Fixes https://github.com/flutter/flutter/issues/123307 - for Android, iOS, and Web, for the main display only (https://github.com/flutter/flutter/issues/125938 tracks supporting multiple displays, https://github.com/flutter/flutter/issues/125939 for desktop).
Desktop will need to be implemented for this, but given priority for a couple of our customers targetting foldable devices on Android I'm inclined to get this in before desktop can be finished.
The main concern for this right now is that on some Android foldable devices, setting a preferred orientation will cause letterboxing and the `MediaQuery` will _never_ get the full screen size when unfolded. This causes apps to think the screen is smaller than it is, as they've mainly been using `MediaQueryData.size` to figure this out. Android's recommendation is to not set a preferred orientation, and if you must to use the new method introduced in `ViewUtil.java` to calculate the maximal window size.
This introduces `PlatformDispatcher.implicitView`, a low-level primitive for the framework's bootstrapping. Most code, including the framework after bootstrapping, will use `View.of(context)` instead of this new API. This new primitive will let us deprecate the `window` global.
Goals:
1. **Enable multi-window**. The `PlatformDispatcher.implicitView` is nullable. If `null`, the app must create a window to get a view it can draw into.
2. **Backwards compatibility**. For "single window" apps, `PlatformDispatcher.instance.implicitView` should behave as similar to `window` as possible.
1. The `PlatformDispatcher.instance.implicitView.viewId` should be `0`.
1. The `PlatformDispatcher.instance.implicitView` must be available synchronously at root isolate startup. This allows the framework to determine if it can make single window assumptions at startup.
2. The `PlatformDispatcher.instance.implicitView` reference must not change after startup: if it is null at startup, it must always be null; if it is non-null at startup, it must always be non-null. If "single window" app enters headless mode, the implicit view must remain non-null.
In the future, the embedder will control whether an implicit view is created: mobile & legacy desktop apps will have an implicit view, multi-window desktop apps won't have an implicit view. This requires updating the engine's embedder API and is out-of-scope for this change. For now, all apps will have an implicit view.
Part of https://github.com/flutter/flutter/issues/120306
This patch also eliminates some extraneous tracing that is happening
every frame. It is possible to get the same trace calls by enabling
the API stream if needed.
Also refactors the NotifyIdle callsites to just always work in
TimeDeltas rather than converting back and forth between them and
TimePoints, which I think reads more clearly.
* Add calls to Dart_NotifyDestroyed when the flutter view is destroyed.
* Add unit test case.
* Format.
* Ensure the destroy task runs.
* Address code review comments.
This PR changes how embedder API's SendKeyData sends ui.KeyData to the framework. The packets are now sent over the existing platform messenger, reusing the entirety of its code path and functionalities while keeping the embedder API unchanged
Group together externally-managed UIDartState.
It's a frequent pattern to enable access to shell resources from the
framework via UIDartState. These handles are passed through several
other objects, where they lay mostly dormant. This refactor just aims
to ease maintenance of this state.
UIDartState is essentially just an easy to extend bus for dropping
off the shell kids in UIDartState, with constructors/operators that
remove the need for providing a full initializer lists in unittests.
* Revert "Revert "Set SkPath::setIsVolatile based on whether the path survives at least two frames (#22620)" (#23044)"
This reverts commit feda80cb42f99e2588a9a6b9ab3dd1f812d0f45b.
* Fix tracing
This re-lands #20496 and #21780 after fixing the semantics-enabling code that was causing the post-submit web_smoke_test to fail.
Below is the description from the original PR:
This is a PR for converting the dart:ui code in the engine to use a multi-window API. The goal here is to convert from the window singleton to an API that has the concept of multiple windows. Also, I'm matching up the new PlatformDispatcher class to talk directly to the PlatformConfiguration class in the engine. I'm not attempting to actually enable creating multiple windows here, just migrate to an API that has a concept of multiple windows. The multi-window API in this PR currently only ever creates one window.
The design doc for this change is here.
The major changes in this PR:
Move the platfom-specific attributes out of Window, and into the new PlatformDispatcher class that holds all of the platform state, so that the platform code need only update the configuration on this class.
Create FlutterView, FlutterWindow, and SingletonFlutterWindow classes to separate out the concepts of a view (of which there may be multiple in a window), a window (of which there may be multiple on a screen, and they host views), and a window where there is only ever expected to be one (this hosts the entire API of the former Window class, and will eventually be the type of the window singleton).
Next step after this PR lands:
Remove the Window class entirely (it is replaced by SingletonFlutterWindow). Some minor changes in the Framework are needed to switch to using SingletonFlutterWindow directly first.
The Window class still exists in this PR, but will be removed as soon as the framework is converted to point to the SingletonFlutterWindow class instead. They share the same API, just have different names (Window is currently a subclass of SingletonFlutterWindow). The intention is that the Window name will be freed up to use as a widget class name in the framework for managing windows. The singleton called window will remain, and keep the same API it has now.
This regression was introduced in https://github.com/flutter/engine/pull/21820
for sound-null safety. The settings used to launch the VM were incorrectly used
to determine the isolate lifecycle callbacks. Since the first shell/engine in
the process also starts the VM, these objects are usually identical. However,
for subsequent engine shell/engine launches, the callbacks attached to the new
settings object would be ignored. The unit-test harness is also structured in
such a way that each test case tears down the VM before the next. So all
existing tests created a bespoke VM for the test run, and, the tests that did
create multiple isolates did not also test attaching callbacks to the settings
object.
Fixes https://github.com/flutter/engine/pull/22041
Snapshots compiled with sound null-safety enabled require changes to the way in
which isolates are launched. Specifically, the `Dart_IsolateFlags::null_safety`
field needs to be known upfront. The value of this field can only be determined
once the kernel snapshot is available. This poses a problem in the engine
because the engine used to launch the isolate at shell initialization and only
need the kernel mappings later at isolate launch (when transitioning the root
isolate to the `DartIsolate::Phase::Running` phase). This patch delays launch of
the isolate on the UI task runner till a kernel mapping is available. The side
effects of this delay (callers no longer having access to the non-running
isolate handle) have been addressed in this patch. The DartIsolate API has also
been amended to hide the method that could return a non-running isolate to the
caller. Instead, it has been replaced with a method that requires a valid
isolate configuration that returns a running root isolate. The isolate will be
launched by asking the isolate configuration for its null-safety
characteristics.
A side effect of enabling null-safety is that Dart APIs that work with legacy
types will now terminate the process if used with an isolate that has sound
null-safety enabled. These APIs may no longer be used in the engine. This
primarily affects the Dart Convertors in Tonic that convert certain C++ objects
into the Dart counterparts. All known Dart Converters have been updated to
convert C++ objects to non-nullable Dart types inferred using type traits of the
corresponding C++ object. The few spots in the engine that used the old Dart
APIs directly have been manually updated. To ensure that no usage of the legacy
APIs remain in the engine (as these would cause runtime process terminations),
the legacy APIs were prefixed with the `DART_LEGACY_API` macro and the macro
defined to `[[deprecated]]` in all engine translation units. While the engine
now primarily works with non-nullable Dart types, callers can still use
`Dart_TypeToNonNullableType` to acquire nullable types for use directly or with
Tonic. One use case that is not addressed with the Tonic Dart Convertors is the
creation of non-nullable lists of nullable types. This hasn’t come up so far in
the engine.
A minor related change is reworking tonic to define a single library target.
This allows the various tonic subsystems to depend on one another. Primarily,
this is used to make the Dart convertors use the logging utilities. This now
allows errors to be more descriptive as the presence of error handles is caught
(and logged) earlier.
Fixes https://github.com/flutter/flutter/issues/59879
* Revert "Fix documentation build for window changes. (#21780)"
This reverts commit a539d91840d2fbbb4aa07eeed6a92d654db167ab.
* Revert "Migration to PlatformDispatcher and multi-window (#20496)"
This reverts commit a58fec63f196175eedfc5fbaedce9336dab5c508.
This reverts commit 19ebd61442fd3bf6a69af2156c8b118fc8578ec2.
Additionally, the following _flutter.runInView deadlock is fixed.
Previously, a deadlock would occur when service protocol
_flutter.runInView is used to restart the engine wihtout tearing down
the shell: the shared mutex of the service protocol will be locked
during the restart as it's in the middle of handling a service protocol
message; if ServiceProtocol::AddHandler is also called during the
restart, the deadlock happens as AddHandler also requires such lock.
test/integration.shard/background_isolate_test.dart would fail
without this fix.
This is a PR for converting the dart:ui code in the engine to use a multi-window API. The goal here is to convert from the window singleton to an API that has the concept of multiple windows. Also, I'm matching up the new PlatformDispatcher class to talk directly to the PlatformConfiguration class in the engine. I'm not attempting to actually enable creating multiple windows here, just migrate to an API that has a concept of multiple windows. The multi-window API in this PR currently only ever creates one window.
The design doc for this change is here.
The major changes in this PR:
Move the platfom-specific attributes out of Window, and into the new PlatformDispatcher class that holds all of the platform state, so that the platform code need only update the configuration on this class.
Create FlutterView, FlutterWindow, and SingletonFlutterWindow classes to separate out the concepts of a view (of which there may be multiple in a window), a window (of which there may be multiple on a screen, and they host views), and a window where there is only ever expected to be one (this hosts the entire API of the former Window class, and will eventually be the type of the window singleton).
Next step after this PR lands:
Remove the Window class entirely (it is replaced by SingletonFlutterWindow). Some minor changes in the Framework are needed to switch to using SingletonFlutterWindow directly first.
The Window class still exists in this PR, but will be removed as soon as the framework is converted to point to the SingletonFlutterWindow class instead. They share the same API, just have different names (Window is currently a subclass of SingletonFlutterWindow). The intention is that the Window name will be freed up to use as a widget class name in the framework for managing windows. The singleton called window will remain, and keep the same API it has now.
## Description
As the related issue refer, the application may be doing too much work on its main thread even in a simple hello_world demo.
That is because the creation of `Engine` on the ui thread takes a noticeable time, and it is blocking the platform thread in order to run `Shell::Setup` synchronously.
The cost of `Engine`'s constructor is mainly about the creating of root isolate. Actually, there used to be another time-consuming process, the default font manager setup, which was resolved by https://github.com/flutter/engine/pull/18225.
Similar to https://github.com/flutter/engine/pull/18225, this pr move the creation of root isolate out from creating `Engine`. After this action, the main thread blocking is quite an acceptable slice.
## Related Issues
https://github.com/flutter/flutter/issues/40563 could be resolved by this pr.
