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// Copyright Epic Games, Inc. All Rights Reserved.
#include <zenutil/logging/rotatingfilesink.h>
#include <zencore/basicfile.h>
#include <zencore/filesystem.h>
#include <zencore/logging/helpers.h>
#include <zencore/logging/messageonlyformatter.h>
#include <zencore/memory/llm.h>
#include <zencore/thread.h>
#include <atomic>
namespace zen::logging {
struct RotatingFileSink::Impl
{
Impl(const std::filesystem::path& BaseFilename, std::size_t MaxSize, std::size_t MaxFiles, bool RotateOnOpen)
: m_BaseFilename(BaseFilename)
, m_MaxSize(MaxSize)
, m_MaxFiles(MaxFiles)
, m_Formatter(std::make_unique<MessageOnlyFormatter>())
{
ZEN_MEMSCOPE(ELLMTag::Logging);
std::error_code Ec;
if (RotateOnOpen)
{
RwLock::ExclusiveLockScope RotateLock(m_Lock);
Rotate(RotateLock, Ec);
}
else
{
m_CurrentFile.Open(m_BaseFilename, BasicFile::Mode::kWrite, Ec);
if (!Ec)
{
m_CurrentSize = m_CurrentFile.FileSize(Ec);
}
if (!Ec)
{
if (m_CurrentSize > m_MaxSize)
{
RwLock::ExclusiveLockScope RotateLock(m_Lock);
Rotate(RotateLock, Ec);
}
}
}
if (Ec)
{
throw std::system_error(Ec, fmt::format("Failed to open log file '{}'", m_BaseFilename.string()));
}
}
~Impl()
{
try
{
RwLock::ExclusiveLockScope RotateLock(m_Lock);
m_CurrentFile.Close();
}
catch (const std::exception&)
{
}
}
void Rotate(RwLock::ExclusiveLockScope&, std::error_code& OutEc)
{
ZEN_MEMSCOPE(ELLMTag::Logging);
m_CurrentFile.Close();
OutEc = RotateFiles(m_BaseFilename, m_MaxFiles);
if (OutEc)
{
return;
}
m_CurrentFile.Open(m_BaseFilename, BasicFile::Mode::kWrite, OutEc);
if (OutEc)
{
return;
}
m_CurrentSize = m_CurrentFile.FileSize(OutEc);
if (OutEc)
{
// FileSize failed but we have an open file — reset to 0
// so we can at least attempt writes from the start
m_CurrentSize = 0;
OutEc.clear();
}
}
bool TrySinkIt(const LogMessage& Msg, MemoryBuffer& OutFormatted)
{
ZEN_MEMSCOPE(ELLMTag::Logging);
RwLock::SharedLockScope Lock(m_Lock);
if (!m_CurrentFile.IsOpen())
{
return false;
}
m_Formatter->Format(Msg, OutFormatted);
helpers::StripAnsiSgrSequences(OutFormatted);
size_t AddSize = OutFormatted.size();
size_t WritePos = m_CurrentSize.fetch_add(AddSize);
if (WritePos + AddSize > m_MaxSize)
{
return false;
}
std::error_code Ec;
m_CurrentFile.Write(OutFormatted.data(), OutFormatted.size(), WritePos, Ec);
if (Ec)
{
return false;
}
m_NeedFlush = true;
return true;
}
bool TrySinkIt(const MemoryBuffer& Formatted)
{
ZEN_MEMSCOPE(ELLMTag::Logging);
RwLock::SharedLockScope Lock(m_Lock);
if (!m_CurrentFile.IsOpen())
{
return false;
}
size_t AddSize = Formatted.size();
size_t WritePos = m_CurrentSize.fetch_add(AddSize);
if (WritePos + AddSize > m_MaxSize)
{
return false;
}
std::error_code Ec;
m_CurrentFile.Write(Formatted.data(), Formatted.size(), WritePos, Ec);
if (Ec)
{
return false;
}
m_NeedFlush = true;
return true;
}
RwLock m_Lock;
const std::filesystem::path m_BaseFilename;
const std::size_t m_MaxSize;
const std::size_t m_MaxFiles;
std::unique_ptr<Formatter> m_Formatter;
std::atomic_size_t m_CurrentSize;
BasicFile m_CurrentFile;
std::atomic<bool> m_NeedFlush = false;
};
RotatingFileSink::RotatingFileSink(const std::filesystem::path& BaseFilename, std::size_t MaxSize, std::size_t MaxFiles, bool RotateOnOpen)
: m_Impl(std::make_unique<Impl>(BaseFilename, MaxSize, MaxFiles, RotateOnOpen))
{
}
RotatingFileSink::~RotatingFileSink() = default;
void
RotatingFileSink::Log(const LogMessage& Msg)
{
ZEN_MEMSCOPE(ELLMTag::Logging);
try
{
MemoryBuffer Formatted;
if (m_Impl->TrySinkIt(Msg, Formatted))
{
return;
}
// This intentionally has no limit on the number of retries, see
// comment above.
for (;;)
{
{
RwLock::ExclusiveLockScope RotateLock(m_Impl->m_Lock);
// Only rotate if no-one else has rotated before us
if (m_Impl->m_CurrentSize > m_Impl->m_MaxSize || !m_Impl->m_CurrentFile.IsOpen())
{
std::error_code Ec;
m_Impl->Rotate(RotateLock, Ec);
if (Ec)
{
return;
}
}
}
if (m_Impl->TrySinkIt(Formatted))
{
return;
}
}
}
catch (const std::exception&)
{
// Silently eat errors
}
}
void
RotatingFileSink::Flush()
{
if (!m_Impl->m_NeedFlush)
{
return;
}
ZEN_MEMSCOPE(ELLMTag::Logging);
try
{
RwLock::SharedLockScope Lock(m_Impl->m_Lock);
if (m_Impl->m_CurrentFile.IsOpen())
{
m_Impl->m_CurrentFile.Flush();
}
}
catch (const std::exception&)
{
// Silently eat errors
}
m_Impl->m_NeedFlush = false;
}
void
RotatingFileSink::SetFormatter(std::unique_ptr<Formatter> InFormatter)
{
ZEN_MEMSCOPE(ELLMTag::Logging);
try
{
RwLock::ExclusiveLockScope _(m_Impl->m_Lock);
m_Impl->m_Formatter = std::move(InFormatter);
}
catch (const std::exception&)
{
// Silently eat errors
}
}
} // namespace zen::logging
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