logging api example

PLLog.h

/*
 * Author: Landon Fuller <landonf@plausible.coop>
 *
 * Copyright (c) 2008 Plausible Labs.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of any contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

typedef enum {
    PL_LOG_ERR,
    PL_LOG_WARNING,
    PL_LOG_INFO,
    PL_LOG_DEBUG
} pl_loglevel_t;

@interface PLLog : NSObject {
}

#define DO_LOG_DECL(logName) \
    + (void) logName: (NSString *) message, ...;

DO_LOG_DECL(error);
DO_LOG_DECL(warning);
DO_LOG_DECL(info);
DO_LOG_DECL(debug);

#undef DO_LOG_DECL

+ (void) log: (pl_loglevel_t) level withMessage: (NSString *) message, ...;

@end

PLLog.m

/*
 * Author: Landon Fuller <landonf@plausible.coop>
 *
 * Copyright (c) 2008 Plausible Labs.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of any contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#import "PLLog.h"

#include <stdarg.h>

/**
 * This logger provides programmer-oriented debug logging on an application-wide basis.
 */
@implementation PLLog

+ (void) log: (pl_loglevel_t) level withMessage: (NSString *) message withArgs: (va_list) args {
    /* TODO: Filter on level */
    NSLogv(message, args);
}

+ (void) log: (pl_loglevel_t) level withMessage: (NSString *) message, ... {
    va_list ap;
    
    /* Fetch the arguments */
    va_start(ap, message);
    [self log: level withMessage: message withArgs: ap];
    va_end(ap);
}

/* Generate easy-to-use logging methods */
#define DO_LOG(logName, level) \
    /** Log a priority message. */ \
    + (void) logName: (NSString *) message, ... { \
        va_list ap; \
        va_start(ap, message); \
        [self log: level withMessage: message withArgs: ap]; \
        va_end(ap); \
    }

DO_LOG(error, PL_LOG_ERR);
DO_LOG(warning, PL_LOG_WARNING);
DO_LOG(info, PL_LOG_INFO);
DO_LOG(debug, PL_LOG_DEBUG);

#undef DO_LOG

@end