Convert string Find methods to return an Optional

The Find and ReverseFind methods for WideString, WideStringC,
ByteString, and ByteStringC have been converted from returning a raw
FX_STRSIZE, to returning Optional<FX_STRSIZE>, so that success/failure
can be indicated without using FX_STRNPOS.

This allows for removing FX_STRNPOS and by association makes the
conversion of FX_STRSIZE to size_t easier, since it forces checking
the return value of Find to be explictly done as well as taking the
error value out of the range of FX_STRSIZE.

New Contains methods have been added for cases where the success or
failure is all the call site to Find cared about, and the actual
position was ignored.

BUG=pdfium:828


Change-Id: Id827e508c8660affa68cc08a13d96121369364b7
Reviewed-on: https://pdfium-review.googlesource.com/11350
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

8 files changed, 54 insertions, 60 deletions

diff --git a/core/fxge/android/cfpf_skiafontmgr.cpp b/core/fxge/android/cfpf_skiafontmgr.cpp
index 3cee6decac..16a6df5f8f 100644
--- a/core/fxge/android/cfpf_skiafontmgr.cpp
+++ b/core/fxge/android/cfpf_skiafontmgr.cpp
@@ -194,13 +194,13 @@ bool FPF_SkiaIsCJK(uint8_t uCharset) {
 bool FPF_SkiaMaybeSymbol(const CFX_ByteStringC& bsFacename) {
   CFX_ByteString bsName(bsFacename);
   bsName.MakeLower();
-  return bsName.Find("symbol") != FX_STRNPOS;
+  return bsName.Contains("symbol");
 }
 
 bool FPF_SkiaMaybeArabic(const CFX_ByteStringC& bsFacename) {
   CFX_ByteString bsName(bsFacename);
   bsName.MakeLower();
-  return bsName.Find("arabic") != FX_STRNPOS;
+  return bsName.Contains("arabic");
 }
 
 const uint32_t g_FPFSkiaFontCharsets[] = {
diff --git a/core/fxge/apple/fx_mac_imp.cpp b/core/fxge/apple/fx_mac_imp.cpp
index 54aac7bfa6..2eee8e2e62 100644
--- a/core/fxge/apple/fx_mac_imp.cpp
+++ b/core/fxge/apple/fx_mac_imp.cpp
@@ -52,7 +52,7 @@ const char JAPAN_GOTHIC[] = "Hiragino Kaku Gothic Pro W6";
 const char JAPAN_MINCHO[] = "Hiragino Mincho Pro W6";
 
 void GetJapanesePreference(CFX_ByteString* face, int weight, int pitch_family) {
-  if (face->Find("Gothic") != FX_STRNPOS) {
+  if (face->Contains("Gothic")) {
     *face = JAPAN_GOTHIC;
     return;
   }
@@ -82,7 +82,7 @@ void* CFX_MacFontInfo::MapFont(int weight,
   // Times New Roman. A more sophisticated approach would be to find all the
   // fonts in |m_FontList| with |face| in the name, and examine the fonts to
   // see which best matches the requested characteristics.
-  if (face.Find("Bold") == FX_STRNPOS && face.Find("Italic") == FX_STRNPOS) {
+  if (!face.Contains("Bold") && !face.Contains("Italic")) {
     CFX_ByteString new_face = face;
     if (weight > 400)
       new_face += " Bold";
diff --git a/core/fxge/cfx_folderfontinfo.cpp b/core/fxge/cfx_folderfontinfo.cpp
index f16722c4d6..c82d55982a 100644
--- a/core/fxge/cfx_folderfontinfo.cpp
+++ b/core/fxge/cfx_folderfontinfo.cpp
@@ -251,11 +251,11 @@ void CFX_FolderFontInfo::ReportFace(const CFX_ByteString& path,
   m_pMapper->AddInstalledFont(facename, FX_CHARSET_ANSI);
   pInfo->m_Charsets |= CHARSET_FLAG_ANSI;
   pInfo->m_Styles = 0;
-  if (style.Find("Bold") != FX_STRNPOS)
+  if (style.Contains("Bold"))
     pInfo->m_Styles |= FXFONT_BOLD;
-  if (style.Find("Italic") != FX_STRNPOS || style.Find("Oblique") != FX_STRNPOS)
+  if (style.Contains("Italic") || style.Contains("Oblique"))
     pInfo->m_Styles |= FXFONT_ITALIC;
-  if (facename.Find("Serif") != FX_STRNPOS)
+  if (facename.Contains("Serif"))
     pInfo->m_Styles |= FXFONT_SERIF;
 
   m_FontList[facename] = std::move(pInfo);
@@ -288,8 +288,7 @@ void* CFX_FolderFontInfo::FindFont(int weight,
     if (!(pFont->m_Charsets & charset_flag) && charset != FX_CHARSET_Default)
       continue;
 
-    int32_t index = bsName.Find(family);
-    if (bMatchName && index == FX_STRNPOS)
+    if (bMatchName && !bsName.Contains(family))
       continue;
 
     int32_t iSimilarValue =
diff --git a/core/fxge/cfx_font.cpp b/core/fxge/cfx_font.cpp
index 1fd08f2676..8b34819e05 100644
--- a/core/fxge/cfx_font.cpp
+++ b/core/fxge/cfx_font.cpp
@@ -447,7 +447,7 @@ bool CFX_Font::IsItalic() const {
 
   CFX_ByteString str(FXFT_Get_Face_Style_Name(m_Face));
   str.MakeLower();
-  return str.Find("italic") != FX_STRNPOS;
+  return str.Contains("italic");
 }
 
 bool CFX_Font::IsBold() const {
diff --git a/core/fxge/cfx_fontmapper.cpp b/core/fxge/cfx_fontmapper.cpp
index 005c61ae8a..bff9fad5c3 100644
--- a/core/fxge/cfx_fontmapper.cpp
+++ b/core/fxge/cfx_fontmapper.cpp
@@ -172,7 +172,7 @@ const struct CODEPAGE_MAP {
 int CompareFontFamilyString(const void* key, const void* element) {
   CFX_ByteString str_key((const char*)key);
   const AltFontFamily* family = reinterpret_cast<const AltFontFamily*>(element);
-  if (str_key.Find(family->m_pFontName) != FX_STRNPOS)
+  if (str_key.Contains(family->m_pFontName))
     return 0;
   return FXSYS_stricmp(reinterpret_cast<const char*>(key), family->m_pFontName);
 }
@@ -187,9 +187,9 @@ CFX_ByteString TT_NormalizeName(const char* family) {
   norm.Remove(' ');
   norm.Remove('-');
   norm.Remove(',');
-  FX_STRSIZE pos = norm.Find('+');
-  if (pos != 0 && pos != FX_STRNPOS)
-    norm = norm.Left(pos);
+  auto pos = norm.Find('+');
+  if (pos.has_value() && pos.value() != 0)
+    norm = norm.Left(pos.value());
   norm.MakeLower();
   return norm;
 }
@@ -208,14 +208,14 @@ uint8_t GetCharsetFromCodePage(uint16_t codepage) {
 }
 
 CFX_ByteString GetFontFamily(CFX_ByteString fontName, int nStyle) {
-  if (fontName.Find("Script") >= 0) {
+  if (fontName.Contains("Script")) {
     if ((nStyle & FX_FONT_STYLE_Bold) == FX_FONT_STYLE_Bold)
       fontName = "ScriptMTBold";
-    else if (fontName.Find("Palace") >= 0)
+    else if (fontName.Contains("Palace"))
       fontName = "PalaceScriptMT";
-    else if (fontName.Find("French") >= 0)
+    else if (fontName.Contains("French"))
       fontName = "FrenchScriptMT";
-    else if (fontName.Find("FreeStyle") >= 0)
+    else if (fontName.Contains("FreeStyle"))
       fontName = "FreeStyleScript";
     return fontName;
   }
@@ -449,11 +449,11 @@ FXFT_Face CFX_FontMapper::FindSubstFont(const CFX_ByteString& name,
   CFX_ByteString style;
   bool bHasComma = false;
   bool bHasHyphen = false;
-  int find = SubstName.Find(",", 0);
-  if (find >= 0) {
-    family = SubstName.Left(find);
+  auto pos = SubstName.Find(",", 0);
+  if (pos.has_value()) {
+    family = SubstName.Left(pos.value());
     PDF_GetStandardFontName(&family);
-    style = SubstName.Right(SubstName.GetLength() - (find + 1));
+    style = SubstName.Right(SubstName.GetLength() - (pos.value() + 1));
     bHasComma = true;
   } else {
     family = SubstName;
@@ -478,10 +478,10 @@ FXFT_Face CFX_FontMapper::FindSubstFont(const CFX_ByteString& name,
   } else {
     iBaseFont = kNumStandardFonts;
     if (!bHasComma) {
-      find = family.ReverseFind('-');
-      if (find >= 0) {
-        style = family.Right(family.GetLength() - (find + 1));
-        family = family.Left(find);
+      pos = family.ReverseFind('-');
+      if (pos.has_value()) {
+        style = family.Right(family.GetLength() - (pos.value() + 1));
+        family = family.Left(pos.value());
         bHasHyphen = true;
       }
     }
@@ -580,15 +580,18 @@ FXFT_Face CFX_FontMapper::FindSubstFont(const CFX_ByteString& name,
         weight = old_weight;
       }
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_LINUX_
-      if (SubstName.Find("Narrow") > 0 || SubstName.Find("Condensed") > 0)
-        family = "LiberationSansNarrow";
+      const char* narrow_family = "LiberationSansNarrow";
 #elif _FXM_PLATFORM_ == _FXM_PLATFORM_ANDROID_
-      if (family.Find("Narrow") > 0 || family.Find("Condensed") > 0)
-        family = "RobotoCondensed";
+      const char* narrow_family = "RobotoCondensed";
 #else
-      if (family.Find("Narrow") > 0 || family.Find("Condensed") > 0)
-        family = "ArialNarrow";
+      const char* narrow_family = "ArialNarrow";
 #endif  // _FXM_PLATFORM_ == _FXM_PLATFORM_LINUX_
+      auto pos = SubstName.Find("Narrow");
+      if (pos.has_value() && pos.value() != 0)
+        family = narrow_family;
+      pos = SubstName.Find("Condensed");
+      if (pos.has_value() && pos.value() != 0)
+        family = narrow_family;
     } else {
       pSubstFont->m_bSubstCJK = true;
       if (nStyle)
diff --git a/core/fxge/cfx_renderdevice.cpp b/core/fxge/cfx_renderdevice.cpp
index e088bc4f9a..d0c52e8ade 100644
--- a/core/fxge/cfx_renderdevice.cpp
+++ b/core/fxge/cfx_renderdevice.cpp
@@ -337,7 +337,7 @@ bool ShouldDrawDeviceText(const CFX_Font* pFont, uint32_t text_flags) {
     return false;
 
   const CFX_ByteString bsPsName = pFont->GetPsName();
-  if (bsPsName.Find("+ZJHL") != FX_STRNPOS)
+  if (bsPsName.Contains("+ZJHL"))
     return false;
 
   if (bsPsName == "CNAAJI+cmex10")
diff --git a/core/fxge/fx_ge_linux.cpp b/core/fxge/fx_ge_linux.cpp
index 0552f1c58c..d17ddf2d3d 100644
--- a/core/fxge/fx_ge_linux.cpp
+++ b/core/fxge/fx_ge_linux.cpp
@@ -45,18 +45,16 @@ size_t GetJapanesePreference(const char* facearr,
                              int weight,
                              int pitch_family) {
   CFX_ByteString face = facearr;
-  if (face.Find("Gothic") != FX_STRNPOS ||
-      face.Find("\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
-    if (face.Find("PGothic") != FX_STRNPOS ||
-        face.Find("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
+  if (face.Contains("Gothic") ||
+      face.Contains("\x83\x53\x83\x56\x83\x62\x83\x4e")) {
+    if (face.Contains("PGothic") ||
+        face.Contains("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e")) {
       return 0;
     }
     return 1;
   }
-  if (face.Find("Mincho") != FX_STRNPOS ||
-      face.Find("\x96\xbe\x92\xa9") != FX_STRNPOS) {
-    if (face.Find("PMincho") != FX_STRNPOS ||
-        face.Find("\x82\x6f\x96\xbe\x92\xa9") != FX_STRNPOS) {
+  if (face.Contains("Mincho") || face.Contains("\x96\xbe\x92\xa9")) {
+    if (face.Contains("PMincho") || face.Contains("\x82\x6f\x96\xbe\x92\xa9")) {
       return 2;
     }
     return 3;
diff --git a/core/fxge/win32/fx_win32_device.cpp b/core/fxge/win32/fx_win32_device.cpp
index fd1944a1b4..9c8da591c6 100644
--- a/core/fxge/win32/fx_win32_device.cpp
+++ b/core/fxge/win32/fx_win32_device.cpp
@@ -503,7 +503,7 @@ void* CFX_Win32FallbackFontInfo::MapFont(int weight,
 void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
                                         int weight,
                                         int picth_family) {
-  if (face.Find("KaiTi") != FX_STRNPOS || face.Find("\xbf\xac") != FX_STRNPOS) {
+  if (face.Contains("KaiTi") || face.Contains("\xbf\xac")) {
     if (m_KaiTi.IsEmpty()) {
       m_KaiTi = FindFont("KaiTi");
       if (m_KaiTi.IsEmpty()) {
@@ -511,8 +511,7 @@ void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
       }
     }
     face = m_KaiTi;
-  } else if (face.Find("FangSong") != FX_STRNPOS ||
-             face.Find("\xb7\xc2\xcb\xce") != FX_STRNPOS) {
+  } else if (face.Contains("FangSong") || face.Contains("\xb7\xc2\xcb\xce")) {
     if (m_FangSong.IsEmpty()) {
       m_FangSong = FindFont("FangSong");
       if (m_FangSong.IsEmpty()) {
@@ -520,11 +519,9 @@ void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
       }
     }
     face = m_FangSong;
-  } else if (face.Find("SimSun") != FX_STRNPOS ||
-             face.Find("\xcb\xce") != FX_STRNPOS) {
+  } else if (face.Contains("SimSun") || face.Contains("\xcb\xce")) {
     face = "SimSun";
-  } else if (face.Find("SimHei") != FX_STRNPOS ||
-             face.Find("\xba\xda") != FX_STRNPOS) {
+  } else if (face.Contains("SimHei") || face.Contains("\xba\xda")) {
     face = "SimHei";
   } else if (!(picth_family & FF_ROMAN) && weight > 550) {
     face = "SimHei";
@@ -536,16 +533,15 @@ void CFX_Win32FontInfo::GetGBPreference(CFX_ByteString& face,
 void CFX_Win32FontInfo::GetJapanesePreference(CFX_ByteString& face,
                                               int weight,
                                               int picth_family) {
-  if (face.Find("Gothic") != FX_STRNPOS ||
-      face.Find("\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
-    if (face.Find("PGothic") != FX_STRNPOS ||
-        face.Find("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e") != FX_STRNPOS) {
+  if (face.Contains("Gothic") ||
+      face.Contains("\x83\x53\x83\x56\x83\x62\x83\x4e")) {
+    if (face.Contains("PGothic") ||
+        face.Contains("\x82\x6f\x83\x53\x83\x56\x83\x62\x83\x4e")) {
       face = "MS PGothic";
-    } else if (face.Find("UI Gothic") != FX_STRNPOS) {
+    } else if (face.Contains("UI Gothic")) {
       face = "MS UI Gothic";
     } else {
-      if (face.Find("HGSGothicM") != FX_STRNPOS ||
-          face.Find("HGMaruGothicMPRO") != FX_STRNPOS) {
+      if (face.Contains("HGSGothicM") || face.Contains("HGMaruGothicMPRO")) {
         face = "MS PGothic";
       } else {
         face = "MS Gothic";
@@ -553,10 +549,8 @@ void CFX_Win32FontInfo::GetJapanesePreference(CFX_ByteString& face,
     }
     return;
   }
-  if (face.Find("Mincho") != FX_STRNPOS ||
-      face.Find("\x96\xbe\x92\xa9") != FX_STRNPOS) {
-    if (face.Find("PMincho") != FX_STRNPOS ||
-        face.Find("\x82\x6f\x96\xbe\x92\xa9") != FX_STRNPOS) {
+  if (face.Contains("Mincho") || face.Contains("\x96\xbe\x92\xa9")) {
+    if (face.Contains("PMincho") || face.Contains("\x82\x6f\x96\xbe\x92\xa9")) {
       face = "MS PMincho";
     } else {
       face = "MS Mincho";
@@ -640,7 +634,7 @@ void* CFX_Win32FontInfo::MapFont(int weight,
       face = "Gulim";
       break;
     case FX_CHARSET_ChineseTraditional:
-      if (face.Find("MSung") != FX_STRNPOS) {
+      if (face.Contains("MSung")) {
         face = "MingLiU";
       } else {
         face = "PMingLiU";