core, proxy, handler: use DeferCall::defer everywhere (#48103)

Author: jkarneges

src/core/qzmq/src/qzmqvalve.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2012-2020 Justin Karneges
+ * Copyright (C) 2025 Fastly, Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
@@ -25,6 +26,7 @@
 
 #include <QPointer>
 #include "qzmqsocket.h"
+#include "defercall.h"
 
 namespace QZmq {
 
@@ -39,6 +41,7 @@ class Valve::Private : public QObject
 	bool pendingRead;
 	int maxReadsPerEvent;
 	boost::signals2::scoped_connection rrConnection;
+	DeferCall deferCall;
 
 	Private(Valve *_q) :
 		QObject(_q),
@@ -62,7 +65,7 @@ class Valve::Private : public QObject
 			return;
 
 		pendingRead = true;
-		QMetaObject::invokeMethod(this, "queuedRead", Qt::QueuedConnection);
+		deferCall.defer([=] { queuedRead(); });
 	}
 
 	void tryRead()
@@ -99,7 +102,6 @@ class Valve::Private : public QObject
 		tryRead();
 	}
 
-private slots:
 	void queuedRead()
 	{
 		pendingRead = false;

src/core/zrpcrequest.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2014-2015 Fanout, Inc.
- * Copyright (C) 2024 Fastly, Inc.
+ * Copyright (C) 2024-2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -31,6 +31,7 @@
 #include "uuidutil.h"
 #include "log.h"
 #include "rtimer.h"
+#include "defercall.h"
 
 using Connection = boost::signals2::scoped_connection;
 
@@ -52,6 +53,7 @@ class ZrpcRequest::Private : public QObject
 	QByteArray conditionString;
 	std::unique_ptr<RTimer> timer;
 	Connection timerConnection;
+	DeferCall deferCall;
 
 	Private(ZrpcRequest *_q) :
 		QObject(_q),
@@ -136,7 +138,6 @@ class ZrpcRequest::Private : public QObject
 		q->finished();
 	}
 
-private slots:
 	void doStart()
 	{
 		if(!manager->canWriteImmediately())
@@ -238,7 +239,7 @@ void ZrpcRequest::start(const QString &method, const QVariantHash &args)
 {
 	d->method = method;
 	d->args = args;
-	QMetaObject::invokeMethod(d, "doStart", Qt::QueuedConnection);
+	d->deferCall.defer([=] { d->doStart(); });
 }
 
 void ZrpcRequest::respond(const QVariant &result)

src/core/zwebsocket.cpp

@@ -96,6 +96,7 @@ class ZWebSocket::Private : public QObject
 	bool multi;
 	Connection expireTimerConnection;
 	Connection keepAliveTimerConnection;
+	DeferCall deferCall;
 
 	Private(ZWebSocket *_q) :
 		QObject(_q),
@@ -266,7 +267,7 @@ class ZWebSocket::Private : public QObject
 		if(!pendingUpdate)
 		{
 			pendingUpdate = true;
-			QMetaObject::invokeMethod(this, "doUpdate", Qt::QueuedConnection);
+			deferCall.defer([=] { doUpdate(); });
 		}
 	}
 
@@ -298,7 +299,7 @@ class ZWebSocket::Private : public QObject
 
 		state = Idle;
 		cleanup();
-		QMetaObject::invokeMethod(this, "doClosed", Qt::QueuedConnection);
+		deferCall.defer([=] { doClosed(); });
 	}
 
 	Frame readFrame()
@@ -338,7 +339,7 @@ class ZWebSocket::Private : public QObject
 				// if peer was already closed, then we're done!
 				state = Idle;
 				cleanup();
-				QMetaObject::invokeMethod(this, "doClosed", Qt::QueuedConnection);
+				deferCall.defer([=] { doClosed(); });
 			}
 			else
 			{
@@ -977,7 +978,6 @@ class ZWebSocket::Private : public QObject
 			return ErrorGeneric;
 	}
 
-public slots:
 	void doClosed()
 	{
 		q->closed();
@@ -1067,7 +1067,6 @@ public slots:
 		}
 	}
 
-public:
 	void expire_timeout()
 	{
 		state = Idle;

src/handler/deferred.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 Fanout, Inc.
+ * Copyright (C) 2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -42,7 +43,7 @@ void Deferred::setFinished(bool ok, const QVariant &value)
 	result_.success = ok;
 	result_.value = value;
 
-	QMetaObject::invokeMethod(this, "doFinish", Qt::QueuedConnection);
+	deferCall_.defer([=] { doFinish(); });
 }
 
 void Deferred::doFinish()

src/handler/deferred.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 Fanout, Inc.
+ * Copyright (C) 2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -26,6 +27,7 @@
 #include <QVariant>
 #include <QObject>
 #include <boost/signals2.hpp>
+#include "defercall.h"
 
 class DeferredResult
 {
@@ -63,11 +65,11 @@ class Deferred : public QObject
 
 	void setFinished(bool ok, const QVariant &value = QVariant());
 
-private slots:
-	void doFinish();
-
 private:
 	DeferredResult result_;
+	DeferCall deferCall_;
+
+	void doFinish();
 };
 
 #endif

src/handler/handlermain.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2016 Fanout, Inc.
- * Copyright (C) 2024 Fastly, Inc.
+ * Copyright (C) 2024-2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -22,7 +22,6 @@
  */
 
 #include <QCoreApplication>
-#include <QTimer>
 #include "rtimer.h"
 #include "defercall.h"
 #include "handlerapp.h"
@@ -53,7 +52,8 @@ int handler_main(int argc, char **argv)
 	QCoreApplication qapp(argc, argv);
 
 	HandlerAppMain appMain;
-	QTimer::singleShot(0, [&appMain]() {appMain.start();});
+	DeferCall deferCall;
+	deferCall.defer([&] { appMain.start(); });
 	int ret = qapp.exec();
 
 	// ensure deferred deletes are processed

src/handler/httpsession.cpp

@@ -206,6 +206,7 @@ class HttpSession::Private : public QObject
 	Connection timerConnection;
 	Connection retryTimerConnection;
 	Connection messageFiltersFinishedConnection;
+	DeferCall deferCall;
 
 	Private(HttpSession *_q, ZhttpRequest *_req, const HttpSession::AcceptData &_adata, const Instruct &_instruct, ZhttpManager *_outZhttp, StatsManager *_stats, RateLimiter *_updateLimiter, PublishLastIds *_publishLastIds, HttpSessionUpdateManager *_updateManager, int _connectionSubscriptionMax) :
 		QObject(_q),
@@ -1164,7 +1165,7 @@ class HttpSession::Private : public QObject
 		if(!outZhttp)
 		{
 			errorMessage = "Instruct contained link, but handler not configured for outbound requests.";
-			QMetaObject::invokeMethod(this, "doError", Qt::QueuedConnection);
+			deferCall.defer([=] { doError(); });
 			return;
 		}
 
@@ -1457,7 +1458,6 @@ class HttpSession::Private : public QObject
 		}
 	}
 
-private slots:
 	void doError()
 	{
 		if(instruct.holdMode == Instruct::ResponseHold)
@@ -1621,7 +1621,6 @@ private slots:
 		}
 	}
 
-private:
 	void timer_timeout()
 	{
 		if(instruct.holdMode == Instruct::ResponseHold)

src/proxy/domainmap.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2012-2022 Fanout, Inc.
- * Copyright (C) 2023-2024 Fastly, Inc.
+ * Copyright (C) 2023-2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -205,6 +205,7 @@ class DomainMap::Worker : public QObject
 	RTimer t;
 	Connection tConnection;
 	QFileSystemWatcher watcher;
+	DeferCall deferCall;
 
 	Worker() :
 		watcher(this)
@@ -292,7 +293,7 @@ class DomainMap::Worker : public QObject
 
 		log_info("routes loaded with %d entries", allRules.count());
 
-		QMetaObject::invokeMethod(this, "doChanged", Qt::QueuedConnection);
+		deferCall.defer([=] { doChanged(); });
 	}
 
 	// mutex must be locked when calling this method
@@ -312,11 +313,6 @@ class DomainMap::Worker : public QObject
 	Signal changed;
 
 public slots:
-	void doChanged()
-	{
-		changed();
-	}
-
 	void start()
 	{
 		if(!fileName.isEmpty())
@@ -719,6 +715,11 @@ public slots:
 
 		return AddRuleOk;
 	}
+
+	void doChanged()
+	{
+		changed();
+	}
 };
 
 class DomainMap::Thread : public QThread

src/proxy/main.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2016 Fanout, Inc.
+ * Copyright (C) 2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -22,15 +23,13 @@
 
 #include <QCoreApplication>
 #include "app.h"
+#include "defercall.h"
 
-class AppMain : public QObject
+class AppMain
 {
-	Q_OBJECT
-
 public:
 	App *app;
 
-public slots:
 	void start()
 	{
 		app = new App;
@@ -53,10 +52,17 @@ int proxy_main(int argc, char **argv)
 	QCoreApplication qapp(argc, argv);
 
 	AppMain appMain;
-	QMetaObject::invokeMethod(&appMain, "start", Qt::QueuedConnection);
-	return qapp.exec();
-}
+	DeferCall deferCall;
+	deferCall.defer([&] { appMain.start(); });
+	int ret = qapp.exec();
+
+	// ensure deferred deletes are processed
+	QCoreApplication::instance()->sendPostedEvents();
 
+	// deinit here, after all event loop activity has completed
+	DeferCall::cleanup();
+
+	return ret;
 }
 
-#include "main.moc"
+}

src/proxy/requestsession.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2012-2023 Fanout, Inc.
- * Copyright (C) 2024 Fastly, Inc.
+ * Copyright (C) 2024-2025 Fastly, Inc.
  *
  * This file is part of Pushpin.
  *
@@ -36,6 +36,7 @@
 #include "qtcompat.h"
 #include "bufferlist.h"
 #include "log.h"
+#include "defercall.h"
 #include "layertracker.h"
 #include "sockjsmanager.h"
 #include "inspectdata.h"
@@ -200,6 +201,7 @@ class RequestSession::Private : public QObject
 	ZhttpReqConnections zhttpReqConnections;
 	Connection inspectFinishedConnection;
 	Connection acceptFinishedConnection;
+	DeferCall deferCall;
 
 	Private(RequestSession *_q, int _workerId, DomainMap *_domainMap = 0, SockJsManager *_sockJsManager = 0, ZrpcManager *_inspectManager = 0, ZrpcChecker *_inspectChecker = 0, ZrpcManager *_acceptManager = 0, StatsManager *_stats = 0) :
 		QObject(_q),
@@ -308,7 +310,7 @@ class RequestSession::Private : public QObject
 				isSockJs = true;
 				sockJsManager->giveRequest(zhttpRequest, route.sockJsPath.length(), route.sockJsAsPath, route);
 				zhttpRequest = 0;
-				QMetaObject::invokeMethod(this, "doFinished", Qt::QueuedConnection);
+				deferCall.defer([=] { doFinished(); });
 				return;
 			}
 		}
@@ -480,7 +482,7 @@ class RequestSession::Private : public QObject
 				if(!inspectRequest)
 				{
 					log_debug("inspect not available");
-					QMetaObject::invokeMethod(this, "doInspectError", Qt::QueuedConnection);
+					deferCall.defer([=] { doInspectError(); });
 				}
 			}
 		}
@@ -559,7 +561,7 @@ class RequestSession::Private : public QObject
 		if(!pendingResponseUpdate)
 		{
 			pendingResponseUpdate = true;
-			QMetaObject::invokeMethod(this, "doResponseUpdate", Qt::QueuedConnection);
+			deferCall.defer([=] { doResponseUpdate(); });
 		}
 	}
 
@@ -973,7 +975,6 @@ class RequestSession::Private : public QObject
 		}
 	}
 
-public slots:
 	void doResponseUpdate()
 	{
 		pendingResponseUpdate = false;