This patch will make Mapbox GL Core never use OpenGL
directly. We should consider locking into OpenGL ES 2.0
to simplify the code path and remove #ifdefs.
* Introduce AspiringActor, EstablishedActor
This pair of objects represents the two-phase (parent-thread /
child-thread) construction that's needed to support constructing
Thread<Object> without blocking until the child thread is up and
running.
An `AspiringActor<O>` is responsible for:
- ownership of the actor's `Mailbox`
- allocating the memory for (but *not* constructing) the target object `O`
Using these two pieces--the mailbox and a stable address for `O`--an
`AspiringActor<O>` can accept messages for the target object, or provide
`ActorRef<O>`s that do so, before the object has actually been
constructed by the corresponding `EstablishedActor<O>`. (Such messages
are queued in the mailbox until after the object is constructed.)
This allows for an `AspiringActor<O>` to be created and safely used by a
thread other than the one on which the target object will (eventually)
live.
An `EstablishedActor<O>` is responsible for managing the lifetime of the
target object `O` and the open/closed state of the parent's `mailbox`.
The `O` object's lifetime is contained by that of its owning
`EstablishedActor<O>`: the `EstablishedActor` constructor executes the
`O` constructor via "placement new", constructing it at the address
provided by the parent `AspiringActor`, and the `~EstablishedActor`
destructor similarly executes the `~O` destructor (after closing the
mailbox). `EstablishedActor` should therefore live entirely on the
thread intended to own `O`.
* Remove Actor#{invoke,ask}
* Eliminate unnecessary temporary in VTableStack::move, which also fixes calling the destructor on the incorrect instance
* Make move consistent: it destructs the src, not the dest, which is always empty
* delete doesn't need a null guard
* Conversions to void* don't need a cast
* [core] Parse TileJSON bounds property
* [core] Add TileRange and LatLngBounds::contains(CanonicalTileID)
Move LatLngBounds::contains impl to cpp file
* [core] Skip tile creation outside of tileset bounds
* [core] Fix TileRange for wrapped bounds and use for CustomTileLoader instead of LatLngBounds comparisons for tiles.
ThreadLocal should not own the pointer it is managing because
the use case in Mapbox GL is to keep a pointer to a stack allocated
object, like:
```
MyObject foo;
threadLocal.set(&foo);
```
To keep consistency, it is required that we clear the managed
object before ThreadLocal gets destroyed by setting it to `nullptr`.
