This patch adds support for time-based locking of discussions.
Discussions are automatically locked after a user-definable period of
inactivity. After this time, only those with the the relevant capability
are able to add replies.
This has been designed to add support for other types of discussion locking
at a later date with relative ease.
After some time discussing with integrators, we decided that this
slightly yukky solution probably fits safely, so just making its usage
better explained and speciifc.
Users that don't have permission to view timed posts outside of the release
time frame will have discussions that have entered the visible frame appear
in an odd order from their point of view on the discussion list.
Example:
Discussion 1, modified 2015-01-01, hidden till 2015-01-03
Discussion 2, modified 2015-01-02, not hidden
The standard 'modified descending' order means that D2 is listed at the top
even after D1 becomes visible. When scanning the list of discussions for new
posts, the user could be tricked into thinking they'd already read it.
This fix instead takes into account the release time of the discussion when
timed forum posts are enabled.
I opted to use CASE statements to handle this instead of GREATEST as the
latter is not supported by MSSQL.
This adds the following changes when viewing a list of discussions and
forum_enabletimedposts is turned on.
* Discussions a student wouldnt see right now are dimmed (timestart in
future or timeend in the past).
* A icon appears next to the discussion subject, the tooltip for this
icon displays the display start and/or end time. This only appears for
the user that made the discussion or has permission to
viewhiddentimedposts.
These two changes achieve a couple of important things, namely, teachers
will not mistakenly think their students can see a discussion when
viewing the list if they've later forgot that they set a time limit on
it (or indeed if someone else put it on their discussion without them
realising). Additionally it makes it easy to see from the list when
different discussions are set to be released without having to go in and
edit them to find out.
Change-Id: Ia1818b33c00adae0dad72df8e170a078fb66cd76
David Monllao