[native_assets_cli] Add example for downloading assets

.github/workflows/download_asset.yaml

@@ -0,0 +1,134 @@
+name: download_asset
+
+permissions:
+  contents: write
+
+on:
+  pull_request:
+    branches: [ main ]
+    paths:
+      - .github/workflows/download_asset.yaml
+      - pkgs/native_assets_cli/example/build/download_asset/
+  push:
+    tags:
+      - 'download_asset-prebuild-assets-*'
+  workflow_dispatch:
+
+jobs:
+  build:
+    name: Prebuilt native libraries
+
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu, macos, windows]
+
+    runs-on: ${{ matrix.os }}-latest
+
+    defaults:
+        run:
+          working-directory: pkgs/native_assets_cli/example/build/download_asset/
+
+    steps:
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+
+    - uses: dart-lang/setup-dart@e630b99d28a3b71860378cafdc2a067c71107f94
+      with:
+        sdk: stable
+
+    - uses: nttld/setup-ndk@afb4c9964b521afb97c864b7d40b11e6911bd410
+      with:
+        ndk-version: r27
+      if: ${{ matrix.os == 'ubuntu' }} # Only build on one host.
+
+    - name: Install native toolchains
+      run: sudo apt-get update && sudo apt-get install clang-15 gcc-i686-linux-gnu gcc-aarch64-linux-gnu gcc-arm-linux-gnueabihf gcc-riscv64-linux-gnu
+      if: ${{ matrix.os == 'ubuntu' }}
+
+    - run: dart pub get
+
+    - name: Build Linux host
+      if: matrix.os == 'ubuntu'
+      run: |
+        dart tool/build.dart -oandroid -aarm
+        dart tool/build.dart -oandroid -aarm64
+        dart tool/build.dart -oandroid -aia32
+        dart tool/build.dart -oandroid -ariscv64
+        dart tool/build.dart -oandroid -ax64
+        dart tool/build.dart -olinux -aarm
+        dart tool/build.dart -olinux -aarm64
+        dart tool/build.dart -olinux -aia32
+        dart tool/build.dart -olinux -ariscv64
+        dart tool/build.dart -olinux -ax64
+  
+    - name: Build MacOS host
+      if: matrix.os == 'macos'
+      run: |
+        dart tool/build.dart -omacos -aarm64
+        dart tool/build.dart -omacos -ax64
+        dart tool/build.dart -oios -iiphoneos -aarm64
+        dart tool/build.dart -oios -iiphonesimulator -aarm64
+        dart tool/build.dart -oios -iiphonesimulator -ax64
+  
+    - name: Build Windows host
+      if: matrix.os == 'windows'
+      run: |
+        dart tool/build.dart -owindows -aarm
+        dart tool/build.dart -owindows -aarm64
+        dart tool/build.dart -owindows -aia32
+        dart tool/build.dart -owindows -ax64
+    
+    # - name: Upload artifacts
+    #   uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882
+    #   with:
+    #     name: dart-${{matrix.os}}-${{ matrix.compiletype }}-libs
+    #     path: submodules/icu4x/bin
+
+#   check_hashes:
+#     needs: dart-libs
+#     runs-on: ubuntu-latest
+
+#     env:
+#       ICU4X_BUILD_MODE: local
+
+#     steps:
+#       - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9
+#         with:
+#           submodules: true
+
+#       - name: Download binaries
+#         uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16
+#         with:
+#           merge-multiple: true
+
+#       - name: Display structure of downloaded files
+#         run: ls -R
+
+#       - uses: dart-lang/setup-dart@0a8a0fc875eb934c15d08629302413c671d3f672
+#         with:
+#           sdk: dev
+
+#       - name: Check hashes of released artifacts
+#         run: |
+#           cd pkgs/intl4x
+#           dart pub get
+#           dart --enable-experiment=native-assets tool/regenerate_hashes.dart
+#           git diff --exit-code
+
+#   release:
+#     needs: dart-libs
+#     runs-on: ubuntu-latest
+#     if: github.event_name == 'push'
+#     steps:
+#       - name: Download binaries
+#         uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16
+
+#       - name: Display structure of downloaded files
+#         run: ls -R
+
+#       - name: Release
+#         uses: softprops/action-gh-release@e7a8f85e1c67a31e6ed99a94b41bd0b71bbee6b8
+#         with:
+#           files: '**'
+#           fail_on_unmatched_files: true
+#           body: "Build artifacts for `package:intl4x`, based on ICU4X at ref ${{ github.ref_name }}"

.github/workflows/native.yaml

@@ -105,6 +105,9 @@ jobs:
       - run: dart pub get -C test_data/native_dynamic_linking/
         if: ${{ matrix.package == 'native_assets_builder' }}
 
+      - run: dart pub get -C example/build/download_asset/
+        if: ${{ matrix.package == 'native_assets_cli' }}
+
       - run: dart pub get -C example/build/native_dynamic_linking/
         if: ${{ matrix.package == 'native_assets_cli' }}
 

pkgs/native_assets_cli/example/build/download_asset/README.md

@@ -0,0 +1,14 @@
+An example of a library depending on prebuilt assets which are downloaded in
+the build hook.
+
+## Usage
+
+Run tests with `dart --enable-experiment=native-assets test`.
+
+## Code organization
+
+A typical layout of a package which downloads assets:
+
+* `hook/build.dart` downloads the prebuilt assets.
+* `lib/` contains Dart code which uses the assets.
+* `tool/build.dart` prebuilts assets and is exercised from the GitHub CI.

pkgs/native_assets_cli/example/build/download_asset/ffigen.yaml

@@ -0,0 +1,20 @@
+# Run with `flutter pub run ffigen --config ffigen.yaml`.
+name: NativeAddBindings
+description: |
+  Bindings for `src/native_add.h`.
+
+  Regenerate bindings with `flutter pub run ffigen --config ffigen.yaml`.
+output: 'lib/native_add.dart'
+headers:
+  entry-points:
+    - 'src/native_add.h'
+  include-directives:
+    - 'src/native_add.h'
+preamble: |
+  // Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+  // for details. All rights reserved. Use of this source code is governed by a
+  // BSD-style license that can be found in the LICENSE file.
+comments:
+  style: any
+  length: full
+ffi-native:

pkgs/native_assets_cli/example/build/download_asset/hook/build.dart

@@ -0,0 +1,27 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:logging/logging.dart';
+import 'package:native_assets_cli/native_assets_cli.dart';
+import 'package:native_toolchain_c/native_toolchain_c.dart';
+
+void main(List<String> args) async {
+  await build(args, (config, output) async {
+    final packageName = config.packageName;
+    final cbuilder = CBuilder.library(
+      name: packageName,
+      assetName: '$packageName.dart',
+      sources: [
+        'src/$packageName.c',
+      ],
+    );
+    await cbuilder.run(
+      config: config,
+      output: output,
+      logger: Logger('')
+        ..level = Level.ALL
+        ..onRecord.listen((record) => print(record.message)),
+    );
+  });
+}

pkgs/native_assets_cli/example/build/download_asset/lib/native_add.dart

@@ -0,0 +1,15 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// AUTO GENERATED FILE, DO NOT EDIT.
+//
+// Generated by `package:ffigen`.
+// ignore_for_file: type=lint
+import 'dart:ffi' as ffi;
+
+@ffi.Native<ffi.Int32 Function(ffi.Int32, ffi.Int32)>(symbol: 'add')
+external int add(
+  int a,
+  int b,
+);

pkgs/native_assets_cli/example/build/download_asset/lib/src/build_helpers.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+const androidTargetNdkApi = 30;
+const int macOSTargetVersion = 13;
+const iOSTargetVersion = 16;

pkgs/native_assets_cli/example/build/download_asset/pubspec.yaml

@@ -0,0 +1,24 @@
+publish_to: none
+
+name: download_asset
+description: Sums two numbers with native code, prebuilt assets.
+version: 0.1.0
+repository: https://github.com/dart-lang/native/tree/main/pkgs/native_assets_cli/example/build/download_asset
+
+environment:
+  sdk: '>=3.3.0 <4.0.0'
+
+dependencies:
+  logging: ^1.1.1
+  native_assets_cli: ^0.10.0
+  # native_assets_cli:
+  #   path: ../../../../native_assets_cli/
+  native_toolchain_c: ^0.7.0
+  # native_toolchain_c:
+  #   path: ../../../../native_toolchain_c/
+
+dev_dependencies:
+  args: ^2.6.0
+  ffigen: ^8.0.2
+  lints: ^3.0.0
+  test: ^1.21.0

pkgs/native_assets_cli/example/build/download_asset/src/native_add.c

@@ -0,0 +1,7 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "native_add.h"
+
+int32_t add(int32_t a, int32_t b) { return a + b; }

pkgs/native_assets_cli/example/build/download_asset/src/native_add.h

@@ -0,0 +1,13 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include <stdint.h>
+
+#if _WIN32
+#define MYLIB_EXPORT __declspec(dllexport)
+#else
+#define MYLIB_EXPORT
+#endif
+
+MYLIB_EXPORT int32_t add(int32_t a, int32_t b);

pkgs/native_assets_cli/example/build/download_asset/test/native_add_test.dart

@@ -0,0 +1,12 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:download_asset/native_add.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('invoke native function', () {
+    expect(add(24, 18), 42);
+  });
+}