1 files changed, 155 insertions, 0 deletions
diff --git a/core/fpdfdoc/cpdf_structtree.cpp b/core/fpdfdoc/cpdf_structtree.cpp
new file mode 100644
index 0000000000..51ad2c775c
--- /dev/null
+++ b/core/fpdfdoc/cpdf_structtree.cpp
@@ -0,0 +1,155 @@
+// Copyright 2017 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 "core/fpdfdoc/cpdf_structtree.h"
+
+#include "core/fpdfapi/parser/cpdf_array.h"
+#include "core/fpdfapi/parser/cpdf_document.h"
+#include "core/fpdfapi/parser/cpdf_number.h"
+#include "core/fpdfapi/parser/cpdf_reference.h"
+#include "core/fpdfdoc/cpdf_numbertree.h"
+#include "core/fpdfdoc/cpdf_structelement.h"
+#include "third_party/base/stl_util.h"
+
+namespace {
+
+const int nMaxRecursion = 32;
+
+bool IsTagged(const CPDF_Document* pDoc) {
+  CPDF_Dictionary* pCatalog = pDoc->GetRoot();
+  CPDF_Dictionary* pMarkInfo = pCatalog->GetDictFor("MarkInfo");
+  return pMarkInfo && pMarkInfo->GetIntegerFor("Marked");
+}
+
+}  // namespace
+
+// static
+std::unique_ptr<CPDF_StructTree> CPDF_StructTree::LoadPage(
+    const CPDF_Document* pDoc,
+    const CPDF_Dictionary* pPageDict) {
+  if (!IsTagged(pDoc))
+    return nullptr;
+
+  auto pTree = pdfium::MakeUnique<CPDF_StructTree>(pDoc);
+  pTree->LoadPageTree(pPageDict);
+  return pTree;
+}
+
+CPDF_StructTree::CPDF_StructTree(const CPDF_Document* pDoc)
+    : m_pTreeRoot(pDoc->GetRoot()->GetDictFor("StructTreeRoot")),
+      m_pRoleMap(m_pTreeRoot ? m_pTreeRoot->GetDictFor("RoleMap") : nullptr),
+      m_pPage(nullptr) {}
+
+CPDF_StructTree::~CPDF_StructTree() {}
+
+int CPDF_StructTree::CountTopElements() const {
+  return pdfium::CollectionSize<int>(m_Kids);
+}
+
+CPDF_StructElement* CPDF_StructTree::GetTopElement(int i) const {
+  return m_Kids[i].Get();
+}
+
+void CPDF_StructTree::LoadPageTree(const CPDF_Dictionary* pPageDict) {
+  m_pPage = pPageDict;
+  if (!m_pTreeRoot)
+    return;
+
+  CPDF_Object* pKids = m_pTreeRoot->GetDirectObjectFor("K");
+  if (!pKids)
+    return;
+
+  uint32_t dwKids = 0;
+  if (pKids->IsDictionary())
+    dwKids = 1;
+  else if (CPDF_Array* pArray = pKids->AsArray())
+    dwKids = pArray->GetCount();
+  else
+    return;
+
+  m_Kids.clear();
+  m_Kids.resize(dwKids);
+  CPDF_Dictionary* pParentTree = m_pTreeRoot->GetDictFor("ParentTree");
+  if (!pParentTree)
+    return;
+
+  CPDF_NumberTree parent_tree(pParentTree);
+  int parents_id = pPageDict->GetIntegerFor("StructParents", -1);
+  if (parents_id < 0)
+    return;
+
+  CPDF_Array* pParentArray = ToArray(parent_tree.LookupValue(parents_id));
+  if (!pParentArray)
+    return;
+
+  std::map<CPDF_Dictionary*, CFX_RetainPtr<CPDF_StructElement>> element_map;
+  for (size_t i = 0; i < pParentArray->GetCount(); i++) {
+    if (CPDF_Dictionary* pParent = pParentArray->GetDictAt(i))
+      AddPageNode(pParent, &element_map);
+  }
+}
+
+CFX_RetainPtr<CPDF_StructElement> CPDF_StructTree::AddPageNode(
+    CPDF_Dictionary* pDict,
+    std::map<CPDF_Dictionary*, CFX_RetainPtr<CPDF_StructElement>>* map,
+    int nLevel) {
+  if (nLevel > nMaxRecursion)
+    return nullptr;
+
+  auto it = map->find(pDict);
+  if (it != map->end())
+    return it->second;
+
+  auto pElement = pdfium::MakeRetain<CPDF_StructElement>(this, nullptr, pDict);
+  (*map)[pDict] = pElement;
+  CPDF_Dictionary* pParent = pDict->GetDictFor("P");
+  if (!pParent || pParent->GetStringFor("Type") == "StructTreeRoot") {
+    if (!AddTopLevelNode(pDict, pElement))
+      map->erase(pDict);
+    return pElement;
+  }
+
+  CFX_RetainPtr<CPDF_StructElement> pParentElement =
+      AddPageNode(pParent, map, nLevel + 1);
+  bool bSave = false;
+  for (CPDF_StructKid& kid : *pParentElement->GetKids()) {
+    if (kid.m_Type == CPDF_StructKid::Element && kid.m_pDict == pDict) {
+      kid.m_pElement = pElement;
+      bSave = true;
+    }
+  }
+  if (!bSave)
+    map->erase(pDict);
+  return pElement;
+}
+
+bool CPDF_StructTree::AddTopLevelNode(
+    CPDF_Dictionary* pDict,
+    const CFX_RetainPtr<CPDF_StructElement>& pElement) {
+  CPDF_Object* pObj = m_pTreeRoot->GetDirectObjectFor("K");
+  if (!pObj)
+    return false;
+
+  if (pObj->IsDictionary()) {
+    if (pObj->GetObjNum() != pDict->GetObjNum())
+      return false;
+    m_Kids[0] = pElement;
+  }
+
+  CPDF_Array* pTopKids = pObj->AsArray();
+  if (!pTopKids)
+    return true;
+
+  bool bSave = false;
+  for (size_t i = 0; i < pTopKids->GetCount(); i++) {
+    CPDF_Reference* pKidRef = ToReference(pTopKids->GetObjectAt(i));
+    if (pKidRef && pKidRef->GetRefObjNum() == pDict->GetObjNum()) {
+      m_Kids[i] = pElement;
+      bSave = true;
+    }
+  }
+  return bSave;
+}