telodendria/include/Cytoplasm/Log.h
Jordan Bancino 461357b526 Move headers from src/include to include/Cytoplasm.
This makes it easier to build Cytoplasm as a component of another
program (for example, Telodendria), or as a standalone system library.
2024-01-13 18:40:31 -05:00

196 lines
6.4 KiB
C

/*
* Copyright (C) 2022-2024 Jordan Bancino <@jordan:bancino.net>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef CYTOPLASM_LOG_H
#define CYTOPLASM_LOG_H
/***
* @Nm Log
* @Nd A simple logging framework for logging to multiple destinations.
* @Dd April 27 2023
* @Xr Stream
*
* .Nm
* is a simple C logging library that allows for colorful outputs,
* timestamps, and custom log levels. It also features the ability to
* have multiple logs open at one time, although Cytoplasm primarily
* utilizes the global log. All logs are thread safe.
*/
#include <stdio.h>
#include <stddef.h>
#include <syslog.h>
#include "Stream.h"
#define LOG_FLAG_COLOR (1 << 0)
#define LOG_FLAG_SYSLOG (1 << 1)
/**
* A log is defined as a configuration that describes the properties
* of the log. This opaque structure can be manipulated by the
* functions defined in this API.
*/
typedef struct LogConfig LogConfig;
/**
* Create a new log configuration with sane defaults that can be used
* immediately with the logging functions.
*/
extern LogConfig * LogConfigCreate(void);
/**
* Get the global log configuration, creating a new one with
* .Fn LogConfigCreate
* if necessary.
*/
extern LogConfig * LogConfigGlobal(void);
/**
* Free the given log configuration. Note that this does not close the
* underlying stream associated with the log, if there is one. Also
* note that to avoid memory leaks, the global log configuration must
* also be freed, but it cannot be used after it is freed.
*/
extern void LogConfigFree(LogConfig *);
/**
* Set the current log level on the specified log configuration.
* This indicates that only messages at or above this level should be
* logged; all others are silently discarded. The passed log level
* should be one of the log levels defined by
* .Xr syslog 3 .
* Refer to that page for a complete list of acceptable log levels,
* and note that passing an invalid log level will result in undefined
* behavior.
*/
extern void LogConfigLevelSet(LogConfig *, int);
/**
* Cause the log output to be indented two more spaces than it was
* previously. This can be helpful when generating stack traces or
* other hierarchical output. This is a simple convenience wrapper
* around
* .Fn LogConfigIndentSet .
*/
extern void LogConfigIndent(LogConfig *);
/**
* Cause the log output to be indented two less spaces than it was
* previously. This is a simple convenience wrapper around
* .Fn LogConfigIndentSet .
*/
extern void LogConfigUnindent(LogConfig *);
/**
* Indent future log output using the specified config by some
* arbitrary amount.
*/
extern void LogConfigIndentSet(LogConfig *, size_t);
/**
* Set the file stream that logging output should be written to. This
* defaults to standard output, but it can be set to standard error,
* or any other arbitrary stream. Passing a NULL value for the stream
* pointer sets the log output to the standard output. Note that the
* output stream is only used if
* .Va LOG_FLAG_SYSLOG
* is not set.
*/
extern void LogConfigOutputSet(LogConfig *, Stream *);
/**
* Set a number of boolean options on a log configuration. This
* function uses bitwise operators, so multiple options can be set with
* a single function call using bitwise OR operators. The flags are
* defined as preprocessor macros, and are as follows:
* .Bl -tag -width Ds
* .It LOG_FLAG_COLOR
* When set, enable color-coded output on TTYs. Note that colors are
* implemented as ANSI escape sequences, and are not written to file
* streams that are not actually connected to a TTY, to prevent those
* sequences from being written to a file.
* .Xr isatty 3
* is checked before writing any terminal sequences.
* .It LOG_FLAG_SYSLOG
* When set, log output to the syslog using
* .Xr syslog 3 ,
* instead of logging to the file set by
* .Fn LogConfigOutputSet .
* This flag always overrides the stream set by that function,
* regardless of when it was set, even if it was set after this flag
* was set.
* .El
*/
extern void LogConfigFlagSet(LogConfig *, int);
/**
* Clear a boolean flag from the specified log format. See above for
* the list of flags.
*/
extern void LogConfigFlagClear(LogConfig *, int);
/**
* Set a custom timestamp to be prepended to each message if the
* output is not going to the system log. Consult your system's
* documentation for
* .Xr strftime 3 .
* A value of NULL disables the timestamp output before messages.
*/
extern void LogConfigTimeStampFormatSet(LogConfig *, char *);
/**
* This function does the actual logging of messages using a
* specified configuration. It takes the configuration, the log
* level, a format string, and then a list of arguments, all in that
* order. This function only logs messages if their level is above
* or equal to the currently configured log level, making it easy to
* turn some messages on or off.
* .Pp
* This function has the same usage as
* .Xr vprintf 3 .
* Consult that page for the list of format specifiers and their
* arguments. This function is typically not used directly, see the
* other log functions for the most common use cases.
*/
extern void Logv(LogConfig *, int, const char *, va_list);
/**
* Log a message using
* .Fn Logv .
* with the specified configuration. This function has the same usage
* as
* .Xr printf 3 .
*/
extern void LogTo(LogConfig *, int, const char *, ...);
/**
* Log a message to the global log using
* .Fn Logv .
* This function has the same usage as
* .Xr printf 3 .
*/
extern void Log(int, const char *, ...);
#endif