/*
    Copyright (c) 2005-2021 Intel Corporation

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

#ifndef __TBB_global_control_H
#define __TBB_global_control_H

#include "detail/_config.h"
#include "detail/_namespace_injection.h"
#include "detail/_assert.h"
#include "detail/_template_helpers.h"
#include "detail/_exception.h"

#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
#include <new> // std::nothrow_t
#endif
#include <cstddef>

namespace tbb {
namespace detail {

namespace d1 {
class global_control;
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
class task_scheduler_handle;
#endif
}

namespace r1 {
TBB_EXPORT void __TBB_EXPORTED_FUNC create(d1::global_control&);
TBB_EXPORT void __TBB_EXPORTED_FUNC destroy(d1::global_control&);
TBB_EXPORT std::size_t __TBB_EXPORTED_FUNC global_control_active_value(int);
struct global_control_impl;
struct control_storage_comparator;
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
void release_impl(d1::task_scheduler_handle& handle);
bool finalize_impl(d1::task_scheduler_handle& handle);
TBB_EXPORT void __TBB_EXPORTED_FUNC get(d1::task_scheduler_handle&);
TBB_EXPORT bool __TBB_EXPORTED_FUNC finalize(d1::task_scheduler_handle&, std::intptr_t mode);
#endif
}

namespace d1 {

class global_control {
public:
    enum parameter {
        max_allowed_parallelism,
        thread_stack_size,
        terminate_on_exception,
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
        scheduler_handle, // not a public parameter
#else
        reserved1, // not a public parameter
#endif
        parameter_max // insert new parameters above this point
    };

    global_control(parameter p, std::size_t value) :
        my_value(value), my_reserved(), my_param(p) {
        suppress_unused_warning(my_reserved);
        __TBB_ASSERT(my_param < parameter_max, "Invalid parameter");
#if __TBB_WIN8UI_SUPPORT && (_WIN32_WINNT < 0x0A00)
        // For Windows 8 Store* apps it's impossible to set stack size
        if (p==thread_stack_size)
            return;
#elif __TBB_x86_64 && (_WIN32 || _WIN64)
        if (p==thread_stack_size)
            __TBB_ASSERT_RELEASE((unsigned)value == value, "Stack size is limited to unsigned int range");
#endif
        if (my_param==max_allowed_parallelism)
            __TBB_ASSERT_RELEASE(my_value>0, "max_allowed_parallelism cannot be 0.");
        r1::create(*this);
    }

    ~global_control() {
        __TBB_ASSERT(my_param < parameter_max, "Invalid parameter");
#if __TBB_WIN8UI_SUPPORT && (_WIN32_WINNT < 0x0A00)
        // For Windows 8 Store* apps it's impossible to set stack size
        if (my_param==thread_stack_size)
            return;
#endif
        r1::destroy(*this);
    }

    static std::size_t active_value(parameter p) {
        __TBB_ASSERT(p < parameter_max, "Invalid parameter");
        return r1::global_control_active_value((int)p);
    }

private:
    std::size_t my_value;
    std::intptr_t my_reserved; // TODO: substitution of global_control* not to break backward compatibility
    parameter my_param;

    friend struct r1::global_control_impl;
    friend struct r1::control_storage_comparator;
};

#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
//! Finalization options.
//! Outside of the class to avoid extensive friendship.
static constexpr std::intptr_t release_nothrowing = 0;
static constexpr std::intptr_t finalize_nothrowing = 1;
static constexpr std::intptr_t finalize_throwing = 2;

//! User side wrapper for a task scheduler lifetime control object
class task_scheduler_handle {
public:
    task_scheduler_handle() = default;
    ~task_scheduler_handle() {
        release(*this);
    }

    //! No copy
    task_scheduler_handle(const task_scheduler_handle& other) = delete;
    task_scheduler_handle& operator=(const task_scheduler_handle& other) = delete;

    //! Move only
    task_scheduler_handle(task_scheduler_handle&& other) noexcept : m_ctl{nullptr} {
        std::swap(m_ctl, other.m_ctl);
    }
    task_scheduler_handle& operator=(task_scheduler_handle&& other) noexcept {
        std::swap(m_ctl, other.m_ctl);
        return *this;
    };

    explicit operator bool() const noexcept {
        return m_ctl != nullptr;
    }

    //! Get and active instance of task_scheduler_handle
    static task_scheduler_handle get() {
         task_scheduler_handle handle;
         r1::get(handle);
         return handle;
    }

    //! Release the reference and deactivate handle
    static void release(task_scheduler_handle& handle) {
        if (handle.m_ctl != nullptr) {
            r1::finalize(handle, release_nothrowing);
        }
    }

private:
    friend void r1::release_impl(task_scheduler_handle& handle);
    friend bool r1::finalize_impl(task_scheduler_handle& handle);
    friend void __TBB_EXPORTED_FUNC r1::get(task_scheduler_handle&);

    global_control* m_ctl{nullptr};
};

#if TBB_USE_EXCEPTIONS
//! Waits for worker threads termination. Throws exception on error.
inline void finalize(task_scheduler_handle& handle) {
    r1::finalize(handle, finalize_throwing);
}
#endif
//! Waits for worker threads termination. Returns false on error.
inline bool finalize(task_scheduler_handle& handle, const std::nothrow_t&) noexcept {
    return r1::finalize(handle, finalize_nothrowing);
}
#endif // __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE

} // namespace d1
} // namespace detail

inline namespace v1 {
using detail::d1::global_control;
#if __TBB_SUPPORTS_WORKERS_WAITING_IN_TERMINATE
using detail::d1::finalize;
using detail::d1::task_scheduler_handle;
using detail::r1::unsafe_wait;
#endif
} // namespace v1

} // namespace tbb

#endif // __TBB_global_control_H