Overview
Dart artifacts are not built the same way in Fuchsia as they are on other platforms.
Instead of relying on pub
to manage dependencies, sources of
third-party packages we depend on are checked into the tree under
//third_party/dart-pkg
.
This is to ensure we use consistent versions of our dependencies across multiple
builds.
Likewise, no build output is placed in the source tree as everything goes under
out/
. That includes package_config.json
files, which are generated as part of the build
based on a target's dependency.
Exiting Dart programs
The Dart runner for Fuchsia does not
monitor the FIDL channels opened by Dart programs and as a result does not end
the program normally, but rather waits for the explicit call to fuchsia.exit()
to indicate the program should be ended.
import 'package:fuchsia/fuchsia.dart' as fuchsia;
void main(List<String> args) {
print('Hello Dart!');
fuchsia.exit(23);
}
Targets
There are five gn targets for building Dart:
dart_library
defines a library that can be used by other Dart targets;dart_component
defines a Fuchsia component based on a Dart library, that can be packaged using GN targetsfuchsia_package
orfuchsia_test_package
;dart_tool
defines a Dart tool for the host;flutter_component
defines a Flutter component;dart_test
defines a group of test.
See the definitions of each of these targets for how to use them.
Package layout
We use a layout very similar to the standard layout.
my_package/
|
|-- pubspec.yaml # Empty, used as a marker [mandatory]
|-- BUILD.gn # Contains all targets
|-- analysis_options.yaml # Analysis configuration [mandatory]
|-- lib/ # dart_library contents
|-- bin/ # dart_binary's (target) or dart_tool's (host)
|-- test/ # dart_test contents