Core/Misc: std::string -> std::string_view in a bunch of places, notably chat commands and Util.h

(cherry picked from commit a41bbd9ad9adedb15c7133bdef1575a6ec0eb1ab)

4 files changed, 104 insertions, 112 deletions

diff --git a/src/common/Utilities/Util.cpp b/src/common/Utilities/Util.cpp
index 42064cc3466..914aed5816c 100644
--- a/src/common/Utilities/Util.cpp
+++ b/src/common/Utilities/Util.cpp
@@ -35,10 +35,10 @@
   #include <arpa/inet.h>
 #endif
 
-Tokenizer::Tokenizer(const std::string &src, const char sep, uint32 vectorReserve /*= 0*/, bool keepEmptyStrings /*= true*/)
+Tokenizer::Tokenizer(std::string_view src, const char sep, uint32 vectorReserve /*= 0*/, bool keepEmptyStrings /*= true*/)
 {
     m_str = new char[src.length() + 1];
-    memcpy(m_str, src.c_str(), src.length() + 1);
+    memcpy(m_str, src.data(), src.length() + 1);
 
     if (vectorReserve)
         m_storage.reserve(vectorReserve);
@@ -400,12 +400,12 @@ bool Utf8toWStr(char const* utf8str, size_t csize, wchar_t* wstr, size_t& wsize)
     return true;
 }
 
-bool Utf8toWStr(const std::string& utf8str, std::wstring& wstr)
+bool Utf8toWStr(std::string_view utf8str, std::wstring& wstr)
 {
     wstr.clear();
     try
     {
-        utf8::utf8to16(utf8str.c_str(), utf8str.c_str()+utf8str.size(), std::back_inserter(wstr));
+        utf8::utf8to16(utf8str.begin(), utf8str.end(), std::back_inserter(wstr));
     }
     catch (std::exception const&)
     {
@@ -439,7 +439,7 @@ bool WStrToUtf8(wchar_t const* wstr, size_t size, std::string& utf8str)
     return true;
 }
 
-bool WStrToUtf8(std::wstring const& wstr, std::string& utf8str)
+bool WStrToUtf8(std::wstring_view wstr, std::string& utf8str)
 {
     try
     {
@@ -448,7 +448,7 @@ bool WStrToUtf8(std::wstring const& wstr, std::string& utf8str)
 
         if (wstr.size())
         {
-            char* oend = utf8::utf16to8(wstr.c_str(), wstr.c_str()+wstr.size(), &utf8str2[0]);
+            char* oend = utf8::utf16to8(wstr.begin(), wstr.end(), &utf8str2[0]);
             utf8str2.resize(oend-(&utf8str2[0]));                // remove unused tail
         }
         utf8str = utf8str2;
@@ -462,7 +462,12 @@ bool WStrToUtf8(std::wstring const& wstr, std::string& utf8str)
     return true;
 }
 
-std::wstring wstrCaseAccentInsensitiveParse(std::wstring const& wstr, LocaleConstant locale)
+void wstrToUpper(std::wstring& str) { std::transform(std::begin(str), std::end(str), std::begin(str), wcharToUpper); }
+void wstrToLower(std::wstring& str) { std::transform(std::begin(str), std::end(str), std::begin(str), wcharToLower); }
+void strToUpper(std::string& str) { std::transform(std::begin(str), std::end(str), std::begin(str), charToUpper); }
+void strToLower(std::string& str) { std::transform(std::begin(str), std::end(str), std::begin(str), charToLower); }
+
+std::wstring wstrCaseAccentInsensitiveParse(std::wstring_view wstr, LocaleConstant locale)
 {
     std::wstring result;
     result.reserve(wstr.length() * 2);
@@ -647,21 +652,6 @@ std::wstring wstrCaseAccentInsensitiveParse(std::wstring const& wstr, LocaleCons
     return result;
 }
 
-void wstrToUpper(std::wstring& str)
-{
-    std::transform(str.begin(), str.end(), str.begin(), wcharToUpper);
-}
-
-void strToLower(std::string& str)
-{
-    std::transform(str.begin(), str.end(), str.begin(), [](char c) { return std::tolower(c); });
-}
-
-void wstrToLower(std::wstring& str)
-{
-    std::transform(str.begin(), str.end(), str.begin(), wcharToLower);
-}
-
 std::wstring GetMainPartOfName(std::wstring const& wname, uint32 declension)
 {
     // supported only Cyrillic cases
@@ -711,7 +701,7 @@ std::wstring GetMainPartOfName(std::wstring const& wname, uint32 declension)
     return wname;
 }
 
-bool utf8ToConsole(const std::string& utf8str, std::string& conStr)
+bool utf8ToConsole(std::string_view utf8str, std::string& conStr)
 {
 #if TRINITY_PLATFORM == TRINITY_PLATFORM_WINDOWS
     std::wstring wstr;
@@ -728,7 +718,7 @@ bool utf8ToConsole(const std::string& utf8str, std::string& conStr)
     return true;
 }
 
-bool consoleToUtf8(const std::string& conStr, std::string& utf8str)
+bool consoleToUtf8(std::string_view conStr, std::string& utf8str)
 {
 #if TRINITY_PLATFORM == TRINITY_PLATFORM_WINDOWS
     std::wstring wstr;
@@ -743,7 +733,7 @@ bool consoleToUtf8(const std::string& conStr, std::string& utf8str)
 #endif
 }
 
-bool Utf8FitTo(const std::string& str, std::wstring const& search)
+bool Utf8FitTo(std::string_view str, std::wstring_view search)
 {
     std::wstring temp;
 
@@ -823,7 +813,7 @@ std::string Trinity::Impl::ByteArrayToHexStr(uint8 const* bytes, size_t arrayLen
     return ss.str();
 }
 
-void Trinity::Impl::HexStrToByteArray(std::string const& str, uint8* out, size_t outlen, bool reverse /*= false*/)
+void Trinity::Impl::HexStrToByteArray(std::string_view str, uint8* out, size_t outlen, bool reverse /*= false*/)
 {
     ASSERT(str.size() == (2 * outlen));
 
@@ -846,14 +836,12 @@ void Trinity::Impl::HexStrToByteArray(std::string const& str, uint8* out, size_t
     }
 }
 
-bool StringToBool(std::string const& str)
+bool StringToBool(std::string_view str)
 {
-    std::string lowerStr = str;
-    std::transform(str.begin(), str.end(), lowerStr.begin(), [](char c) { return char(::tolower(c)); });
-    return lowerStr == "1" || lowerStr == "true" || lowerStr == "yes";
+    return ((str == "1") || StringEqualI(str, "true") || StringEqualI(str, "yes"));
 }
 
-bool StringEqualI(std::string const& str1, std::string const& str2)
+bool StringEqualI(std::string_view str1, std::string_view str2)
 {
     return std::equal(str1.begin(), str1.end(), str2.begin(), str2.end(),
                       [](char a, char b)
@@ -862,12 +850,12 @@ bool StringEqualI(std::string const& str1, std::string const& str2)
                       });
 }
 
-bool StringStartsWith(std::string const& haystack, std::string const& needle)
+bool StringStartsWith(std::string_view haystack, std::string_view needle)
 {
     return (haystack.rfind(needle, 0) == 0);
 }
 
-bool StringContainsStringI(std::string const& haystack, std::string const& needle)
+bool StringContainsStringI(std::string_view haystack, std::string_view needle)
 {
     return haystack.end() !=
         std::search(haystack.begin(), haystack.end(), needle.begin(), needle.end(), [](char c1, char c2) { return std::toupper(c1) == std::toupper(c2); });
diff --git a/src/common/Utilities/Util.h b/src/common/Utilities/Util.h
index d048f3437aa..95c1fd0ee00 100644
--- a/src/common/Utilities/Util.h
+++ b/src/common/Utilities/Util.h
@@ -22,6 +22,7 @@
 #include "Errors.h"
 #include <array>
 #include <string>
+#include <string_view>
 #include <utility>
 #include <vector>
 
@@ -46,7 +47,7 @@ public:
     typedef StorageType::const_reference const_reference;
 
 public:
-    Tokenizer(const std::string &src, char const sep, uint32 vectorReserve = 0, bool keepEmptyStrings = true);
+    Tokenizer(std::string_view src, char const sep, uint32 vectorReserve = 0, bool keepEmptyStrings = true);
     ~Tokenizer() { delete[] m_str; }
 
     const_iterator begin() const { return m_storage.begin(); }
@@ -110,17 +111,17 @@ template <class T>
 inline T square(T x) { return x*x; }
 
 // UTF8 handling
-TC_COMMON_API bool Utf8toWStr(const std::string& utf8str, std::wstring& wstr);
+TC_COMMON_API bool Utf8toWStr(std::string_view utf8str, std::wstring& wstr);
 
 // in wsize==max size of buffer, out wsize==real string size
 TC_COMMON_API bool Utf8toWStr(char const* utf8str, size_t csize, wchar_t* wstr, size_t& wsize);
 
-inline bool Utf8toWStr(const std::string& utf8str, wchar_t* wstr, size_t& wsize)
+inline bool Utf8toWStr(std::string_view utf8str, wchar_t* wstr, size_t& wsize)
 {
-    return Utf8toWStr(utf8str.c_str(), utf8str.size(), wstr, wsize);
+    return Utf8toWStr(utf8str.data(), utf8str.size(), wstr, wsize);
 }
 
-TC_COMMON_API bool WStrToUtf8(std::wstring const& wstr, std::string& utf8str);
+TC_COMMON_API bool WStrToUtf8(std::wstring_view wstr, std::string& utf8str);
 // size==real string size
 TC_COMMON_API bool WStrToUtf8(wchar_t const* wstr, size_t size, std::string& utf8str);
 
@@ -212,34 +213,34 @@ inline bool isNumericOrSpace(wchar_t wchar)
     return isNumeric(wchar) || wchar == L' ';
 }
 
-inline bool isBasicLatinString(const std::wstring &wstr, bool numericOrSpace)
+inline bool isBasicLatinString(std::wstring_view wstr, bool numericOrSpace)
 {
-    for (size_t i = 0; i < wstr.size(); ++i)
-        if (!isBasicLatinCharacter(wstr[i]) && (!numericOrSpace || !isNumericOrSpace(wstr[i])))
+    for (wchar_t c : wstr)
+        if (!isBasicLatinCharacter(c) && (!numericOrSpace || !isNumericOrSpace(c)))
             return false;
     return true;
 }
 
-inline bool isExtendedLatinString(const std::wstring &wstr, bool numericOrSpace)
+inline bool isExtendedLatinString(std::wstring_view wstr, bool numericOrSpace)
 {
-    for (size_t i = 0; i < wstr.size(); ++i)
-        if (!isExtendedLatinCharacter(wstr[i]) && (!numericOrSpace || !isNumericOrSpace(wstr[i])))
+    for (wchar_t c : wstr)
+        if (!isExtendedLatinCharacter(c) && (!numericOrSpace || !isNumericOrSpace(c)))
             return false;
     return true;
 }
 
-inline bool isCyrillicString(const std::wstring &wstr, bool numericOrSpace)
+inline bool isCyrillicString(std::wstring_view wstr, bool numericOrSpace)
 {
-    for (size_t i = 0; i < wstr.size(); ++i)
-        if (!isCyrillicCharacter(wstr[i]) && (!numericOrSpace || !isNumericOrSpace(wstr[i])))
+    for (wchar_t c : wstr)
+        if (!isCyrillicCharacter(c) && (!numericOrSpace || !isNumericOrSpace(c)))
             return false;
     return true;
 }
 
-inline bool isEastAsianString(const std::wstring &wstr, bool numericOrSpace)
+inline bool isEastAsianString(std::wstring_view wstr, bool numericOrSpace)
 {
-    for (size_t i = 0; i < wstr.size(); ++i)
-        if (!isEastAsianCharacter(wstr[i]) && (!numericOrSpace || !isNumericOrSpace(wstr[i])))
+    for (wchar_t c : wstr)
+        if (!isEastAsianCharacter(c) && (!numericOrSpace || !isNumericOrSpace(c)))
             return false;
     return true;
 }
@@ -321,17 +322,21 @@ inline bool isUpper(wchar_t wchar)
     return !isLower(wchar);
 }
 
-TC_COMMON_API std::wstring wstrCaseAccentInsensitiveParse(std::wstring const& wstr, LocaleConstant locale);
+inline char charToUpper(char c) { return std::toupper(c); }
+inline char charToLower(char c) { return std::tolower(c); }
 
 TC_COMMON_API void wstrToUpper(std::wstring& str);
-TC_COMMON_API void strToLower(std::string& str);
 TC_COMMON_API void wstrToLower(std::wstring& str);
+TC_COMMON_API void strToUpper(std::string& str);
+TC_COMMON_API void strToLower(std::string& str);
+
+TC_COMMON_API std::wstring wstrCaseAccentInsensitiveParse(std::wstring_view wstr, LocaleConstant locale);
 
 TC_COMMON_API std::wstring GetMainPartOfName(std::wstring const& wname, uint32 declension);
 
-TC_COMMON_API bool utf8ToConsole(const std::string& utf8str, std::string& conStr);
-TC_COMMON_API bool consoleToUtf8(const std::string& conStr, std::string& utf8str);
-TC_COMMON_API bool Utf8FitTo(const std::string& str, std::wstring const& search);
+TC_COMMON_API bool utf8ToConsole(std::string_view utf8str, std::string& conStr);
+TC_COMMON_API bool consoleToUtf8(std::string_view conStr, std::string& utf8str);
+TC_COMMON_API bool Utf8FitTo(std::string_view str, std::wstring_view search);
 TC_COMMON_API void utf8printf(FILE* out, const char *str, ...);
 TC_COMMON_API void vutf8printf(FILE* out, const char *str, va_list* ap);
 TC_COMMON_API bool Utf8ToUpperOnlyLatin(std::string& utf8String);
@@ -344,7 +349,7 @@ TC_COMMON_API uint32 GetPID();
 namespace Trinity::Impl
 {
     TC_COMMON_API std::string ByteArrayToHexStr(uint8 const* bytes, size_t length, bool reverse = false);
-    TC_COMMON_API void HexStrToByteArray(std::string const& str, uint8* out, size_t outlen, bool reverse = false);
+    TC_COMMON_API void HexStrToByteArray(std::string_view str, uint8* out, size_t outlen, bool reverse = false);
 }
 
 template <typename Container>
@@ -354,19 +359,19 @@ std::string ByteArrayToHexStr(Container const& c, bool reverse = false)
 }
 
 template <size_t Size>
-void HexStrToByteArray(std::string const& str, std::array<uint8, Size>& buf, bool reverse = false)
+void HexStrToByteArray(std::string_view str, std::array<uint8, Size>& buf, bool reverse = false)
 {
     Trinity::Impl::HexStrToByteArray(str, buf.data(), Size, reverse);
 }
 template <size_t Size>
-std::array<uint8, Size> HexStrToByteArray(std::string const& str, bool reverse = false)
+std::array<uint8, Size> HexStrToByteArray(std::string_view str, bool reverse = false)
 {
     std::array<uint8, Size> arr;
     HexStrToByteArray(str, arr, reverse);
     return arr;
 }
 
-inline std::vector<uint8> HexStrToByteVector(std::string const& str, bool reverse = false)
+inline std::vector<uint8> HexStrToByteVector(std::string_view str, bool reverse = false)
 {
     std::vector<uint8> buf;
     size_t const sz = (str.size() / 2);
@@ -375,14 +380,14 @@ inline std::vector<uint8> HexStrToByteVector(std::string const& str, bool revers
     return buf;
 }
 
-TC_COMMON_API bool StringToBool(std::string const& str);
+TC_COMMON_API bool StringToBool(std::string_view str);
 TC_COMMON_API float DegToRad(float degrees);
 
-TC_COMMON_API bool StringEqualI(std::string const& str1, std::string const& str2);
-TC_COMMON_API bool StringStartsWith(std::string const& haystack, std::string const& needle);
-TC_COMMON_API bool StringContainsStringI(std::string const& haystack, std::string const& needle);
+TC_COMMON_API bool StringEqualI(std::string_view str1, std::string_view str2);
+TC_COMMON_API bool StringStartsWith(std::string_view haystack, std::string_view needle);
+TC_COMMON_API bool StringContainsStringI(std::string_view haystack, std::string_view needle);
 template <typename T>
-inline bool ValueContainsStringI(std::pair<T, std::string> const& haystack, std::string const& needle)
+inline bool ValueContainsStringI(std::pair<T, std::string_view> const& haystack, std::string_view needle)
 {
     return StringContainsStringI(haystack.second, needle);
 }
@@ -599,16 +604,13 @@ constexpr typename std::underlying_type<E>::type AsUnderlyingType(E enumValue)
     return static_cast<typename std::underlying_type<E>::type>(enumValue);
 }
 
-template<typename Ret, typename Only>
-Ret* Coalesce(Only* arg)
-{
-    return arg;
-}
-
 template<typename Ret, typename T1, typename... T>
 Ret* Coalesce(T1* first, T*... rest)
 {
-    return static_cast<Ret*>(first ? static_cast<Ret*>(first) : Coalesce<Ret>(rest...));
+    if constexpr (sizeof...(T) > 0)
+        return (first ? static_cast<Ret*>(first) : Coalesce<Ret>(rest...));
+    else
+        return static_cast<Ret*>(first);
 }
 
 template<typename T>
diff --git a/src/server/game/Chat/ChatCommands/ChatCommandArgs.h b/src/server/game/Chat/ChatCommands/ChatCommandArgs.h
index a90790265ca..8a723686196 100644
--- a/src/server/game/Chat/ChatCommands/ChatCommandArgs.h
+++ b/src/server/game/Chat/ChatCommands/ChatCommandArgs.h
@@ -22,7 +22,10 @@
 #include "ChatCommandTags.h"
 #include "SmartEnum.h"
 #include "Util.h"
+#include <charconv>
 #include <map>
+#include <string>
+#include <string_view>
 
 struct GameTele;
 
@@ -43,42 +46,26 @@ namespace ChatCommands
 template <typename T, typename = void>
 struct ArgInfo { static_assert(!std::is_same_v<T,T>, "Invalid command parameter type - see ChatCommandArgs.h for possible types"); };
 
-// catch-all for signed integral types
+// catch-all for integral types
 template <typename T>
-struct ArgInfo<T, std::enable_if_t<std::is_integral_v<T> && std::is_signed_v<T>>>
+struct ArgInfo<T, std::enable_if_t<std::is_integral_v<T>>>
 {
     static char const* TryConsume(T& val, char const* args)
     {
         char const* next = args;
-        std::string token(args, Trinity::Impl::ChatCommands::tokenize(next));
-        try
-        {
-            size_t processedChars = 0;
-            val = std::stoll(token, &processedChars, 0);
-            if (processedChars != token.length())
-                return nullptr;
-        }
-        catch (...) { return nullptr; }
-        return next;
-    }
-};
+        std::string_view token(args, Trinity::Impl::ChatCommands::tokenize(next));
+
+        std::from_chars_result result;
+        if (StringStartsWith(token, "0x"))
+            result = std::from_chars(token.data() + 2, token.data() + token.length(), val, 16);
+        else if (StringStartsWith(token, "0b"))
+            result = std::from_chars(token.data() + 2, token.data() + token.length(), val, 2);
+        else
+            result = std::from_chars(token.data(), token.data() + token.length(), val, 10);
+
+        if ((token.data() + token.length()) != result.ptr)
+            return nullptr;
 
-// catch-all for unsigned integral types
-template <typename T>
-struct ArgInfo<T, std::enable_if_t<std::is_integral_v<T> && std::is_unsigned_v<T>>>
-{
-    static char const* TryConsume(T& val, char const* args)
-    {
-        char const* next = args;
-        std::string token(args, Trinity::Impl::ChatCommands::tokenize(next));
-        try
-        {
-            size_t processedChars = 0;
-            val = std::stoull(token, &processedChars, 0);
-            if (processedChars != token.length())
-                return nullptr;
-        }
-        catch (...) { return nullptr; }
         return next;
     }
 };
@@ -93,6 +80,7 @@ struct ArgInfo<T, std::enable_if_t<std::is_floating_point_v<T>>>
         std::string token(args, Trinity::Impl::ChatCommands::tokenize(next));
         try
         {
+            // @todo replace this once libc++ supports double args to from_chars for required minimum
             size_t processedChars = 0;
             val = std::stold(token, &processedChars);
             if (processedChars != token.length())
@@ -103,16 +91,16 @@ struct ArgInfo<T, std::enable_if_t<std::is_floating_point_v<T>>>
     }
 };
 
-// string
+// string_view
 template <>
-struct ArgInfo<std::string, void>
+struct ArgInfo<std::string_view, void>
 {
-    static char const* TryConsume(std::string& val, char const* args)
+    static char const* TryConsume(std::string_view& val, char const* args)
     {
         char const* next = args;
         if (size_t len = Trinity::Impl::ChatCommands::tokenize(next))
         {
-            val.assign(args, len);
+            val = std::string_view(args, len);
             return next;
         }
         else
@@ -120,19 +108,33 @@ struct ArgInfo<std::string, void>
     }
 };
 
+// string
+template <>
+struct ArgInfo<std::string, void>
+{
+    static char const* TryConsume(std::string& val, char const* args)
+    {
+        std::string_view view;
+        args = ArgInfo<std::string_view>::TryConsume(view, args);
+        if (args)
+            val.assign(view);
+        return args;
+    }
+};
+
 // wstring
 template <>
 struct ArgInfo<std::wstring, void>
 {
     static char const* TryConsume(std::wstring& val, char const* args)
     {
-        std::string utf8Str;
-        char const* ret = ArgInfo<std::string>::TryConsume(utf8Str, args);
+        std::string_view utf8view;
+        char const* ret = ArgInfo<std::string_view>::TryConsume(utf8view, args);
 
         if (!ret)
             return nullptr;
 
-        if (!Utf8toWStr(utf8Str, val))
+        if (!Utf8toWStr(utf8view, val))
             return nullptr;
 
         return ret;
diff --git a/src/server/scripts/Commands/cs_go.cpp b/src/server/scripts/Commands/cs_go.cpp
index a3bb2ce09e3..47f402d8122 100644
--- a/src/server/scripts/Commands/cs_go.cpp
+++ b/src/server/scripts/Commands/cs_go.cpp
@@ -441,7 +441,7 @@ public:
         return DoTeleport(handler, loc);
     }
 
-    static bool HandleGoInstanceCommand(ChatHandler* handler, std::vector<std::string> const& labels)
+    static bool HandleGoInstanceCommand(ChatHandler* handler, std::vector<std::string_view> labels)
     {
         if (labels.empty())
             return false;
@@ -453,7 +453,7 @@ public:
             uint32 count = 0;
             std::string const& scriptName = sObjectMgr->GetScriptName(pair.second.ScriptId);
             char const* mapName = ASSERT_NOTNULL(sMapStore.LookupEntry(pair.first))->MapName[handler->GetSessionDbcLocale()];
-            for (auto const& label : labels)
+            for (std::string_view label : labels)
                 if (StringContainsStringI(scriptName, label))
                     ++count;
 
@@ -526,7 +526,7 @@ public:
         return false;
     }
 
-    static bool HandleGoBossCommand(ChatHandler* handler, std::vector<std::string> const& needles)
+    static bool HandleGoBossCommand(ChatHandler* handler, std::vector<std::string_view> needles)
     {
         if (needles.empty())
             return false;
@@ -543,7 +543,7 @@ public:
 
             uint32 count = 0;
             std::string const& scriptName = sObjectMgr->GetScriptName(data.ScriptID);
-            for (auto const& label : needles)
+            for (std::string_view label : needles)
                 if (StringContainsStringI(scriptName, label) || StringContainsStringI(data.Name, label))
                     ++count;