[history-ot] initial implementation of using doc-level history-ot (#25054)

* [history-v1-ot] initial implementation of using doc-level history-v1-ot

* [web] fix advancing of the otMigrationStage

Use 'nextStage' for the user provided, desired stage when advancing.

Co-authored-by: Brian Gough <brian.gough@overleaf.com>

* [document-updater] document size check in editor-core

* [history-ot] rename history-v1-ot to history-ot and add types

* [history-ot] apply review feedback

- remove extra !!
- merge variable assignment when processing diff-match-match output
- add helper function for getting docstore lines view of StringFileData

Co-authored-by: Alf Eaton <alf.eaton@overleaf.com>

* Revert "[document-updater] add safe rollback point for history-ot (#25283)"

This reverts commit d7230dd14a379a27d2c6ab03a006463a18979d06

Signed-off-by: Jakob Ackermann <jakob.ackermann@overleaf.com>

---------

Signed-off-by: Jakob Ackermann <jakob.ackermann@overleaf.com>
Co-authored-by: Brian Gough <brian.gough@overleaf.com>
Co-authored-by: Alf Eaton <alf.eaton@overleaf.com>
GitOrigin-RevId: 89c497782adb0427635d50d02263d6f535b12481

services/real-time/app/js/HttpApiController.js

@@ -1,8 +1,23 @@
 const WebsocketLoadBalancer = require('./WebsocketLoadBalancer')
 const DrainManager = require('./DrainManager')
+const ConnectedUsersManager = require('./ConnectedUsersManager')
 const logger = require('@overleaf/logger')
 
 module.exports = {
+  countConnectedClients(req, res) {
+    const { projectId } = req.params
+    ConnectedUsersManager.countConnectedClients(
+      projectId,
+      (err, nConnectedClients) => {
+        if (err) {
+          logger.err({ err, projectId }, 'count connected clients failed')
+          return res.sendStatus(500)
+        }
+        res.json({ nConnectedClients })
+      }
+    )
+  },
+
   sendMessage(req, res) {
     logger.debug({ message: req.params.message }, 'sending message')
     if (Array.isArray(req.body)) {