96 lines
3.2 KiB
Markdown
96 lines
3.2 KiB
Markdown
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# readability
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A new Flutter FFI plugin project.
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## Getting Started
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This project is a starting point for a Flutter
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[FFI plugin](https://docs.flutter.dev/development/platform-integration/c-interop),
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a specialized package that includes native code directly invoked with Dart FFI.
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## Project structure
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This template uses the following structure:
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* `src`: Contains the native source code, and a CmakeFile.txt file for building
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that source code into a dynamic library.
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* `lib`: Contains the Dart code that defines the API of the plugin, and which
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calls into the native code using `dart:ffi`.
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* platform folders (`android`, `ios`, `windows`, etc.): Contains the build files
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for building and bundling the native code library with the platform application.
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## Building and bundling native code
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The `pubspec.yaml` specifies FFI plugins as follows:
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```yaml
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plugin:
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platforms:
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some_platform:
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ffiPlugin: true
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```
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This configuration invokes the native build for the various target platforms
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and bundles the binaries in Flutter applications using these FFI plugins.
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This can be combined with dartPluginClass, such as when FFI is used for the
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implementation of one platform in a federated plugin:
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```yaml
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plugin:
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implements: some_other_plugin
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platforms:
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some_platform:
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dartPluginClass: SomeClass
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ffiPlugin: true
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```
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A plugin can have both FFI and method channels:
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```yaml
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plugin:
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platforms:
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some_platform:
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pluginClass: SomeName
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ffiPlugin: true
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```
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The native build systems that are invoked by FFI (and method channel) plugins are:
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* For Android: Gradle, which invokes the Android NDK for native builds.
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* See the documentation in android/build.gradle.
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* For iOS and MacOS: Xcode, via CocoaPods.
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* See the documentation in ios/readability.podspec.
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* See the documentation in macos/readability.podspec.
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* For Linux and Windows: CMake.
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* See the documentation in linux/CMakeLists.txt.
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* See the documentation in windows/CMakeLists.txt.
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## Binding to native code
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To use the native code, bindings in Dart are needed.
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To avoid writing these by hand, they are generated from the header file
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(`src/readability.h`) by `package:ffigen`.
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Regenerate the bindings by running `dart run ffigen --config ffigen.yaml`.
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## Invoking native code
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Very short-running native functions can be directly invoked from any isolate.
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For example, see `sum` in `lib/readability.dart`.
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Longer-running functions should be invoked on a helper isolate to avoid
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dropping frames in Flutter applications.
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For example, see `sumAsync` in `lib/readability.dart`.
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## Flutter help
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For help getting started with Flutter, view our
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[online documentation](https://flutter.dev/docs), which offers tutorials,
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samples, guidance on mobile development, and a full API reference.
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The plugin project was generated without specifying the `--platforms` flag, so no platforms are currently supported.
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To add platforms, run `flutter create -t plugin_ffi --platforms <platforms> .` in this directory.
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You can also find a detailed instruction on how to add platforms in the `pubspec.yaml` at https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
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