Native assets support for MacOS and iOS (#130494) Support for FFI calls with `@Native external` functions through Native assets on MacOS and iOS. This enables bundling native code without any build-system boilerplate code. For more info see: * https://github.com/flutter/flutter/issues/129757 ### Implementation details for MacOS and iOS. Dylibs are bundled by (1) making them fat binaries if multiple architectures are targeted, (2) code signing these, and (3) copying them to the frameworks folder. These steps are done manual rather than via CocoaPods. CocoaPods would have done the same steps, but (a) needs the dylibs to be there before the `xcodebuild` invocation (we could trick it, by having a minimal dylib in the place and replace it during the build process, that works), and (b) can't deal with having no dylibs to be bundled (we'd have to bundle a dummy dylib or include some dummy C code in the build file). The dylibs are build as a new target inside flutter assemble, as that is the moment we know what build-mode and architecture to target. The mapping from asset id to dylib-path is passed in to every kernel compilation path. The interesting case is hot-restart where the initial kernel file is compiled by the "inner" flutter assemble, while after hot restart the "outer" flutter run compiled kernel file is pushed to the device. Both kernel files need to contain the mapping. The "inner" flutter assemble gets its mapping from the NativeAssets target which builds the native assets. The "outer" flutter run get its mapping from a dry-run invocation. Since this hot restart can be used for multiple target devices (`flutter run -d all`) it contains the mapping for all known targets. ### Example vs template The PR includes a new template that uses the new native assets in a package and has an app importing that. Separate discussion in: https://github.com/flutter/flutter/issues/131209. ### Tests This PR adds new tests to cover the various use cases. * dev/devicelab/bin/tasks/native_assets_ios.dart * Runs an example app with native assets in all build modes, doing hot reload and hot restart in debug mode. * dev/devicelab/bin/tasks/native_assets_ios_simulator.dart * Runs an example app with native assets, doing hot reload and hot restart. * packages/flutter_tools/test/integration.shard/native_assets_test.dart * Runs (incl hot reload/hot restart), builds, builds frameworks for iOS, MacOS and flutter-tester. * packages/flutter_tools/test/general.shard/build_system/targets/native_assets_test.dart * Unit tests the new Target in the backend. * packages/flutter_tools/test/general.shard/ios/native_assets_test.dart * packages/flutter_tools/test/general.shard/macos/native_assets_test.dart * Unit tests the native assets being packaged on a iOS/MacOS build. It also extends various existing tests: * dev/devicelab/bin/tasks/module_test_ios.dart * Exercises the add2app scenario. * packages/flutter_tools/test/general.shard/features_test.dart * Unit test the new feature flag. https://dart.googlesource.com/external/github.com/flutter/flutter/+/aa36db1d29eb53b74dd1dda5a12e37800c628358
Monorepo is:
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
Flutter's instructions for building the engine are at Compiling the engine
They can be followed closely, with a few changes:
goma_ctl ensure_start is sufficient.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 $(command -v gclient))/.cipd_bin goma_ctl ensure_start pushd engine/src flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk autoninja -C out/host_debug_unopt popd
The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.
For example, to build and run the Flutter spinning square sample on the web platform,
MONOREPO_PATH=$PWD cd flutter/examples/layers flutter --local-engine=host_debug_unopt \ -d chrome run widgets/spinning_square.dart cd $MONOREPO_PATH
To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command
flutter create --platforms=windows,macos,linux
on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter
Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:
MONOREPO_PATH=$PWD cd flutter/packages/flutter flutter test --local-engine=host_debug_unopt cd $MONOREPO_PATH
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.gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.