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memory.js 

/*
 * memory.js: Simple memory storage engine for nconf configuration(s)
 *
 * (C) 2011, Charlie Robbins
 *
 */

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

function Memory (options)

@options {Object} Options for this instance

Constructor function for the Memory nconf store which maintains a nested json structure based on key delimiters :.

e.g. my:nested:key ==> { my: { nested: { key: } } } 

var Memory = exports.Memory = function (options) {
  options       = options || {};
  this.type     = 'memory';
  this.store    = {};
  this.mtimes   = {};
  this.readOnly = false;
  this.loadFrom = options.loadFrom || null;
  
  if (this.loadFrom) {
    this.store = common.loadFilesSync(this.loadFrom);
  }
};

function get (key)

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

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

 
Memory.prototype.get = function (key) {
  var target = this.store, 
      path   = common.path(key);

Scope into the object to get the appropriate nested context

 
  while (path.length > 0) {
    key = path.shift();
    if (!(target && key in target)) {
      return;
    }
    
    target = target[key];
    if (path.length === 0) {
      return target;
    }
  }
};

function set (key, value)

@key {string} Key to set in this instance

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

Sets the value for the specified key in this instance.

 
Memory.prototype.set = function (key, value) {
  if (this.readOnly) {
    return false;
  }
  
  var target = this.store, 
      path   = common.path(key);

Update the mtime (modified time) of the key

 
  this.mtimes[key] = Date.now();

Scope into the object to get the appropriate nested context

 
  while (path.length > 1) {
    key = path.shift();
    if (!target[key] || typeof target[key] !== 'object') {
      target[key] = {};
    }
    
    target = target[key];
  }

Set the specified value in the nested JSON structure

 
  key = path.shift();
  target[key] = value;
  return true;
};

function clear (key)

@key {string} Key to remove from this instance

Removes the value for the specified key from this instance.

 
Memory.prototype.clear = function (key) {
  if (this.readOnly) {
    return false;
  }
  
  var target = this.store, 
      path   = common.path(key);

Remove the key from the set of mtimes (modified times)

 
  delete this.mtimes[key];

Scope into the object to get the appropriate nested context

 
  while (path.length > 1) {
    key = path.shift();
    if (!target[key]) {
      return;
    }
    
    target = target[key];
  }

Delete the key from the nested JSON structure

 
  key = path.shift();
  delete target[key];
  return true;
};

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.

 
Memory.prototype.merge = function (key, value) {
  if (this.readOnly) {
    return false;
  }

If the key is not an Object or is an Array, then simply set it. Merging is for Objects.

 
  if (typeof value !== 'object' || Array.isArray(value)) {
    return this.set(key, value);
  }
  
  var self    = this,
      target  = this.store, 
      path    = common.path(key),
      fullKey = key;

Update the mtime (modified time) of the key

 
  this.mtimes[key] = Date.now();

Scope into the object to get the appropriate nested context

 
  while (path.length > 1) {
    key = path.shift();
    if (!target[key]) {
      target[key] = {};
    }
    
    target = target[key];
  }

Set the specified value in the nested JSON structure

 
  key = path.shift();

If the current value at the key target is not an Object, or is an Array then simply override it because the new value is an Object.

 
  if (typeof target[key] !== 'object' || Array.isArray(target[key])) {
    target[key] = value;
    return true;
  }
  
  return Object.keys(value).every(function (nested) {
    return self.merge(fullKey + ':' + nested, value[nested]);
  });
};

function reset (callback)

Clears all keys associated with this instance.

 
Memory.prototype.reset = function () {
  if (this.readOnly) {
    return false;
  }
  
  this.mtimes = {};
  this.store  = {};
  return true;
};