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1 // Copyright 2016 PDFium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
6 
7 #include "core/fpdfapi/parser/cpdf_indirect_object_holder.h"
8 
9 #include <algorithm>
10 #include <utility>
11 
12 #include "core/fpdfapi/parser/cpdf_object.h"
13 #include "core/fpdfapi/parser/cpdf_parser.h"
14 #include "third_party/base/logging.h"
15 
CPDF_IndirectObjectHolder()16 CPDF_IndirectObjectHolder::CPDF_IndirectObjectHolder()
17     : m_LastObjNum(0),
18       m_pByteStringPool(pdfium::MakeUnique<CFX_ByteStringPool>()) {}
19 
~CPDF_IndirectObjectHolder()20 CPDF_IndirectObjectHolder::~CPDF_IndirectObjectHolder() {
21   m_pByteStringPool.DeleteObject();  // Make weak.
22 }
23 
GetIndirectObject(uint32_t objnum) const24 CPDF_Object* CPDF_IndirectObjectHolder::GetIndirectObject(
25     uint32_t objnum) const {
26   auto it = m_IndirectObjs.find(objnum);
27   return it != m_IndirectObjs.end() ? it->second.get() : nullptr;
28 }
29 
GetOrParseIndirectObject(uint32_t objnum)30 CPDF_Object* CPDF_IndirectObjectHolder::GetOrParseIndirectObject(
31     uint32_t objnum) {
32   if (objnum == 0)
33     return nullptr;
34 
35   CPDF_Object* pObj = GetIndirectObject(objnum);
36   if (pObj)
37     return pObj->GetObjNum() != CPDF_Object::kInvalidObjNum ? pObj : nullptr;
38 
39   std::unique_ptr<CPDF_Object> pNewObj = ParseIndirectObject(objnum);
40   if (!pNewObj)
41     return nullptr;
42 
43   pNewObj->m_ObjNum = objnum;
44   m_LastObjNum = std::max(m_LastObjNum, objnum);
45   m_IndirectObjs[objnum] = std::move(pNewObj);
46   return m_IndirectObjs[objnum].get();
47 }
48 
ParseIndirectObject(uint32_t objnum)49 std::unique_ptr<CPDF_Object> CPDF_IndirectObjectHolder::ParseIndirectObject(
50     uint32_t objnum) {
51   return nullptr;
52 }
53 
AddIndirectObject(std::unique_ptr<CPDF_Object> pObj)54 CPDF_Object* CPDF_IndirectObjectHolder::AddIndirectObject(
55     std::unique_ptr<CPDF_Object> pObj) {
56   CHECK(!pObj->m_ObjNum);
57   CPDF_Object* pUnowned = pObj.get();
58   pObj->m_ObjNum = ++m_LastObjNum;
59   if (m_IndirectObjs[m_LastObjNum])
60     m_OrphanObjs.push_back(std::move(m_IndirectObjs[m_LastObjNum]));
61 
62   m_IndirectObjs[m_LastObjNum] = std::move(pObj);
63   return pUnowned;
64 }
65 
ReplaceIndirectObjectIfHigherGeneration(uint32_t objnum,std::unique_ptr<CPDF_Object> pObj)66 bool CPDF_IndirectObjectHolder::ReplaceIndirectObjectIfHigherGeneration(
67     uint32_t objnum,
68     std::unique_ptr<CPDF_Object> pObj) {
69   ASSERT(objnum);
70   if (!pObj)
71     return false;
72 
73   CPDF_Object* pOldObj = GetIndirectObject(objnum);
74   if (pOldObj && pObj->GetGenNum() <= pOldObj->GetGenNum())
75     return false;
76 
77   pObj->m_ObjNum = objnum;
78   m_IndirectObjs[objnum] = std::move(pObj);
79   m_LastObjNum = std::max(m_LastObjNum, objnum);
80   return true;
81 }
82 
DeleteIndirectObject(uint32_t objnum)83 void CPDF_IndirectObjectHolder::DeleteIndirectObject(uint32_t objnum) {
84   CPDF_Object* pObj = GetIndirectObject(objnum);
85   if (!pObj || pObj->GetObjNum() == CPDF_Object::kInvalidObjNum)
86     return;
87 
88   m_IndirectObjs.erase(objnum);
89 }
90