Utils: Separate non-widget related base code from layoutbuilder

Change-Id: Ie7e7d413ed8cd4af8cdfc88c35fbdd9944d5e8b4
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/libs/utils/builderutils.h

@@ -0,0 +1,111 @@
+// Copyright (C) 2020 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include <functional>
+
+#if defined(UTILS_LIBRARY)
+#  define QTCREATOR_UTILS_EXPORT Q_DECL_EXPORT
+#elif defined(UTILS_STATIC_LIBRARY)
+#  define QTCREATOR_UTILS_EXPORT
+#else
+#  define QTCREATOR_UTILS_EXPORT Q_DECL_IMPORT
+#endif
+
+namespace Building {
+
+class NestId {};
+
+template <typename Id, typename Arg>
+class IdAndArg
+{
+public:
+    IdAndArg(Id, const Arg &arg) : arg(arg) {}
+    const Arg arg; // FIXME: Could be const &, but this would currently break bindTo().
+};
+
+template<typename T1, typename T2>
+struct Arg2
+{
+    Arg2(const T1 &a1, const T2 &a2)
+        : p1(a1)
+        , p2(a2)
+    {}
+    const T1 p1;
+    const T2 p2;
+};
+
+template<typename T1, typename T2, typename T3>
+struct Arg3
+{
+    Arg3(const T1 &a1, const T2 &a2, const T3 &a3)
+        : p1(a1)
+        , p2(a2)
+        , p3(a3)
+    {}
+    const T1 p1;
+    const T2 p2;
+    const T3 p3;
+};
+
+template<typename T1, typename T2, typename T3, typename T4>
+struct Arg4
+{
+    Arg4(const T1 &a1, const T2 &a2, const T3 &a3, const T4 &a4)
+        : p1(a1)
+        , p2(a2)
+        , p3(a3)
+        , p4(a4)
+    {}
+    const T1 p1;
+    const T2 p2;
+    const T3 p3;
+    const T4 p4;
+};
+
+// The main dispatcher
+
+void doit(auto x, auto id, auto p);
+
+template <typename X> class BuilderItem
+{
+public:
+    // Property setter
+    template <typename Id, typename Arg>
+    BuilderItem(IdAndArg<Id, Arg> && idarg)
+    {
+        apply = [&idarg](X *x) { doit(x, Id{}, idarg.arg); };
+    }
+
+    // Nested child object
+    template <typename Inner>
+    BuilderItem(Inner && p)
+    {
+        apply = [&p](X *x) { doit(x, NestId{}, std::forward<Inner>(p)); };
+    }
+
+    std::function<void(X *)> apply;
+};
+
+#define QTC_DEFINE_BUILDER_SETTER(name, setter) \
+    class name##_TAG {}; \
+    inline auto name(auto p) { return Building::IdAndArg{name##_TAG{}, p}; } \
+    inline void doit(auto x, name##_TAG, auto p) { x->setter(p); }
+
+#define QTC_DEFINE_BUILDER_SETTER2(name, setter) \
+    class name##_TAG {}; \
+    inline auto name(auto p1, auto p2) { return Building::IdAndArg{name##_TAG{}, Building::Arg2{p1, p2}}; } \
+    inline void doit(auto x, name##_TAG, auto p) { x->setter(p.p1, p.p2); }
+
+#define QTC_DEFINE_BUILDER_SETTER3(name, setter) \
+    class name##_TAG {}; \
+    inline auto name(auto p1, auto p2, auto p3) { return Building::IdAndArg{name##_TAG{}, Building::Arg3{p1, p2, p3}}; } \
+    inline void doit(auto x, name##_TAG, auto p) { x->setter(p.p1, p.p2, p.p3); }
+
+#define QTC_DEFINE_BUILDER_SETTER4(name, setter) \
+    class name##_TAG {}; \
+    inline auto name(auto p1, auto p2, auto p3, auto p4) { return Building::IdAndArg{name##_TAG{}, Building::Arg4{p1, p2, p3, p4}}; } \
+    inline void doit(auto x, name##_TAG, auto p) { x->setter(p.p1, p.p2, p.p3, p.p4); }
+
+} // Building