File: yui/js/yui-log.js

            /**
             * Provides console log capability and exposes a custom event for
             * console implementations. This module is a `core` YUI module,
             * <a href="../classes/YUI.html#method_log">it's documentation is located under the YUI class</a>.
             *
             * @module yui
             * @submodule yui-log
             */
            
            var INSTANCE = Y,
                LOGEVENT = 'yui:log',
                UNDEFINED = 'undefined',
                LEVELS = { debug: 1,
                           info: 2,
                           warn: 4,
                           error: 8 };
            
            /**
             * If the 'debug' config is true, a 'yui:log' event will be
             * dispatched, which the Console widget and anything else
             * can consume.  If the 'useBrowserConsole' config is true, it will
             * write to the browser console if available.  YUI-specific log
             * messages will only be present in the -debug versions of the
             * JS files.  The build system is supposed to remove log statements
             * from the raw and minified versions of the files.
             *
             * @method log
             * @for YUI
             * @param  {String}  msg  The message to log.
             * @param  {String}  cat  The log category for the message.  Default
             *                        categories are "info", "warn", "error", "debug".
             *                        Custom categories can be used as well. (opt).
             * @param  {String}  src  The source of the the message (opt).
             * @param  {boolean} silent If true, the log event won't fire.
             * @return {YUI}      YUI instance.
             */
            INSTANCE.log = function(msg, cat, src, silent) {
                var bail, excl, incl, m, f, minlevel,
                    Y = INSTANCE,
                    c = Y.config,
                    publisher = (Y.fire) ? Y : YUI.Env.globalEvents;
                // suppress log message if the config is off or the event stack
                // or the event call stack contains a consumer of the yui:log event
                if (c.debug) {
                    // apply source filters
                    src = src || "";
                    if (typeof src !== "undefined") {
                        excl = c.logExclude;
                        incl = c.logInclude;
                        if (incl && !(src in incl)) {
                            bail = 1;
                        } else if (incl && (src in incl)) {
                            bail = !incl[src];
                        } else if (excl && (src in excl)) {
                            bail = excl[src];
                        }
            
                        // Set a default category of info if the category was not defined.
                        if ((typeof cat === 'undefined')) {
                            cat = 'info';
                        }
            
                        // Determine the current minlevel as defined in configuration
                        Y.config.logLevel = Y.config.logLevel || 'debug';
                        minlevel = LEVELS[Y.config.logLevel.toLowerCase()];
            
                        if (cat in LEVELS && LEVELS[cat] < minlevel) {
                            // Skip this message if the we don't meet the defined minlevel
                            bail = 1;
                        }
                    }
                    if (!bail) {
                        if (c.useBrowserConsole) {
                            m = (src) ? src + ': ' + msg : msg;
                            if (Y.Lang.isFunction(c.logFn)) {
                                c.logFn.call(Y, msg, cat, src);
                            } else if (typeof console !== UNDEFINED && console.log) {
                                f = (cat && console[cat] && (cat in LEVELS)) ? cat : 'log';
                                console[f](m);
                            } else if (typeof opera !== UNDEFINED) {
                                opera.postError(m);
                            }
                        }
            
                        if (publisher && !silent) {
            
                            if (publisher === Y && (!publisher.getEvent(LOGEVENT))) {
                                publisher.publish(LOGEVENT, {
                                    broadcast: 2
                                });
                            }
            
                            publisher.fire(LOGEVENT, {
                                msg: msg,
                                cat: cat,
                                src: src
                            });
                        }
                    }
                }
            
                return Y;
            };
            
            /**
             * Write a system message.  This message will be preserved in the
             * minified and raw versions of the YUI files, unlike log statements.
             * @method message
             * @for YUI
             * @param  {String}  msg  The message to log.
             * @param  {String}  cat  The log category for the message.  Default
             *                        categories are "info", "warn", "error", "debug".
             *                        Custom categories can be used as well. (opt).
             * @param  {String}  src  The source of the the message (opt).
             * @param  {boolean} silent If true, the log event won't fire.
             * @return {YUI}      YUI instance.
             */
            INSTANCE.message = function() {
                return INSTANCE.log.apply(INSTANCE, arguments);
            };