This is the first step in making Flutter aware of and responsive to Z
bound overflow. On its own this patch shouldn't result in any changes in
behavior. This will need to be followed up with a patch in Fuchsia's
Flutter runner to set the Z bounds after this lands, and another patch
in the engine actually implementing the desired overflow behavior.
This Z bound info is routed through the engine itself to make sure the
bounds in flow are truly consistent from the Fuchsia runner. However
these values should eventually be exposed to the framework as well.
Some components in the Flutter engine were derived from the forked blink codebase. While the forked components have either been removed or rewritten, the use of the blink namespace has mostly (and inconsistently) remained. This renames the blink namesapce to flutter for consistency. There are no functional changes in this patch.
The shell was already designed to cleanly shut down the VM but it couldnt
earlier as |Dart_Initialize| could never be called after a |Dart_Cleanup|. This
meant that shutting down an engine instance could not shut down the VM to save
memory because newly created engines in the process after that point couldn't
restart the VM. There can only be one VM running in a process at a time.
This patch separate the previous DartVM object into one that references a
running instance of the DartVM and a set of immutable dependencies that
components can reference even as the VM is shutting down.
Unit tests have been added to assert that non-overlapping engine launches use
difference VM instances.
* Support real fonts in 'flutter test'
Change the order of font_managers to query in font_collection
so that dynamic_font_manager fonts will be resolved.
Tested with test case in `flutter/flutter` repo:
`packages/flutter/test/rendering/localized_fonts_test.dart`
Ensured:
- A font loaded with FontLoader will be used
- The default 'Ahem' font is still loaded by default
The test above still cannot be fixed because FontLoader and the
underlying mechanisms don't cover Locale-specific font loading
and therefore a CJK font-family won't be able to be loaded as needed
for that test.
Fixes#17700
* Format fixup
The service protocol's ListViews method needs to return description data for
each engine in the process. Previously ListViews would queue a task to each
UI thread to gather this data. However, the UI thread might be blocked from
executing tasks (e.g. if the Dart isolate is paused), resulting in a deadlock.
This change provides a copy of the engine's description data to the
ServiceProtocol's global list of engines, allowing ListViews to run without
accessing any UI threads.
Fixes https://github.com/flutter/flutter/issues/24400
TL;DR: Offscreen surface is created on the render thread and device to host
transfer performed there before task completion on the UI thread.
While attempting to snapshot layer trees, the engine was attempting to use the
IO thread context. The reasoning was that this would be safe to do because any
textures uploaded to the GPU as a result of async texture upload would have
originated from this context and hence the handles would be valid in either
context. As it turns out, while the handles are valid, Skia does not support
this use-case because cross-context images transfer ownership of the image from
one context to another. So, when we made the hop from the UI thread to the IO
thread (for snapshotting), if either the UI or GPU threads released the last
reference to the texture backed image, the image would be invalid. This led to
such images being absent from the layer tree snapshot.
Simply referencing the images as they are being used on the IO thread is not
sufficient because accessing images on one context after their ownership has
already been transferred to another is not safe behavior (from Skia's
perspective, the handles are still valid in the sharegroup).
To work around these issues, it was decided that an offscreen render target
would be created on the render thread. The color attachment of this render
target could then be transferred as a cross context image to the IO thread for
the device to host tranfer.
Again, this is currently not quite possible because the only way to create
cross context images is from encoded data. Till Skia exposes the functionality
to create cross-context images from textures in one context, we do a device to
host transfer on the GPU thread. The side effect of this is that this is now
part of the frame workload (image compression, which dominate the wall time,
is still done of the IO thread).
A minor side effect of this patch is that the GPU latch needs to be waited on
before the UI thread tasks can be completed before shell initialization.
- Switch core snapshot to Dart 2 and remove support for loading platform.dill.
- Remove support for loading script snapshots.
- Remove support for loading source.
- Remove settings and fix names to reflect the above.
- Remove support for loading the service isolate from source.
When these delegate methods were initially added, it was expected that a single
shell would be able to own mutliple platform views, engines and animators. This
plan was abandoned in favor of creating multiple shells with their own platform
views, engines, etc.. The arguments were meant to ease the disambiguate the
instances of the variaous objects managed by the shell. This is no longer
necessary.
* Flush all embedded Android view on hot restart.
Adds an OnEngineRestarted method to PlatformView, this is currently only
implemented for Android where we need to use it for embedded views.
* review comments followup
* rename to OnPreEngineRestart, call before Clone
Previously the engine would load all embedded fonts listed in the app's
font manifest during startup. This change creates a Skia font manager that
is backed by the engine's AssetManager and can load embedded font assets
on demand.
