320 lines
		
	
	
		
			9.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			320 lines
		
	
	
		
			9.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| /**
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|  * Cross-browser support for logging in a web application.
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|  *
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|  * @author David I. Lehn <dlehn@digitalbazaar.com>
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|  *
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|  * Copyright (c) 2008-2013 Digital Bazaar, Inc.
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|  */
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| var forge = require('./forge');
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| require('./util');
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| 
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| /* LOG API */
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| module.exports = forge.log = forge.log || {};
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| 
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| /**
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|  * Application logging system.
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|  *
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|  * Each logger level available as it's own function of the form:
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|  *   forge.log.level(category, args...)
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|  * The category is an arbitrary string, and the args are the same as
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|  * Firebug's console.log API. By default the call will be output as:
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|  *   'LEVEL [category] <args[0]>, args[1], ...'
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|  * This enables proper % formatting via the first argument.
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|  * Each category is enabled by default but can be enabled or disabled with
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|  * the setCategoryEnabled() function.
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|  */
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| // list of known levels
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| forge.log.levels = [
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|   'none', 'error', 'warning', 'info', 'debug', 'verbose', 'max'];
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| // info on the levels indexed by name:
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| //   index: level index
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| //   name: uppercased display name
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| var sLevelInfo = {};
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| // list of loggers
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| var sLoggers = [];
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| /**
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|  * Standard console logger. If no console support is enabled this will
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|  * remain null. Check before using.
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|  */
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| var sConsoleLogger = null;
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| 
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| // logger flags
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| /**
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|  * Lock the level at the current value. Used in cases where user config may
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|  * set the level such that only critical messages are seen but more verbose
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|  * messages are needed for debugging or other purposes.
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|  */
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| forge.log.LEVEL_LOCKED = (1 << 1);
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| /**
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|  * Always call log function. By default, the logging system will check the
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|  * message level against logger.level before calling the log function. This
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|  * flag allows the function to do its own check.
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|  */
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| forge.log.NO_LEVEL_CHECK = (1 << 2);
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| /**
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|  * Perform message interpolation with the passed arguments. "%" style
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|  * fields in log messages will be replaced by arguments as needed. Some
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|  * loggers, such as Firebug, may do this automatically. The original log
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|  * message will be available as 'message' and the interpolated version will
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|  * be available as 'fullMessage'.
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|  */
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| forge.log.INTERPOLATE = (1 << 3);
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| 
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| // setup each log level
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| for(var i = 0; i < forge.log.levels.length; ++i) {
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|   var level = forge.log.levels[i];
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|   sLevelInfo[level] = {
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|     index: i,
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|     name: level.toUpperCase()
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|   };
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| }
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| 
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| /**
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|  * Message logger. Will dispatch a message to registered loggers as needed.
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|  *
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|  * @param message message object
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|  */
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| forge.log.logMessage = function(message) {
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|   var messageLevelIndex = sLevelInfo[message.level].index;
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|   for(var i = 0; i < sLoggers.length; ++i) {
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|     var logger = sLoggers[i];
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|     if(logger.flags & forge.log.NO_LEVEL_CHECK) {
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|       logger.f(message);
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|     } else {
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|       // get logger level
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|       var loggerLevelIndex = sLevelInfo[logger.level].index;
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|       // check level
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|       if(messageLevelIndex <= loggerLevelIndex) {
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|         // message critical enough, call logger
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|         logger.f(logger, message);
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|       }
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|     }
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|   }
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| };
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| 
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| /**
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|  * Sets the 'standard' key on a message object to:
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|  * "LEVEL [category] " + message
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|  *
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|  * @param message a message log object
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|  */
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| forge.log.prepareStandard = function(message) {
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|   if(!('standard' in message)) {
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|     message.standard =
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|       sLevelInfo[message.level].name +
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|       //' ' + +message.timestamp +
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|       ' [' + message.category + '] ' +
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|       message.message;
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|   }
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| };
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| 
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| /**
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|  * Sets the 'full' key on a message object to the original message
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|  * interpolated via % formatting with the message arguments.
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|  *
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|  * @param message a message log object.
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|  */
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| forge.log.prepareFull = function(message) {
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|   if(!('full' in message)) {
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|     // copy args and insert message at the front
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|     var args = [message.message];
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|     args = args.concat([] || message['arguments']);
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|     // format the message
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|     message.full = forge.util.format.apply(this, args);
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|   }
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| };
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| 
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| /**
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|  * Applies both preparseStandard() and prepareFull() to a message object and
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|  * store result in 'standardFull'.
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|  *
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|  * @param message a message log object.
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|  */
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| forge.log.prepareStandardFull = function(message) {
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|   if(!('standardFull' in message)) {
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|     // FIXME implement 'standardFull' logging
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|     forge.log.prepareStandard(message);
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|     message.standardFull = message.standard;
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|   }
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| };
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| 
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| // create log level functions
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| if(true) {
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|   // levels for which we want functions
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|   var levels = ['error', 'warning', 'info', 'debug', 'verbose'];
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|   for(var i = 0; i < levels.length; ++i) {
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|     // wrap in a function to ensure proper level var is passed
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|     (function(level) {
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|       // create function for this level
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|       forge.log[level] = function(category, message/*, args...*/) {
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|         // convert arguments to real array, remove category and message
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|         var args = Array.prototype.slice.call(arguments).slice(2);
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|         // create message object
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|         // Note: interpolation and standard formatting is done lazily
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|         var msg = {
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|           timestamp: new Date(),
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|           level: level,
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|           category: category,
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|           message: message,
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|           'arguments': args
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|           /*standard*/
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|           /*full*/
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|           /*fullMessage*/
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|         };
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|         // process this message
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|         forge.log.logMessage(msg);
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|       };
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|     })(levels[i]);
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|   }
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| }
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| 
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| /**
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|  * Creates a new logger with specified custom logging function.
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|  *
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|  * The logging function has a signature of:
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|  *   function(logger, message)
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|  * logger: current logger
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|  * message: object:
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|  *   level: level id
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|  *   category: category
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|  *   message: string message
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|  *   arguments: Array of extra arguments
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|  *   fullMessage: interpolated message and arguments if INTERPOLATE flag set
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|  *
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|  * @param logFunction a logging function which takes a log message object
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|  *          as a parameter.
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|  *
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|  * @return a logger object.
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|  */
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| forge.log.makeLogger = function(logFunction) {
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|   var logger = {
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|     flags: 0,
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|     f: logFunction
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|   };
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|   forge.log.setLevel(logger, 'none');
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|   return logger;
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| };
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| 
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| /**
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|  * Sets the current log level on a logger.
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|  *
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|  * @param logger the target logger.
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|  * @param level the new maximum log level as a string.
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|  *
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|  * @return true if set, false if not.
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|  */
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| forge.log.setLevel = function(logger, level) {
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|   var rval = false;
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|   if(logger && !(logger.flags & forge.log.LEVEL_LOCKED)) {
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|     for(var i = 0; i < forge.log.levels.length; ++i) {
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|       var aValidLevel = forge.log.levels[i];
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|       if(level == aValidLevel) {
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|         // set level
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|         logger.level = level;
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|         rval = true;
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|         break;
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|       }
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|     }
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|   }
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| 
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|   return rval;
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| };
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| 
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| /**
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|  * Locks the log level at its current value.
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|  *
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|  * @param logger the target logger.
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|  * @param lock boolean lock value, default to true.
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|  */
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| forge.log.lock = function(logger, lock) {
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|   if(typeof lock === 'undefined' || lock) {
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|     logger.flags |= forge.log.LEVEL_LOCKED;
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|   } else {
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|     logger.flags &= ~forge.log.LEVEL_LOCKED;
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|   }
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| };
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| 
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| /**
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|  * Adds a logger.
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|  *
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|  * @param logger the logger object.
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|  */
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| forge.log.addLogger = function(logger) {
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|   sLoggers.push(logger);
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| };
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| 
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| // setup the console logger if possible, else create fake console.log
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| if(typeof(console) !== 'undefined' && 'log' in console) {
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|   var logger;
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|   if(console.error && console.warn && console.info && console.debug) {
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|     // looks like Firebug-style logging is available
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|     // level handlers map
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|     var levelHandlers = {
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|       error: console.error,
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|       warning: console.warn,
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|       info: console.info,
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|       debug: console.debug,
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|       verbose: console.debug
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|     };
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|     var f = function(logger, message) {
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|       forge.log.prepareStandard(message);
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|       var handler = levelHandlers[message.level];
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|       // prepend standard message and concat args
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|       var args = [message.standard];
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|       args = args.concat(message['arguments'].slice());
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|       // apply to low-level console function
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|       handler.apply(console, args);
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|     };
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|     logger = forge.log.makeLogger(f);
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|   } else {
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|     // only appear to have basic console.log
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|     var f = function(logger, message) {
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|       forge.log.prepareStandardFull(message);
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|       console.log(message.standardFull);
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|     };
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|     logger = forge.log.makeLogger(f);
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|   }
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|   forge.log.setLevel(logger, 'debug');
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|   forge.log.addLogger(logger);
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|   sConsoleLogger = logger;
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| } else {
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|   // define fake console.log to avoid potential script errors on
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|   // browsers that do not have console logging
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|   console = {
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|     log: function() {}
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|   };
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| }
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| 
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| /*
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|  * Check for logging control query vars in current URL.
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|  *
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|  * console.level=<level-name>
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|  * Set's the console log level by name.  Useful to override defaults and
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|  * allow more verbose logging before a user config is loaded.
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|  *
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|  * console.lock=<true|false>
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|  * Lock the console log level at whatever level it is set at.  This is run
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|  * after console.level is processed.  Useful to force a level of verbosity
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|  * that could otherwise be limited by a user config.
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|  */
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| if(sConsoleLogger !== null &&
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|   typeof window !== 'undefined' && window.location
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| ) {
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|   var query = new URL(window.location.href).searchParams;
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|   if(query.has('console.level')) {
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|     // set with last value
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|     forge.log.setLevel(
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|       sConsoleLogger, query.get('console.level').slice(-1)[0]);
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|   }
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|   if(query.has('console.lock')) {
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|     // set with last value
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|     var lock = query.get('console.lock').slice(-1)[0];
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|     if(lock == 'true') {
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|       forge.log.lock(sConsoleLogger);
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|     }
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|   }
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| }
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| 
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| // provide public access to console logger
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| forge.log.consoleLogger = sConsoleLogger;
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