There are a few motivations here:
1) Less boilerplate code (this can be written inline)
2) It's possible to provide multiple constructors for different packet variations to reduce the chance of errors.
3) It makes things catch fire on updates in ways that static analysers can understand.
This has been a pain point for a long time due to the misleading nature of the name "level". It's also confusing when trying to do things like getting the XP level of the player or such, and also does not translate well to other languages.
This transition was already executed on the UI some time ago (language strings) and now it's time for the same change to occur on the API.
This will burn a lot of plugins, but they'll acclimatize. Despite the scary size of this PR, there isn't actually so many changes to make. Most of this came from renaming `Position->getLevel()` to `Position->getWorld()`, or cosmetic changes like changing variable names or doc comments.
some of these (notably the on* methods) are internal and shouldn't be exposed via interface (same crap as Plugin->onEnable() onDisable() etc) and the rest of the stuff is entirely unused.
This is better for performance because these then don't need to be reevaluated every time they are called.
When encountering an unqualified function or constant reference, PHP will first try to locate a symbol in the current namespace by that name, and then fall back to the global namespace.
This short-circuits the check, which has substantial performance effects in some cases - in particular, ord(), chr() and strlen() show ~1500x faster calls when they are fully qualified.
However, this doesn't mean that PM is getting a massive amount faster. In real world terms, this translates to about 10-15% performance improvement.
But before anyone gets excited, you should know that the CodeOptimizer in the PreProcessor repo has been applying fully-qualified symbol optimizations to Jenkins builds for years, which is one of the reasons why Jenkins builds have better performance than home-built or source installations.
We're choosing to do this for the sake of future SafePHP integration and also to be able to get rid of the buggy CodeOptimizer, so that phar and source are more consistent.
This has the triple bonus effect of a) making a lot of code easier to read, b) reducing Server::getInstance() usages, and c) removing a whole bunch of Server dependencies.
The network and block namespaces are untouched by this commit due to potential for merge conflicts. These should be dealt with separately on master.
I considered renaming sendDataPacket() to dataPacket() to reduce the BC breaks, but the parameter set has changed, which might cause astonishing behaviour, so it's better to break it in a loud way. Also, this has a clearer name.
* Implemented InventoryEventProcessor, fixes#1986
Event processors can now be registered and unregistered at will. Entity inventory/armor change events are now handled by event processors instead of the inventories themselves, which allows enabling/disabling the calling of these events at will.
This now avoids stupid things happening when initializing inventory contents, since the callers for those events are now registered _after_ the contents are initialized.
