core/fpdfdoc/cpdf_structelement.cpp

// 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_structelement.h"

#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_dictionary.h"
#include "core/fpdfapi/parser/cpdf_name.h"
#include "core/fpdfapi/parser/cpdf_number.h"
#include "core/fpdfapi/parser/cpdf_object.h"
#include "core/fpdfapi/parser/cpdf_reference.h"
#include "core/fpdfapi/parser/cpdf_stream.h"
#include "core/fpdfdoc/cpdf_structtree.h"
#include "third_party/base/stl_util.h"

namespace {

const int nMaxRecursion = 32;

CPDF_Dictionary* FindAttrDict(CPDF_Object* pAttrs,
                              const CFX_ByteStringC& owner,
                              float nLevel = 0.0F) {
  if (nLevel > nMaxRecursion)
    return nullptr;
  if (!pAttrs)
    return nullptr;

  CPDF_Dictionary* pDict = nullptr;
  if (pAttrs->IsDictionary()) {
    pDict = pAttrs->AsDictionary();
  } else if (CPDF_Stream* pStream = pAttrs->AsStream()) {
    pDict = pStream->GetDict();
  } else if (CPDF_Array* pArray = pAttrs->AsArray()) {
    for (uint32_t i = 0; i < pArray->GetCount(); i++) {
      CPDF_Object* pElement = pArray->GetDirectObjectAt(i);
      pDict = FindAttrDict(pElement, owner, nLevel + 1);
      if (pDict)
        return pDict;
    }
  }
  if (pDict && pDict->GetStringFor("O") == owner)
    return pDict;
  return nullptr;
}

}  // namespace

CPDF_StructKid::CPDF_StructKid()
    : m_Type(Invalid),
      m_pDict(nullptr),
      m_PageObjNum(0),
      m_RefObjNum(0),
      m_ContentId(0) {}

CPDF_StructKid::CPDF_StructKid(const CPDF_StructKid& that) = default;

CPDF_StructKid::~CPDF_StructKid() = default;

CPDF_StructElement::CPDF_StructElement(CPDF_StructTree* pTree,
                                       CPDF_StructElement* pParent,
                                       CPDF_Dictionary* pDict)
    : m_pTree(pTree),
      m_pParent(pParent),
      m_pDict(pDict),
      m_Type(pDict->GetStringFor("S")) {
  if (pTree->GetRoleMap()) {
    CFX_ByteString mapped = pTree->GetRoleMap()->GetStringFor(m_Type);
    if (!mapped.IsEmpty())
      m_Type = mapped;
  }
  LoadKids(pDict);
}

CPDF_StructElement::~CPDF_StructElement() = default;

int CPDF_StructElement::CountKids() const {
  return pdfium::CollectionSize<int>(m_Kids);
}

CPDF_StructElement* CPDF_StructElement::GetKidIfElement(int index) const {
  return m_Kids[index].m_Type == CPDF_StructKid::Element
             ? m_Kids[index].m_pElement.Get()
             : nullptr;
}

void CPDF_StructElement::LoadKids(CPDF_Dictionary* pDict) {
  CPDF_Object* pObj = pDict->GetObjectFor("Pg");
  uint32_t PageObjNum = 0;
  if (CPDF_Reference* pRef = ToReference(pObj))
    PageObjNum = pRef->GetRefObjNum();

  CPDF_Object* pKids = pDict->GetDirectObjectFor("K");
  if (!pKids)
    return;

  m_Kids.clear();
  if (CPDF_Array* pArray = pKids->AsArray()) {
    m_Kids.resize(pArray->GetCount());
    for (uint32_t i = 0; i < pArray->GetCount(); i++) {
      CPDF_Object* pKid = pArray->GetDirectObjectAt(i);
      LoadKid(PageObjNum, pKid, &m_Kids[i]);
    }
    return;
  }

  m_Kids.resize(1);
  LoadKid(PageObjNum, pKids, &m_Kids[0]);
}

void CPDF_StructElement::LoadKid(uint32_t PageObjNum,
                                 CPDF_Object* pKidObj,
                                 CPDF_StructKid* pKid) {
  pKid->m_Type = CPDF_StructKid::Invalid;
  if (!pKidObj)
    return;

  if (pKidObj->IsNumber()) {
    if (m_pTree->GetPage() && m_pTree->GetPage()->GetObjNum() != PageObjNum)
      return;

    pKid->m_Type = CPDF_StructKid::PageContent;
    pKid->m_ContentId = pKidObj->GetInteger();
    pKid->m_PageObjNum = PageObjNum;
    return;
  }

  CPDF_Dictionary* pKidDict = pKidObj->AsDictionary();
  if (!pKidDict)
    return;
  if (CPDF_Reference* pRef = ToReference(pKidDict->GetObjectFor("Pg")))
    PageObjNum = pRef->GetRefObjNum();

  CFX_ByteString type = pKidDict->GetStringFor("Type");
  if ((type == "MCR" || type == "OBJR") && m_pTree->GetPage() &&
      m_pTree->GetPage()->GetObjNum() != PageObjNum) {
    return;
  }

  if (type == "MCR") {
    pKid->m_Type = CPDF_StructKid::StreamContent;
    CPDF_Reference* pRef = ToReference(pKidDict->GetObjectFor("Stm"));
    pKid->m_RefObjNum = pRef ? pRef->GetRefObjNum() : 0;
    pKid->m_PageObjNum = PageObjNum;
    pKid->m_ContentId = pKidDict->GetIntegerFor("MCID");
    return;
  }

  if (type == "OBJR") {
    pKid->m_Type = CPDF_StructKid::Object;
    CPDF_Reference* pObj = ToReference(pKidDict->GetObjectFor("Obj"));
    pKid->m_RefObjNum = pObj ? pObj->GetRefObjNum() : 0;
    pKid->m_PageObjNum = PageObjNum;
    return;
  }

  pKid->m_Type = CPDF_StructKid::Element;
  pKid->m_pDict = pKidDict;
  if (m_pTree->GetPage()) {
    pKid->m_pElement = nullptr;
    return;
  }

  pKid->m_pElement =
      pdfium::MakeRetain<CPDF_StructElement>(m_pTree, this, pKidDict);
}

CPDF_Object* CPDF_StructElement::GetAttr(const CFX_ByteStringC& owner,
                                         const CFX_ByteStringC& name,
                                         bool bInheritable,
                                         float fLevel) {
  if (fLevel > nMaxRecursion)
    return nullptr;

  if (bInheritable) {
    if (CPDF_Object* pAttr = GetAttr(owner, name, false))
      return pAttr;
    if (!m_pParent)
      return nullptr;
    return m_pParent->GetAttr(owner, name, true, fLevel + 1);
  }

  if (CPDF_Object* pA = m_pDict->GetDirectObjectFor("A")) {
    if (CPDF_Dictionary* dict = FindAttrDict(pA, owner)) {
      if (CPDF_Object* attr = dict->GetDirectObjectFor(CFX_ByteString(name)))
        return attr;
    }
  }

  CPDF_Object* pC = m_pDict->GetDirectObjectFor("C");
  if (!pC)
    return nullptr;

  CPDF_Dictionary* pClassMap = m_pTree->GetTreeRoot()->GetDictFor("ClassMap");
  if (!pClassMap)
    return nullptr;

  if (CPDF_Array* pArray = pC->AsArray()) {
    for (uint32_t i = 0; i < pArray->GetCount(); i++) {
      CFX_ByteString class_name = pArray->GetStringAt(i);
      CPDF_Dictionary* pClassDict = pClassMap->GetDictFor(class_name);
      if (pClassDict && pClassDict->GetStringFor("O") == owner)
        return pClassDict->GetDirectObjectFor(CFX_ByteString(name));
    }
    return nullptr;
  }

  CFX_ByteString class_name = pC->GetString();
  CPDF_Dictionary* pClassDict = pClassMap->GetDictFor(class_name);
  if (pClassDict && pClassDict->GetStringFor("O") == owner)
    return pClassDict->GetDirectObjectFor(CFX_ByteString(name));
  return nullptr;
}

CPDF_Object* CPDF_StructElement::GetAttr(const CFX_ByteStringC& owner,
                                         const CFX_ByteStringC& name,
                                         bool bInheritable,
                                         int subindex) {
  CPDF_Object* pAttr = GetAttr(owner, name, bInheritable);
  CPDF_Array* pArray = ToArray(pAttr);
  if (!pArray || subindex == -1)
    return pAttr;
  if (subindex >= static_cast<int>(pArray->GetCount()))
    return pAttr;
  return pArray->GetDirectObjectAt(subindex);
}

CFX_ByteString CPDF_StructElement::GetName(const CFX_ByteStringC& owner,
                                           const CFX_ByteStringC& name,
                                           const CFX_ByteStringC& default_value,
                                           bool bInheritable,
                                           int subindex) {
  CPDF_Object* pAttr = GetAttr(owner, name, bInheritable, subindex);
  if (ToName(pAttr))
    return pAttr->GetString();
  return CFX_ByteString(default_value);
}

FX_ARGB CPDF_StructElement::GetColor(const CFX_ByteStringC& owner,
                                     const CFX_ByteStringC& name,
                                     FX_ARGB default_value,
                                     bool bInheritable,
                                     int subindex) {
  CPDF_Array* pArray = ToArray(GetAttr(owner, name, bInheritable, subindex));
  if (!pArray)
    return default_value;
  return 0xff000000 | (static_cast<int>(pArray->GetNumberAt(0) * 255) << 16) |
         (static_cast<int>(pArray->GetNumberAt(1) * 255) << 8) |
         static_cast<int>(pArray->GetNumberAt(2) * 255);
}

float CPDF_StructElement::GetNumber(const CFX_ByteStringC& owner,
                                    const CFX_ByteStringC& name,
                                    float default_value,
                                    bool bInheritable,
                                    int subindex) {
  CPDF_Object* pAttr = GetAttr(owner, name, bInheritable, subindex);
  return ToNumber(pAttr) ? pAttr->GetNumber() : default_value;
}

int CPDF_StructElement::GetInteger(const CFX_ByteStringC& owner,
                                   const CFX_ByteStringC& name,
                                   int default_value,
                                   bool bInheritable,
                                   int subindex) {
  CPDF_Object* pAttr = GetAttr(owner, name, bInheritable, subindex);
  return ToNumber(pAttr) ? pAttr->GetInteger() : default_value;
}