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vendor/amphp/amp/lib/CancellationToken.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace Amp;
+
+/**
+ * Cancellation tokens are simple objects that allow registering handlers to subscribe to cancellation requests.
+ */
+interface CancellationToken
+{
+    /**
+     * Subscribes a new handler to be invoked on a cancellation request.
+     *
+     * This handler might be invoked immediately in case the token has already been cancelled. Returned generators will
+     * automatically be run as coroutines. Any unhandled exceptions will be throw into the event loop.
+     *
+     * @param callable(CancelledException) $callback Callback to be invoked on a cancellation request. Will receive a
+     * `CancelledException` as first argument that may be used to fail the operation's promise.
+     *
+     * @return string Identifier that can be used to cancel the subscription.
+     */
+    public function subscribe(callable $callback): string;
+
+    /**
+     * Unsubscribes a previously registered handler.
+     *
+     * The handler will no longer be called as long as this method isn't invoked from a subscribed callback.
+     *
+     * @param string $id
+     *
+     * @return void
+     */
+    public function unsubscribe(string $id);
+
+    /**
+     * Returns whether cancellation has been requested yet.
+     *
+     * @return bool
+     */
+    public function isRequested(): bool;
+
+    /**
+     * Throws the `CancelledException` if cancellation has been requested, otherwise does nothing.
+     *
+     * @return void
+     *
+     * @throws CancelledException
+     */
+    public function throwIfRequested();
+}