/**
 * @file llerror.cpp
 * @date   December 2006
 * @brief error message system
 *
 * $LicenseInfo:firstyear=2006&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"

#include "llerror.h"
#include "llerrorcontrol.h"
#include "llsdutil.h"

#include <cctype>
#ifdef __GNUC__
# include <cxxabi.h>
#endif // __GNUC__
#include <sstream>
#if !LL_WINDOWS
# include <syslog.h>
# include <unistd.h>
# include <sys/stat.h>
#else
# include <io.h>
#endif // !LL_WINDOWS
#include <vector>
#include "string.h"

#include "llapp.h"
#include "llapr.h"
#include "llfile.h"
#include "lllivefile.h"
#include "llsd.h"
#include "llsdserialize.h"
#include "llsingleton.h"
#include "llstl.h"
#include "lltimer.h"
#include <boost/fiber/recursive_mutex.hpp>

// On Mac, got:
// #error "Boost.Stacktrace requires `_Unwind_Backtrace` function. Define
// `_GNU_SOURCE` macro or `BOOST_STACKTRACE_GNU_SOURCE_NOT_REQUIRED` if
// _Unwind_Backtrace is available without `_GNU_SOURCE`."
#define BOOST_STACKTRACE_GNU_SOURCE_NOT_REQUIRED
#include <boost/stacktrace.hpp>

namespace {
#if LL_WINDOWS
    void debugger_print(const std::string& s)
    {
        // Be careful when calling OutputDebugString as it throws DBG_PRINTEXCEPTION_C
        // which works just fine under the windows debugger, but can cause users who
        // have enabled SEHOP exception chain validation to crash due to interactions
        // between the Win 32-bit exception handling and boost coroutine fiber stacks. BUG-2707
        //
        if (IsDebuggerPresent())
        {
            // Need UTF16 for Unicode OutputDebugString
            //
            if (s.size())
            {
                OutputDebugString(utf8str_to_utf16str(s).c_str());
                OutputDebugString(TEXT("\n"));
            }
        }
    }
#else
    class RecordToSyslog : public LLError::Recorder
    {
    public:
        RecordToSyslog(const std::string& identity)
            : mIdentity(identity)
        {
            openlog(mIdentity.c_str(), LOG_CONS|LOG_PID, LOG_LOCAL0);
                // we need to set the string from a local copy of the string
                // since apparanetly openlog expects the const char* to remain
                // valid even after it returns (presumably until closelog)
        }

        ~RecordToSyslog()
        {
            closelog();
        }

        virtual bool enabled() override
        {
            return LLError::getEnabledLogTypesMask() & 0x01;
        }

        virtual void recordMessage(LLError::ELevel level,
                                    const std::string& message) override
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
            int syslogPriority = LOG_CRIT;
            switch (level) {
                case LLError::LEVEL_DEBUG:  syslogPriority = LOG_DEBUG; break;
                case LLError::LEVEL_INFO:   syslogPriority = LOG_INFO;  break;
                case LLError::LEVEL_WARN:   syslogPriority = LOG_WARNING; break;
                case LLError::LEVEL_ERROR:  syslogPriority = LOG_CRIT;  break;
                default:                    syslogPriority = LOG_CRIT;
            }

            syslog(syslogPriority, "%s", message.c_str());
        }
    private:
        std::string mIdentity;
    };
#endif

    class RecordToFile : public LLError::Recorder
    {
    public:
        RecordToFile(const std::string& filename):
            mName(filename)
        {
            mFile.open(filename.c_str(), std::ios_base::out | std::ios_base::app);
            if (!mFile)
            {
                LL_INFOS() << "Error setting log file to " << filename << LL_ENDL;
            }
            else
            {
                if (!LLError::getAlwaysFlush())
                {
                    mFile.sync_with_stdio(false);
                }
            }
        }

        ~RecordToFile()
        {
            mFile.close();
        }

        virtual bool enabled() override
        {
#ifdef LL_RELEASE_FOR_DOWNLOAD
            return 1;
#else
            return LLError::getEnabledLogTypesMask() & 0x02;
#endif
        }

        bool okay() const { return mFile.good(); }

        std::string getFilename() const { return mName; }

        virtual void recordMessage(LLError::ELevel level,
                                    const std::string& message) override
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
            if (LLError::getAlwaysFlush())
            {
                mFile << message << std::endl;
            }
            else
            {
                mFile << message << "\n";
            }
        }

    private:
        const std::string mName;
        llofstream mFile;
    };


    class RecordToStderr : public LLError::Recorder
    {
    public:
        RecordToStderr(bool timestamp) : mUseANSI(checkANSI())
        {
            this->showMultiline(true);
        }

        virtual bool enabled() override
        {
            return LLError::getEnabledLogTypesMask() & 0x04;
        }

        LL_FORCE_INLINE std::string createBoldANSI()
        {
            std::string ansi_code;
            ansi_code += '\033';
            ansi_code += "[";
            ansi_code += "1";
            ansi_code += "m";

            return ansi_code;
        }

        LL_FORCE_INLINE std::string createResetANSI()
        {
            std::string ansi_code;
            ansi_code += '\033';
            ansi_code += "[";
            ansi_code += "0";
            ansi_code += "m";

            return ansi_code;
        }

        LL_FORCE_INLINE std::string createANSI(const std::string& color)
        {
            std::string ansi_code;
            ansi_code  += '\033';
            ansi_code  += "[";
            ansi_code += "38;5;";
            ansi_code  += color;
            ansi_code += "m";

            return ansi_code;
        }

        virtual void recordMessage(LLError::ELevel level,
                       const std::string& message) override
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
            // The default colors for error, warn and debug are now a bit more pastel
            // and easier to read on the default (black) terminal background but you
            // now have the option to set the color of each via an environment variables:
            // LL_ANSI_ERROR_COLOR_CODE (default is red)
            // LL_ANSI_WARN_COLOR_CODE  (default is blue)
            // LL_ANSI_DEBUG_COLOR_CODE (default is magenta)
            // The list of color codes can be found in many places but I used this page:
            // https://www.lihaoyi.com/post/BuildyourownCommandLinewithANSIescapecodes.html#256-colors
            // (Note: you may need to restart Visual Studio to pick environment changes)
            char* val = nullptr;
            std::string s_ansi_error_code = "160";
            if ((val = getenv("LL_ANSI_ERROR_COLOR_CODE")) != nullptr) s_ansi_error_code = std::string(val);
            std::string s_ansi_warn_code = "33";
            if ((val = getenv("LL_ANSI_WARN_COLOR_CODE")) != nullptr) s_ansi_warn_code = std::string(val);
            std::string s_ansi_debug_code = "177";
            if ((val = getenv("LL_ANSI_DEBUG_COLOR_CODE")) != nullptr) s_ansi_debug_code = std::string(val);

            static std::string s_ansi_error = createANSI(s_ansi_error_code); // default is red
            static std::string s_ansi_warn  = createANSI(s_ansi_warn_code); // default is blue
            static std::string s_ansi_debug = createANSI(s_ansi_debug_code); // default is magenta

            if (mUseANSI)
            {
                writeANSI((level == LLError::LEVEL_ERROR) ? s_ansi_error :
                          (level == LLError::LEVEL_WARN)  ? s_ansi_warn :
                                                            s_ansi_debug, message);
            }
            else
            {
                LL_PROFILE_ZONE_NAMED("fprintf");
                 fprintf(stderr, "%s\n", message.c_str());
            }
        }

    private:
        bool mUseANSI;

        LL_FORCE_INLINE void writeANSI(const std::string& ansi_code, const std::string& message)
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
            static std::string s_ansi_bold = createBoldANSI();  // bold text
            static std::string s_ansi_reset = createResetANSI();  // reset
            // ANSI color code escape sequence, message, and reset in one fprintf call
            // Default all message levels to bold so we can distinguish our own messages from those dumped by subprocesses and libraries.
            fprintf(stderr, "%s%s\n%s", ansi_code.c_str(), message.c_str(), s_ansi_reset.c_str() );
        }

        static bool checkANSI(void)
        {
            // Check whether it's okay to use ANSI; if stderr is
            // a tty then we assume yes.  Can be turned off with
            // the LL_NO_ANSI_COLOR env var.
            return (0 != isatty(2)) &&
                (NULL == getenv("LL_NO_ANSI_COLOR"));
        }
    };

    class RecordToFixedBuffer : public LLError::Recorder
    {
    public:
        RecordToFixedBuffer(LLLineBuffer* buffer)
            : mBuffer(buffer)
            {
                this->showMultiline(true);
                this->showTags(false);
                this->showLocation(false);
            }

        virtual bool enabled() override
        {
            return LLError::getEnabledLogTypesMask() & 0x08;
        }

        virtual void recordMessage(LLError::ELevel level,
                                   const std::string& message) override
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
            mBuffer->addLine(message);
        }

    private:
        LLLineBuffer* mBuffer;
    };

#if LL_WINDOWS
    class RecordToWinDebug: public LLError::Recorder
    {
    public:
        RecordToWinDebug()
        {
            this->showMultiline(true);
            this->showTags(false);
            this->showLocation(false);
        }

        virtual bool enabled() override
        {
            return LLError::getEnabledLogTypesMask() & 0x10;
        }

        virtual void recordMessage(LLError::ELevel level,
                                   const std::string& message) override
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
            debugger_print(message);
        }
    };
#endif
}


namespace
{
    std::string className(const std::type_info& type)
    {
        return LLError::Log::demangle(type.name());
    }
} // anonymous

namespace LLError
{
    std::string Log::demangle(const char* mangled)
    {
#ifdef __GNUC__
        // GCC: type_info::name() returns a mangled class name,st demangle
        // passing nullptr, 0 forces allocation of a unique buffer we can free
        // fixing MAINT-8724 on OSX 10.14
        int status = -1;
        char* name = abi::__cxa_demangle(mangled, nullptr, 0, &status);
        std::string result(name ? name : mangled);
        free(name);
        return result;

#elif LL_WINDOWS
        // Visual Studio: type_info::name() includes the text "class " at the start
        std::string name = mangled;
        for (const auto& prefix : std::vector<std::string>{ "class ", "struct " })
        {
            if (0 == name.compare(0, prefix.length(), prefix))
            {
                return name.substr(prefix.length());
            }
        }
        // huh, that's odd, we should see one or the other prefix -- but don't
        // try to log unless logging is already initialized
        // in Python, " or ".join(vector) -- but in C++, a PITB
        LL_DEBUGS() << "Did not see 'class' or 'struct' prefix on '"
            << name << "'" << LL_ENDL;
        return name;

#else  // neither GCC nor Visual Studio
        return mangled;
#endif
    }
} // LLError

namespace
{
    std::string functionName(const std::string& preprocessor_name)
    {
#if LL_WINDOWS
        // DevStudio: the __FUNCTION__ macro string includes
        // the type and/or namespace prefixes

        std::string::size_type p = preprocessor_name.rfind(':');
        if (p == std::string::npos)
        {
            return preprocessor_name;
        }
        return preprocessor_name.substr(p + 1);

#else
        return preprocessor_name;
#endif
    }


    class LogControlFile : public LLLiveFile
    {
        LOG_CLASS(LogControlFile);

    public:
        static LogControlFile& fromDirectory(const std::string& user_dir, const std::string& app_dir);

        virtual bool loadFile();

    private:
        LogControlFile(const std::string &filename)
            : LLLiveFile(filename)
            { }
    };

    LogControlFile& LogControlFile::fromDirectory(const std::string& user_dir, const std::string& app_dir)
    {
        // NB: We have no abstraction in llcommon  for the "proper"
        // delimiter but it turns out that "/" works on all three platforms

        std::string file = user_dir + "/logcontrol-dev.xml";

        llstat stat_info;
        if (LLFile::stat(file, &stat_info)) {
            // NB: stat returns non-zero if it can't read the file, for example
            // if it doesn't exist.  LLFile has no better abstraction for
            // testing for file existence.

            file = app_dir + "/logcontrol.xml";
        }
        return * new LogControlFile(file);
            // NB: This instance is never freed
    }

    bool LogControlFile::loadFile()
    {
        LLSD configuration;

        {
            llifstream file(filename().c_str());
            if (!file.is_open())
            {
                LL_WARNS() << filename() << " failed to open file; not changing configuration" << LL_ENDL;
                return false;
            }

            if (LLSDSerialize::fromXML(configuration, file) == LLSDParser::PARSE_FAILURE)
            {
                LL_WARNS() << filename() << " parcing error; not changing configuration" << LL_ENDL;
                return false;
            }

            if (! configuration || !configuration.isMap())
            {
                LL_WARNS() << filename() << " missing, ill-formed, or simply undefined"
                            " content; not changing configuration"
                        << LL_ENDL;
                return false;
            }
        }

        LLError::configure(configuration);
        LL_INFOS("LogControlFile") << "logging reconfigured from " << filename() << LL_ENDL;
        return true;
    }


    typedef std::map<std::string, LLError::ELevel> LevelMap;
    typedef std::vector<LLError::RecorderPtr> Recorders;
    typedef std::vector<LLError::CallSite*> CallSiteVector;

    class SettingsConfig : public LLRefCount
    {
        friend class Globals;

    public:
        virtual ~SettingsConfig();

        LLError::ELevel                     mDefaultLevel;

        bool                                mLogAlwaysFlush;

        U32                                 mEnabledLogTypesMask;

        LevelMap                            mFunctionLevelMap;
        LevelMap                            mClassLevelMap;
        LevelMap                            mFileLevelMap;
        LevelMap                            mTagLevelMap;
        std::map<std::string, unsigned int> mUniqueLogMessages;

        LLError::FatalFunction              mCrashFunction;
        LLError::TimeFunction               mTimeFunction;

        Recorders                           mRecorders;
        boost::fibers::recursive_mutex      mRecorderMutex;

        int                                 mShouldLogCallCounter;

    private:
        SettingsConfig();
    };

    typedef LLPointer<SettingsConfig> SettingsConfigPtr;

    SettingsConfig::SettingsConfig()
        : LLRefCount(),
        mDefaultLevel(LLError::LEVEL_DEBUG),
        mLogAlwaysFlush(true),
        mEnabledLogTypesMask(255),
        mFunctionLevelMap(),
        mClassLevelMap(),
        mFileLevelMap(),
        mTagLevelMap(),
        mUniqueLogMessages(),
        mCrashFunction(NULL),
        mTimeFunction(NULL),
        mRecorders(),
        mRecorderMutex(),
        mShouldLogCallCounter(0)
    {
    }

    SettingsConfig::~SettingsConfig()
    {
        mRecorders.clear();
    }

    class Globals
    {
    public:
        static Globals* getInstance();
    protected:
        Globals();
    public:
        std::string mFatalMessage;

        void addCallSite(LLError::CallSite&);
        void invalidateCallSites();

        SettingsConfigPtr getSettingsConfig();

        void resetSettingsConfig();
        LLError::SettingsStoragePtr saveAndResetSettingsConfig();
        void restore(LLError::SettingsStoragePtr pSettingsStorage);
    private:
        CallSiteVector callSites;
        SettingsConfigPtr mSettingsConfig;
    };

    Globals::Globals()
        :
        callSites(),
        mSettingsConfig(new SettingsConfig())
    {
    }


    Globals* Globals::getInstance()
    {
        // According to C++11 Function-Local Initialization
        // of static variables is supposed to be thread safe
        // without risk of deadlocks.
        static Globals inst;

        return &inst;
    }

    void Globals::addCallSite(LLError::CallSite& site)
    {
        callSites.push_back(&site);
    }

    void Globals::invalidateCallSites()
    {
        for (LLError::CallSite* site : callSites)
        {
            site->invalidate();
        }

        callSites.clear();
    }

    SettingsConfigPtr Globals::getSettingsConfig()
    {
        return mSettingsConfig;
    }

    void Globals::resetSettingsConfig()
    {
        invalidateCallSites();
        mSettingsConfig = new SettingsConfig();
    }

    LLError::SettingsStoragePtr Globals::saveAndResetSettingsConfig()
    {
        LLError::SettingsStoragePtr oldSettingsConfig(mSettingsConfig.get());
        resetSettingsConfig();
        return oldSettingsConfig;
    }

    void Globals::restore(LLError::SettingsStoragePtr pSettingsStorage)
    {
        invalidateCallSites();
        SettingsConfigPtr newSettingsConfig(dynamic_cast<SettingsConfig *>(pSettingsStorage.get()));
        mSettingsConfig = newSettingsConfig;
    }
}

namespace LLError
{
    CallSite::CallSite(ELevel level,
                    const char* file,
                    int line,
                    const std::type_info& class_info,
                    const char* function,
                    bool printOnce,
                    const char** tags,
                    size_t tag_count)
    :   mLevel(level),
        mFile(file),
        mLine(line),
        mClassInfo(class_info),
        mFunction(function),
        mCached(false),
        mShouldLog(false),
        mPrintOnce(printOnce),
        mTags(new const char* [tag_count]),
        mTagCount(tag_count)
    {
        switch (mLevel)
        {
        case LEVEL_DEBUG: mLevelString = "DEBUG";   break;
        case LEVEL_INFO:  mLevelString = "INFO";    break;
        case LEVEL_WARN:  mLevelString = "WARNING"; break;
        case LEVEL_ERROR: mLevelString = "ERROR";   break;
        default:          mLevelString = "XXX";     break;
        };

        mLocationString = llformat("%s(%d)", abbreviateFile(mFile).c_str(), mLine);
#if LL_WINDOWS
        // DevStudio: __FUNCTION__ already includes the full class name
#else
#if LL_LINUX
        // gross, but typeid comparison seems to always fail here with gcc4.1
        if (0 != strcmp(mClassInfo.name(), typeid(NoClassInfo).name()))
#else
        if (mClassInfo != typeid(NoClassInfo))
#endif // LL_LINUX
        {
            mFunctionString = className(mClassInfo) + "::";
        }
#endif
        mFunctionString += std::string(mFunction);

        for (int i = 0; i < tag_count; i++)
        {
            if (strchr(tags[i], ' '))
            {
                LL_ERRS() << "Space is not allowed in a log tag at " << mLocationString << LL_ENDL;
            }
            mTags[i] = tags[i];
        }

        mTagString.append("#");
        // always construct a tag sequence; will be just a single # if no tag
        for (size_t i = 0; i < mTagCount; i++)
        {
            mTagString.append(mTags[i]);
            mTagString.append("#");
        }
    }

    CallSite::~CallSite()
    {
        delete []mTags;
    }

    void CallSite::invalidate()
    {
        mCached = false;
    }
}

namespace
{
    bool shouldLogToStderr()
    {
#if LL_DARWIN
        // On macOS, stderr from apps launched from the Finder goes to the
        // console log.  It's generally considered bad form to spam too much
        // there. That scenario can be detected by noticing that stderr is a
        // character device (S_IFCHR).

        // If stderr is a tty or a pipe, assume the user launched from the
        // command line or debugger and therefore wants to see stderr.
        if (isatty(STDERR_FILENO))
            return true;
        // not a tty, but might still be a pipe -- check
        struct stat st;
        if (fstat(STDERR_FILENO, &st) < 0)
        {
            // capture errno right away, before engaging any other operations
            auto errno_save = errno;
            // this gets called during log-system setup -- can't log yet!
            std::cerr << "shouldLogToStderr: fstat(" << STDERR_FILENO << ") failed, errno "
                      << errno_save << std::endl;
            // if we can't tell, err on the safe side and don't write stderr
            return false;
        }

        // fstat() worked: return true only if stderr is a pipe
        return ((st.st_mode & S_IFMT) == S_IFIFO);
#else
        return true;
#endif
    }

    bool stderrLogWantsTime()
    {
#if LL_WINDOWS
        return false;
#else
        return true;
#endif
    }


    void commonInit(const std::string& user_dir, const std::string& app_dir, bool log_to_stderr = true)
    {
        Globals::getInstance()->resetSettingsConfig();

        LLError::setDefaultLevel(LLError::LEVEL_INFO);
        LLError::setAlwaysFlush(true);
        LLError::setEnabledLogTypesMask(0xFFFFFFFF);
        LLError::setTimeFunction(LLError::utcTime);

        // log_to_stderr is only false in the unit and integration tests to keep builds quieter
        if (log_to_stderr && shouldLogToStderr())
        {
            LLError::logToStderr();
        }

#if LL_WINDOWS
        LLError::RecorderPtr recordToWinDebug(new RecordToWinDebug());
        LLError::addRecorder(recordToWinDebug);
#endif

        LogControlFile& e = LogControlFile::fromDirectory(user_dir, app_dir);

        // NOTE: We want to explicitly load the file before we add it to the event timer
        // that checks for changes to the file.  Else, we're not actually loading the file yet,
        // and most of the initialization happens without any attention being paid to the
        // log control file.  Not to mention that when it finally gets checked later,
        // all log statements that have been evaluated already become dirty and need to be
        // evaluated for printing again.  So, make sure to call checkAndReload()
        // before addToEventTimer().
        e.checkAndReload();
        e.addToEventTimer();
    }
}

namespace LLError
{
    void initForApplication(const std::string& user_dir, const std::string& app_dir, bool log_to_stderr)
    {
        commonInit(user_dir, app_dir, log_to_stderr);
    }

    void setFatalFunction(const FatalFunction& f)
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        s->mCrashFunction = f;
    }

    FatalFunction getFatalFunction()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        return s->mCrashFunction;
    }

    std::string getFatalMessage()
    {
        return Globals::getInstance()->mFatalMessage;
    }

    void setTimeFunction(TimeFunction f)
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        s->mTimeFunction = f;
    }

    void setDefaultLevel(ELevel level)
    {
        Globals *g = Globals::getInstance();
        g->invalidateCallSites();
        SettingsConfigPtr s = g->getSettingsConfig();
        s->mDefaultLevel = level;
    }

    ELevel getDefaultLevel()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        return s->mDefaultLevel;
    }

    void setAlwaysFlush(bool flush)
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        s->mLogAlwaysFlush = flush;
    }

    bool getAlwaysFlush()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        return s->mLogAlwaysFlush;
    }

    void setEnabledLogTypesMask(U32 mask)
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        s->mEnabledLogTypesMask = mask;
    }

    U32 getEnabledLogTypesMask()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        return s->mEnabledLogTypesMask;
    }

    void setFunctionLevel(const std::string& function_name, ELevel level)
    {
        Globals *g = Globals::getInstance();
        g->invalidateCallSites();
        SettingsConfigPtr s = g->getSettingsConfig();
        s->mFunctionLevelMap[function_name] = level;
    }

    void setClassLevel(const std::string& class_name, ELevel level)
    {
        Globals *g = Globals::getInstance();
        g->invalidateCallSites();
        SettingsConfigPtr s = g->getSettingsConfig();
        s->mClassLevelMap[class_name] = level;
    }

    void setFileLevel(const std::string& file_name, ELevel level)
    {
        Globals *g = Globals::getInstance();
        g->invalidateCallSites();
        SettingsConfigPtr s = g->getSettingsConfig();
        s->mFileLevelMap[file_name] = level;
    }

    void setTagLevel(const std::string& tag_name, ELevel level)
    {
        Globals *g = Globals::getInstance();
        g->invalidateCallSites();
        SettingsConfigPtr s = g->getSettingsConfig();
        s->mTagLevelMap[tag_name] = level;
    }

    LLError::ELevel decodeLevel(std::string name)
    {
        static LevelMap level_names;
        if (level_names.empty())
        {
            level_names["ALL"]      = LLError::LEVEL_ALL;
            level_names["DEBUG"]    = LLError::LEVEL_DEBUG;
            level_names["INFO"]     = LLError::LEVEL_INFO;
            level_names["WARN"]     = LLError::LEVEL_WARN;
            level_names["ERROR"]    = LLError::LEVEL_ERROR;
            level_names["NONE"]     = LLError::LEVEL_NONE;
        }

        std::transform(name.begin(), name.end(), name.begin(), toupper);

        LevelMap::const_iterator i = level_names.find(name);
        if (i == level_names.end())
        {
            LL_WARNS() << "unrecognized logging level: '" << name << "'" << LL_ENDL;
            return LLError::LEVEL_INFO;
        }

        return i->second;
    }
}

namespace {
    void setLevels(LevelMap& map, const LLSD& list, LLError::ELevel level)
    {
        LLSD::array_const_iterator i, end;
        for (i = list.beginArray(), end = list.endArray(); i != end; ++i)
        {
            map[*i] = level;
        }
    }
}

namespace LLError
{
    void configure(const LLSD& config)
    {
        Globals *g = Globals::getInstance();
        g->invalidateCallSites();
        SettingsConfigPtr s = g->getSettingsConfig();

        s->mFunctionLevelMap.clear();
        s->mClassLevelMap.clear();
        s->mFileLevelMap.clear();
        s->mTagLevelMap.clear();
        s->mUniqueLogMessages.clear();

        setDefaultLevel(decodeLevel(config["default-level"]));
        if (config.has("log-always-flush"))
        {
            setAlwaysFlush(config["log-always-flush"]);
        }
        if (config.has("enabled-log-types-mask"))
        {
            setEnabledLogTypesMask(config["enabled-log-types-mask"].asInteger());
        }

        if (config.has("settings") && config["settings"].isArray())
        {
            LLSD sets = config["settings"];
            LLSD::array_const_iterator a, end;
            for (a = sets.beginArray(), end = sets.endArray(); a != end; ++a)
            {
                const LLSD& entry = *a;
                if (entry.isMap() && entry.size() != 0)
                {
                    ELevel level = decodeLevel(entry["level"]);

                    setLevels(s->mFunctionLevelMap, entry["functions"], level);
                    setLevels(s->mClassLevelMap, entry["classes"], level);
                    setLevels(s->mFileLevelMap, entry["files"], level);
                    setLevels(s->mTagLevelMap, entry["tags"], level);
                }
            }
        }
    }
}


namespace LLError
{
    Recorder::Recorder()
        : mWantsTime(true)
        , mWantsTags(true)
        , mWantsLevel(true)
        , mWantsLocation(true)
        , mWantsFunctionName(true)
        , mWantsMultiline(false)
    {
    }

    Recorder::~Recorder()
    {
    }

    bool Recorder::wantsTime()
    {
        return mWantsTime;
    }

    // virtual
    bool Recorder::wantsTags()
    {
        return mWantsTags;
    }

    // virtual
    bool Recorder::wantsLevel()
    {
        return mWantsLevel;
    }

    // virtual
    bool Recorder::wantsLocation()
    {
        return mWantsLocation;
    }

    // virtual
    bool Recorder::wantsFunctionName()
    {
        return mWantsFunctionName;
    }

    // virtual
    bool Recorder::wantsMultiline()
    {
        return mWantsMultiline;
    }

    void Recorder::showTime(bool show)
    {
        mWantsTime = show;
    }

    void Recorder::showTags(bool show)
    {
        mWantsTags = show;
    }

    void Recorder::showLevel(bool show)
    {
        mWantsLevel = show;
    }

    void Recorder::showLocation(bool show)
    {
        mWantsLocation = show;
    }

    void Recorder::showFunctionName(bool show)
    {
        mWantsFunctionName = show;
    }

    void Recorder::showMultiline(bool show)
    {
        mWantsMultiline = show;
    }

    void addRecorder(RecorderPtr recorder)
    {
        if (!recorder)
        {
            return;
        }
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        std::unique_lock lock(s->mRecorderMutex);
        s->mRecorders.push_back(recorder);
    }

    void removeRecorder(RecorderPtr recorder)
    {
        if (!recorder)
        {
            return;
        }
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        std::unique_lock lock(s->mRecorderMutex);
        s->mRecorders.erase(std::remove(s->mRecorders.begin(), s->mRecorders.end(), recorder),
                            s->mRecorders.end());
    }

    // Find an entry in SettingsConfig::mRecorders whose RecorderPtr points to
    // a Recorder subclass of type RECORDER. Return, not a RecorderPtr (which
    // points to the Recorder base class), but a shared_ptr<RECORDER> which
    // specifically points to the concrete RECORDER subclass instance, along
    // with a Recorders::iterator indicating the position of that entry in
    // mRecorders. The shared_ptr might be empty (operator!() returns true) if
    // there was no such RECORDER subclass instance in mRecorders.
    //
    // NOTE!!! Requires external mutex lock!!!
    template <typename RECORDER>
    std::pair<std::shared_ptr<RECORDER>, Recorders::iterator>
    findRecorderPos(SettingsConfigPtr &s)
    {
        // Since we promise to return an iterator, use a classic iterator
        // loop.
        auto end{s->mRecorders.end()};
        for (Recorders::iterator it{s->mRecorders.begin()}; it != end; ++it)
        {
            // *it is a RecorderPtr, a shared_ptr<Recorder>. Use a
            // dynamic_pointer_cast to try to downcast to test if it's also a
            // shared_ptr<RECORDER>.
            auto ptr = std::dynamic_pointer_cast<RECORDER>(*it);
            if (ptr)
            {
                // found the entry we want
                return { ptr, it };
            }
        }
        // dropped out of the loop without finding any such entry -- instead
        // of default-constructing Recorders::iterator (which might or might
        // not be valid), return a value that is valid but not dereferenceable.
        return { {}, end };
    }

    // Find an entry in SettingsConfig::mRecorders whose RecorderPtr points to
    // a Recorder subclass of type RECORDER. Return, not a RecorderPtr (which
    // points to the Recorder base class), but a shared_ptr<RECORDER> which
    // specifically points to the concrete RECORDER subclass instance. The
    // shared_ptr might be empty (operator!() returns true) if there was no
    // such RECORDER subclass instance in mRecorders.
    template <typename RECORDER>
    std::shared_ptr<RECORDER> findRecorder()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        std::unique_lock lock(s->mRecorderMutex);
        return findRecorderPos<RECORDER>(s).first;
    }

    // Remove an entry from SettingsConfig::mRecorders whose RecorderPtr
    // points to a Recorder subclass of type RECORDER. Return true if there
    // was one and we removed it, false if there wasn't one to start with.
    template <typename RECORDER>
    bool removeRecorder()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        std::unique_lock lock(s->mRecorderMutex);
        auto found = findRecorderPos<RECORDER>(s);
        if (found.first)
        {
            s->mRecorders.erase(found.second);
        }
        return bool(found.first);
    }
}

namespace LLError
{
    void logToFile(const std::string& file_name)
    {
        // remove any previous Recorder filling this role
        removeRecorder<RecordToFile>();

        if (!file_name.empty())
        {
            std::shared_ptr<RecordToFile> recordToFile(new RecordToFile(file_name));
            if (recordToFile->okay())
            {
                addRecorder(recordToFile);
            }
        }
    }

    std::string logFileName()
    {
        auto found = findRecorder<RecordToFile>();
        return found? found->getFilename() : std::string();
    }

    void logToStderr()
    {
        if (! findRecorder<RecordToStderr>())
        {
            RecorderPtr recordToStdErr(new RecordToStderr(stderrLogWantsTime()));
            addRecorder(recordToStdErr);
        }
    }

    void logToFixedBuffer(LLLineBuffer* fixedBuffer)
    {
        // remove any previous Recorder filling this role
        removeRecorder<RecordToFixedBuffer>();

        if (fixedBuffer)
        {
            RecorderPtr recordToFixedBuffer(new RecordToFixedBuffer(fixedBuffer));
            addRecorder(recordToFixedBuffer);
        }
    }
}

namespace
{
    std::string escapedMessageLines(const std::string& message)
    {
        std::ostringstream out;
        size_t written_out = 0;
        size_t all_content = message.length();
        size_t escape_char_index; // always relative to start of message
        // Use find_first_of to find the next character in message that needs escaping
        for ( escape_char_index = message.find_first_of("\\\n\r");
              escape_char_index != std::string::npos && written_out < all_content;
              // record what we've written this iteration, scan for next char that needs escaping
              written_out = escape_char_index + 1, escape_char_index = message.find_first_of("\\\n\r", written_out)
             )
        {
            // found a character that needs escaping, so write up to that with the escape prefix
            // note that escape_char_index is relative to the start, not to the written_out offset
            out << message.substr(written_out, escape_char_index - written_out) << '\\';

            // write out the appropriate second character in the escape sequence
            char found = message[escape_char_index];
            switch ( found )
            {
            case '\\':
                out << '\\';
                break;
            case '\n':
                out << 'n';
                break;
            case '\r':
                out << 'r';
                break;
            }
        }

        if ( written_out < all_content ) // if the loop above didn't write everything
        {
            // write whatever was left
            out << message.substr(written_out, std::string::npos);
        }
        return out.str();
    }

    void writeToRecorders(const LLError::CallSite& site, const std::string& message)
    {
        LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
        LLError::ELevel level = site.mLevel;
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();

        std::string escaped_message;

        std::unique_lock lock(s->mRecorderMutex);
        for (LLError::RecorderPtr& r : s->mRecorders)
        {
            if (!r->enabled())
            {
                continue;
            }

            std::ostringstream message_stream;

            if (r->wantsTime() && s->mTimeFunction != NULL)
            {
                message_stream << s->mTimeFunction();
            }
            message_stream << " ";

            if (r->wantsLevel())
            {
                message_stream << site.mLevelString;
            }
            message_stream << " ";

            if (r->wantsTags())
            {
                message_stream << site.mTagString;
            }
            message_stream << " ";

            if (r->wantsLocation() || level == LLError::LEVEL_ERROR)
            {
                message_stream << site.mLocationString;
            }
            message_stream << " ";

            if (r->wantsFunctionName())
            {
                message_stream << site.mFunctionString;
            }
            message_stream << " : ";

            if (r->wantsMultiline())
            {
                message_stream << message;
            }
            else
            {
                if (escaped_message.empty())
                {
                    escaped_message = escapedMessageLines(message);
                }
                message_stream << escaped_message;
            }

            r->recordMessage(level, message_stream.str());
        }
    }
}

namespace {
    // We need a couple different mutexes, but we want to use the same mechanism
    // for both. Make getMutex() a template function with different instances
    // for different MutexDiscriminator values.
    enum MutexDiscriminator
    {
        LOG_MUTEX,
        STACKS_MUTEX
    };
    // Some logging calls happen very early in processing -- so early that our
    // module-static variables aren't yet initialized. getMutex() wraps a
    // function-static LLMutex so that early calls can still have a valid
    // LLMutex instance.
    template <MutexDiscriminator MTX>
    LLMutex* getMutex()
    {
        // guaranteed to be initialized the first time control reaches here
        static LLMutex sMutex;
        return &sMutex;
    }

    bool checkLevelMap(const LevelMap& map, const std::string& key,
                        LLError::ELevel& level)
    {
        bool stop_checking;
        LevelMap::const_iterator i = map.find(key);
        if (i == map.end())
        {
            return stop_checking = false;
        }

            level = i->second;
        return stop_checking = true;
    }

    bool checkLevelMap( const LevelMap& map,
                        const char *const * keys,
                        size_t count,
                        LLError::ELevel& level)
    {
        bool found_level = false;

        LLError::ELevel tag_level = LLError::LEVEL_NONE;

        for (size_t i = 0; i < count; i++)
        {
            LevelMap::const_iterator it = map.find(keys[i]);
            if (it != map.end())
            {
                found_level = true;
                tag_level = llmin(tag_level, it->second);
            }
        }

        if (found_level)
        {
            level = tag_level;
        }
        return found_level;
    }
}

namespace LLError
{

    bool Log::shouldLog(CallSite& site)
    {
        LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
        LLMutexTrylock lock(getMutex<LOG_MUTEX>(), 5);
        if (!lock.isLocked())
        {
            return false;
        }

        Globals *g = Globals::getInstance();
        SettingsConfigPtr s = g->getSettingsConfig();

        s->mShouldLogCallCounter++;

        const std::string& class_name = className(site.mClassInfo);
        std::string function_name = functionName(site.mFunction);
#if LL_LINUX
        // gross, but typeid comparison seems to always fail here with gcc4.1
        if (0 != strcmp(site.mClassInfo.name(), typeid(NoClassInfo).name()))
#else
        if (site.mClassInfo != typeid(NoClassInfo))
#endif // LL_LINUX
        {
            function_name = class_name + "::" + function_name;
        }

        ELevel compareLevel = s->mDefaultLevel;

        // The most specific match found will be used as the log level,
        // since the computation short circuits.
        // So, in increasing order of importance:
        // Default < Tags < File < Class < Function
        checkLevelMap(s->mFunctionLevelMap, function_name, compareLevel)
        || checkLevelMap(s->mClassLevelMap, class_name, compareLevel)
        || checkLevelMap(s->mFileLevelMap, abbreviateFile(site.mFile), compareLevel)
        || (site.mTagCount > 0
            ? checkLevelMap(s->mTagLevelMap, site.mTags, site.mTagCount, compareLevel)
            : false);

        site.mCached = true;
        g->addCallSite(site);
        return site.mShouldLog = site.mLevel >= compareLevel;
    }


    void Log::flush(const std::ostringstream& out, const CallSite& site)
    {
        LL_PROFILE_ZONE_SCOPED_CATEGORY_LOGGING
        LLMutexTrylock lock(getMutex<LOG_MUTEX>(),5);
        if (!lock.isLocked())
        {
            return;
        }

        Globals* g = Globals::getInstance();
        SettingsConfigPtr s = g->getSettingsConfig();

        std::string message = out.str();

        if (site.mPrintOnce)
        {
            std::ostringstream message_stream;

            std::map<std::string, unsigned int>::iterator messageIter = s->mUniqueLogMessages.find(message);
            if (messageIter != s->mUniqueLogMessages.end())
            {
                messageIter->second++;
                unsigned int num_messages = messageIter->second;
                if (num_messages == 10 || num_messages == 50 || (num_messages % 100) == 0)
                {
                    message_stream << "ONCE (" << num_messages << "th time seen): ";
                }
                else
                {
                    return;
                }
            }
            else
            {
                message_stream << "ONCE: ";
                s->mUniqueLogMessages[message] = 1;
            }
            message_stream << message;
            message = message_stream.str();
        }

        writeToRecorders(site, message);

        if (site.mLevel == LEVEL_ERROR)
        {
            writeToRecorders(site, stringize(boost::stacktrace::stacktrace()));
            g->mFatalMessage = message;
            if (s->mCrashFunction)
            {
                s->mCrashFunction(message);
            }
        }
    }
}

namespace LLError
{
    SettingsStoragePtr saveAndResetSettings()
    {
        return Globals::getInstance()->saveAndResetSettingsConfig();
    }

    void restoreSettings(SettingsStoragePtr pSettingsStorage)
    {
        return Globals::getInstance()->restore(pSettingsStorage);
    }

    std::string removePrefix(std::string& s, const std::string& p)
    {
        std::string::size_type where = s.find(p);
        if (where == std::string::npos)
        {
            return s;
        }

        return std::string(s, where + p.size());
    }

    void replaceChar(std::string& s, char old, char replacement)
    {
        std::string::size_type i = 0;
        std::string::size_type len = s.length();
        for ( ; i < len; i++ )
        {
            if (s[i] == old)
            {
                s[i] = replacement;
            }
        }
    }

    std::string abbreviateFile(const std::string& filePath)
    {
        std::string f = filePath;
#if LL_WINDOWS
        replaceChar(f, '\\', '/');
#endif
        static std::string indra_prefix = "indra/";
        f = removePrefix(f, indra_prefix);

#if LL_DARWIN
        static std::string newview_prefix = "newview/../";
        f = removePrefix(f, newview_prefix);
#endif

        return f;
    }

    int shouldLogCallCount()
    {
        SettingsConfigPtr s = Globals::getInstance()->getSettingsConfig();
        return s->mShouldLogCallCounter;
    }

    std::string utcTime()
    {
        time_t now = time(NULL);
        const size_t BUF_SIZE = 64;
        char time_str[BUF_SIZE];    /* Flawfinder: ignore */

        auto chars = strftime(time_str, BUF_SIZE,
                                  "%Y-%m-%dT%H:%M:%SZ",
                                  gmtime(&now));

        return chars ? time_str : "time error";
    }
}

namespace LLError
{
    LLCallStacks::StringVector LLCallStacks::sBuffer ;

    //static
    void LLCallStacks::push(const char* function, const int line)
    {
        LLMutexTrylock lock(getMutex<STACKS_MUTEX>(), 5);
        if (!lock.isLocked())
        {
            return;
        }

        if(sBuffer.size() > 511)
        {
            clear() ;
        }

        std::ostringstream out;
        insert(out, function, line);
        sBuffer.push_back(out.str());
    }

    //static
    void LLCallStacks::insert(std::ostream& out, const char* function, const int line)
    {
        out << function << " line " << line << " " ;
    }

    //static
    void LLCallStacks::end(const std::ostringstream& out)
    {
        LLMutexTrylock lock(getMutex<STACKS_MUTEX>(), 5);
        if (!lock.isLocked())
        {
            return;
        }

        if(sBuffer.size() > 511)
        {
            clear() ;
        }

        sBuffer.push_back(out.str());
    }

    //static
    void LLCallStacks::print()
    {
        LLMutexTrylock lock(getMutex<STACKS_MUTEX>(), 5);
        if (!lock.isLocked())
        {
            return;
        }

        if(! sBuffer.empty())
        {
            LL_INFOS() << " ************* PRINT OUT LL CALL STACKS ************* " << LL_ENDL;
            for (StringVector::const_reverse_iterator ri(sBuffer.rbegin()), re(sBuffer.rend());
                 ri != re; ++ri)
            {
                LL_INFOS() << (*ri) << LL_ENDL;
            }
            LL_INFOS() << " *************** END OF LL CALL STACKS *************** " << LL_ENDL;
        }

        cleanup();
    }

    //static
    void LLCallStacks::clear()
    {
        sBuffer.clear();
    }

    //static
    void LLCallStacks::cleanup()
    {
        clear();
    }

    std::ostream& operator<<(std::ostream& out, const LLStacktrace&)
    {
        return out << boost::stacktrace::stacktrace();
    }

    // LLOutOfMemoryWarning
    std::string LLUserWarningMsg::sLocalizedOutOfMemoryTitle;
    std::string LLUserWarningMsg::sLocalizedOutOfMemoryWarning;
    LLUserWarningMsg::Handler LLUserWarningMsg::sHandler;

    void LLUserWarningMsg::show(const std::string& message)
    {
        if (sHandler)
        {
            sHandler(std::string(), message);
        }
    }

    void LLUserWarningMsg::showOutOfMemory()
    {
        if (sHandler && !sLocalizedOutOfMemoryTitle.empty())
        {
            sHandler(sLocalizedOutOfMemoryTitle, sLocalizedOutOfMemoryWarning);
        }
    }

    void LLUserWarningMsg::showMissingFiles()
    {
        // Files Are missing, likely can't localize.
        const std::string error_string =
            "Second Life viewer couldn't access some of the files it needs and will be closed."
            "\n\nPlease reinstall viewer from  https://secondlife.com/support/downloads/ and "
            "contact https://support.secondlife.com if issue persists after reinstall.";
        sHandler("Missing Files", error_string);
    }

    void LLUserWarningMsg::setHandler(const LLUserWarningMsg::Handler &handler)
    {
        sHandler = handler;
    }

    void LLUserWarningMsg::setOutOfMemoryStrings(const std::string& title, const std::string& message)
    {
        sLocalizedOutOfMemoryTitle = title;
        sLocalizedOutOfMemoryWarning = message;
    }
}

void crashdriver(void (*callback)(int*))
{
    // The LLERROR_CRASH macro used to have inline code of the form:
    //int* make_me_crash = NULL;
    //*make_me_crash = 0;

    // But compilers are getting smart enough to recognize that, so we must
    // assign to an address supplied by a separate source file. We could do
    // the assignment here in crashdriver() -- but then BugSplat would group
    // all LL_ERRS() crashes as the fault of this one function, instead of
    // identifying the specific LL_ERRS() source line. So instead, do the
    // assignment in a lambda in the caller's source. We just provide the
    // nullptr target.
    callback(nullptr);
}