Use the same API/pattern for parsing raster tiles as we use for vector
tiles. Forward the error as an exception that will ultimately reach the
StillImageCallback.
Also set the tile to State::obsolete on error like we do for vector
tiles.
Instead of transforming between return value and callback, pass
the wrapped callback on to the invoked function as the last argument.
This eliminates the need for multiple invokeWithArgument overloads
and permits invoked functions to be asynchronous.
For now we set the FileSource for the Worker context
but in the future after fixing #1664 we can assert()
that FileSource are set only for the Map thread context.
mbgl::Thread will keep a ThreadContext for each running instance
in a thread_local so we don't need to lookup a man in the Environment
every time we need some info about the current thread.
This patch is moving the ::currentlyOn check used on Debug build from
the Environment class to the ThreadContext.
~Object is likely to join threads that want to dispatch results
back to this RunLoop. This happens, for example, when MapContext
is destructed: it joins the worker threads, which need to complete
work before shutting down.
Even though we only bind the shared_ptr in the after callback, the
worker thread was still copying the callback and therefore gaining
a shared reference. Here we try to eliminate the copies.
The previous implementation, based on thread-local storage, did not
ensure that the context was destructed before the FileSource run loop.
This resulted in implementations attempting to uv_close handles for a
loop that had already been destroyed.
This change also fixes#1262.
Both Android and iOS now use pause/resume. The map thread is
always running, and be able to receive messages. When paused,
it will just refuse to render.
The Thread object gets access via its constructor. No other object
should have access; off-thread objects can't safely do anything with
it except pass it back to the thread.
Implements a Thread<>::invoke interface that only permits calling
member functions with bound arguments.
Also introduce invokeWithResult, which accepts a callback and invokes
it, passing the result, on the invoking thread's RunLoop. This closes
the loop of two evented threads doing message passing.
