Optimistic locking

.gitignore

@@ -2,3 +2,7 @@
 _site/
 .*.swp
 test.js
+.idea/modules.xml
+.idea/thinky.iml
+.idea/vcs.xml
+.idea/workspace.xml

config.js

@@ -1,4 +1,5 @@
 exports.host = process.env['WERCKER_RETHINKDB_HOST'] || 'localhost';
 exports.port = process.env['WERCKER_RETHINKDB_PORT'] || 28015;
 exports.db = 'thinky_test';
-exports.authKey = '';
+exports.user = 'admin';
+exports.password = 'admin';

lib/document.js

@@ -34,6 +34,7 @@ function Document(model, options) {
   this._options = {};
   this._options.timeFormat = (options.timeFormat != null) ? options.timeFormat : model.getOptions().timeFormat;
   this._options.validate = (options.validate != null) ? options.validate : model.getOptions().validate;
+  this._options.version = (options.version != null) ? options.version : model.getOptions().version;
 
   this._saved = options.saved || false;  // Whether the document is saved or not
 
@@ -723,6 +724,25 @@ Document.prototype._onSavedBelongsTo = function(
   self._saveSelf(copy, docToSave, belongsToKeysSaved, saveAll, savedModel, resolve, reject)
 }
 
+Document.prototype._calculateVersion = function () {
+  var self = this;
+  var model = self._getModel();
+  var r = self._getModel()._thinky.r;
+
+  var versionType = self._getModel()._schema._schema[model._version];
+  if (versionType === undefined) {
+    throw new Error("A version field with name: " + model._version + " cannot be found in the schema definition");
+  }
+  if (type.isDate(versionType)) {
+    return new Date();
+  }
+  else if (type.isNumber(versionType)) {
+    return self[model._version] === undefined ? 0 : self[model._version] + 1;
+  }
+  else {
+    throw new Error("Version columns can only be Date or Number");
+  }
+}
 
 /**
  * Save the document on which `save` was called.
@@ -760,15 +780,36 @@ Document.prototype._saveSelf = function(
   // may throw an error (for example if a Date has not a valid time).
   var buildQuery = function () {
     if (self.__proto__._saved === false) {
+      if (model._version) {
+        copy[model._version] = self._calculateVersion();
+      }
       return querySaveSelf = r.table(constructor.getTableName())
-        .insert(copy, {returnChanges: 'always'})
+          .insert(copy, {returnChanges: 'always'});
     }
     else {
       if (copy[model._pk] === undefined) {
         throw new Error("The document was previously saved, but its primary key is undefined.");
       }
-      return querySaveSelf = r.table(constructor.getTableName())
-        .get(copy[model._pk]).replace(copy, {returnChanges: 'always'})
+      else if (model._version) {
+        var versionType = self._getModel()._schema._schema[model._version];
+        if (versionType === undefined) {
+          throw new Error("A version field with name: " + model._version + " cannot be found in the schema definition");
+        }
+        var newVersion = self._calculateVersion();
+        return querySaveSelf = r.table(constructor.getTableName())
+            .get(copy[model._pk]).replace(function (row) {
+              const existingVersion = copy[model._version];
+              console.log('Replacing ' + constructor.getTableName() + ' version from', existingVersion, 'to', newVersion);
+              copy[model._version] = newVersion;
+              return r.branch(row(model._version).eq(existingVersion), copy, r.error("Versioning failed - there is a different version for " + constructor.getTableName() + " (with pk: " + copy[model._pk] + ") in the database from: " + existingVersion));
+            }, {returnChanges: 'always'});
+
+      }
+      else {
+        return querySaveSelf = r.table(constructor.getTableName())
+            .get(copy[model._pk]).replace(copy, {returnChanges: 'always'})
+      }
+
     }
   }
 
@@ -824,15 +865,20 @@ Document.prototype._onSaved = function(result, docToSave, saveAll, savedModel, r
     self.setSaved();
     self.emit('saved', self);
 
-    var promise = self.validate();
-    if (promise instanceof Promise) {
-      promise.then(function() {
+    if (!self._getModel().getOptions().validate === 'onlyOnSave') {
+        var promise = self.validate();
+        if (promise instanceof Promise) {
+            promise.then(function() {
+                self._saveMany(docToSave, saveAll, savedModel, resolve, reject)
+            }).error(reject);
+        }
+        else {
+            self._saveMany(docToSave, saveAll, savedModel, resolve, reject)
+        }
+    } else {
         self._saveMany(docToSave, saveAll, savedModel, resolve, reject)
-      }).error(reject);
-    }
-    else {
-      self._saveMany(docToSave, saveAll, savedModel, resolve, reject)
     }
+
   }, reject);
 }