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Commit 6c65698e authored by Shai Barack's avatar Shai Barack
Browse files

Optimize LocaleList constructor by avoiding vector and hash resizing 

I saw a lot of resizing in a pprof of an app starting
and figured I could easily fix this.

Test: LocaleTest
Flag: EXEMPT refactor
Change-Id: I11bdf3a3d2657b3450e3d212fce8f80863ea34de
parent ffa1d0d3

core/java/android/os/LocaleList.java

+38 −22
Original line number Diff line number Diff line
@@ -23,13 +23,13 @@ import android.annotation.Size; 
import android.annotation.SuppressLint;

import android.compat.annotation.UnsupportedAppUsage;

import android.icu.util.ULocale;

import android.util.ArraySet;



import com.android.internal.annotations.GuardedBy;



import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.HashSet;

import java.util.List;

import java.util.Locale;
@@ -184,30 +184,46 @@ public final class LocaleList implements Parcelable { 
        if (list.length == 0) {

            mList = sEmptyList;

            mStringRepresentation = "";

        } else {

            final ArrayList<Locale> localeList = new ArrayList<>();

            final HashSet<Locale> seenLocales = new HashSet<Locale>();

            final StringBuilder sb = new StringBuilder();

            return;

        }



        // Ensure capacity is large enough to avoid resizing

        final ArraySet<Locale> seenLocales = new ArraySet(list.length);

        final List<Locale> localeList = new ArrayList<>(list.length);



        // Ensure capacity for all language tags in string representation

        int stringRepresentationLen = 0;



        for (int i = 0; i < list.length; i++) {

            final Locale l = list[i];

            if (l == null) {

                throw new NullPointerException("list[" + i + "] is null");

                } else if (seenLocales.contains(l)) {

                    // Dropping duplicated locale entries.

                } else {

            }



            final Locale localeClone = (Locale) l.clone();

            // Dedupe locales

            if (seenLocales.add(localeClone)) {

                localeList.add(localeClone);

                    sb.append(localeClone.toLanguageTag());

                    if (i < list.length - 1) {

                        sb.append(',');

                stringRepresentationLen += localeClone.toLanguageTag().length();

            }

        }

                    seenLocales.add(localeClone);

        Locale[] localeArray = new Locale[localeList.size()];

        localeList.toArray(localeArray);

        mList = localeArray;



        // Add capacity for comma delimiters

        stringRepresentationLen += mList.length - 1;





        final StringBuilder sb = new StringBuilder(stringRepresentationLen);

        for (int i = 0; i < localeArray.length; i++) {

            sb.append(localeArray[i].toLanguageTag());

            if (i < localeArray.length - 1) {

                sb.append(',');

            }

        }

            mList = localeList.toArray(new Locale[localeList.size()]);

        mStringRepresentation = sb.toString();

    }

    }



    /**

     * Constructs a locale list, with the topLocale moved to the front if it already is