cxx-qt-gen: add signalhandler template and include it

Related to #595

crates/cxx-qt-gen/include/cxxqt_signalhandler.h

@@ -0,0 +1,52 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// clang-format on
+// SPDX-FileContributor: Andrew Hayzen <[email protected]>
+// SPDX-FileContributor: Leon Matthes <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+#pragma once
+
+#include <type_traits>
+
+#include "rust/cxx.h"
+
+namespace rust::cxxqtlib1 {
+
+template<typename CXXArguments>
+class SignalHandler
+{
+
+public:
+  SignalHandler() = delete;
+  SignalHandler(const SignalHandler&) = delete;
+
+  SignalHandler(SignalHandler&& other)
+  {
+    data[0] = other.data[0];
+    data[1] = other.data[1];
+    other.data[0] = nullptr;
+    other.data[1] = nullptr;
+  }
+
+  ~SignalHandler() noexcept;
+  template<typename... Arguments>
+  void operator()(Arguments... args);
+
+private:
+  void* data[2];
+};
+
+} // rust::cxxqtlib1
+
+// Define namespace otherwise we hit a GCC bug
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480
+namespace rust {
+
+template<typename CXXArguments>
+struct IsRelocatable<rust::cxxqtlib1::SignalHandler<CXXArguments>>
+  : ::std::true_type
+{
+};
+
+} // namespace rust

crates/cxx-qt-gen/src/generator/cpp/externcxxqt.rs

@@ -8,10 +8,13 @@ use crate::{
     parser::{externcxxqt::ParsedExternCxxQt, mappings::ParsedCxxMappings},
     CppFragment,
 };
+use std::collections::BTreeSet;
 use syn::Result;
 
 #[derive(Default)]
 pub struct GeneratedCppExternCxxQtBlocks {
+    /// List of includes
+    pub includes: BTreeSet<String>,
     /// List of methods
     pub method: CppFragment,
     /// Namespace of the method block

crates/cxx-qt-gen/src/generator/cpp/signal.rs

@@ -126,6 +126,10 @@ pub fn generate_cpp_free_signal(
             .get(&signal.qobject_ident.to_string()),
     );
 
+    generated
+        .includes
+        .insert("#include <cxx-qt-common/cxxqt_signalhandler.h>".to_owned());
+
     Ok(generated)
 }
 
@@ -137,6 +141,12 @@ pub fn generate_cpp_signals(
     let mut generated = GeneratedCppQObjectBlocks::default();
     let qobject_ident = qobject_idents.cpp_class.cpp.to_string();
 
+    if !signals.is_empty() {
+        generated
+            .includes
+            .insert("#include <cxx-qt-common/cxxqt_signalhandler.h>".to_owned());
+    }
+
     for signal in signals {
         // Prepare the idents
         let idents = QSignalName::from(signal);

crates/cxx-qt-gen/src/lib.rs

@@ -32,6 +32,10 @@ pub fn write_headers(directory: impl AsRef<Path>) {
             include_str!("../include/cxxqt_maybelockguard.h"),
             "cxxqt_maybelockguard.h",
         ),
+        (
+            include_str!("../include/cxxqt_signalhandler.h"),
+            "cxxqt_signalhandler.h",
+        ),
         (include_str!("../include/cxxqt_thread.h"), "cxxqt_thread.h"),
         (
             include_str!("../include/cxxqt_threading.h"),

crates/cxx-qt-gen/src/writer/cpp/header.rs

@@ -131,7 +131,10 @@ pub fn write_cpp_header(generated: &GeneratedCppBlocks) -> String {
     .fold(BTreeSet::<&String>::default(), |mut acc, qobject| {
         acc.extend(qobject.blocks.includes.iter());
         acc
-    }).into_iter().cloned().collect::<Vec<String>>().join("\n"),
+    }).into_iter().chain(generated.extern_cxx_qt.iter().fold(BTreeSet::<&String>::default(), |mut acc, block| {
+        acc.extend(block.includes.iter());
+        acc
+    })).cloned().collect::<Vec<String>>().join("\n"),
     }
 }
 

crates/cxx-qt-gen/test_outputs/passthrough_and_naming.h

@@ -2,6 +2,7 @@
 
 #include <cxx-qt-common/cxxqt_locking.h>
 #include <cxx-qt-common/cxxqt_maybelockguard.h>
+#include <cxx-qt-common/cxxqt_signalhandler.h>
 #include <cxx-qt-common/cxxqt_type.h>
 
 namespace cxx_qt::multi_object {

crates/cxx-qt-gen/test_outputs/properties.h

@@ -2,6 +2,7 @@
 
 #include <cxx-qt-common/cxxqt_locking.h>
 #include <cxx-qt-common/cxxqt_maybelockguard.h>
+#include <cxx-qt-common/cxxqt_signalhandler.h>
 #include <cxx-qt-common/cxxqt_type.h>
 
 namespace cxx_qt::my_object {

crates/cxx-qt-gen/test_outputs/signals.h

@@ -2,6 +2,7 @@
 
 #include <cxx-qt-common/cxxqt_locking.h>
 #include <cxx-qt-common/cxxqt_maybelockguard.h>
+#include <cxx-qt-common/cxxqt_signalhandler.h>
 #include <cxx-qt-common/cxxqt_type.h>
 
 namespace cxx_qt::my_object {