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74 lines
3.2 KiB
Dart
74 lines
3.2 KiB
Dart
// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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part of dart.ui;
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/// Static methods to allow for simple sharing of [SendPort]s across [Isolate]s.
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///
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/// All isolates share a global mapping of names to ports. An isolate can
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/// register a [SendPort] with a given name using [registerPortWithName];
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/// another isolate can then look up that port using [lookupPortByName].
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///
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/// To create a [SendPort], first create a [ReceivePort], then use
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/// [ReceivePort.sendPort].
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///
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/// Since multiple isolates can each obtain the same [SendPort] associated with
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/// a particular [ReceivePort], the protocol built on top of this mechanism
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/// should typically consist of a single message. If more elaborate two-way
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/// communication or multiple-message communication is necessary, it is
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/// recommended to establish a separate communication channel in that first
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/// message (e.g. by passing a dedicated [SendPort]).
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abstract final class IsolateNameServer {
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/// Looks up the [SendPort] associated with a given name.
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///
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/// Returns null if the name does not exist. To register the name in the first
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/// place, consider [registerPortWithName].
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///
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/// The `name` argument must not be null.
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static SendPort? lookupPortByName(String name) {
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return _lookupPortByName(name);
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}
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/// Registers a [SendPort] with a given name.
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///
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/// Returns true if registration is successful, and false if the name entry
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/// already existed (in which case the earlier registration is left
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/// unchanged). To remove a registration, consider [removePortNameMapping].
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///
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/// Once a port has been registered with a name, it can be obtained from any
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/// [Isolate] using [lookupPortByName].
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///
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/// Multiple isolates should avoid attempting to register ports with the same
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/// name, as there is an inherent race condition in doing so.
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///
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/// The `port` and `name` arguments must not be null.
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static bool registerPortWithName(SendPort port, String name) {
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return _registerPortWithName(port, name);
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}
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/// Removes a name-to-[SendPort] mapping given its name.
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///
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/// Returns true if the mapping was successfully removed, false if the mapping
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/// did not exist. To add a registration, consider [registerPortWithName].
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///
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/// Generally, removing a port name mapping is an inherently racy operation
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/// (another isolate could have obtained the name just prior to the name being
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/// removed, and thus would still be able to communicate over the port even
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/// after it has been removed).
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///
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/// The `name` argument must not be null.
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static bool removePortNameMapping(String name) {
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return _removePortNameMapping(name);
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}
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@Native<Handle Function(Handle)>(symbol: 'IsolateNameServerNatives::LookupPortByName')
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external static SendPort? _lookupPortByName(String name);
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@Native<Bool Function(Handle, Handle)>(symbol: 'IsolateNameServerNatives::RegisterPortWithName')
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external static bool _registerPortWithName(SendPort port, String name);
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@Native<Bool Function(Handle)>(symbol: 'IsolateNameServerNatives::RemovePortNameMapping')
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external static bool _removePortNameMapping(String name);
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}
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