IOStream

class ThreadSafeIOStream

A thread-safe version of I/O stream.

The ThreadSafeIOStream class provides thread-safe output capabilities by locking a mutex during output operations. It allows users to set a prefix for output messages, which can help debug and monitor applications with multiple threads.

Note

The stream will only be outputed when the std::endl manipulator is founded, indicating that the line ended.

Public Functions

ThreadSafeIOStream(): Constructs a ThreadSafeIOStream.

void setPrefix(const std::string &prefix)

Sets the prefix printed in front of each output line.

Parameters:: prefix – The prefix string to prepend to the output.

ThreadSafeIOStream &operator<<(std::ostream &(*manip)(std::ostream&))

Handles the std::endl manipulator for proper line breaks.

This function flushes the thread-local buffer to the shared std::cout under a mutex lock when std::endl is encountered.

Parameters:: manip – A pointer to a manipulator function such as std::endl.
Returns:: A reference to ThreadSafeIOStream for chaining.

template<typename T> inline ThreadSafeIOStream &operator<<(const T &value)

Output operator overload to handle various types.

This function writes to a thread-local buffer and flushes it only when a newline is encountered.

Template Parameters:: T – The type of value to output.
Parameters:: value – The value to output.
Returns:: A reference to ThreadSafeIOStream for chaining.

template<typename T> inline ThreadSafeIOStream &operator>>(T &value)

Input operator overload to handle various types.

This function locks a mutex to ensure thread-safe input operations. The prefix will be appended before the input (not always a line)

Template Parameters:: T – The type of value to read.
Parameters:: value – The variable to store the input.
Returns:: A reference to ThreadSafeIOStream for chaining.

Private Members

std::mutex global_mutex_: Mutex to ensure thread-safe access to std::cout.

Private Static Attributes

static thread_local std::ostringstream thread_buffer_: Thread-local buffer for each thread.

static thread_local std::string thread_prefix_: Thread-local prefix for each thread.

class Logger

A flexible, thread-safe logger that supports logging to any stream.

Public Functions

Logger(std::ostream &stream)

Constructs a Logger with a specified output stream.

Parameters:: stream – The initial output stream.

void log(LogLevel level, const std::string &message)

Logs a message with the specified log level.

Parameters:

level – The log level.
message – The message to log.

void setLogLevel(LogLevel level)

Sets the minimum log level. Messages below this level will not be logged.

Parameters:: level – The minimum log level.

Private Functions

std::string levelToString(LogLevel level) const

Converts a log level to its string representation.

Parameters:: level – The log level.
Returns:: The string representation of the log level.

std::string getTimestamp() const

Gets the current timestamp as a string.

Returns:: The timestamp string in the format “YYYY-MM-DD HH:MM:SS”.

Private Members

std::ostream *stream_: Pointer to the current output stream.

std::mutex mutex_: Mutex for thread-safe logging.

LogLevel min_log_level_ = LogLevel::DEBUG: Minimum log level.