fix: Fix issues clang-tidy found (#1708)

Fixes #1706.

src/util/CoroutineGroup.cpp

@@ -41,10 +41,16 @@ CoroutineGroup::~CoroutineGroup()
     ASSERT(childrenCounter_ == 0, "CoroutineGroup is destroyed without waiting for child coroutines to finish");
 }
 
+bool
+CoroutineGroup::canSpawn() const
+{
+    return not maxChildren_.has_value() or childrenCounter_ < *maxChildren_;
+}
+
 bool
 CoroutineGroup::spawn(boost::asio::yield_context yield, std::function<void(boost::asio::yield_context)> fn)
 {
-    if (maxChildren_.has_value() && childrenCounter_ >= *maxChildren_)
+    if (not canSpawn())
         return false;
 
     ++childrenCounter_;

src/util/CoroutineGroup.hpp

@@ -54,6 +54,14 @@ public:
      */
     ~CoroutineGroup();
 
+    /**
+     * @brief Check if a new coroutine can be spawned (i.e. there is space for a new coroutine in the group)
+     *
+     * @return true If a new coroutine can be spawned. false if the maximum number of coroutines has been reached
+     */
+    bool
+    canSpawn() const;
+
     /**
      * @brief Spawn a new coroutine in the group
      *

src/web/ng/impl/ConnectionHandler.cpp

@@ -218,21 +218,21 @@ ConnectionHandler::parallelRequestResponseLoop(Connection& connection, boost::as
             closeConnectionGracefully &= closeGracefully;
             break;
         }
-
-        bool const spawnSuccess = tasksGroup.spawn(
-            yield,  // spawn on the same strand
-            [this, &stop, &closeConnectionGracefully, &connection, request = std::move(expectedRequest).value()](
-                boost::asio::yield_context innerYield
-            ) mutable {
-                auto maybeCloseConnectionGracefully = processRequest(connection, request, innerYield);
-                if (maybeCloseConnectionGracefully.has_value()) {
-                    stop = true;
-                    closeConnectionGracefully &= maybeCloseConnectionGracefully.value();
+        if (tasksGroup.canSpawn()) {
+            bool const spawnSuccess = tasksGroup.spawn(
+                yield,  // spawn on the same strand
+                [this, &stop, &closeConnectionGracefully, &connection, request = std::move(expectedRequest).value()](
+                    boost::asio::yield_context innerYield
+                ) mutable {
+                    auto maybeCloseConnectionGracefully = processRequest(connection, request, innerYield);
+                    if (maybeCloseConnectionGracefully.has_value()) {
+                        stop = true;
+                        closeConnectionGracefully &= maybeCloseConnectionGracefully.value();
+                    }
                 }
-            }
-        );
-
-        if (not spawnSuccess) {
+            );
+            ASSERT(spawnSuccess, "The coroutine was expected to be spawned");
+        } else {
             connection.send(
                 Response{
                     boost::beast::http::status::too_many_requests,

tests/common/util/TestHttpClient.cpp

@@ -33,10 +33,12 @@
 #include <boost/beast/core/flat_buffer.hpp>
 #include <boost/beast/core/stream_traits.hpp>
 #include <boost/beast/core/tcp_stream.hpp>
+#include <boost/beast/http.hpp>
 #include <boost/beast/http/field.hpp>
 #include <boost/beast/http/message.hpp>
 #include <boost/beast/http/string_body.hpp>
 #include <boost/beast/http/verb.hpp>
+#include <boost/beast/http/write.hpp>
 #include <boost/beast/ssl/ssl_stream.hpp>
 #include <boost/beast/version.hpp>
 #include <openssl/err.h>

tests/unit/util/CoroutineGroupTests.cpp

@@ -165,3 +165,17 @@ TEST_F(CoroutineGroupTests, TooManyCoroutines)
         callback3_.Call();
     });
 }
+
+TEST_F(CoroutineGroupTests, CanSpawn)
+{
+    EXPECT_CALL(callback1_, Call);
+
+    runSpawn([this](boost::asio::yield_context yield) {
+        CoroutineGroup group{yield, 1};
+        EXPECT_TRUE(group.canSpawn());
+        group.spawn(yield, [&group, this](boost::asio::yield_context) {
+            callback1_.Call();
+            EXPECT_FALSE(group.canSpawn());
+        });
+    });
+}