Add ConnectivityAnnotations class

This change is to address API review, add respective
@IntDef for network policy API.

Typedef cannot be exposed as SystemApi so add
ConnectivityAnnotations class and add an annotation library
so that it can be used in module and platform.

Bug: 183972925
Test: m, build doc target framework-doc-stubs_annotations.zip
      and check the APIs have an attribute IntDef annotation
Change-Id: Ie3ec40cf48818edd422a4550377774eae387d3b2

framework/Android.bp

@@ -59,6 +59,22 @@ filegroup {
     ],
 }
 
+java_library {
+    name: "framework-connectivity-annotations",
+    sdk_version: "module_current",
+    srcs: [
+        "src/android/net/ConnectivityAnnotations.java",
+    ],
+    libs: [
+        "framework-annotations-lib",
+        "framework-connectivity",
+    ],
+    visibility: [
+        "//frameworks/base:__subpackages__",
+        "//packages/modules/Connectivity:__subpackages__",
+    ],
+}
+
 java_sdk_library {
     name: "framework-connectivity",
     sdk_version: "module_current",

framework/src/android/net/ConnectivityAnnotations.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2021 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.net;
+
+import android.annotation.IntDef;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * Type annotations for constants used in the connectivity API surface.
+ *
+ * The annotations are maintained in a separate class so that it can be built as
+ * a separate library that other modules can build against, as Typedef should not
+ * be exposed as SystemApi.
+ *
+ * @hide
+ */
+public final class ConnectivityAnnotations {
+    private ConnectivityAnnotations() {}
+
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(flag = true, value = {
+            ConnectivityManager.MULTIPATH_PREFERENCE_HANDOVER,
+            ConnectivityManager.MULTIPATH_PREFERENCE_RELIABILITY,
+            ConnectivityManager.MULTIPATH_PREFERENCE_PERFORMANCE,
+    })
+    public @interface MultipathPreference {}
+
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(flag = false, value = {
+            ConnectivityManager.RESTRICT_BACKGROUND_STATUS_DISABLED,
+            ConnectivityManager.RESTRICT_BACKGROUND_STATUS_WHITELISTED,
+            ConnectivityManager.RESTRICT_BACKGROUND_STATUS_ENABLED,
+    })
+    public @interface RestrictBackgroundStatus {}
+}

framework/src/android/net/ConnectivityManager.java

@@ -40,6 +40,8 @@ import android.compat.annotation.UnsupportedAppUsage;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
+import android.net.ConnectivityAnnotations.MultipathPreference;
+import android.net.ConnectivityAnnotations.RestrictBackgroundStatus;
 import android.net.ConnectivityDiagnosticsManager.DataStallReport.DetectionMethod;
 import android.net.IpSecManager.UdpEncapsulationSocket;
 import android.net.SocketKeepalive.Callback;
@@ -4799,16 +4801,6 @@ public class ConnectivityManager {
             MULTIPATH_PREFERENCE_RELIABILITY |
             MULTIPATH_PREFERENCE_PERFORMANCE;
 
-    /** @hide */
-    @Retention(RetentionPolicy.SOURCE)
-    @IntDef(flag = true, value = {
-            MULTIPATH_PREFERENCE_HANDOVER,
-            MULTIPATH_PREFERENCE_RELIABILITY,
-            MULTIPATH_PREFERENCE_PERFORMANCE,
-    })
-    public @interface MultipathPreference {
-    }
-
     /**
      * Provides a hint to the calling application on whether it is desirable to use the
      * multinetwork APIs (e.g., {@link Network#openConnection}, {@link Network#bindSocket}, etc.)
@@ -5030,16 +5022,6 @@ public class ConnectivityManager {
     public static final String ACTION_RESTRICT_BACKGROUND_CHANGED =
             "android.net.conn.RESTRICT_BACKGROUND_CHANGED";
 
-    /** @hide */
-    @Retention(RetentionPolicy.SOURCE)
-    @IntDef(flag = false, value = {
-            RESTRICT_BACKGROUND_STATUS_DISABLED,
-            RESTRICT_BACKGROUND_STATUS_WHITELISTED,
-            RESTRICT_BACKGROUND_STATUS_ENABLED,
-    })
-    public @interface RestrictBackgroundStatus {
-    }
-
     /**
      * Determines if the calling application is subject to metered network restrictions while
      * running on background.

framework/src/android/net/ConnectivitySettingsManager.java

@@ -27,7 +27,7 @@ import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.content.ContentResolver;
 import android.content.Context;
-import android.net.ConnectivityManager.MultipathPreference;
+import android.net.ConnectivityAnnotations.MultipathPreference;
 import android.os.Process;
 import android.os.UserHandle;
 import android.provider.Settings;

service/Android.bp

@@ -65,6 +65,7 @@ java_library {
         "stable.core.platform.api.stubs",
         "android_system_server_stubs_current",
         "framework-annotations-lib",
+        "framework-connectivity-annotations",
         "framework-connectivity.impl",
         "framework-tethering.stubs.module_lib",
         "framework-wifi.stubs.module_lib",

service/src/com/android/server/ConnectivityService.java

@@ -105,12 +105,12 @@ import android.database.ContentObserver;
 import android.net.CaptivePortal;
 import android.net.CaptivePortalData;
 import android.net.ConnectionInfo;
+import android.net.ConnectivityAnnotations.RestrictBackgroundStatus;
 import android.net.ConnectivityDiagnosticsManager.ConnectivityReport;
 import android.net.ConnectivityDiagnosticsManager.DataStallReport;
 import android.net.ConnectivityManager;
 import android.net.ConnectivityManager.BlockedReason;
 import android.net.ConnectivityManager.NetworkCallback;
-import android.net.ConnectivityManager.RestrictBackgroundStatus;
 import android.net.ConnectivityResources;
 import android.net.ConnectivitySettingsManager;
 import android.net.DataStallReportParcelable;