[ffi] NativeCallable.listener example.
Add an example to the NativeCallable.listener documentation. Bug: https://github.com/dart-lang/sdk/issues/53435 Change-Id: I4b664b14ca1dbc474913a9e191e38ca6f290350f Fixes: https://github.com/dart-lang/sdk/issues/53435 CoreLibraryReviewExempt: The FFI package is VM-only Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/326580 Reviewed-by: Daco Harkes <dacoharkes@google.com> Commit-Queue: Liam Appelbe <liama@google.com>
This commit is contained in:
Liam Appelbe
committed by
Commit Queue
Commit Queue
parent
d54f0acd02
commit
5354df624a
@@ -48,6 +48,7 @@ group("runtime") {
|
||||
"runtime/bin:process_test",
|
||||
"runtime/bin:run_vm_tests",
|
||||
"runtime/vm:kernel_platform_files($host_toolchain)",
|
||||
"samples/ffi/http:fake_http",
|
||||
"utils/dartdev:dartdev",
|
||||
"utils/dds:dds",
|
||||
"utils/kernel-service:kernel-service",
|
||||
|
||||
@@ -0,0 +1,6 @@
|
||||
.dart_tool
|
||||
.packages
|
||||
pubspec.lock
|
||||
lib/libfake_http.so
|
||||
lib/libfake_http.dylib
|
||||
lib/fake_http.dll
|
||||
@@ -0,0 +1,9 @@
|
||||
# Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
|
||||
# for details. All rights reserved. Use of this source code is governed by a
|
||||
# BSD-style license that can be found in the LICENSE file.
|
||||
|
||||
shared_library("fake_http") {
|
||||
sources = [ "lib/fake_http.cc" ]
|
||||
include_dirs = [ "." ]
|
||||
ldflags = [ "-rdynamic" ]
|
||||
}
|
||||
@@ -0,0 +1,12 @@
|
||||
This is an example that shows how to use `NativeCallable.listener` to interact
|
||||
with a multi threaded native API.
|
||||
|
||||
The native API is a fake HTTP library with some hard coded requests and
|
||||
responses. To build the dynamic library, run this command:
|
||||
|
||||
```bash
|
||||
c++ -shared -fpic lib/fake_http.cc -lstdc++ -o lib/libfake_http.so
|
||||
```
|
||||
|
||||
On Windows the output library should be `lib/fake_http.dll` and on Mac it should
|
||||
be `lib/libfake_http.dylib`.
|
||||
@@ -0,0 +1,21 @@
|
||||
// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
|
||||
// for details. All rights reserved. Use of this source code is governed by a
|
||||
// BSD-style license that can be found in the LICENSE file.
|
||||
|
||||
import 'dart:ffi';
|
||||
import 'dart:io' show File, Platform;
|
||||
|
||||
Uri dylibPath(String name, Uri path) {
|
||||
if (Platform.isLinux || Platform.isAndroid || Platform.isFuchsia) {
|
||||
return path.resolve("lib$name.so");
|
||||
}
|
||||
if (Platform.isMacOS) return path.resolve("lib$name.dylib");
|
||||
if (Platform.isWindows) return path.resolve("$name.dll");
|
||||
throw Exception("Platform not implemented");
|
||||
}
|
||||
|
||||
DynamicLibrary dlopenPlatformSpecific(String name, {List<Uri>? paths}) =>
|
||||
DynamicLibrary.open((paths ?? [Uri()])
|
||||
.map((path) => dylibPath(name, path))
|
||||
.firstWhere((lib) => File(lib.toFilePath()).existsSync())
|
||||
.path);
|
||||
@@ -0,0 +1,48 @@
|
||||
// Copyright (c) 2023, 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 <atomic>
|
||||
#include <chrono>
|
||||
#include <cstring>
|
||||
#include <thread>
|
||||
|
||||
#if defined(_WIN32)
|
||||
#define DART_EXPORT extern "C" __declspec(dllexport)
|
||||
#else
|
||||
#define DART_EXPORT \
|
||||
extern "C" __attribute__((visibility("default"))) __attribute((used))
|
||||
#endif
|
||||
|
||||
constexpr char kExampleRequest[] = R"(
|
||||
GET / HTTP/1.1
|
||||
Host: www.example.com
|
||||
)";
|
||||
|
||||
constexpr char kExampleResponse[] = R"(
|
||||
HTTP/1.1 200 OK
|
||||
Content-Length: 54
|
||||
Content-Type: text/html; charset=UTF-8
|
||||
|
||||
<html>
|
||||
<body>
|
||||
Hello world!
|
||||
</body>
|
||||
</html>
|
||||
)";
|
||||
|
||||
DART_EXPORT void http_get(const char* uri, void (*onResponse)(const char*)) {
|
||||
std::thread([onResponse]() {
|
||||
std::this_thread::sleep_for(std::chrono::seconds(3));
|
||||
onResponse(strdup(kExampleResponse));
|
||||
}).detach();
|
||||
}
|
||||
|
||||
DART_EXPORT void http_serve(void (*onRequest)(const char*)) {
|
||||
std::thread([onRequest]() {
|
||||
while (true) {
|
||||
std::this_thread::sleep_for(std::chrono::seconds(1));
|
||||
onRequest(strdup(kExampleRequest));
|
||||
}
|
||||
}).detach();
|
||||
}
|
||||
@@ -0,0 +1,97 @@
|
||||
// Copyright (c) 2023, 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 'dart:async';
|
||||
import 'dart:ffi';
|
||||
import 'dart:io';
|
||||
|
||||
import 'package:ffi/ffi.dart';
|
||||
|
||||
import 'dylib_utils.dart';
|
||||
|
||||
// Runs a simple HTTP GET request using a native HTTP library that runs
|
||||
// the request on a background thread.
|
||||
Future<String> httpGet(String uri) async {
|
||||
// Create the NativeCallable.listener.
|
||||
final completer = Completer<String>();
|
||||
void onResponse(Pointer<Utf8> responsePointer) {
|
||||
completer.complete(responsePointer.toDartString());
|
||||
calloc.free(responsePointer);
|
||||
}
|
||||
|
||||
final callback = NativeCallable<HttpCallback>.listener(onResponse);
|
||||
|
||||
// Invoke the native HTTP API. Our example HTTP library runs our GET
|
||||
// request on a background thread, and calls the callback on that same
|
||||
// thread when it receives the response.
|
||||
final uriPointer = uri.toNativeUtf8();
|
||||
nativeHttpGet(uriPointer, callback.nativeFunction);
|
||||
calloc.free(uriPointer);
|
||||
|
||||
// Wait for the response.
|
||||
final response = await completer.future;
|
||||
|
||||
// Remember to close the NativeCallable once the native API is finished
|
||||
// with it, otherwise this isolate will stay alive indefinitely.
|
||||
callback.close();
|
||||
|
||||
return response;
|
||||
}
|
||||
|
||||
// Start a HTTP server on a background thread.
|
||||
void httpServe(void Function(String) onRequest) {
|
||||
// Create the NativeCallable.listener.
|
||||
void onNativeRequest(Pointer<Utf8> requestPointer) {
|
||||
onRequest(requestPointer.toDartString());
|
||||
calloc.free(requestPointer);
|
||||
}
|
||||
|
||||
final callback = NativeCallable<HttpCallback>.listener(onNativeRequest);
|
||||
|
||||
// Invoke the native function to start the HTTP server. Our example
|
||||
// HTTP library will start a server on a background thread, and pass
|
||||
// any requests it receives to out callback.
|
||||
nativeHttpServe(callback.nativeFunction);
|
||||
|
||||
// The server will run indefinitely, and the callback needs to stay
|
||||
// alive for that whole time, so we can't close the callback here.
|
||||
// But we also don't want the callback to keep the isolate alive
|
||||
// forever, so we set keepIsolateAlive to false.
|
||||
callback.keepIsolateAlive = false;
|
||||
}
|
||||
|
||||
// Load the native functions from a DynamicLibrary.
|
||||
late final DynamicLibrary dylib = dlopenPlatformSpecific('fake_http', paths: [
|
||||
Platform.script.resolve('../lib/'),
|
||||
Uri.file(Platform.resolvedExecutable),
|
||||
]);
|
||||
typedef HttpCallback = Void Function(Pointer<Utf8>);
|
||||
|
||||
typedef HttpGetFunction = void Function(
|
||||
Pointer<Utf8>, Pointer<NativeFunction<HttpCallback>>);
|
||||
typedef HttpGetNativeFunction = Void Function(
|
||||
Pointer<Utf8>, Pointer<NativeFunction<HttpCallback>>);
|
||||
final nativeHttpGet =
|
||||
dylib.lookupFunction<HttpGetNativeFunction, HttpGetFunction>('http_get');
|
||||
|
||||
typedef HttpServeFunction = void Function(
|
||||
Pointer<NativeFunction<HttpCallback>>);
|
||||
typedef HttpServeNativeFunction = Void Function(
|
||||
Pointer<NativeFunction<HttpCallback>>);
|
||||
final nativeHttpServe = dylib
|
||||
.lookupFunction<HttpServeNativeFunction, HttpServeFunction>('http_serve');
|
||||
|
||||
Future<void> main() async {
|
||||
print('Sending GET request...');
|
||||
final response = await httpGet('http://example.com');
|
||||
print('Received a response: $response');
|
||||
|
||||
print('Starting HTTP server...');
|
||||
httpServe((String request) {
|
||||
print('Received a request: $request');
|
||||
});
|
||||
|
||||
await Future.delayed(Duration(seconds: 10));
|
||||
print('All done');
|
||||
}
|
||||
@@ -0,0 +1,12 @@
|
||||
name: http
|
||||
version: 0.0.1
|
||||
publish_to: none
|
||||
|
||||
environment:
|
||||
sdk: '>=3.0.0 <4.0.0'
|
||||
|
||||
dependencies:
|
||||
ffi: ^2.1.0
|
||||
|
||||
dev_dependencies:
|
||||
test: ^1.21.1
|
||||
@@ -0,0 +1,25 @@
|
||||
// Copyright (c) 2023, 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 'dart:async';
|
||||
import 'dart:io';
|
||||
|
||||
import 'package:ffi/ffi.dart';
|
||||
import 'package:test/test.dart';
|
||||
|
||||
import '../lib/http.dart';
|
||||
|
||||
Future<void> main() async {
|
||||
test('httpGet', () async {
|
||||
final response = await httpGet('http://example.com');
|
||||
expect(response, contains('Hello world!'));
|
||||
});
|
||||
|
||||
test('httpServe', () async {
|
||||
final completer = Completer<String>();
|
||||
httpServe((request) => completer.complete(request));
|
||||
final request = await completer.future;
|
||||
expect(request, contains('www.example.com'));
|
||||
});
|
||||
}
|
||||
@@ -214,6 +214,83 @@ abstract final class NativeCallable<T extends Function> {
|
||||
///
|
||||
/// This callback must be [close]d when it is no longer needed. The [Isolate]
|
||||
/// that created the callback will be kept alive until [close] is called.
|
||||
///
|
||||
/// For example:
|
||||
///
|
||||
/// ```dart
|
||||
/// import 'dart:async';
|
||||
/// import 'dart:ffi';
|
||||
/// import 'package:ffi/ffi.dart';
|
||||
///
|
||||
/// // Runs a simple HTTP GET request using a native HTTP library that runs
|
||||
/// // the request on a background thread.
|
||||
/// Future<String> httpGet(String uri) async {
|
||||
/// // Create the NativeCallable.listener.
|
||||
/// final completer = Completer<String>();
|
||||
/// void onResponse(Pointer<Utf8> responsePointer) {
|
||||
/// completer.complete(responsePointer.toDartString());
|
||||
/// calloc.free(responsePointer);
|
||||
/// }
|
||||
/// final callback = NativeCallable<HttpCallback>.listener(onResponse);
|
||||
///
|
||||
/// // Invoke the native HTTP API. Our example HTTP library runs our GET
|
||||
/// // request on a background thread, and calls the callback on that same
|
||||
/// // thread when it receives the response.
|
||||
/// final uriPointer = uri.toNativeUtf8();
|
||||
/// nativeHttpGet(uriPointer, callback.nativeFunction);
|
||||
/// calloc.free(uriPointer);
|
||||
///
|
||||
/// // Wait for the response.
|
||||
/// final response = await completer.future;
|
||||
///
|
||||
/// // Remember to close the NativeCallable once the native API is finished
|
||||
/// // with it, otherwise this isolate will stay alive indefinitely.
|
||||
/// callback.close();
|
||||
///
|
||||
/// return response;
|
||||
/// }
|
||||
///
|
||||
/// // Start a HTTP server on a background thread.
|
||||
/// void httpServe(void Function(String) onRequest) {
|
||||
/// // Create the NativeCallable.listener.
|
||||
/// void onNativeRequest(Pointer<Utf8> requestPointer) {
|
||||
/// onRequest(requestPointer.toDartString());
|
||||
/// calloc.free(requestPointer);
|
||||
/// }
|
||||
/// final callback = NativeCallable<HttpCallback>.listener(onNativeRequest);
|
||||
///
|
||||
/// // Invoke the native function to start the HTTP server. Our example
|
||||
/// // HTTP library will start a server on a background thread, and pass
|
||||
/// // any requests it receives to out callback.
|
||||
/// nativeHttpServe(callback.nativeFunction);
|
||||
///
|
||||
/// // The server will run indefinitely, and the callback needs to stay
|
||||
/// // alive for that whole time, so we can't close the callback here.
|
||||
/// // But we also don't want the callback to keep the isolate alive
|
||||
/// // forever, so we set keepIsolateAlive to false.
|
||||
/// callback.keepIsolateAlive = false;
|
||||
/// }
|
||||
///
|
||||
/// // Load the native functions from a DynamicLibrary.
|
||||
/// late final DynamicLibrary dylib = DynamicLibrary.process();
|
||||
/// typedef HttpCallback = Void Function(Pointer<Utf8>);
|
||||
///
|
||||
/// typedef HttpGetFunction = void Function(
|
||||
/// Pointer<Utf8>, Pointer<NativeFunction<HttpCallback>>);
|
||||
/// typedef HttpGetNativeFunction = Void Function(
|
||||
/// Pointer<Utf8>, Pointer<NativeFunction<HttpCallback>>);
|
||||
/// final nativeHttpGet =
|
||||
/// dylib.lookupFunction<HttpGetNativeFunction, HttpGetFunction>(
|
||||
/// 'http_get');
|
||||
///
|
||||
/// typedef HttpServeFunction = void Function(
|
||||
/// Pointer<NativeFunction<HttpCallback>>);
|
||||
/// typedef HttpServeNativeFunction = Void Function(
|
||||
/// Pointer<NativeFunction<HttpCallback>>);
|
||||
/// final nativeHttpServe =
|
||||
/// dylib.lookupFunction<HttpServeNativeFunction, HttpServeFunction>(
|
||||
/// 'http_serve');
|
||||
/// ```
|
||||
factory NativeCallable.listener(
|
||||
@DartRepresentationOf("T") Function callback) {
|
||||
throw UnsupportedError("NativeCallable cannot be constructed dynamically.");
|
||||
|
||||
Reference in New Issue
Block a user