Bulk insert works when no constraint is violated

lib/datastore.js

@@ -247,28 +247,64 @@ Datastore.prototype.getCandidates = function (query) {
  */
 Datastore.prototype._insert = function (newDoc, cb) {
   var callback = cb || function () {}
-    , self = this
-    , insertedDoc
     ;
 
-  // Ensure the document has the right format
   try {
-    newDoc._id = customUtils.uid(16);
-    model.checkObject(newDoc);
-    insertedDoc = model.deepCopy(newDoc);
+    this._insertInCache(newDoc);
   } catch (e) {
     return callback(e);
   }
 
-  // Insert in all indexes (also serves to ensure uniqueness)
-  try { self.addToIndexes(insertedDoc); } catch (e) { return callback(e); }
-
-  this.persistence.persistNewState([newDoc], function (err) {
+  this.persistence.persistNewState(util.isArray(newDoc) ? newDoc : [newDoc], function (err) {
     if (err) { return callback(err); }
     return callback(null, newDoc);
   });
 };
 
+/**
+ * If newDoc is an array of documents, this will insert all documents in the cache
+ * @api private
+ */
+Datastore.prototype._insertInCache = function (newDoc) {
+  var insertedDoc;
+
+  if (util.isArray(newDoc)) { this._insertMultipleDocsInCache(newDoc); return; }
+
+  // Ensure the document has the right format
+  newDoc._id = customUtils.uid(16);
+  model.checkObject(newDoc);
+  insertedDoc = model.deepCopy(newDoc);
+  
+  // Insert in all indexes (also serves to ensure uniqueness)
+  this.addToIndexes(insertedDoc);  
+};
+
+/**
+ * If one insertion fails (e.g. because of a unique constraint), roll back all previous
+ * inserts and throws the error
+ */
+Datastore.prototype._insertMultipleDocsInCache = function (newDocs) {
+  var i, failingI, error;
+
+  for (i = 0; i < newDocs.length; i += 1) {
+    try {
+      this._insertInCache(newDocs[i]);
+    } catch (e) {
+      error = e;
+      failingI = i;
+      break;
+    }
+  }
+  
+  if (error) {
+    for (i = 0; i < failingI; i += 1) {
+      this._removeFromCache(newDocs[i]);
+    }
+    
+    throw error;
+  }
+};
+
 Datastore.prototype.insert = function () {
   this.executor.push({ this: this, fn: this._insert, arguments: arguments });
 };

test/db.test.js

@@ -180,6 +180,30 @@ describe('Database', function () {
       });
     });
     
+    it.only('Can insert an array of documents at once', function (done) {
+      var docs = [{ a: 5, b: 'hello' }, { a: 42, b: 'world' }];
+    
+      d.insert(docs, function (err) {
+        d.find({}, function (err, docs) {
+          var data;
+        
+          docs.length.should.equal(2);
+          _.find(docs, function (doc) { return doc.a === 5; }).b.should.equal('hello');
+          _.find(docs, function (doc) { return doc.a === 42; }).b.should.equal('world');
+          
+          // The data has been persisted correctly
+          data = _.filter(fs.readFileSync(testDb, 'utf8').split('\n'), function (line) { return line.length > 0; });
+          data.length.should.equal(2);
+          model.deserialize(data[0]).a.should.equal(5);
+          model.deserialize(data[0]).b.should.equal('hello');
+          model.deserialize(data[1]).a.should.equal(42);
+          model.deserialize(data[1]).b.should.equal('world');
+                    
+          done();
+        });
+      });
+    });
+
   });   // ==== End of 'Insert' ==== //