RLogger.cxx

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/// \file RLogger.cxx
/// \ingroup Base ROOT7
/// \author Axel Naumann <axel@cern.ch>
/// \date 2015-07-07
/// \warning This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback
/// is welcome!
 
/*************************************************************************
 * Copyright (C) 1995-2020, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include "ROOT/RLogger.hxx"
 
#include "ROOT/RMakeUnique.hxx"
#include "TError.h"
 
#include <algorithm>
#include <array>
#include <vector>
 
using namespace ROOT::Experimental;
 
// pin vtable
RLogHandler::~RLogHandler() {}
 
namespace {
class RLogHandlerDefault : public RLogHandler {
public:
   // Returns false if further emission of this log entry should be suppressed.
   bool Emit(const RLogEntry &entry) override;
};
 
inline bool RLogHandlerDefault::Emit(const RLogEntry &entry)
{
   constexpr static int numLevels = static_cast<int>(ELogLevel::kDebug) + 1;
   int cappedLevel = std::min(static_cast<int>(entry.fLevel), numLevels - 1);
   constexpr static std::array<const char *, numLevels> sTag{
      {"{unset-error-level please report}", "FATAL", "Error", "Warning", "Info", "Debug"}};
 
   std::stringstream strm;
   auto channel = entry.fChannel;
   if (channel && !channel->GetName().empty())
      strm << '[' << channel->GetName() << "] ";
   strm << sTag[cappedLevel];
 
   if (!entry.fLocation.fFile.empty())
      strm << " " << entry.fLocation.fFile << ':' << entry.fLocation.fLine;
   if (!entry.fLocation.fFuncName.empty())
      strm << " in " << entry.fLocation.fFuncName;
 
   static constexpr const int errorLevelOld[] = {kFatal /*unset*/, kFatal, kError, kWarning, kInfo, kInfo /*debug*/};
   (*::GetErrorHandler())(errorLevelOld[cappedLevel], entry.fLevel == ELogLevel::kFatal, strm.str().c_str(),
                          entry.fMessage.c_str());
   return true;
}
} // unnamed namespace
 
RLogManager &RLogManager::Get()
{
   static RLogManager instance(std::make_unique<RLogHandlerDefault>());
   return instance;
}
 
std::unique_ptr<RLogHandler> RLogManager::Remove(RLogHandler *handler)
{
   auto iter = std::find_if(fHandlers.begin(), fHandlers.end(), [&](const std::unique_ptr<RLogHandler> &handlerPtr) {
      return handlerPtr.get() == handler;
   });
   if (iter != fHandlers.end()) {
      std::unique_ptr<RLogHandler> ret;
      swap(*iter, ret);
      fHandlers.erase(iter);
      return ret;
   }
   return {};
}
 
bool RLogManager::Emit(const RLogEntry &entry)
{
   auto channel = entry.fChannel;
 
   Increment(entry.fLevel);
   if (channel != this)
      channel->Increment(entry.fLevel);
 
   // Is there a specific level for the channel? If so, take that,
   // overruling the global one.
   if (channel->GetEffectiveVerbosity(*this) < entry.fLevel)
      return true;
 
   // Lock-protected extraction of handlers, such that they don't get added during the
   // handler iteration.
   std::vector<RLogHandler *> handlers;
 
   {
      std::lock_guard<std::mutex> lock(fMutex);
 
      handlers.resize(fHandlers.size());
      std::transform(fHandlers.begin(), fHandlers.end(), handlers.begin(),
                     [](const std::unique_ptr<RLogHandler> &handlerUPtr) { return handlerUPtr.get(); });
   }
 
   for (auto &&handler : handlers)
      if (!handler->Emit(entry))
         return false;
   return true;
}