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dart / monorepo / / 332a34929fd3f1f57df80f9b2f72dfbf426905fc
commit332a34929fd3f1f57df80f9b2f72dfbf426905fc[log] [tgz]
authorDavid Iglesias <ditman@gmail.com>Wed Jun 05 16:25:53 2024 -0700
committerdart-internal-monorepo <dart-internal-monorepo@dart-ci-internal.iam.gserviceaccount.com>Wed Jun 05 16:32:33 2024 -0700
tree601a0a0a1f42d8bab6ed62eaad8bb26c74b68288
parent242a356e420645f4ce56cb041ec1696c750b06e5 [diff]
[web] Adds allowPlatformDefault for wheel signals. (#51566)

Adds a function to each 'wheel' DataPacket sent to the framework so it can signal whether to `allowPlatformDefault` or not.

The current default is to always `preventDefault` on browser events that get sent to the framework.

This PR enables the framework to call a method on the `DataPacket`s to `allowPlatformDefault: true`, if the framework won't handle the Signal (signals are handled synchronously on the framework).

This lets the engine "wait" for the framework to decide whether to `preventDefault` on a `wheel` event or not.

## Issues

* Needed for: https://github.com/flutter/flutter/issues/139263

## Tests

* Added unit tests for the feature in the engine repo, veryfing whether the event has had its `defaultPrevented` or not.
* Manually tested in a demo app (see below)

## Demo

* https://dit-multiview-scroll.web.app

<details>
<summary>

## Previous approaches

</summary>

1. Add a `handled` bool property to `PointerDataPacket` that the framework can write to (brittle)
2. Modifications to the `PlatformDispatcher` so the framework can `acknowledgePointerData` with a `PointerDataResponse` (fffffatttt change)
3. `acknowledge` function in `PointerDataPacket`

</details>

> [!IMPORTANT]
> * Related: https://github.com/flutter/flutter/pull/145500

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
https://dart.googlesource.com/external/github.com/flutter/engine/+/7ab0cf43b4acbeefa03dd33b14cda12a3afaedd3
2 files changed
tree: 601a0a0a1f42d8bab6ed62eaad8bb26c74b68288
  1. ci/
  2. tools/
  3. .gitignore
  4. commits.json
  5. DEPS
  6. OWNERS
  7. README.md
README.md

Monorepo

A gclient solution for checking out Dart and Flutter source trees

Monorepo is:

  • Optimized for Tip-of-Tree testing: The Monorepo DEPS used to check out Dart and Flutter dependencies comes from the Flutter engine DEPS with updated dependencies from Dart.

Checking out Monorepo

With depot_tools installed and on your path, create a directory for your monorepo checkout and run these commands to create a gclient solution in that directory:

mkdir monorepo
cd monorepo
gclient config --unmanaged https://dart.googlesource.com/monorepo
gclient sync -D

This gives you a checkout in the monorepo directory that contains:

monorepo/
  DEPS - the DEPS used for this gclient checkout
  commits.json - the pinned commits for Dart, flutter/engine,
                 and flutter/flutter
  tools/ - scripts used to create monorepo DEPS
engine/src/ - the flutter/buildroot repo
    flutter/ - the flutter/engine repo
    out/ - the build directory, where Flutter engine builds are created
    third_party/ - Flutter dependencies checked out by DEPS
      dart/ - the Dart SDK checkout.
        third_party - Dart dependencies, also used by Flutter
flutter/ - the flutter/flutter repo

Building Flutter engine

Flutter's instructions for building the engine are at Compiling the engine

They can be followed closely, with a few changes:

  • Googlers working on Dart do not need to switch to Fuchsia's Goma RBE, except for Windows. The GOMA_DIR enviroment variable can just point to the .cipd_bin directory in a depot_tools installation, and just goma_ctl ensure_start is sufficient.
  • The --no-prebuilt-dart-sdk option has to be added to every gn command, so that the build is set up to build and use a local Dart SDK.
  • The --full-dart-sdk option must be added to gn for the host build target if you will be building web or desktop apps.

Example build commands that work on linux:

MONOREPO_PATH=$PWD
if [[ ! $PATH =~ (^|:)$MONOREPO_PATH/flutter/bin(:|$) ]]; then
  PATH=$MONOREPO_PATH/flutter/bin:$PATH
fi

export GOMA_DIR=$(dirname $(command -v gclient))/.cipd_bin
goma_ctl ensure_start

pushd engine/src
flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk
autoninja -C out/host_debug_unopt
popd

Building Flutter apps

The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.

For example, to build and run the Flutter spinning square sample on the web platform,

MONOREPO_PATH=$PWD
cd flutter/examples/layers
flutter --local-engine=host_debug_unopt \
  -d chrome run widgets/spinning_square.dart
cd $MONOREPO_PATH

To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command

flutter create --platforms=windows,macos,linux

on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter

Testing

Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:

MONOREPO_PATH=$PWD
cd flutter/packages/flutter
flutter test --local-engine=host_debug_unopt
cd $MONOREPO_PATH

Troubleshooting

Please file an issue or email the dart-engprod team with any problems with or questions about using monorepo.

We will update this documentation to address them.

  • flutter commands may download the engine and Dart SDK files for the configured channel, even though they will be using the local engine and its SDK.

Windows

  • On Windows, gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.