From e5125013a2661b30f21323f1a3f925103e8d589f Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Tue, 22 Dec 2015 09:25:18 +0100
Subject: Threadboundary cleanup

---
 common/resultprovider.h   |  4 +---
 common/threadboundary.cpp | 22 +++++++++++++++++++++-
 common/threadboundary.h   | 36 +++++++++++++++++-------------------
 3 files changed, 39 insertions(+), 23 deletions(-)

diff --git a/common/resultprovider.h b/common/resultprovider.h
index 2c373c3..7f090e9 100644
--- a/common/resultprovider.h
+++ b/common/resultprovider.h
@@ -97,9 +97,7 @@ private:
         //That way the result emitter implementation doesn't have to care about threadsafety at all.
         //The alternative would be to make all handlers of the emitter threadsafe.
         if (auto emitter = mResultEmitter.toStrongRef()) {
-            emitter->mThreadBoundary.callInMainThread([f]() {
-                f();
-            });
+            emitter->mThreadBoundary.callInMainThread(f);
         }
     }
 
diff --git a/common/threadboundary.cpp b/common/threadboundary.cpp
index 48fd11a..238f5b4 100644
--- a/common/threadboundary.cpp
+++ b/common/threadboundary.cpp
@@ -23,10 +23,30 @@
 Q_DECLARE_METATYPE(std::function<void()>);
 
 namespace async {
-ThreadBoundary::ThreadBoundary(): QObject() { qRegisterMetaType<std::function<void()> >("std::function<void()>"); }
+ThreadBoundary::ThreadBoundary()
+    : QObject()
+{
+    qRegisterMetaType<std::function<void()> >("std::function<void()>");
+}
+
 ThreadBoundary:: ~ThreadBoundary()
 {
 }
 
+void ThreadBoundary::callInMainThread(std::function<void()> f)
+{
+    /*
+     * This implementation causes lambdas to pile up if the target thread is the same as the caller thread, or the caller thread calls faster
+     * than the target thread is able to execute the function calls. In that case any captures will equally pile up, resulting
+     * in significant memory usage i.e. due to Emitter::addHandler calls that each capture a domain object.
+     */
+    QMetaObject::invokeMethod(this, "runInMainThread", Qt::QueuedConnection, QGenericReturnArgument(), Q_ARG(std::function<void()>, f));
+}
+
+void ThreadBoundary::runInMainThread(std::function<void()> f)
+{
+    f();
+}
+
 }
 
diff --git a/common/threadboundary.h b/common/threadboundary.h
index d73bdae..0d8ed3b 100644
--- a/common/threadboundary.h
+++ b/common/threadboundary.h
@@ -24,24 +24,22 @@
 #include <functional>
 
 namespace async {
-    /*
-     * A helper class to invoke a method in a different thread using the event loop.
-     * The ThreadBoundary object must live in the thread where the function should be called.
-     */
-    class ThreadBoundary : public QObject {
-        Q_OBJECT
-    public:
-        ThreadBoundary();
-        virtual ~ThreadBoundary();
 
-        //Call in worker thread
-        void callInMainThread(std::function<void()> f) {
-            QMetaObject::invokeMethod(this, "runInMainThread", Qt::QueuedConnection, QGenericReturnArgument(), Q_ARG(std::function<void()>, f));
-        }
-    public slots:
-        //Get's called in main thread by it's eventloop
-        void runInMainThread(std::function<void()> f) {
-            f();
-        }
-    };
+/*
+* A helper class to invoke a method in a different thread using the event loop.
+* The ThreadBoundary object must live in the thread where the function should be called.
+*/
+class ThreadBoundary : public QObject {
+    Q_OBJECT
+public:
+    ThreadBoundary();
+    virtual ~ThreadBoundary();
+
+    //Call in worker thread
+    void callInMainThread(std::function<void()> f);
+public slots:
+    //Get's called in main thread by it's eventloop
+    void runInMainThread(std::function<void()> f);
+};
+
 }
-- 
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