlapping links and widgets.

core/src/fpdfdoc/doc_form.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../include/fpdfdoc/fpdf_doc.h"
 #include "../../include/fxcrt/fx_xml.h"
 CFX_WideString  GetFullName(CPDF_Dictionary* pFieldDict);
 void                    InitInterFormDict(CPDF_Dictionary*& pFormDict, CPDF_Document* pDocument);
@@ skipping 885 matching lines @@
     if (pAnnotList == NULL) {
         return NULL;
     }
     for (FX_DWORD i = pAnnotList->GetCount(); i > 0; i --) {
         CPDF_Dictionary* pAnnot = pAnnotList->GetDict(i - 1);
         if (pAnnot == NULL) {
             continue;
         }
         CPDF_FormControl* pControl;
         if (!m_ControlMap.Lookup(pAnnot, (FX_LPVOID&)pControl)) {
+            // If there is a link that overlaps the widget, return NULL.
+            if (pAnnot->GetString("Subtype") == "Link") {
+                CPDF_Link link(pAnnot);
+                CPDF_Rect link_rect = link.GetRect();
+                if (link_rect.Contains(pdf_x, pdf_y)) {
+                    return NULL;
+                }
+            }
             continue;
         }
         CFX_FloatRect rect = pControl->GetRect();
         if (rect.Contains(pdf_x, pdf_y)) {
             return pControl;
         }
     }
     return NULL;
 }
 CPDF_FormControl* CPDF_InterForm::GetControlByDict(CPDF_Dictionary* pWidgetDict) const
@@ skipping 739 matching lines @@
                 continue;
             }
             CPDF_FormControl* pControl = NULL;
             if (m_ControlMap.Lookup(pAnnotDict, (void*&)pControl)) {
                 return iNewPage;
             }
         }
     } while (TRUE);
     return -1;
 }