LogSinkGuard Class Reference

RAII guard that temporarily removes an attached stream from a LogStream and re-inserts it on scope exit. More...

#include <OpenMS/CONCEPT/LogStream.h>

Public Member Functions
	LogSinkGuard (LogStream &log_stream, std::ostream &stream)
	Construct a guard that removes stream, if attached, and re-inserts it on destruction.
	~LogSinkGuard ()
	Destructor writes output pending inside the scope to the other destinations, then restores the sink.
	LogSinkGuard (const LogSinkGuard &)=delete
LogSinkGuard &	operator= (const LogSinkGuard &)=delete
	LogSinkGuard (LogSinkGuard &&)=delete
LogSinkGuard &	operator= (LogSinkGuard &&)=delete

Private Attributes
LogStream &	log_stream_
std::ostream &	stream_
const bool	was_attached_
	was the sink attached when the guard was constructed? if not, the guard does nothing
LogStream::GuardedRemoval	removal_
	what the guard removed, restored on destruction

Detailed Description

RAII guard that temporarily removes an attached stream from a LogStream and re-inserts it on scope exit.

This class provides exception-safe temporary removal of output streams from LogStream objects. Use this when you need to temporarily suppress logging to a specific stream (e.g., cout) during operations that may throw exceptions.

Note

The guard acts only on a stream that is attached when it is constructed; for an unattached stream it does nothing (will not insert on scope exit). On a thread-local stream, it suppresses the stream for the calling thread until it ends, also if the global stream inserts it again meanwhile; then the thread-local stream has the destinations it would have without the guard (e.g. not a destination that the global stream removed meanwhile). On a global stream, it removes the destination and inserts it again, with its prefix, at the end (unless it was inserted again meanwhile); the stream must outlive the guard.

The OPENMS_LOG_* macros write to thread-local streams that follow the destinations of the global ones. Guarding a global stream (getGlobalLog*()) suppresses the sink for all threads; guarding a thread-local stream (getThreadLocalLog*()) only for the calling thread. Text pending before and inside the guarded scope goes to the destinations it was written for: for a global stream, this holds for the calling thread, not for other threads.

Example usage:

LogSinkGuard guard(getThreadLocalLogInfo(), cout); // Removes cout, will re-insert on scope exit
some_operation_that_may_throw();
// cout is automatically re-inserted when guard goes out of scope

Constructor & Destructor Documentation

LogSinkGuard() [1/3]

LogSinkGuard ( LogStream &  log_stream, std::ostream &  stream  )

inline

Construct a guard that removes stream, if attached, and re-inserts it on destruction.

Parameters

log_stream	The LogStream to remove the stream from (and re-insert into on destruction)
stream	The stream to temporarily remove (e.g., std::cout); if it is not one of log_stream's destinations, the guard does nothing

~LogSinkGuard()

~LogSinkGuard ( )

inline

Destructor writes output pending inside the scope to the other destinations, then restores the sink.

LogSinkGuard() [2/3]

LogSinkGuard ( const LogSinkGuard &  )

delete

LogSinkGuard() [3/3]

LogSinkGuard ( LogSinkGuard &&  )

delete

Member Function Documentation

operator=() [1/2]

LogSinkGuard & operator= ( const LogSinkGuard &  )

delete

operator=() [2/2]

LogSinkGuard & operator= ( LogSinkGuard &&  )

delete

Member Data Documentation

log_stream_

LogStream& log_stream_

private

removal_

LogStream::GuardedRemoval removal_

private

what the guard removed, restored on destruction

stream_

std::ostream& stream_

private

was_attached_

const bool was_attached_

private

was the sink attached when the guard was constructed? if not, the guard does nothing