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Commit acf3858b authored by Makoto Onuki's avatar Makoto Onuki
Browse files

Optimize UserHandle.of() 

There will be more calls to *ForUser() APIs over time by mainline modules.
Let's avoid creating new objects in common cases.

Bug: 142134660
Fix: 140429319
Test: atest cts/tests/app/src/android/app/cts/UserHandleTest.java
Change-Id: Ie71850bd08a8d9831232ddb40807ae49e3a56841
parent 496d47ab

api/test-current.txt

+8 −0
Original line number Diff line number Diff line
@@ -2033,10 +2033,18 @@ package android.os { 
  public final class UserHandle implements android.os.Parcelable {

    method public static int getAppId(int);

    method public int getIdentifier();

    method public static int getUid(int, int);

    method public static int getUserId(int);

    method public static boolean isApp(int);

    method public static int myUserId();

    method public static android.os.UserHandle of(int);

    field @NonNull public static final android.os.UserHandle ALL;

    field @NonNull public static final android.os.UserHandle CURRENT;

    field public static final int MIN_SECONDARY_USER_ID = 10; // 0xa

    field @NonNull public static final android.os.UserHandle SYSTEM;

    field public static final int USER_ALL = -1; // 0xffffffff

    field public static final int USER_NULL = -10000; // 0xffffd8f0

    field public static final int USER_SYSTEM = 0; // 0x0

  }



  public class UserManager {

core/java/android/os/UserHandle.java

+56 −3
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ public final class UserHandle implements Parcelable { 


    /** @hide A user id to indicate all users on the device */

    @UnsupportedAppUsage

    @TestApi

    public static final @UserIdInt int USER_ALL = -1;



    /** @hide A user handle to indicate all users on the device */
@@ -69,8 +70,11 @@ public final class UserHandle implements Parcelable { 


    /** @hide An undefined user id */

    @UnsupportedAppUsage

    @TestApi

    public static final @UserIdInt int USER_NULL = -10000;



    private static final @NonNull UserHandle NULL = new UserHandle(USER_NULL);



    /**

     * @hide A user id constant to indicate the "owner" user of the device

     * @deprecated Consider using either {@link UserHandle#USER_SYSTEM} constant or
@@ -91,6 +95,7 @@ public final class UserHandle implements Parcelable { 


    /** @hide A user id constant to indicate the "system" user of the device */

    @UnsupportedAppUsage

    @TestApi

    public static final @UserIdInt int USER_SYSTEM = 0;



    /** @hide A user serial constant to indicate the "system" user of the device */
@@ -109,6 +114,27 @@ public final class UserHandle implements Parcelable { 
    @UnsupportedAppUsage

    public static final boolean MU_ENABLED = true;



    /** @hide */

    @TestApi

    public static final int MIN_SECONDARY_USER_ID = 10;



    /**

     * Arbitrary user handle cache size. We use the cache even when {@link #MU_ENABLED} is false

     * anyway, so we can always assume in CTS that UserHandle.of(10) returns a cached instance

     * even on non-multiuser devices.

     */

    private static final int NUM_CACHED_USERS = 4;



    private static final UserHandle[] CACHED_USER_INFOS = new UserHandle[NUM_CACHED_USERS];



    static {

        // Not lazily initializing the cache, so that we can share them across processes.

        // (We'll create them in zygote.)

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

            CACHED_USER_INFOS[i] = new UserHandle(MIN_SECONDARY_USER_ID + i);

        }

    }



    /** @hide */

    @UnsupportedAppUsage

    public static final int ERR_GID = -1;
@@ -209,6 +235,7 @@ public final class UserHandle implements Parcelable { 
     * @hide

     */

    @UnsupportedAppUsage

    @TestApi

    public static @UserIdInt int getUserId(int uid) {

        if (MU_ENABLED) {

            return uid / PER_USER_RANGE;
@@ -229,9 +256,31 @@ public final class UserHandle implements Parcelable { 
    }



    /** @hide */

    @TestApi

    @SystemApi

    public static UserHandle of(@UserIdInt int userId) {

        return userId == USER_SYSTEM ? SYSTEM : new UserHandle(userId);

        if (userId == USER_SYSTEM) {

            return SYSTEM; // Most common.

        }

        // These are sequential; so use a switch. Maybe they'll be optimized to a table lookup.

        switch (userId) {

            case USER_ALL:

                return ALL;



            case USER_CURRENT:

                return CURRENT;



            case USER_CURRENT_OR_SELF:

                return CURRENT_OR_SELF;

        }

        if (userId >= MIN_SECONDARY_USER_ID

                && userId < (MIN_SECONDARY_USER_ID + CACHED_USER_INFOS.length)) {

            return CACHED_USER_INFOS[userId - MIN_SECONDARY_USER_ID];

        }

        if (userId == USER_NULL) { // Not common.

            return NULL;

        }

        return new UserHandle(userId);

    }



    /**
@@ -239,6 +288,7 @@ public final class UserHandle implements Parcelable { 
     * @hide

     */

    @UnsupportedAppUsage

    @TestApi

    public static int getUid(@UserIdInt int userId, @AppIdInt int appId) {

        if (MU_ENABLED) {

            return userId * PER_USER_RANGE + (appId % PER_USER_RANGE);
@@ -404,6 +454,7 @@ public final class UserHandle implements Parcelable { 
     * @hide

     */

    @SystemApi

    @TestApi

    public static @UserIdInt int myUserId() {

        return getUserId(Process.myUid());

    }
@@ -513,7 +564,9 @@ public final class UserHandle implements Parcelable { 
    public static final @android.annotation.NonNull Parcelable.Creator<UserHandle> CREATOR

            = new Parcelable.Creator<UserHandle>() {

        public UserHandle createFromParcel(Parcel in) {

            return new UserHandle(in);

            // Try to avoid allocation; use of() here. Keep this and the constructor below

            // in sync.

            return UserHandle.of(in.readInt());

        }



        public UserHandle[] newArray(int size) {
@@ -532,6 +585,6 @@ public final class UserHandle implements Parcelable { 
     * positioned at the location in the buffer where it was written.

     */

    public UserHandle(Parcel in) {

        mHandle = in.readInt();

        mHandle = in.readInt(); // Keep this and createFromParcel() in sync.

    }

}

services/core/java/com/android/server/pm/UserManagerService.java

+2 −1
Original line number Diff line number Diff line
@@ -209,7 +209,8 @@ public class UserManagerService extends IUserManager.Stub { 
            | UserInfo.FLAG_DEMO;



    @VisibleForTesting

    static final int MIN_USER_ID = 10;

    static final int MIN_USER_ID = UserHandle.MIN_SECONDARY_USER_ID;



    // We need to keep process uid within Integer.MAX_VALUE.

    @VisibleForTesting

    static final int MAX_USER_ID = Integer.MAX_VALUE / UserHandle.PER_USER_RANGE;