From 06dc3fd1bcfb2a6a4aeff8f0cd7587ffc849d7ce Mon Sep 17 00:00:00 2001
From: Pranav Kant <pranavk@collabora.co.uk>
Date: Mon, 11 Jul 2016 10:01:11 +0530
Subject: [PATCH] loolwsd: Give editlock correctly when adding a new session

This should be given to first editable(non-readonly) session.

Change-Id: I3b6e53df4b2450cc799c4b4e6a800f662d90a2c1
---
 loolwsd/DocumentBroker.cpp | 12 ++++++++----
 loolwsd/DocumentBroker.hpp |  1 +
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/loolwsd/DocumentBroker.cpp b/loolwsd/DocumentBroker.cpp
index 09644c33d..0bc67c178 100644
--- a/loolwsd/DocumentBroker.cpp
+++ b/loolwsd/DocumentBroker.cpp
@@ -113,6 +113,7 @@ DocumentBroker::DocumentBroker(const Poco::URI& uriPublic,
     _cursorPosY(0),
     _isLoaded(false),
     _isModified(false),
+    _isEditLockHeld(false),
     _tileVersion(0)
 {
     assert(!_docKey.empty());
@@ -345,12 +346,11 @@ size_t DocumentBroker::addSession(std::shared_ptr<ClientSession>& session)
     {
         Log::debug("Adding a readonly session [" + id + "]");
     }
-    // TODO: Below is not always true. What if readonly session is already opened
-    // In that case we still have to give edit lock to this *second* session.
-    else if (_sessions.size() == 1)
+    else if (!_isEditLockHeld)
     {
-        Log::debug("Giving editing lock to the first session [" + id + "].");
+        Log::debug("Giving editing lock to the first editable session [" + id + "].");
         _sessions.begin()->second->markEditLock(true);
+        _isEditLockHeld = true;
     }
     else
     {
@@ -392,14 +392,18 @@ size_t DocumentBroker::removeSession(const std::string& id)
         if (haveEditLock)
         {
             // pass the edit lock to first non-readonly session in map
+            bool editLockGiven = false;
             for (auto& session: _sessions)
             {
                 if (!session.second->isReadOnly())
                 {
                     session.second->setEditLock(true);
+                    editLockGiven = true;
                     break;
                 }
             }
+
+            _isEditLockHeld = editLockGiven;
         }
     }
 
diff --git a/loolwsd/DocumentBroker.hpp b/loolwsd/DocumentBroker.hpp
index d1ef7c6de..203775f3a 100644
--- a/loolwsd/DocumentBroker.hpp
+++ b/loolwsd/DocumentBroker.hpp
@@ -257,6 +257,7 @@ private:
     mutable std::mutex _mutex;
     std::condition_variable _saveCV;
     std::mutex _saveMutex;
+    std::atomic<bool> _isEditLockHeld;
 
     /// Versioning is used to prevent races between
     /// painting and invalidation.