readability-dart/lib/readability.dart
Sphericalkat e6eee54104
fix: remove linux target for now
Signed-off-by: Sphericalkat <me@kat.bio>
2024-07-18 01:58:17 +05:30

182 lines
6.6 KiB
Dart

// You have generated a new plugin project without specifying the `--platforms`
// flag. An FFI plugin project that supports no platforms is generated.
// To add platforms, run `flutter create -t plugin_ffi --platforms <platforms> .`
// in this directory. 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.
import 'dart:async';
import 'dart:ffi';
import 'dart:io';
import 'dart:isolate';
import 'package:ffi/ffi.dart';
import 'package:readability/article.dart';
import 'readability_bindings_generated.dart';
/// A very short-lived native function.
///
/// For very short-lived functions, it is fine to call them on the main isolate.
/// They will block the Dart execution while running the native function, so
/// only do this for native functions which are guaranteed to be short-lived.
// int sum(int a, int b) => _bindings.sum(a, b);
/// A longer lived native function, which occupies the thread calling it.
///
/// Do not call these kind of native functions in the main isolate. They will
/// block Dart execution. This will cause dropped frames in Flutter applications.
/// Instead, call these native functions on a separate isolate.
///
/// Modify this to suit your own use case. Example use cases:
///
/// 1. Reuse a single isolate for various different kinds of requests.
/// 2. Use multiple helper isolates for parallel execution.
Future<ArticleResponse> parseAsync(String url) async {
final SendPort helperIsolateSendPort = await _helperIsolateSendPort;
final int requestId = _nextParseRequestId++;
final _ParseRequest request = _ParseRequest(url, requestId);
final Completer<ArticleResponse> completer = Completer<ArticleResponse>();
_parseRequests[requestId] = completer;
helperIsolateSendPort.send(request);
return completer.future;
}
const String _libName = 'readability';
/// The dynamic library in which the symbols for [ReadabilityBindings] can be found.
final DynamicLibrary _dylib = () {
if (Platform.isMacOS || Platform.isIOS) {
return DynamicLibrary.open('$_libName.framework/$_libName');
}
if (Platform.isAndroid || Platform.isLinux) {
return DynamicLibrary.open('lib$_libName.so');
}
if (Platform.isWindows) {
return DynamicLibrary.open('$_libName.dll');
}
throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
}();
/// The bindings to the native functions in [_dylib].
final ReadabilityBindings _bindings = ReadabilityBindings(_dylib);
/// A request to compute `sum`.
///
/// Typically sent from one isolate to another.
class _ParseRequest {
final String url;
final int id;
const _ParseRequest(this.url, this.id);
}
class ArticleResponse {
final Article article;
final int id;
ArticleResponse({
required this.article,
required this.id,
});
}
/// Counter to identify [_ParseRequest]s and [ArticleResponse]s.
int _nextParseRequestId = 0;
/// Mapping from [_ParseRequest] `id`s to the completers corresponding to the correct future of the pending request.
final Map<int, Completer<ArticleResponse>> _parseRequests =
<int, Completer<ArticleResponse>>{};
/// The SendPort belonging to the helper isolate.
Future<SendPort> _helperIsolateSendPort = () async {
// The helper isolate is going to send us back a SendPort, which we want to
// wait for.
final Completer<SendPort> completer = Completer<SendPort>();
// Receive port on the main isolate to receive messages from the helper.
// We receive two types of messages:
// 1. A port to send messages on.
// 2. Responses to requests we sent.
final ReceivePort receivePort = ReceivePort()
..listen((dynamic data) {
if (data is SendPort) {
// The helper isolate sent us the port on which we can sent it requests.
completer.complete(data);
return;
}
if (data is ArticleResponse) {
// The helper isolate sent us a response to a request we sent.
final Completer<ArticleResponse> completer = _parseRequests[data.id]!;
_parseRequests.remove(data.id);
completer.complete(data);
return;
}
throw UnsupportedError('Unsupported message type: ${data.runtimeType}');
});
// Start the helper isolate.
await Isolate.spawn((SendPort sendPort) async {
final ReceivePort helperReceivePort = ReceivePort()
..listen((dynamic data) {
// On the helper isolate listen to requests and respond to them.
if (data is _ParseRequest) {
final urlPointer = data.url.toNativeUtf8();
final CArticle article = _bindings.Parse(urlPointer);
// Free the native string.
calloc.free(urlPointer);
// Convert the native article to a Dart article.
final articleDart = Article(
title:
article.title == nullptr ? null : article.title.toDartString(),
author: article.author == nullptr
? null
: article.author.toDartString(),
length: article.length,
excerpt: article.excerpt == nullptr
? null
: article.excerpt.toDartString(),
siteName: article.site_name == nullptr
? null
: article.site_name.toDartString(),
imageUrl: article.image_url == nullptr
? null
: article.image_url.toDartString(),
faviconUrl: article.favicon_url == nullptr
? null
: article.favicon_url.toDartString(),
content: article.content == nullptr
? null
: article.content.toDartString(),
textContent: article.text_content == nullptr
? null
: article.text_content.toDartString(),
language: article.language == nullptr
? null
: article.language.toDartString(),
publishedTime: article.published_time == nullptr
? null
: article.published_time.toDartString(),
);
ArticleResponse articleDartResponse =
ArticleResponse(article: articleDart, id: data.id);
// Free the native article.
_bindings.FreeArticle(article);
sendPort.send(articleDartResponse);
return;
}
throw UnsupportedError('Unsupported message type: ${data.runtimeType}');
});
// Send the port to the main isolate on which we can receive requests.
sendPort.send(helperReceivePort.sendPort);
}, receivePort.sendPort);
// Wait until the helper isolate has sent us back the SendPort on which we
// can start sending requests.
return completer.future;
}();