Merge "delete old ResearchLog files"

import android.inputmethodservice.InputMethodService;

import android.os.Build;

import android.text.TextUtils;

import android.text.format.DateUtils;

import android.util.Log;

import android.view.MotionEvent;

import android.view.inputmethod.CompletionInfo;

import com.android.inputmethod.latin.define.ProductionFlag;

import java.io.File;

import java.io.FileFilter;

import java.io.IOException;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

            Character.codePointAt("\uE000", 0);  // U+E000 is in the "private-use area"

    // U+E001 is in the "private-use area"

    /* package for test */ static final String WORD_REPLACEMENT_STRING = "\uE001";

    private static final String PREF_LAST_CLEANUP_TIME = "pref_last_cleanup_time";

    private static final long DURATION_BETWEEN_DIR_CLEANUP_IN_MS = DateUtils.DAY_IN_MILLIS;

    private static final long MAX_LOGFILE_AGE_IN_MS = DateUtils.DAY_IN_MILLIS;

    // set when LatinIME should ignore an onUpdateSelection() callback that

    // arises from operations in this class

    private static boolean sLatinIMEExpectingUpdateSelection = false;

            mUUIDString = getUUID(prefs);

            sIsLogging = prefs.getBoolean(PREF_USABILITY_STUDY_MODE, false);

            prefs.registerOnSharedPreferenceChangeListener(this);

            final long lastCleanupTime = prefs.getLong(PREF_LAST_CLEANUP_TIME, 0L);

            final long now = System.currentTimeMillis();

            if (lastCleanupTime + DURATION_BETWEEN_DIR_CLEANUP_IN_MS < now) {

                final long timeHorizon = now - MAX_LOGFILE_AGE_IN_MS;

                cleanupLoggingDir(mFilesDir, timeHorizon);

                Editor e = prefs.edit();

                e.putLong(PREF_LAST_CLEANUP_TIME, now);

                e.apply();

            }

        }

        mKeyboardSwitcher = keyboardSwitcher;

    }

    private void cleanupLoggingDir(final File dir, final long time) {

        for (File file : dir.listFiles()) {

            if (file.getName().startsWith(ResearchLogger.FILENAME_PREFIX) &&

                    file.lastModified() < time) {

                file.delete();

            }

        }

    }

    private File createLogFile(File filesDir) {

        final StringBuilder sb = new StringBuilder();

        sb.append(FILENAME_PREFIX).append('-');