Merge to XFA: Add new public APIs to find the z-order for links and widgets.

- Implement FPDFLink_GetLinkZOrderAtPoint().
- Implement FPDFPage_FormFieldZOrderAtPoint().
- Mark FPDPage_HasFormFieldAtPoint() as deprecated.
- Modify CPDF_LinkList and CPDF_InterForm to support new APIs.
- Clean up dead code in CPDF_LinkList and CPDF_InterForm.

BUG=chromium:515837
R=jun_fang@foxitsoftware.com, tsepez@chromium.org

Review URL: https://codereview.chromium.org/1278053004 .

(cherry picked from commit 24fbf134d43a7ec4226de3db601f0a617bbe428b)

Review URL: https://codereview.chromium.org/1295893005 .

4 files changed, 100 insertions, 381 deletions

diff --git a/core/include/fpdfdoc/fpdf_doc.h b/core/include/fpdfdoc/fpdf_doc.h
index 6e444149e4..0d8dd3caec 100644
--- a/core/include/fpdfdoc/fpdf_doc.h
+++ b/core/include/fpdfdoc/fpdf_doc.h
@@ -8,6 +8,7 @@
 #define CORE_INCLUDE_FPDFDOC_FPDF_DOC_H_
 
 #include <map>
+#include <vector>
 
 #include "../../../third_party/base/nonstd_unique_ptr.h"
 #include "../fpdfapi/fpdf_parser.h"
@@ -32,7 +33,6 @@ class CPDF_FormNotify;
 class CPDF_IconFit;
 class CPDF_InterForm;
 class CPDF_Link;
-class CPDF_LinkList;
 class CPDF_LWinParam;
 class CPDF_Metadata;
 class CPDF_NumberTree;
@@ -358,29 +358,25 @@ class CPDF_FileSpec {
  protected:
   CPDF_Object* m_pObj;
 };
+
 class CPDF_LinkList {
  public:
-  CPDF_LinkList(CPDF_Document* pDoc) { m_pDocument = pDoc; }
-
+  CPDF_LinkList();
   ~CPDF_LinkList();
 
-  CPDF_Link GetLinkAtPoint(CPDF_Page* pPage, FX_FLOAT pdf_x, FX_FLOAT pdf_y);
-
-  int CountLinks(CPDF_Page* pPage);
-
-  CPDF_Link GetLink(CPDF_Page* pPage, int index);
-
-  CPDF_Document* GetDocument() const { return m_pDocument; }
-
- protected:
-  CPDF_Document* m_pDocument;
+  CPDF_Link GetLinkAtPoint(CPDF_Page* pPage,
+                           FX_FLOAT pdf_x,
+                           FX_FLOAT pdf_y,
+                           int* z_order);
 
-  CFX_MapPtrToPtr m_PageMap;
+ private:
+  const std::vector<CPDF_Dictionary*>* GetPageLinks(CPDF_Page* pPage);
 
-  CFX_PtrArray* GetPageLinks(CPDF_Page* pPage);
+  void LoadPageLinks(CPDF_Page* pPage, std::vector<CPDF_Dictionary*>* pList);
 
-  void LoadPageLinks(CPDF_Page* pPage, CFX_PtrArray* pList);
+  std::map<FX_DWORD, std::vector<CPDF_Dictionary*>> m_PageMap;
 };
+
 class CPDF_Link {
  public:
   CPDF_Link() : m_pDict(nullptr) {}
@@ -644,29 +640,13 @@ class CPDF_InterForm : public CFX_PrivateData {
 
   CPDF_FormField* GetFieldByDict(CPDF_Dictionary* pFieldDict) const;
 
-  FX_DWORD CountControls(CFX_WideString csFieldName = L"");
-
-  CPDF_FormControl* GetControl(FX_DWORD index,
-                               CFX_WideString csFieldName = L"");
-
-  FX_BOOL IsValidFormControl(const void* pControl);
-
-  int CountPageControls(CPDF_Page* pPage) const;
-
-  CPDF_FormControl* GetPageControl(CPDF_Page* pPage, int index) const;
-
   CPDF_FormControl* GetControlAtPoint(CPDF_Page* pPage,
                                       FX_FLOAT pdf_x,
-                                      FX_FLOAT pdf_y) const;
+                                      FX_FLOAT pdf_y,
+                                      int* z_order) const;
 
   CPDF_FormControl* GetControlByDict(CPDF_Dictionary* pWidgetDict) const;
 
-  FX_DWORD CountInternalFields(const CFX_WideString& csFieldName = L"") const;
-
-  CPDF_Dictionary* GetInternalField(
-      FX_DWORD index,
-      const CFX_WideString& csFieldName = L"") const;
-
   CPDF_Document* GetDocument() const { return m_pDocument; }
 
   CPDF_Dictionary* GetFormDict() const { return m_pFormDict; }
@@ -740,14 +720,10 @@ class CPDF_InterForm : public CFX_PrivateData {
 
   FX_BOOL ResetForm(FX_BOOL bNotify = FALSE);
 
-  void ReloadForm();
-
   CPDF_FormNotify* GetFormNotify() const { return m_pFormNotify; }
 
   void SetFormNotify(const CPDF_FormNotify* pNotify);
 
-  int GetPageWithWidget(int iCurPage, FX_BOOL bNext);
-
   FX_BOOL IsUpdated() { return m_bUpdated; }
 
   void ClearUpdatedFlag() { m_bUpdated = FALSE; }
@@ -790,7 +766,7 @@ class CPDF_InterForm : public CFX_PrivateData {
 
   CPDF_Dictionary* m_pFormDict;
 
-  CFX_MapPtrToPtr m_ControlMap;
+  std::map<const CPDF_Dictionary*, CPDF_FormControl*> m_ControlMap;
 
   CFieldTree* m_pFieldTree;
 
@@ -834,8 +810,6 @@ class CPDF_FormField {
 
   FX_DWORD GetFlags() { return m_Flags; }
 
-  CPDF_InterForm* GetInterForm() const { return m_pForm; }
-
   CPDF_Dictionary* GetFieldDict() const { return m_pDict; }
 
   void SetFieldDict(CPDF_Dictionary* pDict) { m_pDict = pDict; }
@@ -1008,7 +982,7 @@ class CPDF_FormControl {
 
   CPDF_Dictionary* GetWidget() const { return m_pWidgetDict; }
 
-  CFX_FloatRect GetRect();
+  CFX_FloatRect GetRect() const;
 
   void DrawControl(CFX_RenderDevice* pDevice,
                    CFX_AffineMatrix* pMatrix,
diff --git a/core/src/fpdfdoc/doc_form.cpp b/core/src/fpdfdoc/doc_form.cpp
index d25fd27d13..e57ac9aa50 100644
--- a/core/src/fpdfdoc/doc_form.cpp
+++ b/core/src/fpdfdoc/doc_form.cpp
@@ -256,23 +256,19 @@ CPDF_InterForm::CPDF_InterForm(CPDF_Document* pDocument, FX_BOOL bGenerateAP)
     LoadField(pFields->GetDict(i));
   }
 }
+
 CPDF_InterForm::~CPDF_InterForm() {
-  FX_POSITION pos = m_ControlMap.GetStartPosition();
-  while (pos) {
-    void* key;
-    void* value;
-    m_ControlMap.GetNextAssoc(pos, key, value);
-    delete (CPDF_FormControl*)value;
-  }
-  if (m_pFieldTree != NULL) {
+  for (auto it : m_ControlMap)
+    delete it.second;
+  if (m_pFieldTree) {
     int nCount = m_pFieldTree->m_Root.CountFields();
-    for (int i = 0; i < nCount; i++) {
-      CPDF_FormField* pField = m_pFieldTree->m_Root.GetField(i);
-      delete pField;
+    for (int i = 0; i < nCount; ++i) {
+      delete m_pFieldTree->m_Root.GetField(i);
     }
     delete m_pFieldTree;
   }
 }
+
 FX_BOOL CPDF_InterForm::m_bUpdateAP = TRUE;
 FX_BOOL CPDF_InterForm::UpdatingAPEnabled() {
   return m_bUpdateAP;
@@ -791,215 +787,43 @@ CPDF_FormField* CPDF_InterForm::GetFieldByDict(
   CFX_WideString csWName = GetFullName(pFieldDict);
   return m_pFieldTree->GetField(csWName);
 }
-FX_DWORD CPDF_InterForm::CountControls(CFX_WideString csFieldName) {
-  if (csFieldName.IsEmpty()) {
-    return (FX_DWORD)m_ControlMap.GetCount();
-  }
-  CPDF_FormField* pField = m_pFieldTree->GetField(csFieldName);
-  if (pField == NULL) {
-    return 0;
-  }
-  return pField->m_ControlList.GetSize();
-}
-CPDF_FormControl* CPDF_InterForm::GetControl(FX_DWORD index,
-                                             CFX_WideString csFieldName) {
-  CPDF_FormField* pField = m_pFieldTree->GetField(csFieldName);
-  if (pField == NULL) {
-    return NULL;
-  }
-  if (index < (FX_DWORD)pField->m_ControlList.GetSize()) {
-    return (CPDF_FormControl*)pField->m_ControlList.GetAt(index);
-  }
-  return NULL;
-}
-FX_BOOL CPDF_InterForm::IsValidFormControl(const void* pControl) {
-  if (pControl == NULL) {
-    return FALSE;
-  }
-  FX_POSITION pos = m_ControlMap.GetStartPosition();
-  while (pos) {
-    CPDF_Dictionary* pWidgetDict = NULL;
-    void* pFormControl = NULL;
-    m_ControlMap.GetNextAssoc(pos, (void*&)pWidgetDict, pFormControl);
-    if (pControl == pFormControl) {
-      return TRUE;
-    }
-  }
-  return FALSE;
-}
-int CPDF_InterForm::CountPageControls(CPDF_Page* pPage) const {
-  CPDF_Array* pAnnotList = pPage->m_pFormDict->GetArray("Annots");
-  if (pAnnotList == NULL) {
-    return 0;
-  }
-  int count = 0;
-  for (FX_DWORD i = 0; i < pAnnotList->GetCount(); i++) {
-    CPDF_Dictionary* pAnnot = pAnnotList->GetDict(i);
-    if (pAnnot == NULL) {
-      continue;
-    }
-    CPDF_FormControl* pControl;
-    if (!m_ControlMap.Lookup(pAnnot, (void*&)pControl)) {
-      continue;
-    }
-    count++;
-  }
-  return count;
-}
-CPDF_FormControl* CPDF_InterForm::GetPageControl(CPDF_Page* pPage,
-                                                 int index) const {
-  CPDF_Array* pAnnotList = pPage->m_pFormDict->GetArray("Annots");
-  if (pAnnotList == NULL) {
-    return NULL;
-  }
-  int count = 0;
-  for (FX_DWORD i = 0; i < pAnnotList->GetCount(); i++) {
-    CPDF_Dictionary* pAnnot = pAnnotList->GetDict(i);
-    if (pAnnot == NULL) {
-      continue;
-    }
-    CPDF_FormControl* pControl;
-    if (!m_ControlMap.Lookup(pAnnot, (void*&)pControl)) {
-      continue;
-    }
-    if (index == count) {
-      return pControl;
-    }
-    count++;
-  }
-  return NULL;
-}
+
 CPDF_FormControl* CPDF_InterForm::GetControlAtPoint(CPDF_Page* pPage,
                                                     FX_FLOAT pdf_x,
-                                                    FX_FLOAT pdf_y) const {
+                                                    FX_FLOAT pdf_y,
+                                                    int* z_order) const {
   CPDF_Array* pAnnotList = pPage->m_pFormDict->GetArray("Annots");
-  if (pAnnotList == NULL) {
-    return NULL;
-  }
-  for (FX_DWORD i = pAnnotList->GetCount(); i > 0; i--) {
-    CPDF_Dictionary* pAnnot = pAnnotList->GetDict(i - 1);
-    if (pAnnot == NULL) {
+  if (!pAnnotList)
+    return nullptr;
+
+  for (FX_DWORD i = pAnnotList->GetCount(); i > 0; --i) {
+    FX_DWORD annot_index = i - 1;
+    CPDF_Dictionary* pAnnot = pAnnotList->GetDict(annot_index);
+    if (!pAnnot)
       continue;
-    }
-    CPDF_FormControl* pControl;
-    if (!m_ControlMap.Lookup(pAnnot, (void*&)pControl)) {
+
+    const auto it = m_ControlMap.find(pAnnot);
+    if (it == m_ControlMap.end())
       continue;
-    }
+
+    CPDF_FormControl* pControl = it->second;
     CFX_FloatRect rect = pControl->GetRect();
-    if (rect.Contains(pdf_x, pdf_y)) {
-      return pControl;
-    }
+    if (!rect.Contains(pdf_x, pdf_y))
+      continue;
+
+    if (z_order)
+      *z_order = annot_index;
+    return pControl;
   }
-  return NULL;
+  return nullptr;
 }
+
 CPDF_FormControl* CPDF_InterForm::GetControlByDict(
     CPDF_Dictionary* pWidgetDict) const {
-  CPDF_FormControl* pControl = NULL;
-  m_ControlMap.Lookup(pWidgetDict, (void*&)pControl);
-  return pControl;
-}
-FX_DWORD CPDF_InterForm::CountInternalFields(
-    const CFX_WideString& csFieldName) const {
-  if (!m_pFormDict) {
-    return 0;
-  }
-  CPDF_Array* pArray = m_pFormDict->GetArray("Fields");
-  if (!pArray) {
-    return 0;
-  }
-  if (csFieldName.IsEmpty()) {
-    return pArray->GetCount();
-  }
-  int iLength = csFieldName.GetLength();
-  int iPos = 0;
-  CPDF_Dictionary* pDict = NULL;
-  while (pArray != NULL) {
-    CFX_WideString csSub;
-    if (iPos < iLength && csFieldName[iPos] == L'.') {
-      iPos++;
-    }
-    while (iPos < iLength && csFieldName[iPos] != L'.') {
-      csSub += csFieldName[iPos++];
-    }
-    int iCount = pArray->GetCount();
-    FX_BOOL bFind = FALSE;
-    for (int i = 0; i < iCount; i++) {
-      pDict = pArray->GetDict(i);
-      if (pDict == NULL) {
-        continue;
-      }
-      CFX_WideString csT = pDict->GetUnicodeText("T");
-      if (csT == csSub) {
-        bFind = TRUE;
-        break;
-      }
-    }
-    if (!bFind) {
-      return 0;
-    }
-    if (iPos >= iLength) {
-      break;
-    }
-    pArray = pDict->GetArray("Kids");
-  }
-  if (!pDict) {
-    return 0;
-  }
-  pArray = pDict->GetArray("Kids");
-  return pArray ? pArray->GetCount() : 1;
+  const auto it = m_ControlMap.find(pWidgetDict);
+  return it != m_ControlMap.end() ? it->second : nullptr;
 }
 
-CPDF_Dictionary* CPDF_InterForm::GetInternalField(
-    FX_DWORD index,
-    const CFX_WideString& csFieldName) const {
-  if (!m_pFormDict) {
-    return nullptr;
-  }
-  CPDF_Array* pArray = m_pFormDict->GetArray("Fields");
-  if (!pArray) {
-    return nullptr;
-  }
-  if (csFieldName.IsEmpty()) {
-    return pArray->GetDict(index);
-  }
-  int iLength = csFieldName.GetLength();
-  int iPos = 0;
-  CPDF_Dictionary* pDict = NULL;
-  while (pArray != NULL) {
-    CFX_WideString csSub;
-    if (iPos < iLength && csFieldName[iPos] == L'.') {
-      iPos++;
-    }
-    while (iPos < iLength && csFieldName[iPos] != L'.') {
-      csSub += csFieldName[iPos++];
-    }
-    int iCount = pArray->GetCount();
-    FX_BOOL bFind = FALSE;
-    for (int i = 0; i < iCount; i++) {
-      pDict = pArray->GetDict(i);
-      if (pDict == NULL) {
-        continue;
-      }
-      CFX_WideString csT = pDict->GetUnicodeText("T");
-      if (csT == csSub) {
-        bFind = TRUE;
-        break;
-      }
-    }
-    if (!bFind) {
-      return NULL;
-    }
-    if (iPos >= iLength) {
-      break;
-    }
-    pArray = pDict->GetArray("Kids");
-  }
-  if (!pDict) {
-    return nullptr;
-  }
-  pArray = pDict->GetArray("Kids");
-  return pArray ? pArray->GetDict(index) : pDict;
-}
 FX_BOOL CPDF_InterForm::NeedConstructAP() {
   if (m_pFormDict == NULL) {
     return FALSE;
@@ -1175,33 +999,6 @@ FX_BOOL CPDF_InterForm::ResetForm(FX_BOOL bNotify) {
   }
   return TRUE;
 }
-void CPDF_InterForm::ReloadForm() {
-  FX_POSITION pos = m_ControlMap.GetStartPosition();
-  while (pos) {
-    CPDF_Dictionary* pWidgetDict;
-    CPDF_FormControl* pControl;
-    m_ControlMap.GetNextAssoc(pos, (void*&)pWidgetDict, (void*&)pControl);
-    delete pControl;
-  }
-  m_ControlMap.RemoveAll();
-  int nCount = m_pFieldTree->m_Root.CountFields();
-  for (int k = 0; k < nCount; k++) {
-    CPDF_FormField* pField = m_pFieldTree->m_Root.GetField(k);
-    delete pField;
-  }
-  m_pFieldTree->RemoveAll();
-  if (m_pFormDict == NULL) {
-    return;
-  }
-  CPDF_Array* pFields = m_pFormDict->GetArray("Fields");
-  if (pFields == NULL) {
-    return;
-  }
-  int iCount = pFields->GetCount();
-  for (int i = 0; i < iCount; i++) {
-    LoadField(pFields->GetDict(i));
-  }
-}
 void CPDF_InterForm::LoadField(CPDF_Dictionary* pFieldDict, int nLevel) {
   if (nLevel > nMaxRecursion) {
     return;
@@ -1323,16 +1120,13 @@ CPDF_FormField* CPDF_InterForm::AddTerminalField(
 CPDF_FormControl* CPDF_InterForm::AddControl(
     const CPDF_FormField* pField,
     const CPDF_Dictionary* pWidgetDict) {
-  void* rValue = NULL;
-  if (m_ControlMap.Lookup((CPDF_Dictionary*)pWidgetDict, rValue)) {
-    return (CPDF_FormControl*)rValue;
-  }
+  const auto it = m_ControlMap.find(pWidgetDict);
+  if (it != m_ControlMap.end())
+    return it->second;
+
   CPDF_FormControl* pControl = new CPDF_FormControl(
       (CPDF_FormField*)pField, (CPDF_Dictionary*)pWidgetDict);
-  if (pControl == NULL) {
-    return NULL;
-  }
-  m_ControlMap.SetAt((CPDF_Dictionary*)pWidgetDict, pControl);
+  m_ControlMap[pWidgetDict] = pControl;
   ((CPDF_FormField*)pField)->m_ControlList.Add(pControl);
   return pControl;
 }
@@ -1587,45 +1381,3 @@ FX_BOOL CPDF_InterForm::ImportFromFDF(const CFDF_Document* pFDF,
 void CPDF_InterForm::SetFormNotify(const CPDF_FormNotify* pNotify) {
   m_pFormNotify = (CPDF_FormNotify*)pNotify;
 }
-int CPDF_InterForm::GetPageWithWidget(int iCurPage, FX_BOOL bNext) {
-  if (iCurPage < 0) {
-    return -1;
-  }
-  int iPageCount = m_pDocument->GetPageCount();
-  if (iCurPage >= iPageCount) {
-    return -1;
-  }
-  int iNewPage = iCurPage;
-  do {
-    iNewPage += bNext ? 1 : -1;
-    if (iNewPage >= iPageCount) {
-      iNewPage = 0;
-    }
-    if (iNewPage < 0) {
-      iNewPage = iPageCount - 1;
-    }
-    if (iNewPage == iCurPage) {
-      break;
-    }
-    CPDF_Dictionary* pPageDict = m_pDocument->GetPage(iNewPage);
-    if (pPageDict == NULL) {
-      continue;
-    }
-    CPDF_Array* pAnnots = pPageDict->GetArray("Annots");
-    if (pAnnots == NULL) {
-      continue;
-    }
-    FX_DWORD dwCount = pAnnots->GetCount();
-    for (FX_DWORD i = 0; i < dwCount; i++) {
-      CPDF_Object* pAnnotDict = pAnnots->GetElementValue(i);
-      if (pAnnotDict == NULL) {
-        continue;
-      }
-      CPDF_FormControl* pControl = NULL;
-      if (m_ControlMap.Lookup(pAnnotDict, (void*&)pControl)) {
-        return iNewPage;
-      }
-    }
-  } while (TRUE);
-  return -1;
-}
diff --git a/core/src/fpdfdoc/doc_formcontrol.cpp b/core/src/fpdfdoc/doc_formcontrol.cpp
index db7cf37fdb..410f9a1f21 100644
--- a/core/src/fpdfdoc/doc_formcontrol.cpp
+++ b/core/src/fpdfdoc/doc_formcontrol.cpp
@@ -11,7 +11,7 @@ CPDF_FormControl::CPDF_FormControl(CPDF_FormField* pField,
   m_pWidgetDict = pWidgetDict;
   m_pForm = m_pField->m_pForm;
 }
-CFX_FloatRect CPDF_FormControl::GetRect() {
+CFX_FloatRect CPDF_FormControl::GetRect() const {
   return m_pWidgetDict->GetRect("Rect");
 }
 CFX_ByteString CPDF_FormControl::GetOnStateName() {
diff --git a/core/src/fpdfdoc/doc_link.cpp b/core/src/fpdfdoc/doc_link.cpp
index 15bd14c31e..fbf18f99e5 100644
--- a/core/src/fpdfdoc/doc_link.cpp
+++ b/core/src/fpdfdoc/doc_link.cpp
@@ -6,75 +6,68 @@
 
 #include "../../include/fpdfdoc/fpdf_doc.h"
 
+CPDF_LinkList::CPDF_LinkList() {
+}
+
 CPDF_LinkList::~CPDF_LinkList() {
-  FX_POSITION pos = m_PageMap.GetStartPosition();
-  while (pos) {
-    void* key;
-    void* value;
-    m_PageMap.GetNextAssoc(pos, key, value);
-    delete (CFX_PtrArray*)value;
-  }
 }
-CFX_PtrArray* CPDF_LinkList::GetPageLinks(CPDF_Page* pPage) {
+
+const std::vector<CPDF_Dictionary*>* CPDF_LinkList::GetPageLinks(
+    CPDF_Page* pPage) {
   FX_DWORD objnum = pPage->m_pFormDict->GetObjNum();
-  if (objnum == 0) {
-    return NULL;
-  }
-  CFX_PtrArray* pPageLinkList = NULL;
-  if (!m_PageMap.Lookup((void*)(uintptr_t)objnum, (void*&)pPageLinkList)) {
-    pPageLinkList = new CFX_PtrArray;
-    m_PageMap.SetAt((void*)(uintptr_t)objnum, pPageLinkList);
-    LoadPageLinks(pPage, pPageLinkList);
-  }
-  return pPageLinkList;
-}
-int CPDF_LinkList::CountLinks(CPDF_Page* pPage) {
-  CFX_PtrArray* pPageLinkList = GetPageLinks(pPage);
-  if (pPageLinkList == NULL) {
-    return 0;
-  }
-  return pPageLinkList->GetSize();
-}
-CPDF_Link CPDF_LinkList::GetLink(CPDF_Page* pPage, int index) {
-  CFX_PtrArray* pPageLinkList = GetPageLinks(pPage);
-  if (!pPageLinkList) {
-    return CPDF_Link();
-  }
-  return CPDF_Link((CPDF_Dictionary*)pPageLinkList->GetAt(index));
+  if (objnum == 0)
+    return nullptr;
+
+  auto it = m_PageMap.find(objnum);
+  if (it != m_PageMap.end())
+    return &it->second;
+
+  // std::map::operator[] forces the creation of a map entry.
+  std::vector<CPDF_Dictionary*>& page_link_list = m_PageMap[objnum];
+  LoadPageLinks(pPage, &page_link_list);
+  return &page_link_list;
 }
+
 CPDF_Link CPDF_LinkList::GetLinkAtPoint(CPDF_Page* pPage,
                                         FX_FLOAT pdf_x,
-                                        FX_FLOAT pdf_y) {
-  CFX_PtrArray* pPageLinkList = GetPageLinks(pPage);
-  if (!pPageLinkList) {
+                                        FX_FLOAT pdf_y,
+                                        int* z_order) {
+  const std::vector<CPDF_Dictionary*>* pPageLinkList = GetPageLinks(pPage);
+  if (!pPageLinkList)
     return CPDF_Link();
-  }
-  int size = pPageLinkList->GetSize();
-  for (int i = size - 1; i >= 0; --i) {
-    CPDF_Link link((CPDF_Dictionary*)pPageLinkList->GetAt(i));
+
+  for (size_t i = pPageLinkList->size(); i > 0; --i) {
+    size_t annot_index = i - 1;
+    CPDF_Dictionary* pAnnot = (*pPageLinkList)[annot_index];
+    if (!pAnnot)
+      continue;
+
+    CPDF_Link link(pAnnot);
     CPDF_Rect rect = link.GetRect();
-    if (rect.Contains(pdf_x, pdf_y)) {
-      return link;
-    }
+    if (!rect.Contains(pdf_x, pdf_y))
+      continue;
+
+    if (z_order)
+      *z_order = annot_index;
+    return link;
   }
   return CPDF_Link();
 }
-void CPDF_LinkList::LoadPageLinks(CPDF_Page* pPage, CFX_PtrArray* pList) {
+
+void CPDF_LinkList::LoadPageLinks(CPDF_Page* pPage,
+                                  std::vector<CPDF_Dictionary*>* pList) {
   CPDF_Array* pAnnotList = pPage->m_pFormDict->GetArray("Annots");
-  if (pAnnotList == NULL) {
+  if (!pAnnotList)
     return;
-  }
-  for (FX_DWORD i = 0; i < pAnnotList->GetCount(); i++) {
+
+  for (FX_DWORD i = 0; i < pAnnotList->GetCount(); ++i) {
     CPDF_Dictionary* pAnnot = pAnnotList->GetDict(i);
-    if (pAnnot == NULL) {
-      continue;
-    }
-    if (pAnnot->GetString("Subtype") != "Link") {
-      continue;
-    }
-    pList->Add(pAnnot);
+    bool add_link = (pAnnot && pAnnot->GetString("Subtype") == "Link");
+    // Add non-links as nullptrs to preserve z-order.
+    pList->push_back(add_link ? pAnnot : nullptr);
   }
 }
+
 CPDF_Rect CPDF_Link::GetRect() {
   return m_pDict->GetRect("Rect");
 }