1 files changed, 90 insertions, 0 deletions
diff --git a/core/java/android/os/UserId.java b/core/java/android/os/UserId.java
new file mode 100644
index 0000000..4124d51
--- /dev/null
+++ b/core/java/android/os/UserId.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2011 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 android.os;
+
+/**
+ * @hide
+ */
+public final class UserId {
+    /**
+     * Range of IDs allocated for a user.
+     *
+     * @hide
+     */
+    public static final int PER_USER_RANGE = 100000;
+
+    public static final int USER_ALL = -1;
+
+    /**
+     * Enable multi-user related side effects. Set this to false if there are problems with single
+     * user usecases.
+     * */
+    public static final boolean MU_ENABLED = true;
+
+    /**
+     * Checks to see if the user id is the same for the two uids, i.e., they belong to the same
+     * user.
+     * @hide
+     */
+    public static final boolean isSameUser(int uid1, int uid2) {
+        return getUserId(uid1) == getUserId(uid2);
+    }
+
+    /**
+     * Checks to see if both uids are referring to the same app id, ignoring the user id part of the
+     * uids.
+     * @param uid1 uid to compare
+     * @param uid2 other uid to compare
+     * @return whether the appId is the same for both uids
+     * @hide
+     */
+    public static final boolean isSameApp(int uid1, int uid2) {
+        return getAppId(uid1) == getAppId(uid2);
+    }
+
+    /**
+     * Returns the user id for a given uid.
+     * @hide
+     */
+    public static final int getUserId(int uid) {
+        if (MU_ENABLED) {
+            return uid / PER_USER_RANGE;
+        } else {
+            return 0;
+        }
+    }
+
+    /**
+     * Returns the uid that is composed from the userId and the appId.
+     * @hide
+     */
+    public static final int getUid(int userId, int appId) {
+        if (MU_ENABLED) {
+            return userId * PER_USER_RANGE + (appId % PER_USER_RANGE);
+        } else {
+            return appId;
+        }
+    }
+
+    /**
+     * Returns the app id (or base uid) for a given uid, stripping out the user id from it.
+     * @hide
+     */
+    public static final int getAppId(int uid) {
+        return uid % PER_USER_RANGE;
+    }
+}