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This auto-formats all *.dart files in the `engine` subdirectory and enforces that these files stay formatted with a presubmit check.
73 lines
2.5 KiB
Dart
73 lines
2.5 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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/// A wrapper for a raw callback handle.
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///
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/// This is the return type for [PluginUtilities.getCallbackHandle].
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class CallbackHandle {
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/// Create an instance using a raw callback handle.
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///
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/// Only values produced by a call to [CallbackHandle.toRawHandle] should be
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/// used, otherwise this object will be an invalid handle.
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CallbackHandle.fromRawHandle(this._handle);
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final int _handle;
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/// Get the raw callback handle to pass over a [MethodChannel] or [SendPort]
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/// (to pass to another [Isolate]).
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int toRawHandle() => _handle;
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@override
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bool operator ==(Object other) {
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if (runtimeType != other.runtimeType) {
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return false;
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}
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return other is CallbackHandle && other._handle == _handle;
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}
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@override
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int get hashCode => _handle.hashCode;
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}
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/// Functionality for Flutter plugin authors.
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///
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/// See also:
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///
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/// * [IsolateNameServer], which provides utilities for dealing with
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/// [Isolate]s.
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abstract final class PluginUtilities {
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static final Map<Function, CallbackHandle?> _forwardCache = <Function, CallbackHandle?>{};
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static final Map<CallbackHandle, Function?> _backwardCache = <CallbackHandle, Function?>{};
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/// Get a handle to a named top-level or static callback function which can
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/// be easily passed between isolates.
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///
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/// The `callback` argument must not be null.
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///
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/// Returns a [CallbackHandle] that can be provided to
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/// [PluginUtilities.getCallbackFromHandle] to retrieve a tear-off of the
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/// original callback. If `callback` is not a top-level or static function,
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/// null is returned.
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static CallbackHandle? getCallbackHandle(Function callback) {
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return _forwardCache.putIfAbsent(callback, () {
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final int? handle = _getCallbackHandle(callback);
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return handle != null ? CallbackHandle.fromRawHandle(handle) : null;
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});
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}
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/// Get a tear-off of a named top-level or static callback represented by a
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/// handle.
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///
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/// The `handle` argument must not be null.
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///
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/// If `handle` is not a valid handle returned by
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/// [PluginUtilities.getCallbackHandle], null is returned. Otherwise, a
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/// tear-off of the callback associated with `handle` is returned.
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static Function? getCallbackFromHandle(CallbackHandle handle) {
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return _backwardCache.putIfAbsent(handle, () => _getCallbackFromHandle(handle.toRawHandle()));
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}
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}
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