Merge "Pull out library needed for Notification CTS test." into rvc-dev

services/core/Android.bp

@@ -150,6 +150,10 @@ java_library {
     static_libs: ["services.core.priorityboosted"],
 }
 
+java_library_host {
+    name: "core_cts_test_resources",
+    srcs: ["java/com/android/server/notification/SmallHash.java"]
+}
 
 prebuilt_etc {
     name: "gps_debug.conf",

services/core/java/com/android/server/notification/NotificationChannelLogger.java

@@ -184,14 +184,14 @@ public interface NotificationChannelLogger {
      * @return Small hash of the channel ID, if present, or 0 otherwise.
      */
     static int getIdHash(@NonNull NotificationChannel channel) {
-        return NotificationRecordLogger.smallHash(channel.getId());
+        return SmallHash.hash(channel.getId());
     }
 
     /**
      * @return Small hash of the channel ID, if present, or 0 otherwise.
      */
     static int getIdHash(@NonNull NotificationChannelGroup group) {
-        return NotificationRecordLogger.smallHash(group.getId());
+        return SmallHash.hash(group.getId());
     }
 
     /**

services/core/java/com/android/server/notification/NotificationRecordLogger.java

@@ -359,43 +359,24 @@ public interface NotificationRecordLogger {
          * @return Small hash of the notification ID, and tag (if present).
          */
         int getNotificationIdHash() {
-            return smallHash(Objects.hashCode(r.getSbn().getTag()) ^ r.getSbn().getId());
+            return SmallHash.hash(Objects.hashCode(r.getSbn().getTag()) ^ r.getSbn().getId());
         }
 
         /**
          * @return Small hash of the channel ID, if present, or 0 otherwise.
          */
         int getChannelIdHash() {
-            return smallHash(r.getSbn().getNotification().getChannelId());
+            return SmallHash.hash(r.getSbn().getNotification().getChannelId());
         }
 
         /**
          * @return Small hash of the group ID, respecting group override if present. 0 otherwise.
          */
         int getGroupIdHash() {
-            return smallHash(r.getSbn().getGroup());
+            return SmallHash.hash(r.getSbn().getGroup());
         }
 
     }
 
-    // "Small" hashes will be in the range [0, MAX_HASH).
-    int MAX_HASH = (1 << 13);
-
-    /**
-     * Maps in to the range [0, MAX_HASH), keeping similar values distinct.
-     * @param in An arbitrary integer.
-     * @return in mod MAX_HASH, signs chosen to stay in the range [0, MAX_HASH).
-     */
-    static int smallHash(int in) {
-        return Math.floorMod(in, MAX_HASH);
-    }
-
-    /**
-     * @return Small hash of the string, if non-null, or 0 otherwise.
-     */
-    static int smallHash(@Nullable String in) {
-        return smallHash(Objects.hashCode(in));
-    }
-
 
 }

services/core/java/com/android/server/notification/SmallHash.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2020 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 com.android.server.notification;
+
+import java.util.Objects;
+
+/**
+ * A simple hash function for use in privacy-sensitive logging.  Few bits = lots of collisions.
+ * See {@link NotificationRecordLogger}.
+ */
+public class SmallHash {
+    // Hashes will be in the range [0, MAX_HASH).
+    public static final int MAX_HASH = (1 << 13);
+
+    /**
+     * @return Small hash of the string, if non-null, or 0 otherwise.
+     */
+    public static int hash(String in) {
+        return hash(Objects.hashCode(in));
+    }
+
+    /**
+     * Maps in to the range [0, MAX_HASH), keeping similar values distinct.
+     * @param in An arbitrary integer.
+     * @return in mod MAX_HASH, signs chosen to stay in the range [0, MAX_HASH).
+     */
+    public static int hash(int in) {
+        return Math.floorMod(in, MAX_HASH);
+    }
+}

services/tests/uiservicestests/src/com/android/server/notification/NotificationRecordLoggerTest.java

@@ -60,16 +60,16 @@ public class NotificationRecordLoggerTest extends UiServiceTestCase {
 
     @Test
     public void testSmallHash() {
-        assertEquals(0, NotificationRecordLogger.smallHash(0));
+        assertEquals(0, SmallHash.hash(0));
-        final int maxHash = NotificationRecordLogger.MAX_HASH;
+        final int maxHash = SmallHash.MAX_HASH;
         assertEquals(0,
-                NotificationRecordLogger.smallHash(maxHash));
+                SmallHash.hash(maxHash));
         assertEquals(0,
-                NotificationRecordLogger.smallHash(17 * maxHash));
+                SmallHash.hash(17 * maxHash));
         assertEquals(maxHash - 1,
-                NotificationRecordLogger.smallHash(maxHash - 1));
+                SmallHash.hash(maxHash - 1));
         assertEquals(maxHash - 1,
-                NotificationRecordLogger.smallHash(-1));
+                SmallHash.hash(-1));
     }
 
     @Test
@@ -78,10 +78,10 @@ public class NotificationRecordLoggerTest extends UiServiceTestCase {
                 getNotificationRecordPair(0, null).getNotificationIdHash());
         assertEquals(1,
                 getNotificationRecordPair(1, null).getNotificationIdHash());
-        assertEquals(NotificationRecordLogger.MAX_HASH - 1,
+        assertEquals(SmallHash.MAX_HASH - 1,
                 getNotificationRecordPair(-1, null).getNotificationIdHash());
         final String tag = "someTag";
-        final int hash = NotificationRecordLogger.smallHash(tag.hashCode());
+        final int hash = SmallHash.hash(tag.hashCode());
         assertEquals(hash, getNotificationRecordPair(0, tag).getNotificationIdHash());
         // We xor the tag and hashcode together before compressing the range. The order of
         // operations doesn't matter if id is small.
@@ -89,19 +89,19 @@ public class NotificationRecordLoggerTest extends UiServiceTestCase {
                 getNotificationRecordPair(1, tag).getNotificationIdHash());
         // But it does matter for an id with more 1 bits than fit in the small hash.
         assertEquals(
-                NotificationRecordLogger.smallHash(-1 ^ tag.hashCode()),
+                SmallHash.hash(-1 ^ tag.hashCode()),
                 getNotificationRecordPair(-1, tag).getNotificationIdHash());
         assertNotEquals(-1 ^ hash,
-                NotificationRecordLogger.smallHash(-1 ^ tag.hashCode()));
+                SmallHash.hash(-1 ^ tag.hashCode()));
     }
 
     @Test
     public void testGetChannelIdHash() {
         assertEquals(
-                NotificationRecordLogger.smallHash(CHANNEL_ID.hashCode()),
+                SmallHash.hash(CHANNEL_ID.hashCode()),
                 getNotificationRecordPair(0, null).getChannelIdHash());
         assertNotEquals(
-                NotificationRecordLogger.smallHash(CHANNEL_ID.hashCode()),
+                SmallHash.hash(CHANNEL_ID.hashCode()),
                 CHANNEL_ID.hashCode());
     }
 
@@ -113,7 +113,7 @@ public class NotificationRecordLoggerTest extends UiServiceTestCase {
         final String group = "someGroup";
         p.r.setOverrideGroupKey(group);
         assertEquals(
-                NotificationRecordLogger.smallHash(group.hashCode()),
+                SmallHash.hash(group.hashCode()),
                 p.getGroupIdHash());
     }
 }