Terminal: Add Terminal plugin

Adds a new Terminal plugin that provides a Terminal pane inside
Qt Creator.

Fixes: QTCREATORBUG-8511
Change-Id: I7eacb3efa2463d7df9f383ae3fc33254fb9019a9
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/terminalhooks.h

@@ -0,0 +1,70 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include "commandline.h"
+#include "environment.h"
+#include "filepath.h"
+
+#include <functional>
+#include <memory>
+
+namespace Utils {
+class ProcessInterface;
+
+template<typename R, typename... Params>
+class Hook
+{
+public:
+    using Callback = std::function<R(Params...)>;
+
+public:
+    Hook() = delete;
+    Hook(const Hook &other) = delete;
+    Hook(Hook &&other) = delete;
+    Hook &operator=(const Hook &other) = delete;
+    Hook &operator=(Hook &&other) = delete;
+
+    explicit Hook(Callback defaultCallback) { set(defaultCallback); }
+
+    void set(Callback cb) { m_callback = cb; }
+    R operator()(Params &&...params) { return m_callback(std::forward<Params>(params)...); }
+
+private:
+    Callback m_callback;
+};
+
+namespace Terminal {
+struct HooksPrivate;
+
+enum class ExitBehavior { Close, Restart, Keep };
+
+struct OpenTerminalParameters
+{
+    std::optional<CommandLine> shellCommand;
+    std::optional<FilePath> workingDirectory;
+    std::optional<Environment> environment;
+    ExitBehavior m_exitBehavior{ExitBehavior::Close};
+};
+
+class QTCREATOR_UTILS_EXPORT Hooks
+{
+public:
+    using OpenTerminalHook = Hook<void, const OpenTerminalParameters &>;
+    using CreateTerminalProcessInterfaceHook = Hook<ProcessInterface *>;
+
+public:
+    static Hooks &instance();
+
+    OpenTerminalHook &openTerminalHook();
+    CreateTerminalProcessInterfaceHook &createTerminalProcessInterfaceHook();
+
+    ~Hooks();
+private:
+    Hooks();
+    std::unique_ptr<HooksPrivate> d;
+};
+
+} // namespace Terminal
+} // namespace Utils