Daniel@0: /*!
Daniel@0:  * js-logger - http://github.com/jonnyreeves/js-logger 
Daniel@0:  * Jonny Reeves, http://jonnyreeves.co.uk/
Daniel@0:  * js-logger may be freely distributed under the MIT license. 
Daniel@0:  */
Daniel@0: 
Daniel@0: /*jshint sub:true*/
Daniel@0: /*global console:true,define:true, module:true*/
Daniel@0: (function (global) {
Daniel@0: 	"use strict";
Daniel@0: 
Daniel@0: 	// Top level module for the global, static logger instance.
Daniel@0: 	var Logger = { };
Daniel@0: 	
Daniel@0: 	// For those that are at home that are keeping score.
Daniel@0: 	Logger.VERSION = "0.9.14";
Daniel@0: 	
Daniel@0: 	// Function which handles all incoming log messages.
Daniel@0: 	var logHandler;
Daniel@0: 	
Daniel@0: 	// Map of ContextualLogger instances by name; used by Logger.get() to return the same named instance.
Daniel@0: 	var contextualLoggersByNameMap = {};
Daniel@0: 	
Daniel@0: 	// Polyfill for ES5's Function.bind.
Daniel@0: 	var bind = function(scope, func) {
Daniel@0: 		return function() {
Daniel@0: 			return func.apply(scope, arguments);
Daniel@0: 		};
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Super exciting object merger-matron 9000 adding another 100 bytes to your download.
Daniel@0: 	var merge = function () {
Daniel@0: 		var args = arguments, target = args[0], key, i;
Daniel@0: 		for (i = 1; i < args.length; i++) {
Daniel@0: 			for (key in args[i]) {
Daniel@0: 				if (!(key in target) && args[i].hasOwnProperty(key)) {
Daniel@0: 					target[key] = args[i][key];
Daniel@0: 				}
Daniel@0: 			}
Daniel@0: 		}
Daniel@0: 		return target;
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Helper to define a logging level object; helps with optimisation.
Daniel@0: 	var defineLogLevel = function(value, name) {
Daniel@0: 		return { value: value, name: name };
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Predefined logging levels.
Daniel@0: 	Logger.DEBUG = defineLogLevel(1, 'DEBUG');
Daniel@0: 	Logger.INFO = defineLogLevel(2, 'INFO');
Daniel@0: 	Logger.WARN = defineLogLevel(4, 'WARN');
Daniel@0: 	Logger.ERROR = defineLogLevel(8, 'ERROR');
Daniel@0: 	Logger.OFF = defineLogLevel(99, 'OFF');
Daniel@0: 
Daniel@0: 	// Inner class which performs the bulk of the work; ContextualLogger instances can be configured independently
Daniel@0: 	// of each other.
Daniel@0: 	var ContextualLogger = function(defaultContext) {
Daniel@0: 		this.context = defaultContext;
Daniel@0: 		this.setLevel(defaultContext.filterLevel);
Daniel@0: 		this.log = this.info;  // Convenience alias.
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	ContextualLogger.prototype = {
Daniel@0: 		// Changes the current logging level for the logging instance.
Daniel@0: 		setLevel: function (newLevel) {
Daniel@0: 			// Ensure the supplied Level object looks valid.
Daniel@0: 			if (newLevel && "value" in newLevel) {
Daniel@0: 				this.context.filterLevel = newLevel;
Daniel@0: 			}
Daniel@0: 		},
Daniel@0: 
Daniel@0: 		// Is the logger configured to output messages at the supplied level?
Daniel@0: 		enabledFor: function (lvl) {
Daniel@0: 			var filterLevel = this.context.filterLevel;
Daniel@0: 			return lvl.value >= filterLevel.value;
Daniel@0: 		},
Daniel@0: 
Daniel@0: 		debug: function () {
Daniel@0: 			this.invoke(Logger.DEBUG, arguments);
Daniel@0: 		},
Daniel@0: 
Daniel@0: 		info: function () {
Daniel@0: 			this.invoke(Logger.INFO, arguments);
Daniel@0: 		},
Daniel@0: 
Daniel@0: 		warn: function () {
Daniel@0: 			this.invoke(Logger.WARN, arguments);
Daniel@0: 		},
Daniel@0: 
Daniel@0: 		error: function () {
Daniel@0: 			this.invoke(Logger.ERROR, arguments);
Daniel@0: 		},
Daniel@0: 
Daniel@0: 		// Invokes the logger callback if it's not being filtered.
Daniel@0: 		invoke: function (level, msgArgs) {
Daniel@0: 			if (logHandler && this.enabledFor(level)) {
Daniel@0: 				logHandler(msgArgs, merge({ level: level }, this.context));
Daniel@0: 			}
Daniel@0: 		}
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Protected instance which all calls to the to level `Logger` module will be routed through.
Daniel@0: 	var globalLogger = new ContextualLogger({ filterLevel: Logger.OFF });
Daniel@0: 
Daniel@0: 	// Configure the global Logger instance.
Daniel@0: 	(function() {
Daniel@0: 		// Shortcut for optimisers.
Daniel@0: 		var L = Logger;
Daniel@0: 
Daniel@0: 		L.enabledFor = bind(globalLogger, globalLogger.enabledFor);
Daniel@0: 		L.debug = bind(globalLogger, globalLogger.debug);
Daniel@0: 		L.info = bind(globalLogger, globalLogger.info);
Daniel@0: 		L.warn = bind(globalLogger, globalLogger.warn);
Daniel@0: 		L.error = bind(globalLogger, globalLogger.error);
Daniel@0: 
Daniel@0: 		// Don't forget the convenience alias!
Daniel@0: 		L.log = L.info;
Daniel@0: 	}());
Daniel@0: 
Daniel@0: 	// Set the global logging handler.  The supplied function should expect two arguments, the first being an arguments
Daniel@0: 	// object with the supplied log messages and the second being a context object which contains a hash of stateful
Daniel@0: 	// parameters which the logging function can consume.
Daniel@0: 	Logger.setHandler = function (func) {
Daniel@0: 		logHandler = func;
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Sets the global logging filter level which applies to *all* previously registered, and future Logger instances.
Daniel@0: 	// (note that named loggers (retrieved via `Logger.get`) can be configured independently if required).
Daniel@0: 	Logger.setLevel = function(level) {
Daniel@0: 		// Set the globalLogger's level.
Daniel@0: 		globalLogger.setLevel(level);
Daniel@0: 
Daniel@0: 		// Apply this level to all registered contextual loggers.
Daniel@0: 		for (var key in contextualLoggersByNameMap) {
Daniel@0: 			if (contextualLoggersByNameMap.hasOwnProperty(key)) {
Daniel@0: 				contextualLoggersByNameMap[key].setLevel(level);
Daniel@0: 			}
Daniel@0: 		}
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Retrieve a ContextualLogger instance.  Note that named loggers automatically inherit the global logger's level,
Daniel@0: 	// default context and log handler.
Daniel@0: 	Logger.get = function (name) {
Daniel@0: 		// All logger instances are cached so they can be configured ahead of use.
Daniel@0: 		return contextualLoggersByNameMap[name] ||
Daniel@0: 			(contextualLoggersByNameMap[name] = new ContextualLogger(merge({ name: name }, globalLogger.context)));
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Configure and example a Default implementation which writes to the `window.console` (if present).
Daniel@0: 	Logger.useDefaults = function(defaultLevel) {
Daniel@0: 		// Check for the presence of a logger.
Daniel@0: 		if (typeof console === "undefined") {
Daniel@0: 			return;
Daniel@0: 		}
Daniel@0: 
Daniel@0: 		Logger.setLevel(defaultLevel || Logger.DEBUG);
Daniel@0: 		Logger.setHandler(function(messages, context) {
Daniel@0: 			var hdlr = console.log;
Daniel@0: 
Daniel@0: 			// Prepend the logger's name to the log message for easy identification.
Daniel@0: 			if (context.name) {
Daniel@0: 				messages[0] = "[" + context.name + "] " + messages[0];
Daniel@0: 			}
Daniel@0: 
Daniel@0: 			// Delegate through to custom warn/error loggers if present on the console.
Daniel@0: 			if (context.level === Logger.WARN && console.warn) {
Daniel@0: 				hdlr = console.warn;
Daniel@0: 			} else if (context.level === Logger.ERROR && console.error) {
Daniel@0: 				hdlr = console.error;
Daniel@0: 			} else if (context.level === Logger.INFO && console.info) {
Daniel@0: 				hdlr = console.info;
Daniel@0: 			}
Daniel@0: 
Daniel@0: 			// Support for IE8+ (and other, slightly more sane environments)
Daniel@0: 			Function.prototype.apply.call(hdlr, console, messages);
Daniel@0: 		});
Daniel@0: 	};
Daniel@0: 
Daniel@0: 	// Export to popular environments boilerplate.
Daniel@0: 	if (typeof define === 'function' && define.amd) {
Daniel@0: 		define(Logger);
Daniel@0: 	}
Daniel@0: 	else if (typeof module !== 'undefined' && module.exports) {
Daniel@0: 		module.exports = Logger;
Daniel@0: 	}
Daniel@0: 	else {
Daniel@0: 		Logger._prevLogger = global.Logger;
Daniel@0: 
Daniel@0: 		Logger.noConflict = function () {
Daniel@0: 			global.Logger = Logger._prevLogger;
Daniel@0: 			return Logger;
Daniel@0: 		};
Daniel@0: 
Daniel@0: 		global.Logger = Logger;
Daniel@0:     }
Daniel@0: }(this));