The tile parsing is done in a worker thread and if it fails,
we set the tile state to "obsolete" and set an error message.
When the completion callback is fired, we check for the error
message and if it is set, we emit the error signal.
The trick here is the signal cannot be emitted directly from
the worker thread because that would violate data ownership rules.
We only emit signals when the number of buckets increase (i.e. the
new data that arrived added a new bucket to the tile).
Also, if we try to reparse a partial tile but it is not possible, we
keep the flag up for trying to reparse it again on the next update,
because the data might have arrived after the bucket that is waiting
for the data was processed but before the end of the parsing.
Fixes#1458
When parsing a tile, we request resources from the network, like
sprites and glyphs.
In the rare case of the resources arriving before the tile is
parsed for the first time, if we don't mark it for being parsed
again, it can end up with a tile eternally stuck in the partial
state.
Partial tiles are now only processed again when there is a new resource
available. If we don't have new resources - like new glyphs - the end result
of the reparsing is the same, because no new SymbolBuckets would are created.
In my tests debugging with PowerTOP, this patch drops the CPU utilization
during the sampling period from 100ms/s to 40ms/s. The improvements on
slow connections (i.e. more time waiting for resources) are even more
noticeable.
If the request is cancelled, the response callback won't be called, and
~Source ensures that the request is cancelled. So it's safe to bind
`this` in the lambda.
Also add a virtual setState() method to give subclasses a chance
to intercept the change of state. This will be used by VectorTileData
to release resources when the TileData becomes immutable.
This still has the unwanted side effect off blocking the Map thread
waiting for the workers to return (because they hold a reference
to the Map thread main loop).
Maybe the only way to solve this would be having a I/O thread for
dispatching messages.
The Request is not bound anymore to the invoker thread because the workers
will request for glyphs, but the reply will arrive at the Map thread.
This change will add a new state to the tile called "partial" which
is a state where the tile can be rendered but some information might
be missing.
For now we skip the SymbolBucket if the Sprites are not loaded (will
also do the same for the glyphs in the future). When the Sprites are
finally loaded, we trigger another update, this time the Tile will
get completely re-rendered and change the state to "parsed".
This pattern, in contrast with callbacks, allows us to clearly see
the dependency and hierarchy between the objects. It will also help
on writing unit tests as we can count how many times a notification
was triggered.
We are also removing the code that is passing the Environment around
and instead, we get now the Environment in the TileData using
Environment::Get().
When processing the job, the work will be temporally registered to
the Environment as "TileWorker_0/0/0" which can be used for logging
in the future. At the end of the job, it gets unregistered
automatically from the Environment.
fixes#838
instead of rendering ad libitum on the map thread, we are now driving rendering from the UI thread on iOS via the map.renderSync() function. There are still white bars during the rotation, but the general content of the view is kept visible.
- upgrades GLFW to 3.1
- removes swapped/needsSwap in favor of a more explicit scheme
- View#invalidate() now replaces View#swap() and is called whenever the View needs to trigger a rerender. GLFW and Android to this right away, while iOS goes back to the main thread and does the Map redrawing as part of the GLKView update
- sets all iOS deployment targets to 7.0
- disables SQLite3 version check, since the library version changed on iOS 8.2
we are now scoping all file requests to an environment object. The FileSource implementation treats
this as an opaque pointer, but allows canceling all Requests that are associated with that pointer.
This is necessary to abort all file requests that originated from a particular Map object. Aborting
a file request is different from canceling a file request: A canceled request doesn't have its
callback called, while an aborted request will have its callback called with an error, indicating
that the environment is going to be shut down.
