Fix lockup when adding requests during shutdown

include/coeurl/client.hpp

@@ -177,6 +177,7 @@ struct Client {
     CURLM *multi{};
     int still_running = 0;
     std::atomic<bool> stopped{false};
+    std::atomic<bool> prevent_new_requests{false};
     bool verify_peer_ = true;
 
     long connection_timeout_ = 0;

include/coeurl/errors.hpp

@@ -6,9 +6,8 @@
 #include <curl/curl.h>
 
 namespace coeurl {
-    const char* to_string(CURLcode c);
-    //const char* to_string(CURLUcode c);
-    const char* to_string(CURLMcode c);
-    const char* to_string(CURLSHcode c);
-};
-
+const char *to_string(CURLcode c);
+// const char* to_string(CURLUcode c);
+const char *to_string(CURLMcode c);
+const char *to_string(CURLSHcode c);
+}; // namespace coeurl

lib/client.cpp

@@ -133,15 +133,21 @@ void Client::cancel_requests_cb(evutil_socket_t, short, void *userp) {
 
     Client *g = (Client *)userp;
 
-    {
         // prevent new requests from being added
-        const std::scoped_lock lock(g->pending_requests_mutex);
+        {
+            g->prevent_new_requests = true;
+        }
 
         // safe to access now, since we are running on the worker thread and only
         // there running_requests is modified
         while (!g->running_requests.empty())
             g->remove_request(g->running_requests.back().get());
-    }
+
+        // Allow for new requests
+        {
+            g->prevent_new_requests = false;
+        }
+
 
     CURLMcode rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0, &g->still_running);
     mcode_or_die("timer_cb: curl_multi_socket_action", rc);
@@ -297,6 +303,14 @@ void Client::check_multi_info() {
 void Client::submit_request(std::shared_ptr<Request> conn) {
     Client::log->trace("SUBMIT");
 
+    if (this->prevent_new_requests) {
+        conn->curl_error = CURLE_ABORTED_BY_CALLBACK;
+        conn->status = Request::Status::Canceled;
+        if (conn->on_complete_)
+            conn->on_complete_(*conn.get());
+        return;
+    }
+
     {
         const std::scoped_lock lock(pending_requests_mutex);
 

tests/requests.cpp

@@ -201,3 +201,18 @@ TEST_CASE("Basic simple DELETE request with body") {
         CHECK(r.response() == "hello");
     });
 }
+
+TEST_CASE("Shutdown") {
+    Client g{};
+
+    g.get("http://localhost:5000/", [&g](const Request &r) {
+        CHECK(r.url() == "http://localhost:5000/");
+        CHECK(r.response_code() != 200);
+
+        g.get("http://localhost:5000/", [](const Request &r) {
+            CHECK(r.url() == "http://localhost:5000/");
+            CHECK(r.error_code() == CURLE_ABORTED_BY_CALLBACK);
+        });
+    });
+    g.shutdown();
+}

tests/requests_tls.cpp

@@ -219,3 +219,18 @@ TEST_CASE("Basic simple DELETE request with body") {
         CHECK(r.response() == "hello");
     });
 }
+
+TEST_CASE("Shutdown") {
+    Client g{};
+
+    g.get("https://localhost:5443/", [&g](const Request &r) {
+        CHECK(r.url() == "https://localhost:5443/");
+        CHECK(r.response_code() != 200);
+
+        g.get("https://localhost:5000/", [](const Request &r) {
+            CHECK(r.url() == "https://localhost:5443/");
+            CHECK(r.error_code() == CURLE_ABORTED_BY_CALLBACK);
+        });
+    });
+    g.shutdown();
+}