Implement undo/redo

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = LF
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true

.travis.yml

@@ -1,10 +1,8 @@
 language: node_js
 node_js:
   - "10"
-  - "9"
   - "8"
   - "6"
-  - "4"
-script: "npm run jshint && npm run test-cover"
+script: "ln -s .. node_modules/sharedb; npm run jshint && npm run test-cover"
 # Send coverage data to Coveralls
 after_script: "cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js"

README.md

@@ -19,6 +19,7 @@ tracker](https://github.com/share/sharedb/issues).
 
 - Realtime synchronization of any JSON document
 - Concurrent multi-user collaboration
+- Local undo and redo
 - Synchronous editing API with asynchronous eventual consistency
 - Realtime query subscriptions
 - Simple integration with any database - [MongoDB](https://github.com/share/sharedb-mongo), [PostgresQL](https://github.com/share/sharedb-postgres) (experimental)
@@ -38,7 +39,7 @@ var socket = new WebSocket('ws://' + window.location.host);
 var connection = new sharedb.Connection(socket);
 ```
 
-The native Websocket object that you feed to ShareDB's `Connection` constructor **does not** handle reconnections. 
+The native Websocket object that you feed to ShareDB's `Connection` constructor **does not** handle reconnections.
 
 The easiest way is to give it a WebSocket object that does reconnect. There are plenty of example on the web. The most important thing is that the custom reconnecting websocket, must have the same API as the native rfc6455 version.
 
@@ -228,9 +229,15 @@ changes. Returns a [`ShareDB.Query`](#class-sharedbquery) instance.
 * `options.*`
   All other options are passed through to the database adapter.
 
+`connection.createUndoManager(options)` creates a new `UndoManager`.
+
+* `options.source` if specified, only the operations from that `source` will be undo-able. If `null` or `undefined`, the `source` filter is disabled.
+* `options.limit` the max number of operations to keep on the undo stack.
+* `options.composeInterval` the max time difference between operations in milliseconds, which still allows the operations to be composed on the undo stack.
+
 ### Class: `ShareDB.Doc`
 
-`doc.type` _(String_)
+`doc.type` _(String)_
 The [OT type](https://github.com/ottypes/docs) of this document
 
 `doc.id` _(String)_
@@ -287,6 +294,19 @@ Apply operation to document and send it to the server.
 [operations for the default `'ot-json0'` type](https://github.com/ottypes/json0#summary-of-operations).
 Call this after you've either fetched or subscribed to the document.
 * `options.source` Argument passed to the `'op'` event locally. This is not sent to the server or other clients. Defaults to `true`.
+* `options.skipNoop` Should processing be skipped entirely, if `op` is a no-op. Defaults to `false`.
+* `options.undoable` Should it be possible to undo this operation. Defaults to `false`.
+* `options.fixUp` If true, this operation is meant to fix the current invalid state of the snapshot. It also updates UndoManagers accordingly. This feature requires the OT type to implement `compose`.
+
+`doc.submitSnapshot(snapshot[, options][, function(err) {...}])`
+Diff the current and the provided snapshots to generate an operation, apply the operation to the document and send it to the server.
+`snapshot` structure depends on the document type.
+Call this after you've either fetched or subscribed to the document.
+* `options.source` Argument passed to the `'op'` event locally. This is not sent to the server or other clients. Defaults to `true`.
+* `options.skipNoop` Should processing be skipped entirely, if `op` is a no-op. Defaults to `false`.
+* `options.undoable` Should it be possible to undo this operation. Defaults to `false`.
+* `options.fixUp` If true, this operation is meant to fix the current invalid state of the snapshot. It also updates UndoManagers accordingly. This feature requires the OT type to implement `compose`.
+* `options.diffHint` A hint passed into the `diff`/`diffX` functions defined by the document type.
 
 `doc.del([options][, function(err) {...}])`
 Delete the document locally and send delete operation to the server.
@@ -338,6 +358,28 @@ after a sequence of diffs are handled.
 `query.on('extra', function() {...}))`
 (Only fires on subscription queries) `query.extra` changed.
 
+### Class: `ShareDB.UndoManager`
+
+`undoManager.canUndo()`
+Return `true`, if there's an operation on the undo stack that can be undone, otherwise `false`.
+
+`undoManager.undo([options][, function(err) {...}])`
+Undo a previously applied undoable or redo operation.
+* `options.source` Argument passed to the `'op'` event locally. This is not sent to the server or other clients. Defaults to `true`.
+
+`undoManager.canRedo()`
+Return `true`, if there's an operation on the redo stack that can be undone, otherwise `false`.
+
+`undoManager.redo([options][, function(err) {...}])`
+Redo a previously applied undo operation.
+* `options.source` Argument passed to the `'op'` event locally. This is not sent to the server or other clients. Defaults to `true`.
+
+`undoManager.clear(doc)`
+Remove operations from the undo and redo stacks.
+* `doc` if specified, only the operations on that doc are removed, otherwise all operations are removed.
+
+`undoManager.destroy()`
+Remove all operations from the undo and redo stacks, and stop recording new operations.
 
 ## Error codes
 
@@ -376,6 +418,8 @@ Additional fields may be added to the error object for debugging context dependi
 * 4021 - Invalid client id
 * 4022 - Database adapter does not support queries
 * 4023 - Cannot project snapshots of this type
+* 4024 - OT Type does not support `diff` nor `diffX`
+* 4025 - OT Type does not support `invert` nor `applyAndInvert`
 
 ### 5000 - Internal error
 

lib/client/connection.js

@@ -1,5 +1,6 @@
 var Doc = require('./doc');
 var Query = require('./query');
+var UndoManager = require('./undoManager');
 var emitter = require('../emitter');
 var ShareDBError = require('../error');
 var types = require('../types');
@@ -33,6 +34,9 @@ function Connection(socket) {
   // (created documents MUST BE UNIQUE)
   this.collections = {};
 
+  // A list of active UndoManagers.
+  this.undoManagers = [];
+
   // Each query is created with an id that the server uses when it sends us
   // info about the query (updates, etc)
   this.nextQueryId = 1;
@@ -584,3 +588,46 @@ Connection.prototype._firstQuery = function(fn) {
     }
   }
 };
+
+Connection.prototype.createUndoManager = function(options) {
+  var undoManager = new UndoManager(this, options);
+  this.undoManagers.push(undoManager);
+  return undoManager;
+};
+
+Connection.prototype.removeUndoManager = function(undoManager) {
+  var index = this.undoManagers.indexOf(undoManager);
+  if (index >= 0) {
+    this.undoManagers.splice(index, 1);
+  }
+};
+
+Connection.prototype.onDocLoad = function(doc) {
+  for (var i = 0; i < this.undoManagers.length; i++) {
+    this.undoManagers[i].onDocLoad(doc);
+  }
+};
+
+Connection.prototype.onDocDestroy = function(doc) {
+  for (var i = 0; i < this.undoManagers.length; i++) {
+    this.undoManagers[i].onDocDestroy(doc);
+  }
+};
+
+Connection.prototype.onDocCreate = function(doc) {
+  for (var i = 0; i < this.undoManagers.length; i++) {
+    this.undoManagers[i].onDocCreate(doc);
+  }
+};
+
+Connection.prototype.onDocDelete = function(doc) {
+  for (var i = 0; i < this.undoManagers.length; i++) {
+    this.undoManagers[i].onDocDelete(doc);
+  }
+};
+
+Connection.prototype.onDocOp = function(doc, op, undoOp, source, undoable, fixUp) {
+  for (var i = 0; i < this.undoManagers.length; i++) {
+    this.undoManagers[i].onDocOp(doc, op, undoOp, source, undoable, fixUp);
+  }
+};