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provider.js 

/*
 * provider.js: Abstraction providing an interface into pluggable configuration storage.
 *
 * (C) 2011, Charlie Robbins
 *
 */

var stores = require('./stores');

function Provider (options)

@options {Object} Options for this instance.

Constructor function for the Provider object responsible for exposing the pluggable storage features of nconf.

 
var Provider = exports.Provider = function (options) {
  options = options || {};
  this.store = stores.create(options.type || 'memory', options);
};

function use (type, options)

@type {string} Type of the nconf store to use.

@options {Object} Options for the store instance.

Sets the active this.store to a new instance of the specified type.

 
Provider.prototype.use = function (type, options) {
  if (!this.store || type.toLowerCase() !== this.store.type) {
    this.store = stores.create(type, options);
  }
};

function get (key, callback)

@key {string} Key to retrieve for this instance.

@callback {function} Optional Continuation to respond to when complete.

Retrieves the value for the specified key (if any).

 
Provider.prototype.get = function (key, callback) {
  return this.store.get(key, callback);
};

function set (key, value, callback)

@key {string} Key to set in this instance

@value {literal|Object} Value for the specified key

@callback {function} Optional Continuation to respond to when complete.

Sets the value for the specified key in this instance.

 
Provider.prototype.set = function (key, value, callback) {
  return this.store.set(key, value, callback);
};

function merge (key, value)

@key {string} Key to merge the value into

@value {literal|Object} Value to merge into the key

Merges the properties in value into the existing object value at key. If the existing value key is not an Object, it will be completely overwritten.

 
Provider.prototype.merge = function (key, value, callback) {
  return this.store.merge(key, value, callback);
}

function clear (key, callback)

@key {string} Key to remove from this instance

@callback {function} Optional Continuation to respond to when complete.

Removes the value for the specified key from this instance.

 
Provider.prototype.clear = function (key, callback) {
  return this.store.clear(key, callback);
};

function load (callback)

@callback {function} Continuation to respond to when complete.

Responds with an Object representing all keys associated in this instance.

 
Provider.prototype.load = function (callback) {

If we don't have a callback and the current store is capable of loading synchronously then do so.

 
  if (!callback && this.store.loadSync) {
    return this.store.loadSync();
  }
  
  
  if (!this.store.load) {
    var error = new Error('nconf store ' + this.store.type + ' has no load() method');
    if (callback) {
      return callback (error);
    }
    
    throw error;
  }
  
  return this.store.load(callback);
};

function save (value, callback)

@value {Object} Optional Config object to set for this instance

@callback {function} Continuation to respond to when complete.

Removes any existing configuration settings that may exist in this instance and then adds all key-value pairs in value. 

Provider.prototype.save = function (value, callback) {
  if (!callback) {
    callback = value;
    value = null;

If we still don't have a callback and the current store is capable of saving synchronously then do so.

 
    if (!callback && this.store.saveSync) {
      return this.store.saveSync();
    }
  }
  
  if (!this.store.save) {
    var error = new Error('nconf store ' + this.store.type + ' has no save() method');
    if (callback) {
      return callback (error);
    }
    
    throw error;
  }
  
  return this.store.save(value, callback);
};

function reset (callback)

@callback {function} Optional Continuation to respond to when complete.

Clears all keys associated with this instance.

 
Provider.prototype.reset = function (callback) {
  return this.store.reset(callback);
};