examples: add basic widgets example

Cargo.toml

@@ -16,6 +16,7 @@ members = [
     "examples/demo_threading/rust",
     "examples/qml_features/rust",
     "examples/qml_minimal/rust",
+    "examples/widgets_minimal",
 
     "tests/basic_cxx_only/rust",
     "tests/basic_cxx_qt/rust",

examples/widgets_minimal/Cargo.toml

@@ -0,0 +1,25 @@
+# SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+# SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+#
+# SPDX-License-Identifier: MIT OR Apache-2.0
+
+[package]
+name = "widgets-minimal-no-cmake"
+version = "0.1.0"
+authors = [
+  "Andrew Hayzen <andrew.hayzen@kdab.com>",
+  "Be Wilson <be.wilson@kdab.com>",
+  "Gerhard de Clercq <gerhard.declercq@kdab.com>",
+  "Leon Matthes <leon.matthes@kdab.com>"
+]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+cxx.workspace = true
+cxx-qt.workspace = true
+cxx-qt-lib.workspace = true
+
+[build-dependencies]
+# The link_qt_object_files feature is required for statically linking Qt 6.
+cxx-qt-build = { workspace = true, features = [ "link_qt_object_files" ] }

examples/widgets_minimal/build.rs

@@ -0,0 +1,26 @@
+// SPDX-FileCopyrightText: 2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// SPDX-FileContributor: Be Wilson <be.wilson@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use cxx_qt_build::CxxQtBuilder;
+
+fn main() {
+    CxxQtBuilder::new()
+        // Link Qt's Network library
+        // - Qt Core is always linked
+        // - Qt Gui is linked by enabling the qt_gui Cargo feature (default).
+        // - Qt Qml is linked by enabling the qt_qml Cargo feature (default).
+        // - Qt Qml requires linking Qt Network on macOS
+        .qt_module("Network")
+        .qt_module("Widgets")
+        // Generate C++ from the `#[cxx_qt::bridge]` module
+        .file("src/qapplication_cxx.rs")
+        .file("src/qpushbutton_cxx.rs")
+        .cc_builder(|cc| {
+            cc.include("./cpp");
+            cc.file("./cpp/qapplication.cpp");
+            cc.file("./cpp/qpushbutton.cpp");
+        })
+        .build();
+}

examples/widgets_minimal/cpp/qapplication.cpp

@@ -0,0 +1,26 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// clang-format on
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#include "qapplication.h"
+
+#include <cxx-qt-lib/qcoreapplication.h>
+
+::std::unique_ptr<QApplication>
+qapplicationNew(const QVector<QByteArray>& args)
+{
+  // Ensure that our QVector has the same lifetime as the QGuiApplication
+  // by storing it inside a QObject that has QGuiApplication as it's parent
+  auto argsData = new ::rust::cxxqtlib1::ApplicationArgsData(args);
+  // Note that QGuiApplication uses a reference to an int for the size here
+  // so we need to ensure that reference remains valid
+  auto ptr =
+    ::std::make_unique<QApplication>(argsData->size(), argsData->data());
+  Q_ASSERT(ptr != nullptr);
+  argsData->setParent(ptr.get());
+
+  return ptr;
+}

examples/widgets_minimal/cpp/qapplication.h

@@ -0,0 +1,22 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// clang-format on
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#pragma once
+
+#include <QtWidgets/QApplication>
+
+#include <memory>
+
+::std::unique_ptr<QApplication>
+qapplicationNew(const QVector<QByteArray>& args);
+
+template<typename T>
+::std::int32_t
+qapplicationExec(T& app)
+{
+  return static_cast<::std::int32_t>(app.exec());
+}

examples/widgets_minimal/cpp/qpushbutton.cpp

@@ -0,0 +1,14 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// clang-format on
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#include "qpushbutton.h"
+
+::std::unique_ptr<QPushButton>
+qpushbuttonNew()
+{
+  return ::std::make_unique<QPushButton>();
+}

examples/widgets_minimal/cpp/qpushbutton.h

@@ -0,0 +1,15 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// clang-format on
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#pragma once
+
+#include <QtWidgets/QPushButton>
+
+#include <memory>
+
+::std::unique_ptr<QPushButton>
+qpushbuttonNew();

examples/widgets_minimal/src/main.rs

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+//! This example provides demostrations of building a Cargo only CXX-Qt application
+
+mod qapplication_cxx;
+mod qpushbutton_cxx;
+
+use cxx_qt_lib::QString;
+use qapplication_cxx::QApplication;
+use qpushbutton_cxx::QPushButton;
+
+fn main() {
+    let mut app = QApplication::new();
+
+    let mut push_button = QPushButton::new();
+
+    if let Some(mut push_button) = push_button.as_mut() {
+        push_button
+            .as_mut()
+            .set_text(&QString::from("Hello World!"));
+
+        push_button
+            .as_mut()
+            .on_clicked(|_, _| {
+                println!("Button Clicked!");
+            })
+            .release();
+
+        push_button.show();
+    }
+
+    if let Some(app) = app.as_mut() {
+        app.exec();
+    }
+}

examples/widgets_minimal/src/qapplication_cxx.rs

@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#[cxx_qt::bridge(cxx_file_stem = "qapplication_cxx")]
+mod ffi {
+    unsafe extern "C++Qt" {
+        include!(<QtWidgets/QApplication>);
+        type QApplication;
+
+        include!("cxx-qt-lib/qbytearray.h");
+        type QByteArray = cxx_qt_lib::QByteArray;
+        include!("cxx-qt-lib/qvector.h");
+        type QVector_QByteArray = cxx_qt_lib::QVector<QByteArray>;
+    }
+
+    unsafe extern "C++Qt" {
+        include!("qapplication.h");
+        #[doc(hidden)]
+        #[rust_name = "qapplication_new"]
+        fn qapplicationNew(args: &QVector_QByteArray) -> UniquePtr<QApplication>;
+
+        #[doc(hidden)]
+        #[rust_name = "qapplication_exec"]
+        fn qapplicationExec(app: Pin<&mut QApplication>) -> i32;
+    }
+}
+
+impl ffi::QApplication {
+    pub fn new() -> cxx::UniquePtr<Self> {
+        let mut vector = cxx_qt_lib::QVector::<ffi::QByteArray>::default();
+
+        // Construct an owned QVector of the args
+        // as we need the args_os data to outlive this method
+        // so we pass a QVector to C++ which is then stored
+        for arg in std::env::args_os() {
+            // Unix OsStrings can be directly converted to bytes.
+            #[cfg(unix)]
+            use std::os::unix::ffi::OsStrExt;
+
+            // Windows OsStrings are WTF-8 encoded, so they need to be
+            // converted to UTF-8 Strings before being converted to bytes.
+            // https://simonsapin.github.io/wtf-8/
+            #[cfg(windows)]
+            let arg = arg.to_string_lossy();
+
+            vector.append(ffi::QByteArray::from(arg.as_bytes()));
+        }
+
+        ffi::qapplication_new(&vector)
+    }
+
+    pub fn exec(self: core::pin::Pin<&mut Self>) -> i32 {
+        ffi::qapplication_exec(self)
+    }
+}
+
+pub use ffi::QApplication;

examples/widgets_minimal/src/qpushbutton_cxx.rs

@@ -0,0 +1,41 @@
+// SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+// SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#[cxx_qt::bridge(cxx_file_stem = "qpushbutton_cxx")]
+mod ffi {
+
+    unsafe extern "C++Qt" {
+        include!(<QtWidgets/QPushButton>);
+        type QPushButton;
+
+        include!("cxx-qt-lib/qstring.h");
+        type QString = cxx_qt_lib::QString;
+
+        #[qsignal]
+        #[allow(dead_code)]
+        fn clicked(self: Pin<&mut QPushButton>, checked: bool);
+
+        #[rust_name = "set_text"]
+        fn setText(self: Pin<&mut QPushButton>, text: &QString);
+
+        fn show(self: Pin<&mut QPushButton>);
+    }
+
+    unsafe extern "C++Qt" {
+        include!("qpushbutton.h");
+
+        #[doc(hidden)]
+        #[cxx_name = "qpushbuttonNew"]
+        fn qpushbutton_new() -> UniquePtr<QPushButton>;
+    }
+}
+
+impl ffi::QPushButton {
+    pub fn new() -> cxx::UniquePtr<Self> {
+        ffi::qpushbutton_new()
+    }
+}
+
+pub use ffi::QPushButton;