// Copyright 2014 The Flutter Authors. 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 '_isolates_io.dart' if (dart.library.html) '_isolates_web.dart' as _isolates; /// Signature for the callback passed to [compute]. /// /// {@macro flutter.foundation.compute.types} /// /// Instances of [ComputeCallback] must be top-level functions or static methods /// of classes, not closures or instance methods of objects. /// /// {@macro flutter.foundation.compute.limitations} typedef ComputeCallback<Q, R> = FutureOr<R> Function(Q message); /// The signature of [compute], which spawns an isolate, runs `callback` on /// that isolate, passes it `message`, and (eventually) returns the value /// returned by `callback`. /// /// This is useful for operations that take longer than a few milliseconds, and /// which would therefore risk skipping frames. For tasks that will only take a /// few milliseconds, consider [SchedulerBinding.scheduleTask] instead. /// /// {@template flutter.foundation.compute.types} /// `Q` is the type of the message that kicks off the computation. /// /// `R` is the type of the value returned. /// {@endtemplate} /// /// The `callback` argument must be a top-level function, not a closure or an /// instance or static method of a class. /// /// {@template flutter.foundation.compute.limitations} /// There are limitations on the values that can be sent and received to and /// from isolates. These limitations constrain the values of `Q` and `R` that /// are possible. See the discussion at [SendPort.send]. /// {@endtemplate} /// /// The `debugLabel` argument can be specified to provide a name to add to the /// [Timeline]. This is useful when profiling an application. typedef ComputeImpl = Future<R> Function<Q, R>(ComputeCallback<Q, R> callback, Q message, { String? debugLabel }); /// A function that spawns an isolate and runs a callback on that isolate. /// /// See also: /// /// * [ComputeImpl], for function parameters and usage details. const ComputeImpl compute = _isolates.compute;