Fix a bug when assign the generation number of indirect objects

core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.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/fpdfapi/fpdf_parser.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fpdfapi/fpdf_page.h"
 #include "../../../../third_party/numerics/safe_math.h"
@@ skipping 1363 matching lines @@
     FX_DWORD real_objnum = FXSYS_atoi(word);
     if (objnum && real_objnum != objnum) {
         m_Syntax.RestorePos(SavedPos);
         return NULL;
     }
     word = m_Syntax.GetNextWord(bIsNumber);
     if (!bIsNumber) {
         m_Syntax.RestorePos(SavedPos);
         return NULL;
     }
     FX_DWORD gennum = FXSYS_atoi(word);

[Tom Sepez, 2014/08/29 17:28:01]

nit: I'd call this real_gennum for parallelism with the real_objnum derived from
the parser above.  I found it confusing that objnum was a paramenter,
real_objnum was returned from the parser, but gennum wasn't a paramenter but was
returned from the parser, eh?

If you wanted to be really clear, I might get rid of the real_ prefix (what does
that mean, really) and call it parser_objnum or objnum_from_parser.

Your call on what to do here.  Thanks for listening.

[Bo Xu, 2014/09/19 21:48:19]

I feel parser_objnum is better.

     if (m_Syntax.GetKeyword() != FX_BSTRC("obj")) {
         m_Syntax.RestorePos(SavedPos);
         return NULL;
     }
     CPDF_Object* pObj = m_Syntax.GetObject(pObjList, objnum, gennum, 0, pContext);
     FX_FILESIZE endOffset = m_Syntax.SavePos();
     CFX_ByteString bsWord = m_Syntax.GetKeyword();
     if (bsWord == FX_BSTRC("endobj")) {
         endOffset = m_Syntax.SavePos();
     }
     m_Syntax.RestorePos(SavedPos);
-    if (pObj && !objnum) {
+    if(pObj) {

[Bo Xu, 2014/08/29 03:09:27]

Here when objnum >1, real_objnum must equal objnum here, so no need to check
!objnum.

[Tom Sepez, 2014/08/29 17:28:01]

yes, I think you want this block to read

if (pObj) {
    if (!objnum)
        pObj->m_ObjNum = real_objnum;
    pObj->m_GenNum = gennum

[Bo Xu, 2014/09/19 21:48:19]

Done.

         pObj->m_ObjNum = real_objnum;
         pObj->m_GenNum = gennum;
     }
     return pObj;
 }
 CPDF_Object* CPDF_Parser::ParseIndirectObjectAtByStrict(CPDF_IndirectObjects* pObjList, FX_FILESIZE pos, FX_DWORD objnum,
         struct PARSE_CONTEXT* pContext, FX_FILESIZE *pResultPos)
 {
     FX_FILESIZE SavedPos = m_Syntax.SavePos();
     m_Syntax.RestorePos(pos);
@@ skipping 3018 matching lines @@
 {
     FX_INT32 iSize = m_childNode.GetSize();
     for (FX_INT32 i = 0; i < iSize; ++i) {
         CPDF_PageNode *pNode = (CPDF_PageNode*)m_childNode[i];
         if (pNode) {
             delete pNode;
         }
     }
     m_childNode.RemoveAll();
 }