When a player triggers a chunk load via walking around or teleporting there
is no need to stop everything and get this chunk on the main thread. The
client is used to having to wait some time for this chunk and the server
doesn't immediately do anything with it except send it to the player. At
the same time chunk loading is the last major source of file IO that still
runs on the main thread.
These two facts make it possible to offload chunks loaded for this reason
to another thread. However, not all parts of chunk loading can happen off
the main thread. For this we use the new AsynchronousExecutor system to
split chunk loading in to three pieces. The first is loading data from
disk, decompressing it, and parsing it in to an NBT structure. The second
piece is creating entities and tile entities in the chunk and adding them
to the world, this is still done on the main thread. The third piece is
informing everyone who requested a chunk load that the load is finished.
For this we register callbacks and then run them on the main thread once
the previous two stages are finished.
There are still cases where a chunk is needed immediately and these will
still trigger chunk loading entirely on the main thread. The most obvious
case is plugins using the API to request a chunk load. We also must load
the chunk immediately when something in the world tries to access it. In
these cases we ignore any possibly pending or in progress chunk loading
that is happening asynchronously as we will have the chunk loaded by the
time they are finished.
The hope is that overall this system will result in less CPU time and
pauses due to blocking file IO on the main thread thus giving more
consistent performance. Testing so far has shown that this also speeds up
chunk loading client side although some of this is likely to be because
we are sending less chunks at once for the client to process.
Thanks for @ammaraskar for help with the implementation of this feature.
When a player has canPickUpLoot set to true the code for mob pickup is
triggerd which does not know how to deal with player inventory. Since
players have their own logic for picking up items we simply disable this
code for them.
The old flag for picking up loot was default to false, making existing players not able to pickup items. We now use this flag for Players, which gives us the problem we had in 48b46f83.
To fix this, we add an incremental flag that will be cross-examined to check if the data was saved before or after the flag level was introduced.
Addresses BUKKIT-3143
As an added feature, players defaulted to being able to not pick up items if the flag was false. However, since minecraft doesn't normally use the flag on players, the flag was always false.
Adds:
- Getting/Setting equipment
- getting/setting drop rates
- getting/setting ability to pick up items
-- As an added feature, players with this flag start off with a canceled PlayerPickupItemEvent
When a mob is marked with the persistent flag (animal or anything with
setRemoveWhenFarAway(false)) the entire block of code for checking if they
should be despawned is skipped. However, one part of this code updates the
mob state if a player is close enough to them. It turns out this state is
used by the AI system to decide if the mob should move around randomly or
not. To stop mobs from being frozen in place we now update this state if
the persistent flag is set as well.
Currently when a plugin wants to get the location of something it calls
getLocation() which returns a new Location object. In some scenarios this
can cause enough object creation/destruction churn to be a significant
overhead. For this cases we add a method that updates a provided Location
object so there is no object creation done. This allows well written code
to work on several locations with only a single Location object getting
created.
Providing a more efficient way to set a location was also looked at but
the current solution is the fastest we can provide. You are not required
to create a new Location object every time you want to set something's
location so, with proper design, you can set locations with only a single
Location object being created.
The old default for the persistent flag on mobs was false which was then
written out to their NBT data when they were saved. We now use this data
for all mobs, not just non-animal mobs. However, this means animals that
spawned before that change will now start despawning like monsters do.
To avoid this we add a new flag to the mob's saved data to mark if the
data was saved before or after we started using it and ignore it if it
was before.
As of 1.4 mobs have a flag to determine if they despawn when away from a
player or not. Unfortunately animals still use their own system to prevent
despawning instead of making use of this flag. This change modifies them
to use the new system (defaults to true) and to add API for plugins to adjust
this.
If the player is not in Creative (i.e. does not have the ability to
instantly build) we need to decrement the MonsterEgg item stack when used
on a breedable parent mob.
Stale player references will add a player back into the world when
teleporting them, causing a cascade of issues relating to ghost entities
and servers failing to stop.
On join we unconditionally add the player to the world they logged out in.
If a plugin teleports a player during PlayerJoinEvent in a way that adds
them to a world (cross-world teleport) we end up with one player in two
places. To avoid this we check to see if the player has changed worlds or
is already added to the world we have we skip adding them again.
