allow providing a callback to uv_messenger_stop to prevent mismatched new/free

include/mbgl/util/uv-messenger.h

@@ -15,13 +15,14 @@ struct uv_messenger_s {
     uv_mutex_t mutex;
     uv_async_t async;
     uv_messenger_cb callback;
+    uv_messenger_stop_cb stop_callback;
     void *data;
     void *queue[2];
 };
 
 int uv_messenger_init(uv_loop_t *loop, uv_messenger_t *msgr, uv_messenger_cb callback);
 void uv_messenger_send(uv_messenger_t *msgr, void *arg);
-void uv_messenger_stop(uv_messenger_t *msgr);
+void uv_messenger_stop(uv_messenger_t *msgr, uv_messenger_stop_cb stop_callback);
 void uv_messenger_ref(uv_messenger_t *msgr);
 void uv_messenger_unref(uv_messenger_t *msgr);
 

src/storage/file_source.cpp

@@ -23,9 +23,9 @@ FileSource::FileSource(uv_loop_t *loop_, const std::string &path)
 
 FileSource::~FileSource() {
     assert(thread_id == uv_thread_self());
-    uv_messenger_stop(queue);
-    // NOTE: We don't need to delete the messenger since it will be deleted by the
-    // uv_messenger_stop() function.
+    uv_messenger_stop(queue, [](uv_messenger_t *msgr) {
+        delete msgr;
+    });
 
     util::ptr<BaseRequest> req;
 

src/util/uv-messenger.c

@@ -2,6 +2,7 @@
 #include <mbgl/util/queue.h>
 
 #include <stdlib.h>
+#include <assert.h>
 
 typedef struct {
     void *data;
@@ -46,6 +47,7 @@ int uv_messenger_init(uv_loop_t *loop, uv_messenger_t *msgr, uv_messenger_cb cal
     }
 
     msgr->callback = callback;
+    msgr->stop_callback = NULL;
 
     QUEUE_INIT(&msgr->queue);
 
@@ -73,9 +75,12 @@ void uv_messenger_unref(uv_messenger_t *msgr) {
 }
 
 void uv__messenger_stop_callback(uv_handle_t *handle) {
-    free((uv_messenger_t *)handle->data);
+    uv_messenger_t *msgr = (uv_messenger_t *)handle->data;
+    msgr->stop_callback(msgr);
 }
 
-void uv_messenger_stop(uv_messenger_t *msgr) {
+void uv_messenger_stop(uv_messenger_t *msgr, uv_messenger_stop_cb stop_callback) {
+    assert(!msgr->stop_callback);
+    msgr->stop_callback = stop_callback;
     uv_close((uv_handle_t *)&msgr->async, uv__messenger_stop_callback);
 }

src/util/uv-worker.c

@@ -18,6 +18,10 @@ struct uv__worker_thread_s {
     uv_thread_t thread;
 };
 
+void uv__worker_free_messenger(uv_messenger_t *msgr) {
+    free(msgr);
+}
+
 void uv__worker_thread_finished(uv__worker_thread_t *worker_thread) {
     uv_worker_t *worker = worker_thread->worker;
 
@@ -35,7 +39,7 @@ void uv__worker_thread_finished(uv__worker_thread_t *worker_thread) {
     worker->count--;
     if (worker->count == 0) {
         uv_chan_destroy(&worker->chan);
-        uv_messenger_stop(worker->msgr);
+        uv_messenger_stop(worker->msgr, uv__worker_free_messenger);
         if (worker->close_cb) {
             worker->close_cb(worker);
         }