Merge to XFA: Use std::map as CPDF_Dictionary's underlying store.

Replaces CFX_CMapByteStringToPtr. XFA still uses CFX_CMapByteStringToPtr
so it's not completely removed just yet.

Adds begin()/end() to CPDF_Dictionary and removes the
GetStartPos()/GetNextElement() functions to traverse the dictionary.
Callers are changed accordingly. AddValue() is also removed.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1541703003 .

(cherry picked from commit 14f39950451bb9c2a11fbc7173fd47367410f80f)

Review URL: https://codereview.chromium.org/1576033002 .

7 files changed, 96 insertions, 138 deletions

diff --git a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
index c1ef37dab6..65bb3d985e 100644
--- a/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
+++ b/core/src/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
@@ -15,6 +15,8 @@
 #define PDF_OBJECTSTREAM_MAXLENGTH (256 * 1024)
 #define PDF_XREFSTREAM_MAXSIZE 10000
 
+// TODO(ochang): Make helper for appending "objnum 0 R ".
+
 namespace {
 
 int32_t PDF_CreatorAppendObject(const CPDF_Object* pObj,
@@ -112,10 +114,9 @@ int32_t PDF_CreatorAppendObject(const CPDF_Object* pObj,
       }
       offset += 2;
       const CPDF_Dictionary* p = pObj->AsDictionary();
-      FX_POSITION pos = p->GetStartPos();
-      while (pos) {
-        CFX_ByteString key;
-        CPDF_Object* pValue = p->GetNextElement(pos, key);
+      for (const auto& it : *p) {
+        const CFX_ByteString& key = it.first;
+        CPDF_Object* pValue = it.second;
         if (pFile->AppendString("/") < 0) {
           return -1;
         }
@@ -184,10 +185,9 @@ int32_t PDF_CreatorWriteTrailer(CPDF_Document* pDocument,
   CPDF_Parser* pParser = (CPDF_Parser*)pDocument->GetParser();
   if (pParser) {
     CPDF_Dictionary* p = pParser->GetTrailer();
-    FX_POSITION pos = p->GetStartPos();
-    while (pos) {
-      CFX_ByteString key;
-      CPDF_Object* pValue = p->GetNextElement(pos, key);
+    for (const auto& it : *p) {
+      const CFX_ByteString& key = it.first;
+      CPDF_Object* pValue = it.second;
       if (key == "Encrypt" || key == "Size" || key == "Filter" ||
           key == "Index" || key == "Length" || key == "Prev" || key == "W" ||
           key == "XRefStm" || key == "Type" || key == "ID") {
@@ -1238,11 +1238,10 @@ int32_t CPDF_Creator::WriteDirectObj(FX_DWORD objnum,
       m_Offset += 2;
       const CPDF_Dictionary* p = pObj->AsDictionary();
       bool bSignDict = IsSignatureDict(p);
-      FX_POSITION pos = p->GetStartPos();
-      while (pos) {
+      for (const auto& it : *p) {
         FX_BOOL bSignValue = FALSE;
-        CFX_ByteString key;
-        CPDF_Object* pValue = p->GetNextElement(pos, key);
+        const CFX_ByteString& key = it.first;
+        CPDF_Object* pValue = it.second;
         if (m_File.AppendString("/") < 0) {
           return -1;
         }
@@ -1773,10 +1772,11 @@ int32_t CPDF_Creator::WriteDoc_Stage4(IFX_Pause* pPause) {
     }
     if (m_pParser) {
       CPDF_Dictionary* p = m_pParser->m_pTrailer;
-      FX_POSITION pos = p->GetStartPos();
-      while (pos) {
-        CFX_ByteString key;
-        CPDF_Object* pValue = p->GetNextElement(pos, key);
+      for (const auto& it : *p) {
+        const CFX_ByteString& key = it.first;
+        CPDF_Object* pValue = it.second;
+        // TODO(ochang): Consolidate with similar check in
+        // PDF_CreatorWriteTrailer.
         if (key == "Encrypt" || key == "Size" || key == "Filter" ||
             key == "Index" || key == "Length" || key == "Prev" || key == "W" ||
             key == "XRefStm" || key == "ID") {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index c9eee8e380..168cbf3a61 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -1213,11 +1213,9 @@ CPDF_ColorSpace* CPDF_ColorSpace::Load(CPDF_Document* pDoc, CPDF_Object* pObj) {
     if (!pDict)
       return nullptr;
 
-    CPDF_ColorSpace* pRet = nullptr;
-    FX_POSITION pos = pDict->GetStartPos();
-    while (pos) {
-      CFX_ByteString bsKey;
-      CPDF_Object* pValue = pDict->GetNextElement(pos, bsKey);
+    for (const auto& it : *pDict) {
+      CPDF_ColorSpace* pRet = nullptr;
+      CPDF_Object* pValue = it.second;
       if (ToName(pValue))
         pRet = _CSFromName(pValue->GetString());
       if (pRet)
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
index d8f21c692d..dd16aa85ce 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp
@@ -458,10 +458,9 @@ void CPDF_AllStates::SetLineDash(CPDF_Array* pArray,
 void CPDF_AllStates::ProcessExtGS(CPDF_Dictionary* pGS,
                                   CPDF_StreamContentParser* pParser) {
   CPDF_GeneralStateData* pGeneralState = m_GeneralState.GetModify();
-  FX_POSITION pos = pGS->GetStartPos();
-  while (pos) {
-    CFX_ByteString key_str;
-    CPDF_Object* pElement = pGS->GetNextElement(pos, key_str);
+  for (const auto& it : *pGS) {
+    const CFX_ByteString& key_str = it.first;
+    CPDF_Object* pElement = it.second;
     CPDF_Object* pObject = pElement ? pElement->GetDirect() : nullptr;
     if (!pObject)
       continue;
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index d0cf9ed719..3fbd3e486e 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -496,10 +496,9 @@ void PDF_ReplaceAbbr(CPDF_Object* pObj) {
   switch (pObj->GetType()) {
     case PDFOBJ_DICTIONARY: {
       CPDF_Dictionary* pDict = pObj->AsDictionary();
-      FX_POSITION pos = pDict->GetStartPos();
-      while (pos) {
-        CFX_ByteString key;
-        CPDF_Object* value = pDict->GetNextElement(pos, key);
+      for (const auto& it : *pDict) {
+        CFX_ByteString key = it.first;
+        CPDF_Object* value = it.second;
         CFX_ByteStringC fullname = PDF_FindFullName(
             PDF_InlineKeyAbbr, FX_ArraySize(PDF_InlineKeyAbbr), key);
         if (!fullname.IsEmpty()) {
@@ -544,10 +543,9 @@ void PDF_ReplaceFull(CPDF_Object* pObj) {
   switch (pObj->GetType()) {
     case PDFOBJ_DICTIONARY: {
       CPDF_Dictionary* pDict = pObj->AsDictionary();
-      FX_POSITION pos = pDict->GetStartPos();
-      while (pos) {
-        CFX_ByteString key;
-        CPDF_Object* value = pDict->GetNextElement(pos, key);
+      for (const auto& it : *pDict) {
+        CFX_ByteString key = it.first;
+        CPDF_Object* value = it.second;
         CFX_ByteStringC abbrName = PDF_FindAbbrName(
             PDF_InlineKeyAbbr, FX_ArraySize(PDF_InlineKeyAbbr), key);
         if (!abbrName.IsEmpty()) {
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
index 685becaf69..2cb81002fb 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_objects.cpp
@@ -267,12 +267,9 @@ CPDF_Object* CPDF_Object::CloneInternal(FX_BOOL bDirect,
     case PDFOBJ_DICTIONARY: {
       CPDF_Dictionary* pCopy = new CPDF_Dictionary();
       const CPDF_Dictionary* pThis = AsDictionary();
-      FX_POSITION pos = pThis->m_Map.GetStartPosition();
-      while (pos) {
-        CFX_ByteString key;
-        CPDF_Object* value;
-        pThis->m_Map.GetNextAssoc(pos, key, (void*&)value);
-        pCopy->m_Map.SetAt(key, value->CloneInternal(bDirect, visited));
+      for (const auto& it : *pThis) {
+        pCopy->m_Map.insert(std::make_pair(
+            it.first, it.second->CloneInternal(bDirect, visited)));
       }
       return pCopy;
     }
@@ -578,38 +575,23 @@ FX_BOOL CPDF_Array::Identical(CPDF_Array* pOther) const {
   return TRUE;
 }
 CPDF_Dictionary::~CPDF_Dictionary() {
-  FX_POSITION pos = m_Map.GetStartPosition();
-  while (pos) {
-    if (CPDF_Object* value = static_cast<CPDF_Object*>(m_Map.GetNextValue(pos)))
-      value->Release();
-  }
-}
-FX_POSITION CPDF_Dictionary::GetStartPos() const {
-  return m_Map.GetStartPosition();
-}
-CPDF_Object* CPDF_Dictionary::GetNextElement(FX_POSITION& pos,
-                                             CFX_ByteString& key) const {
-  if (!pos) {
-    return NULL;
+  for (const auto& it : m_Map) {
+    it.second->Release();
   }
-  CPDF_Object* p;
-  m_Map.GetNextAssoc(pos, key, (void*&)p);
-  return p;
 }
 CPDF_Object* CPDF_Dictionary::GetElement(const CFX_ByteStringC& key) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
-  return p;
+  auto it = m_Map.find(key);
+  if (it == m_Map.end())
+    return nullptr;
+  return it->second;
 }
 CPDF_Object* CPDF_Dictionary::GetElementValue(
     const CFX_ByteStringC& key) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
-  return p ? p->GetDirect() : NULL;
+  CPDF_Object* p = GetElement(key);
+  return p ? p->GetDirect() : nullptr;
 }
 CFX_ByteString CPDF_Dictionary::GetString(const CFX_ByteStringC& key) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetString();
   }
@@ -617,8 +599,7 @@ CFX_ByteString CPDF_Dictionary::GetString(const CFX_ByteStringC& key) const {
 }
 CFX_ByteStringC CPDF_Dictionary::GetConstString(
     const CFX_ByteStringC& key) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetConstString();
   }
@@ -626,16 +607,14 @@ CFX_ByteStringC CPDF_Dictionary::GetConstString(
 }
 CFX_WideString CPDF_Dictionary::GetUnicodeText(const CFX_ByteStringC& key,
                                                CFX_CharMap* pCharMap) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (CPDF_Reference* pRef = ToReference(p))
     p = pRef->GetDirect();
   return p ? p->GetUnicodeText(pCharMap) : CFX_WideString();
 }
 CFX_ByteString CPDF_Dictionary::GetString(const CFX_ByteStringC& key,
                                           const CFX_ByteStringC& def) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetString();
   }
@@ -644,32 +623,28 @@ CFX_ByteString CPDF_Dictionary::GetString(const CFX_ByteStringC& key,
 CFX_ByteStringC CPDF_Dictionary::GetConstString(
     const CFX_ByteStringC& key,
     const CFX_ByteStringC& def) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetConstString();
   }
   return CFX_ByteStringC(def);
 }
 int CPDF_Dictionary::GetInteger(const CFX_ByteStringC& key) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetInteger();
   }
   return 0;
 }
 int CPDF_Dictionary::GetInteger(const CFX_ByteStringC& key, int def) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetInteger();
   }
   return def;
 }
 FX_FLOAT CPDF_Dictionary::GetNumber(const CFX_ByteStringC& key) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (p) {
     return p->GetNumber();
   }
@@ -677,8 +652,7 @@ FX_FLOAT CPDF_Dictionary::GetNumber(const CFX_ByteStringC& key) const {
 }
 FX_BOOL CPDF_Dictionary::GetBoolean(const CFX_ByteStringC& key,
                                     FX_BOOL bDefault) const {
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
+  CPDF_Object* p = GetElement(key);
   if (ToBoolean(p))
     return p->GetInteger();
   return bDefault;
@@ -714,67 +688,67 @@ CFX_Matrix CPDF_Dictionary::GetMatrix(const CFX_ByteStringC& key) const {
   return matrix;
 }
 FX_BOOL CPDF_Dictionary::KeyExist(const CFX_ByteStringC& key) const {
-  void* value;
-  return m_Map.Lookup(key, value);
+  return pdfium::ContainsKey(m_Map, key);
 }
 
 void CPDF_Dictionary::SetAt(const CFX_ByteStringC& key, CPDF_Object* pObj) {
   ASSERT(IsDictionary());
-  void* pValue = nullptr;
-  m_Map.Lookup(key, pValue);
-  CPDF_Object* pExisting = static_cast<CPDF_Object*>(pValue);
-  if (pExisting == pObj)
+  // Avoid 2 constructions of CFX_ByteString.
+  CFX_ByteString key_bytestring = key;
+  auto it = m_Map.find(key_bytestring);
+  if (it == m_Map.end()) {
+    if (pObj) {
+      m_Map.insert(std::make_pair(key_bytestring, pObj));
+    }
     return;
+  }
 
-  if (pExisting)
-    pExisting->Release();
+  if (it->second == pObj)
+    return;
+  it->second->Release();
 
   if (pObj)
-    m_Map.SetAt(key, pObj);
+    it->second = pObj;
   else
-    m_Map.RemoveKey(key);
-}
-
-void CPDF_Dictionary::AddValue(const CFX_ByteStringC& key, CPDF_Object* pObj) {
-  ASSERT(m_Type == PDFOBJ_DICTIONARY);
-  m_Map.AddValue(key, pObj);
+    m_Map.erase(it);
 }
 void CPDF_Dictionary::RemoveAt(const CFX_ByteStringC& key) {
   ASSERT(m_Type == PDFOBJ_DICTIONARY);
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(key, (void*&)p);
-  if (!p) {
+  auto it = m_Map.find(key);
+  if (it == m_Map.end())
     return;
-  }
-  p->Release();
-  m_Map.RemoveKey(key);
+
+  it->second->Release();
+  m_Map.erase(it);
 }
 void CPDF_Dictionary::ReplaceKey(const CFX_ByteStringC& oldkey,
                                  const CFX_ByteStringC& newkey) {
   ASSERT(m_Type == PDFOBJ_DICTIONARY);
-  CPDF_Object* p = NULL;
-  m_Map.Lookup(oldkey, (void*&)p);
-  if (!p) {
+  auto old_it = m_Map.find(oldkey);
+  if (old_it == m_Map.end())
     return;
+
+  // Avoid 2 constructions of CFX_ByteString.
+  CFX_ByteString newkey_bytestring = newkey;
+  auto new_it = m_Map.find(newkey_bytestring);
+  if (new_it != m_Map.end()) {
+    new_it->second->Release();
+    new_it->second = old_it->second;
+  } else {
+    m_Map.insert(std::make_pair(newkey_bytestring, old_it->second));
   }
-  m_Map.RemoveKey(oldkey);
-  m_Map.SetAt(newkey, p);
+  m_Map.erase(old_it);
 }
 FX_BOOL CPDF_Dictionary::Identical(CPDF_Dictionary* pOther) const {
   if (!pOther) {
     return FALSE;
   }
-  if (m_Map.GetCount() != pOther->m_Map.GetCount()) {
+  if (m_Map.size() != pOther->m_Map.size()) {
     return FALSE;
   }
-  FX_POSITION pos = m_Map.GetStartPosition();
-  while (pos) {
-    CFX_ByteString key;
-    void* value;
-    m_Map.GetNextAssoc(pos, key, value);
-    if (!value)
-      return FALSE;
-    if (!static_cast<CPDF_Object*>(value)->IsIdentical(pOther->GetElement(key)))
+  for (const auto& it : m_Map) {
+    const CFX_ByteString& key = it.first;
+    if (!it.second->IsIdentical(pOther->GetElement(key)))
       return FALSE;
   }
   return TRUE;
@@ -798,7 +772,7 @@ void CPDF_Dictionary::SetAtReference(const CFX_ByteStringC& key,
 void CPDF_Dictionary::AddReference(const CFX_ByteStringC& key,
                                    CPDF_IndirectObjects* pDoc,
                                    FX_DWORD objnum) {
-  AddValue(key, new CPDF_Reference(pDoc, objnum));
+  SetAt(key, new CPDF_Reference(pDoc, objnum));
 }
 void CPDF_Dictionary::SetAtNumber(const CFX_ByteStringC& key, FX_FLOAT f) {
   CPDF_Number* pNumber = new CPDF_Number;
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index 236ecaa837..3ab4423172 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -869,11 +869,9 @@ FX_BOOL CPDF_Parser::RebuildCrossRef() {
                       if (!pRoot ||
                           (pRef && IsValidObjectNumber(pRef->GetRefObjNum()) &&
                            m_ObjectInfo[pRef->GetRefObjNum()].pos != 0)) {
-                        FX_POSITION trailer_pos = pTrailer->GetStartPos();
-                        while (trailer_pos) {
-                          CFX_ByteString key;
-                          CPDF_Object* pElement =
-                              pTrailer->GetNextElement(trailer_pos, key);
+                        for (const auto& it : *pTrailer) {
+                          const CFX_ByteString& key = it.first;
+                          CPDF_Object* pElement = it.second;
                           FX_DWORD dwObjNum =
                               pElement ? pElement->GetObjNum() : 0;
                           if (dwObjNum) {
@@ -2162,13 +2160,7 @@ CPDF_Object* CPDF_SyntaxParser::GetObject(CPDF_IndirectObjects* pObjList,
         continue;
 
       CFX_ByteStringC keyNoSlash(key.c_str() + 1, key.GetLength() - 1);
-      // TODO(thestig): Remove this conditional once CPDF_Dictionary has a
-      // better underlying map implementation.
-      if (nKeys < 32) {
-        pDict->SetAt(keyNoSlash, pObj);
-      } else {
-        pDict->AddValue(keyNoSlash, pObj);
-      }
+      pDict->SetAt(keyNoSlash, pObj);
     }
 
     if (IsSignatureDict(pDict.get())) {
@@ -2315,8 +2307,8 @@ CPDF_Object* CPDF_SyntaxParser::GetObjectByStrict(
         return nullptr;
       }
       if (key.GetLength() > 1) {
-        pDict->AddValue(CFX_ByteStringC(key.c_str() + 1, key.GetLength() - 1),
-                        obj.release());
+        pDict->SetAt(CFX_ByteStringC(key.c_str() + 1, key.GetLength() - 1),
+                     obj.release());
       }
     }
     if (pContext) {
@@ -3058,11 +3050,9 @@ FX_BOOL CPDF_DataAvail::IsObjectsAvail(
         if (pDict && pDict->GetString("Type") == "Page" && !bParsePage) {
           continue;
         }
-        FX_POSITION pos = pDict->GetStartPos();
-        while (pos) {
-          CPDF_Object* value;
-          CFX_ByteString key;
-          value = pDict->GetNextElement(pos, key);
+        for (const auto& it : *pDict) {
+          const CFX_ByteString& key = it.first;
+          CPDF_Object* value = it.second;
           if (key != "Parent") {
             new_obj_array.Add(value);
           }
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
index ec155a8d02..1abf665d65 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
@@ -383,10 +383,9 @@ CFX_ByteTextBuf& operator<<(CFX_ByteTextBuf& buf, const CPDF_Object* pObj) {
     case PDFOBJ_DICTIONARY: {
       const CPDF_Dictionary* p = pObj->AsDictionary();
       buf << "<<";
-      FX_POSITION pos = p->GetStartPos();
-      while (pos) {
-        CFX_ByteString key;
-        CPDF_Object* pValue = p->GetNextElement(pos, key);
+      for (const auto& it : *p) {
+        const CFX_ByteString& key = it.first;
+        CPDF_Object* pValue = it.second;
         buf << "/" << PDF_NameEncode(key);
         if (pValue && pValue->GetObjNum()) {
           buf << " " << pValue->GetObjNum() << " 0 R ";