Merge "Do not immediately send new queries on cache hit"

service-t/src/com/android/server/connectivity/mdns/MdnsServiceTypeClient.java

@@ -178,6 +178,7 @@ public class MdnsServiceTypeClient {
             @NonNull MdnsSearchOptions searchOptions) {
         synchronized (lock) {
             this.searchOptions = searchOptions;
+            boolean hadReply = false;
             if (listeners.put(listener, searchOptions) == null) {
                 for (MdnsResponse existingResponse : instanceNameToResponse.values()) {
                     if (!responseMatchesOptions(existingResponse, searchOptions)) continue;
@@ -186,6 +187,7 @@ public class MdnsServiceTypeClient {
                     listener.onServiceNameDiscovered(info);
                     if (existingResponse.isComplete()) {
                         listener.onServiceFound(info);
+                        hadReply = true;
                     }
                 }
             }
@@ -195,14 +197,16 @@ public class MdnsServiceTypeClient {
             }
             // Keep tracking the ScheduledFuture for the task so we can cancel it if caller is not
             // interested anymore.
-            requestTaskFuture =
-                    executor.submit(
-                            new QueryTask(
-                                    new QueryTaskConfig(
-                                            searchOptions.getSubtypes(),
-                                            searchOptions.isPassiveMode(),
-                                            ++currentSessionId,
-                                            searchOptions.getNetwork())));
+            final QueryTaskConfig taskConfig = new QueryTaskConfig(
+                    searchOptions.getSubtypes(),
+                    searchOptions.isPassiveMode(),
+                    ++currentSessionId,
+                    searchOptions.getNetwork());
+            if (hadReply) {
+                requestTaskFuture = scheduleNextRunLocked(taskConfig);
+            } else {
+                requestTaskFuture = executor.submit(new QueryTask(taskConfig));
+            }
         }
     }
 
@@ -590,11 +594,14 @@ public class MdnsServiceTypeClient {
                         }
                     }
                 }
-                QueryTaskConfig config = this.config.getConfigForNextRun();
-                requestTaskFuture =
-                        executor.schedule(
-                                new QueryTask(config), config.timeToRunNextTaskInMs, MILLISECONDS);
+                requestTaskFuture = scheduleNextRunLocked(this.config);
             }
         }
     }
+
+    @NonNull
+    private Future<?> scheduleNextRunLocked(@NonNull QueryTaskConfig lastRunConfig) {
+        QueryTaskConfig config = lastRunConfig.getConfigForNextRun();
+        return executor.schedule(new QueryTask(config), config.timeToRunNextTaskInMs, MILLISECONDS);
+    }
 }

tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceTypeClientTests.java

@@ -21,6 +21,7 @@ import static com.android.testutils.DevSdkIgnoreRuleKt.SC_V2;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
@@ -424,6 +425,34 @@ public class MdnsServiceTypeClientTests {
         assertNull(currentThreadExecutor.getAndClearLastScheduledRunnable());
     }
 
+    @Test
+    public void testQueryScheduledWhenAnsweredFromCache() {
+        final MdnsSearchOptions searchOptions = MdnsSearchOptions.getDefaultOptions();
+        client.startSendAndReceive(mockListenerOne, searchOptions);
+        assertNotNull(currentThreadExecutor.getAndClearSubmittedRunnable());
+
+        client.processResponse(createResponse(
+                "service-instance-1", "192.0.2.123", 5353,
+                SERVICE_TYPE_LABELS,
+                Collections.emptyMap(), TEST_TTL), /* interfaceIndex= */ 20, mockNetwork);
+
+        verify(mockListenerOne).onServiceNameDiscovered(any());
+        verify(mockListenerOne).onServiceFound(any());
+
+        // File another identical query
+        client.startSendAndReceive(mockListenerTwo, searchOptions);
+
+        verify(mockListenerTwo).onServiceNameDiscovered(any());
+        verify(mockListenerTwo).onServiceFound(any());
+
+        // This time no query is submitted, only scheduled
+        assertNull(currentThreadExecutor.getAndClearSubmittedRunnable());
+        assertNotNull(currentThreadExecutor.getAndClearLastScheduledRunnable());
+        // This just skips the first query of the first burst
+        assertEquals(MdnsConfigs.timeBetweenQueriesInBurstMs(),
+                currentThreadExecutor.getAndClearLastScheduledDelayInMs());
+    }
+
     private static void verifyServiceInfo(MdnsServiceInfo serviceInfo, String serviceName,
             String[] serviceType, List<String> ipv4Addresses, List<String> ipv6Addresses, int port,
             List<String> subTypes, Map<String, String> attributes, int interfaceIndex,