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							317 lines
						
					
					
						
							9.0 KiB
						
					
					
				/** | 
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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. | 
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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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  var query = forge.util.getQueryVariables(); | 
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  if('console.level' in query) { | 
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    // set with last value | 
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    forge.log.setLevel( | 
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      sConsoleLogger, query['console.level'].slice(-1)[0]); | 
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  } | 
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  if('console.lock' in query) { | 
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    // set with last value | 
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    var lock = query['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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 |