[api] Add .saveSync() and .loadSync() methods to File store

lib/nconf.js

@@ -69,6 +69,16 @@ nconf.clear = function (key, callback) {
 // Responds with an Object representing all keys associated in this instance.
 //
 nconf.load = function (callback) {
+  //
+  // If we don't have a callback and the current 
+  // store is capable of loading synchronously
+  // then do so.
+  //
+  if (!callback && nconf.store.loadSync) {
+    return nconf.store.loadSync();
+  }
+  
+  
   if (!nconf.store.load) {
     var error = new Error('nconf store ' + nconf.store.type + ' has no load() method');
     if (callback) {
@@ -92,6 +102,15 @@ nconf.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 && nconf.store.saveSync) {
+      return nconf.store.saveSync();
+    }
   }
   
   if (!nconf.store.save) {

lib/nconf/stores/file.js

@@ -53,6 +53,36 @@ File.prototype.save = function (value, callback) {
   });
 };
 
+//
+// ### function saveSync (value, callback) 
+// #### @value {Object} _Ignored_ Left here for consistency
+// #### @callback {function} **Optional** Continuation to respond to when complete.
+// Saves the current configuration object to disk at `this.file` 
+// using the format specified by `this.format` synchronously.
+//
+File.prototype.saveSync = function (value, callback) {
+  if (!callback) {
+    callback = value;
+    value = null;
+  }
+  
+  var err;
+  try {
+    fs.writeFileSync(this.file, this.format.stringify(this.store));
+  }
+  catch (ex) {
+    err = ex;
+  }
+  
+  if (callback) {
+    return callback(err);
+  }
+  
+  if (err) {
+    throw err;
+  }
+};
+
 //
 // ### function load (callback)
 // #### @callback {function} Continuation to respond to when complete.
@@ -69,4 +99,31 @@ File.prototype.load = function (callback) {
     self.store = data;
     callback(null, self.store);
   });
+};
+
+//
+// ### function load (callback)
+// #### @callback {function} **Optional** Continuation to respond to when complete.
+// Attempts to load the data stored in `this.file` synchronously and responds appropriately.
+//
+File.prototype.loadSync = function (callback) {
+  var err, data;
+  
+  try {
+    data = fs.readFileSync(this.file, 'utf8');
+    this.store = this.format.parse(data);
+  }
+  catch (ex) {
+    err = ex;
+  }
+  
+  if (callback) {
+    return callback(err, data);
+  }
+  
+  if (err) {
+    throw err;
+  }
+  
+  return data;
 };

test/file-store-test.js

@@ -38,7 +38,7 @@ vows.describe('nconf/stores/file').addBatch({
     topic: function () {
       var tmpPath = path.join(__dirname, 'fixtures', 'tmp.json'),
           tmpStore = new nconf.stores.File({ file: tmpPath });
-      return tmpStore
+      return tmpStore;
     },
     "the save() method": {
       topic: function (tmpStore) {