Append-only format used for updates

lib/datastore.js

@@ -200,6 +200,29 @@ Datastore.prototype.persistWholeDatabase = function (data, cb) {
 };
 
 
+/**
+ * Persist new state for the given newDocs (can be update or removal)
+ * @param {Array} newDocs Can be empty if no doc was updated/removed
+ * @param {Function} cb Optional, signature: err
+ */
+Datastore.prototype.persistNewState = function (newDocs, cb) {
+  var self = this
+    , toPersist = ''
+    , callback = cb || function () {}
+    ;
+
+  newDocs.forEach(function (doc) {
+    toPersist += model.serialize(doc) + '\n';
+  });
+
+  if (toPersist.length === 0) { return callback(); }
+
+  fs.appendFile(self.filename, toPersist, 'utf8', function (err) {
+    return callback(err);
+  });
+};
+
+
 /**
  * Update all docs matching query
  * For now, very naive implementation (recalculating the whole database)
@@ -217,7 +240,10 @@ Datastore.prototype._update = function (query, updateQuery, options, cb) {
     , self = this
     , numReplaced = 0
     , multi, upsert
-    , newData = [];
+    , modifiedDoc
+    , newData = []
+    , updatedData = []
+    ;
 
   if (typeof options === 'function') { cb = options; options = {}; }
   callback = cb || function () {};
@@ -247,7 +273,10 @@ Datastore.prototype._update = function (query, updateQuery, options, cb) {
       self.data.forEach(function (d) {
         if (model.match(d, query) && (multi || numReplaced === 0)) {
           numReplaced += 1;
-          newData.push(model.modify(d, updateQuery));
+          modifiedDoc = model.modify(d, updateQuery);
+
+          newData.push(modifiedDoc);
+          updatedData.push(modifiedDoc);
         } else {
           newData.push(d);
         }
@@ -256,7 +285,7 @@ Datastore.prototype._update = function (query, updateQuery, options, cb) {
       return callback(err);
     }
 
-    self.persistWholeDatabase(newData, function (err) {
+    self.persistNewState(updatedData, function (err) {
       if (err) { return callback(err); }
       self.data = newData;
       return callback(null, numReplaced);

test/db.test.js

@@ -151,7 +151,6 @@ describe('Database', function () {
                 docs[0].somedata.should.equal('ok');
                 assert.isDefined(docs[0]._id);
 
-
                 done();
               });
             });
@@ -724,6 +723,72 @@ describe('Database', function () {
       });
     });
 
+    it('Non-multi updates are persistent', function (done) {
+      d.insert({ a:1, hello: 'world' }, function (err, doc1) {
+        d.insert({ a:2, hello: 'earth' }, function (err, doc2) {
+          d.update({ a: 2 }, { $set: { hello: 'changed' } }, {}, function (err) {
+            assert.isNull(err);
+
+            d.find({}, function (err, docs) {
+              docs.sort(function (a, b) { return a.a - b.a; });
+              docs.length.should.equal(2);
+              _.isEqual(docs[0], { _id: doc1._id, a:1, hello: 'world' }).should.equal(true);
+              _.isEqual(docs[1], { _id: doc2._id, a:2, hello: 'changed' }).should.equal(true);
+
+              // Even after a reload the database state hasn't changed
+              d.loadDatabase(function (err) {
+                assert.isUndefined(err);
+
+                d.find({}, function (err, docs) {
+                  docs.sort(function (a, b) { return a.a - b.a; });
+                  docs.length.should.equal(2);
+                  _.isEqual(docs[0], { _id: doc1._id, a:1, hello: 'world' }).should.equal(true);
+                  _.isEqual(docs[1], { _id: doc2._id, a:2, hello: 'changed' }).should.equal(true);
+
+                  done();
+                });
+              });
+            });
+          });
+        });
+      });
+    });
+
+    it('Multi updates are persistent', function (done) {
+      d.insert({ a:1, hello: 'world' }, function (err, doc1) {
+        d.insert({ a:2, hello: 'earth' }, function (err, doc2) {
+          d.insert({ a:5, hello: 'pluton' }, function (err, doc3) {
+            d.update({ a: { $in: [1, 2] } }, { $set: { hello: 'changed' } }, { multi: true }, function (err) {
+              assert.isNull(err);
+
+              d.find({}, function (err, docs) {
+                docs.sort(function (a, b) { return a.a - b.a; });
+                docs.length.should.equal(3);
+                _.isEqual(docs[0], { _id: doc1._id, a:1, hello: 'changed' }).should.equal(true);
+                _.isEqual(docs[1], { _id: doc2._id, a:2, hello: 'changed' }).should.equal(true);
+                _.isEqual(docs[2], { _id: doc3._id, a:5, hello: 'pluton' }).should.equal(true);
+
+                // Even after a reload the database state hasn't changed
+                d.loadDatabase(function (err) {
+                  assert.isUndefined(err);
+
+                  d.find({}, function (err, docs) {
+                    docs.sort(function (a, b) { return a.a - b.a; });
+                    docs.length.should.equal(3);
+                    _.isEqual(docs[0], { _id: doc1._id, a:1, hello: 'changed' }).should.equal(true);
+                    _.isEqual(docs[1], { _id: doc2._id, a:2, hello: 'changed' }).should.equal(true);
+                    _.isEqual(docs[2], { _id: doc3._id, a:5, hello: 'pluton' }).should.equal(true);
+
+                    done();
+                  });
+                });
+              });
+            });
+          });
+        });
+      });
+    });
+
   });   // ==== End of 'Update' ==== //