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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.launcher3.util;
import static com.android.launcher3.util.Executors.MAIN_EXECUTOR;
import android.content.Context;
import android.os.Looper;
import androidx.annotation.VisibleForTesting;
import com.android.launcher3.graphics.LauncherPreviewRenderer.PreviewContext;
import com.android.launcher3.util.ResourceBasedOverride.Overrides;
import java.util.concurrent.ExecutionException;
/**
* Utility class for defining singletons which are initiated on main thread.
*/
public class MainThreadInitializedObject<T> {
private final ObjectProvider<T> mProvider;
private T mValue;
public MainThreadInitializedObject(ObjectProvider<T> provider) {
mProvider = provider;
}
public T get(Context context) {
if (context instanceof PreviewContext) {
return ((PreviewContext) context).getObject(this, mProvider);
}
if (mValue == null) {
if (Looper.myLooper() == Looper.getMainLooper()) {
mValue = TraceHelper.allowIpcs("main.thread.object",
() -> mProvider.get(context.getApplicationContext()));
} else {
try {
return MAIN_EXECUTOR.submit(() -> get(context)).get();
} catch (InterruptedException|ExecutionException e) {
throw new RuntimeException(e);
}
}
}
return mValue;
}
public T getNoCreate() {
return mValue;
}
@VisibleForTesting
public void initializeForTesting(T value) {
mValue = value;
}
/**
* Initializes a provider based on resource overrides
*/
public static <T extends ResourceBasedOverride> MainThreadInitializedObject<T> forOverride(
Class<T> clazz, int resourceId) {
return new MainThreadInitializedObject<>(c -> Overrides.getObject(clazz, c, resourceId));
}
public interface ObjectProvider<T> {
T get(Context context);
}
}