Python: add pyside uic extra compiler

To be able to autocomplete code from .ui forms we need to feed the
python language server the compiled form. The uic extra compiler
generates a temporary ui_name.py file for uncompiled or unsaved ui
files. These files are inside a folder that gets appended to the python
path environment variable for the python language server.

Change-Id: I9f48d2012162f33986639315189c41e0a7e0dad2
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/python/pysideuicextracompiler.h

@@ -0,0 +1,53 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <projectexplorer/extracompiler.h>
+
+namespace Python {
+namespace Internal {
+
+class PySideUicExtraCompiler : public ProjectExplorer::ProcessExtraCompiler
+{
+public:
+    PySideUicExtraCompiler(const Utils::FilePath &pySideUic,
+                           const ProjectExplorer::Project *project,
+                           const Utils::FilePath &source,
+                           const Utils::FilePaths &targets,
+                           QObject *parent = nullptr);
+
+    Utils::FilePath pySideUicPath() const;
+
+private:
+    Utils::FilePath command() const override;
+    ProjectExplorer::FileNameToContentsHash handleProcessFinished(
+        Utils::QtcProcess *process) override;
+
+    Utils::FilePath m_pySideUic;
+};
+
+} // namespace Internal
+} // namespace Python