FolderWatcher: reliability and data-loss signal

Add state and signal to catch the following two known problems:
* Linux: inotify user watch pool is exhausted. Folder watcher becomes
unreliable.
* Windows: buffer is too small, some notifications are lost but watching
stays reliable.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gui/folderwatcher_linux.cpp b/src/gui/folderwatcher_linux.cpp
index f0e0eb0e4..37d79211a 100644
--- a/src/gui/folderwatcher_linux.cpp
+++ b/src/gui/folderwatcher_linux.cpp
@@ -78,6 +78,12 @@ void FolderWatcherPrivate::inotifyRegisterPath(const QString &path)
             IN_CLOSE_WRITE | IN_ATTRIB | IN_MOVE | IN_CREATE | IN_DELETE | IN_DELETE_SELF | IN_MOVE_SELF | IN_UNMOUNT | IN_ONLYDIR);
         if (wd > -1) {
             _watches.insert(wd, path);
+        } else {
+            // If we're running out of memory or inotify watches, become
+            // unreliable.
+            if (errno == ENOMEM || errno == ENOSPC) {
+                _parent->_isReliable = false;
+            }
         }
     }
 }