54 lines
913 B
PHP
54 lines
913 B
PHP
<?php
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namespace Amp;
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/**
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* A NullCancellationToken can be used to avoid conditionals to check whether a token has been provided.
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*
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* Instead of writing
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*
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* ```php
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* if ($token) {
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* $token->throwIfRequested();
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* }
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* ```
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*
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* potentially multiple times, it allows writing
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*
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* ```php
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* $token = $token ?? new NullCancellationToken;
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*
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* // ...
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*
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* $token->throwIfRequested();
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* ```
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*
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* instead.
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*/
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final class NullCancellationToken implements CancellationToken
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{
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/** @inheritdoc */
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public function subscribe(callable $callback): string
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{
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return "null-token";
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}
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/** @inheritdoc */
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public function unsubscribe(string $id)
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{
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// nothing to do
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}
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/** @inheritdoc */
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public function isRequested(): bool
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{
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return false;
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}
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/** @inheritdoc */
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public function throwIfRequested()
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{
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// nothing to do
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}
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}
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