32 lines
981 B
Java
32 lines
981 B
Java
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// Copyright 2023 The Chromium Authors
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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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package org.chromium.base;
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import androidx.annotation.NonNull;
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/**
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* A simple single-argument callback to handle the result of a computation that must be called
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* exactly once.
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*
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* @param <T> The type of the computation's result.
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*/
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public class RequiredCallback<T> implements Callback<T> {
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// Enforces (under test) that this callback is invoked before it is GC'd.
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private final LifetimeAssert mLifetimeAssert = LifetimeAssert.create(this);
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private Callback<T> mCallback;
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public RequiredCallback(@NonNull Callback<T> callback) {
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mCallback = callback;
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}
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@Override
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public void onResult(T result) {
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assert mCallback != null : "Callback was already called.";
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mCallback.onResult(result);
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LifetimeAssert.setSafeToGc(mLifetimeAssert, true);
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mCallback = null;
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}
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}
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