Merge "Allow DiskRead ThreadPolicy in LetterboxConfigurationPersister" into udc-dev

package com.android.server.wm;

import static android.os.StrictMode.setThreadPolicy;

import static com.android.server.wm.WindowManagerDebugConfig.TAG_WITH_CLASS_NAME;

import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;

import android.annotation.Nullable;

import android.content.Context;

import android.os.Environment;

import android.os.StrictMode;

import android.os.StrictMode.ThreadPolicy;

import android.util.AtomicFile;

import android.util.Slog;

        final File prefFiles = new File(configFolder, LETTERBOX_CONFIGURATION_FILENAME);

        mConfigurationFile = new AtomicFile(prefFiles);

        mPersisterQueue = persisterQueue;

        readCurrentConfiguration();

        runWithDiskReadsThreadPolicy(this::readCurrentConfiguration);

    }

    /**

        }

    }

    // The LetterboxConfigurationDeviceConfig needs to access the

    // file with the current reachability position once when the

    // device boots. Because DisplayThread uses allowIo=false

    // accessing a file triggers a DiskReadViolation.

    // Here we use StrictMode to allow the current thread to read

    // the AtomicFile once in the current thread restoring the

    // original ThreadPolicy after that.

    private void runWithDiskReadsThreadPolicy(Runnable runnable) {

        final ThreadPolicy currentPolicy = StrictMode.getThreadPolicy();

        setThreadPolicy(new ThreadPolicy.Builder().permitDiskReads().build());

        runnable.run();

        setThreadPolicy(currentPolicy);

    }

    private static class UpdateValuesCommand implements

            PersisterQueue.WriteQueueItem<UpdateValuesCommand> {