Consolidate handler thread check functions in HandlerUtils

Moved common handler thread check functions from MdnsUtils.java
to HandlerUtils.java within the staticlib to facilitate reuse by
both Connectivity and NetworkStack modules.

Test: TH
Change-Id: Id96f6558c32c44fbdf2d2ce3e57c14da0cbf3ed7
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsDiscoveryManager.java b/service-t/src/com/android/server/connectivity/mdns/MdnsDiscoveryManager.java
index f540f10..c833422 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsDiscoveryManager.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsDiscoveryManager.java
@@ -35,7 +35,6 @@
 import com.android.net.module.util.DnsUtils;
 import com.android.net.module.util.HandlerUtils;
 import com.android.net.module.util.SharedLog;
-import com.android.server.connectivity.mdns.util.MdnsUtils;
 
 import java.io.IOException;
 import java.io.PrintWriter;
@@ -211,7 +210,7 @@
 
         void ensureRunningOnHandlerThread() {
             synchronized (pendingTasks) {
-                MdnsUtils.ensureRunningOnHandlerThread(handler);
+                HandlerUtils.ensureRunningOnHandlerThread(handler);
             }
         }
 
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java b/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java
index c575d40..36fad31 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClient.java
@@ -16,7 +16,7 @@
 
 package com.android.server.connectivity.mdns;
 
-import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
+import static com.android.net.module.util.HandlerUtils.ensureRunningOnHandlerThread;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsReplySender.java b/service-t/src/com/android/server/connectivity/mdns/MdnsReplySender.java
index db3845a..a89b004 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsReplySender.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsReplySender.java
@@ -16,9 +16,9 @@
 
 package com.android.server.connectivity.mdns;
 
+import static com.android.net.module.util.HandlerUtils.ensureRunningOnHandlerThread;
 import static com.android.server.connectivity.mdns.MdnsConstants.IPV4_SOCKET_ADDR;
 import static com.android.server.connectivity.mdns.MdnsConstants.IPV6_SOCKET_ADDR;
-import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
 
 import android.annotation.NonNull;
 import android.annotation.RequiresApi;
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceCache.java b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceCache.java
index 22f7a03..4ae8701 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceCache.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceCache.java
@@ -18,8 +18,8 @@
 
 import static com.android.net.module.util.DnsUtils.equalsIgnoreDnsCase;
 import static com.android.net.module.util.DnsUtils.toDnsUpperCase;
+import static com.android.net.module.util.HandlerUtils.ensureRunningOnHandlerThread;
 import static com.android.server.connectivity.mdns.MdnsResponse.EXPIRATION_NEVER;
-import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
 
 import static java.lang.Math.min;
 
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java
index b0e3ba4..4f01599 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java
@@ -16,12 +16,12 @@
 
 package com.android.server.connectivity.mdns;
 
+import static com.android.net.module.util.HandlerUtils.ensureRunningOnHandlerThread;
 import static com.android.server.connectivity.mdns.MdnsSearchOptions.AGGRESSIVE_QUERY_MODE;
 import static com.android.server.connectivity.mdns.MdnsServiceCache.ServiceExpiredCallback;
 import static com.android.server.connectivity.mdns.MdnsServiceCache.findMatchedResponse;
 import static com.android.server.connectivity.mdns.util.MdnsUtils.Clock;
 import static com.android.server.connectivity.mdns.util.MdnsUtils.buildMdnsServiceInfoFromResponse;
-import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
index 5c9ec09..b640c32 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsSocketProvider.java
@@ -19,7 +19,8 @@
 import static android.net.NetworkCapabilities.TRANSPORT_CELLULAR;
 import static android.net.NetworkCapabilities.TRANSPORT_VPN;
 import static android.net.NetworkCapabilities.TRANSPORT_WIFI;
-import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
+
+import static com.android.net.module.util.HandlerUtils.ensureRunningOnHandlerThread;
 import static com.android.server.connectivity.mdns.util.MdnsUtils.isNetworkMatched;
 
 import android.annotation.NonNull;
diff --git a/service-t/src/com/android/server/connectivity/mdns/MulticastPacketReader.java b/service-t/src/com/android/server/connectivity/mdns/MulticastPacketReader.java
index 70451f3..4d7e4bc 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MulticastPacketReader.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MulticastPacketReader.java
@@ -16,7 +16,7 @@
 
 package com.android.server.connectivity.mdns;
 
-import static com.android.server.connectivity.mdns.util.MdnsUtils.ensureRunningOnHandlerThread;
+import static com.android.net.module.util.HandlerUtils.ensureRunningOnHandlerThread;
 
 import android.annotation.NonNull;
 import android.os.Handler;
diff --git a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
index 85a8961..41b15dd 100644
--- a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
+++ b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
@@ -24,7 +24,6 @@
 import android.annotation.Nullable;
 import android.net.Network;
 import android.os.Build;
-import android.os.Handler;
 import android.os.SystemClock;
 import android.util.ArraySet;
 import android.util.Pair;
@@ -88,21 +87,6 @@
         }
     }
 
-    /*** Ensure that current running thread is same as given handler thread */
-    public static void ensureRunningOnHandlerThread(@NonNull Handler handler) {
-        if (!isRunningOnHandlerThread(handler)) {
-            throw new IllegalStateException(
-                    "Not running on Handler thread: " + Thread.currentThread().getName());
-        }
-    }
-
-    /*** Check that current running thread is same as given handler thread */
-    public static boolean isRunningOnHandlerThread(@NonNull Handler handler) {
-        if (handler.getLooper().getThread() == Thread.currentThread()) {
-            return true;
-        }
-        return false;
-    }
 
     /*** Check whether the target network matches the current network */
     public static boolean isNetworkMatched(@Nullable Network targetNetwork,
diff --git a/staticlibs/device/com/android/net/module/util/HandlerUtils.java b/staticlibs/device/com/android/net/module/util/HandlerUtils.java
index c620368..991df8f 100644
--- a/staticlibs/device/com/android/net/module/util/HandlerUtils.java
+++ b/staticlibs/device/com/android/net/module/util/HandlerUtils.java
@@ -102,4 +102,37 @@
         if (e != null) throw e;
         return true;
     }
+
+    /**
+     * Ensures that the current running thread is the same as the thread associated with the given
+     * handler.
+     *
+     * @param handler The handler whose thread to compare.
+     * @throws IllegalStateException if the thread associated with the given handler is not the same
+     *                               as the current running thread.
+     * @hide
+     */
+    public static void ensureRunningOnHandlerThread(@NonNull Handler handler) {
+        if (!isRunningOnHandlerThread(handler)) {
+            throw new IllegalStateException(
+                    "Not running on Handler thread: " + Thread.currentThread().getName());
+        }
+    }
+
+    /**
+     * Checks if the current running thread is the same as the thread associated with the given
+     * handler.
+     *
+     * @param handler The handler whose thread to compare.
+     * @return {@code true} if the thread associated with the given handler is the same as the
+     *         current running thread, {@code false} otherwise.
+     *
+     * @hide
+     */
+    public static boolean isRunningOnHandlerThread(@NonNull Handler handler) {
+        if (handler.getLooper().getThread() == Thread.currentThread()) {
+            return true;
+        }
+        return false;
+    }
 }
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/HandlerUtilsTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/HandlerUtilsTest.kt
index f2c902f..845a2c3 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/HandlerUtilsTest.kt
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/HandlerUtilsTest.kt
@@ -19,11 +19,14 @@
 import android.os.HandlerThread
 import com.android.testutils.DevSdkIgnoreRunner
 import com.android.testutils.DevSdkIgnoreRunner.MonitorThreadLeak
+import com.android.testutils.waitForIdle
 import kotlin.test.assertEquals
 import kotlin.test.assertTrue
 import org.junit.After
 import org.junit.Test
 import org.junit.runner.RunWith
+import kotlin.test.assertFailsWith
+import kotlin.test.assertFalse
 
 const val THREAD_BLOCK_TIMEOUT_MS = 1000L
 const val TEST_REPEAT_COUNT = 100
@@ -52,6 +55,24 @@
         }
     }
 
+    @Test
+    fun testIsRunningOnHandlerThread() {
+        assertFalse(HandlerUtils.isRunningOnHandlerThread(handler))
+        handler.post{
+            assertTrue(HandlerUtils.isRunningOnHandlerThread(handler))
+        }
+        handler.waitForIdle(THREAD_BLOCK_TIMEOUT_MS)
+    }
+
+    @Test
+    fun testEnsureRunningOnHandlerThread() {
+        assertFailsWith<IllegalStateException>{ HandlerUtils.ensureRunningOnHandlerThread(handler) }
+        handler.post{
+            HandlerUtils.ensureRunningOnHandlerThread(handler)
+        }
+        handler.waitForIdle(THREAD_BLOCK_TIMEOUT_MS)
+    }
+
     @After
     fun tearDown() {
         handlerThread.quitSafely()