From e9a64615c8e18692a775765787f404266767260b Mon Sep 17 00:00:00 2001
From: Russell Yanofsky <russ@yanofsky.org>
Date: Mon, 27 Mar 2017 14:34:38 -0400
Subject: Make qt wallet test compatible with qt4

Unlike Qt5, the Qt4 signals implementation doesn't allow a signal to be
directly connected to a c++ lambda expression. Work around this by defining a
Callback QObject with a virtual method that can forward calls to a closure.

The Qt4 error was reported by Patrick Strateman <patrick.strateman@gmail.com>
in https://github.com/bitcoin/bitcoin/pull/10039#issuecomment-289248763
---
 src/qt/callback.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 src/qt/callback.h

(limited to 'src/qt/callback.h')

diff --git a/src/qt/callback.h b/src/qt/callback.h
new file mode 100644
index 0000000000..a8b593a652
--- /dev/null
+++ b/src/qt/callback.h
@@ -0,0 +1,30 @@
+#ifndef BITCOIN_QT_CALLBACK_H
+#define BITCOIN_QT_CALLBACK_H
+
+#include <QObject>
+
+class Callback : public QObject
+{
+    Q_OBJECT
+public Q_SLOTS:
+    virtual void call() = 0;
+};
+
+template <typename F>
+class FunctionCallback : public Callback
+{
+    F f;
+
+public:
+    FunctionCallback(F f_) : f(std::move(f_)) {}
+    ~FunctionCallback() override {}
+    void call() override { f(this); }
+};
+
+template <typename F>
+FunctionCallback<F>* makeCallback(F f)
+{
+    return new FunctionCallback<F>(std::move(f));
+}
+
+#endif // BITCOIN_QT_CALLBACK_H
-- 
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