Merge pull request #399 from share/snapshot-throw

Catch errors thrown in `ot.applyOps`

Author: alecgibson

lib/error.js

@@ -39,6 +39,7 @@ ShareDBError.CODES = {
   ERR_OP_VERSION_MISMATCH_DURING_TRANSFORM: 'ERR_OP_VERSION_MISMATCH_DURING_TRANSFORM',
   ERR_OP_VERSION_NEWER_THAN_CURRENT_SNAPSHOT: 'ERR_OP_VERSION_NEWER_THAN_CURRENT_SNAPSHOT',
   ERR_OT_OP_BADLY_FORMED: 'ERR_OT_OP_BADLY_FORMED',
+  ERR_OT_OP_NOT_APPLIED: 'ERR_OT_OP_NOT_APPLIED',
   ERR_OT_OP_NOT_PROVIDED: 'ERR_OT_OP_NOT_PROVIDED',
   ERR_PRESENCE_TRANSFORM_FAILED: 'ERR_PRESENCE_TRANSFORM_FAILED',
   ERR_PROTOCOL_VERSION_NOT_SUPPORTED: 'ERR_PROTOCOL_VERSION_NOT_SUPPORTED',

lib/ot.js

@@ -167,23 +167,27 @@ exports.applyOps = function(snapshot, ops) {
     if (!type) return new ShareDBError(ERROR_CODE.ERR_DOC_TYPE_NOT_RECOGNIZED, 'Unknown type');
   }
 
-  for (var index = 0; index < ops.length; index++) {
-    var op = ops[index];
-
-    snapshot.v = op.v + 1;
-
-    if (op.create) {
-      type = types[op.create.type];
-      if (!type) return new ShareDBError(ERROR_CODE.ERR_DOC_TYPE_NOT_RECOGNIZED, 'Unknown type');
-      snapshot.data = type.create(op.create.data);
-      snapshot.type = type.uri;
-    } else if (op.del) {
-      snapshot.data = undefined;
-      type = null;
-      snapshot.type = null;
-    } else {
-      snapshot.data = type.apply(snapshot.data, op.op);
+  try {
+    for (var index = 0; index < ops.length; index++) {
+      var op = ops[index];
+
+      snapshot.v = op.v + 1;
+
+      if (op.create) {
+        type = types[op.create.type];
+        if (!type) return new ShareDBError(ERROR_CODE.ERR_DOC_TYPE_NOT_RECOGNIZED, 'Unknown type');
+        snapshot.data = type.create(op.create.data);
+        snapshot.type = type.uri;
+      } else if (op.del) {
+        snapshot.data = undefined;
+        type = null;
+        snapshot.type = null;
+      } else {
+        snapshot.data = type.apply(snapshot.data, op.op);
+      }
     }
+  } catch (error) {
+    return new ShareDBError(ERROR_CODE.ERR_OT_OP_NOT_APPLIED, error.message);
   }
 };
 

test/ot.js

@@ -3,7 +3,9 @@ var ot = require('../lib/ot');
 var types = require('../lib/types');
 var type = types.defaultType;
 var presenceType = require('./client/presence/presence-test-type').type;
+var ShareDBError = require('../lib/error');
 
+var ERROR_CODE = ShareDBError.CODES;
 types.register(presenceType);
 
 describe('ot', function() {
@@ -369,4 +371,115 @@ describe('ot', function() {
       });
     });
   });
+
+  describe('applyOps', function() {
+    it('applies an op to a snapshot', function() {
+      var snapshot = {
+        type: 'json0',
+        data: {title: 'Wee Free Men'}
+      };
+
+      var ops = [
+        {
+          v: 1,
+          op: [{p: ['title', 0], si: 'The '}]
+        }
+      ];
+
+      var error = ot.applyOps(snapshot, ops);
+      expect(error).to.be.undefined;
+      expect(snapshot.data).to.eql({title: 'The Wee Free Men'});
+      expect(snapshot.v).to.equal(2);
+    });
+
+    it('applies multiple ops', function() {
+      var snapshot = {
+        type: 'json0',
+        data: {title: 'Wee Free Men'}
+      };
+
+      var ops = [
+        {
+          v: 1,
+          op: [{p: ['title', 0], si: 'The '}]
+        },
+        {
+          v: 2,
+          op: [{p: ['author'], oi: 'Terry Pratchett'}]
+        }
+      ];
+
+      ot.applyOps(snapshot, ops);
+      expect(snapshot.data).to.eql({
+        author: 'Terry Pratchett',
+        title: 'The Wee Free Men'
+      });
+      expect(snapshot.v).to.equal(3);
+    });
+
+    it('applies a del to a snapshot', function() {
+      var snapshot = {
+        type: 'json0',
+        data: {title: 'Wee Free Men'}
+      };
+
+      var ops = [{v: 1, del: true}];
+
+      ot.applyOps(snapshot, ops);
+      expect(snapshot.data).to.be.undefined;
+    });
+
+    it('applies a create to a snapshot', function() {
+      var snapshot = {};
+      var ops = [
+        {
+          v: 1,
+          create: {
+            type: 'json0',
+            data: {title: 'Wee Free Men'}
+          }
+        }
+      ];
+
+      ot.applyOps(snapshot, ops);
+      expect(snapshot.data).to.eql({title: 'Wee Free Men'});
+    });
+
+    it('returns an error if the snapshot has an unknown type', function() {
+      var snapshot = {type: 'unknown-type', data: {}};
+      var ops = [];
+      var error = ot.applyOps(snapshot, ops);
+      expect(error.code).to.equal(ERROR_CODE.ERR_DOC_TYPE_NOT_RECOGNIZED);
+    });
+
+    it('returns an error if a create op has an unknown type', function() {
+      var snapshot = {};
+      var ops = [
+        {
+          v: 1,
+          create: {
+            type: 'unknown-type',
+            data: {}
+          }
+        }
+      ];
+      var error = ot.applyOps(snapshot, ops);
+      expect(error.code).to.equal(ERROR_CODE.ERR_DOC_TYPE_NOT_RECOGNIZED);
+    });
+
+    it('catches and returns an error thrown by type.apply', function() {
+      var snapshot = {
+        type: 'json0',
+        data: {title: 'Wee Free Men'}
+      };
+
+      var ops = [{
+        v: 1,
+        op: [{p: ['title'], li: 'not a list'}]
+      }];
+
+      var error = ot.applyOps(snapshot, ops);
+      expect(error.code).to.equal(ERROR_CODE.ERR_OT_OP_NOT_APPLIED);
+    });
+  });
 });