Fix memory leaks involving InsertIndirectObject()

core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp

Index: core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
index 752a09d83d9672e7c35541b452451910700eea6c..10bd3118fbf9daed6ef8b3b736b613546389645f 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
@@ -1156,25 +1156,26 @@ void CPDF_IndirectObjects::ReleaseIndirectObject(FX_DWORD objnum) {
   pValue->Destroy();
   m_IndirectObjs.RemoveKey((void*)(uintptr_t)objnum);
 }
-void CPDF_IndirectObjects::InsertIndirectObject(FX_DWORD objnum,
-                                                CPDF_Object* pObj) {
-  if (objnum == 0 || pObj == NULL) {
-    return;
-  }
-  void* value = NULL;
+FX_BOOL CPDF_IndirectObjects::InsertIndirectObject(FX_DWORD objnum,
+                                                   CPDF_Object* pObj) {
+  if (!objnum || !pObj)
+    return FALSE;
+  void* value = nullptr;
   if (m_IndirectObjs.Lookup((void*)(uintptr_t)objnum, value)) {
     if (value) {
       CPDF_Object* pValue = static_cast<CPDF_Object*>(value);
-      if (pObj->GetGenNum() <= pValue->GetGenNum())
-        return;
+      if (pObj->GetGenNum() <= pValue->GetGenNum()) {

[jun_fang, 2015/12/10 16:02:40]

The current object is older than the one in m_IndirectObjs. Don't insert but
release it.

[Tom Sepez, 2015/12/10 17:32:13]

nit: You mean younger?  It might be clearer if pValue were name pExistingObj or
somthing. Then pObj->GetGenNum() <= pExistingObj->GetGenNum() clearly reads as
"pObj younger".

[Lei Zhang, 2015/12/10 18:57:05]

I think Jun is saying old vs new, whereas you are thinking of young vs old.

[jun_fang, 2015/12/10 23:55:58]

A non-negative integer generation number. In a newly created file, 
all indirect objects shall have generation numbers of 0. Nonzero 
generation numbers may be introduced when the file is later updated; 

+        pObj->Destroy();
+        return FALSE;
+      }
       pValue->Destroy();

[jun_fang, 2015/12/10 16:02:39]

We need to destroy the older one before inserting the newer version of object.

     }
   }
   pObj->m_ObjNum = objnum;
   m_IndirectObjs.SetAt((void*)(uintptr_t)objnum, pObj);
-  if (m_LastObjNum < objnum) {
+  if (m_LastObjNum < objnum)
     m_LastObjNum = objnum;
-  }
+  return TRUE;
 }
 FX_DWORD CPDF_IndirectObjects::GetLastObjNum() const {
   return m_LastObjNum;