Expose AStatsSocket_close() from the statsd apex

As part of statsd becoming a Mainline module in R, we need to formalize
the statsd APIs called from outside the statsd apex.

Bug: 145923416
Test: m
Change-Id: I296a018cc93d95bda77d95f8161acbbe983a5d51

libstats/socket/Android.bp

@@ -25,6 +25,7 @@ cc_library {
         // TODO(b/145573568): Remove stats_event_list once stats_event
         // migration is complete.
         "stats_event_list.c",
+        "stats_socket.c",
         "statsd_writer.c",
     ],
     host_supported: true,

libstats/socket/include/stats_socket.h

@@ -0,0 +1,33 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+/**
+ * Helpers to manage the statsd socket.
+ **/
+
+#ifdef __cplusplus
+extern "C" {
+#endif  // __CPLUSPLUS
+
+/**
+ * Closes the statsd socket file descriptor.
+ **/
+void AStatsSocket_close();
+#ifdef __cplusplus
+}
+#endif  // __CPLUSPLUS

libstats/socket/libstatssocket.map.txt

@@ -14,6 +14,7 @@ LIBSTATSSOCKET {
         AStatsEvent_writeAttributionChain; # apex # introduced=30
         AStatsEvent_addBoolAnnotation; # apex # introduced=30
         AStatsEvent_addInt32Annotation; # apex # introduced=30
+        AStatsSocket_close; # apex # introduced=30
     local:
         *;
 };

libstats/socket/stats_socket.c

@@ -0,0 +1,22 @@
+/*
+ * 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.
+ */
+
+#include "include/stats_socket.h"
+#include "stats_buffer_writer.h"
+
+void AStatsSocket_close() {
+    stats_log_close();
+}