/***
 * Copyright (C) Microsoft. All rights reserved.
 * Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
 *
 * =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
 *
 * Windows specific pplx implementations
 *
 * For the latest on this and related APIs, please see: https://github.com/Microsoft/cpprestsdk
 *
 * =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 ****/

#pragma once

#if !defined(_WIN32) || _MSC_VER < 1800 || CPPREST_FORCE_PPLX

#include "cpprest/details/cpprest_compat.h"
#include "pplx/pplxinterface.h"

namespace pplx
{
namespace details
{
namespace platform
{
/// <summary>
/// Returns a unique identifier for the execution thread where this routine in invoked
/// </summary>
_PPLXIMP long __cdecl GetCurrentThreadId();

/// <summary>
/// Yields the execution of the current execution thread - typically when spin-waiting
/// </summary>
_PPLXIMP void __cdecl YieldExecution();

/// <summary>
/// Captures the callstack
/// </summary>
__declspec(noinline) _PPLXIMP size_t __cdecl CaptureCallstack(void**, size_t, size_t);

#if defined(__cplusplus_winrt)
/// <summary>
// Internal API which retrieves the next async id.
/// </summary>
_PPLXIMP unsigned int __cdecl GetNextAsyncId();
#endif
} // namespace platform

/// <summary>
/// Manual reset event
/// </summary>
class event_impl
{
public:
    static const unsigned int timeout_infinite = 0xFFFFFFFF;

    _PPLXIMP event_impl();

    _PPLXIMP ~event_impl();

    _PPLXIMP void set();

    _PPLXIMP void reset();

    _PPLXIMP unsigned int wait(unsigned int timeout);

    unsigned int wait() { return wait(event_impl::timeout_infinite); }

private:
    // Windows events
    void* _M_impl;

    event_impl(const event_impl&);                  // no copy constructor
    event_impl const& operator=(const event_impl&); // no assignment operator
};

/// <summary>
/// Mutex - lock for mutual exclusion
/// </summary>
class critical_section_impl
{
public:
    _PPLXIMP critical_section_impl();

    _PPLXIMP ~critical_section_impl();

    _PPLXIMP void lock();

    _PPLXIMP void unlock();

private:
    typedef void* _PPLX_BUFFER;

    // Windows critical section
    _PPLX_BUFFER _M_impl[8];

    critical_section_impl(const critical_section_impl&);                  // no copy constructor
    critical_section_impl const& operator=(const critical_section_impl&); // no assignment operator
};

#if _WIN32_WINNT >= _WIN32_WINNT_VISTA
/// <summary>
/// Reader writer lock
/// </summary>
class reader_writer_lock_impl
{
public:
    class scoped_lock_read
    {
    public:
        explicit scoped_lock_read(reader_writer_lock_impl& _Reader_writer_lock)
            : _M_reader_writer_lock(_Reader_writer_lock)
        {
            _M_reader_writer_lock.lock_read();
        }

        ~scoped_lock_read() { _M_reader_writer_lock.unlock(); }

    private:
        reader_writer_lock_impl& _M_reader_writer_lock;
        scoped_lock_read(const scoped_lock_read&);                  // no copy constructor
        scoped_lock_read const& operator=(const scoped_lock_read&); // no assignment operator
    };

    _PPLXIMP reader_writer_lock_impl();

    _PPLXIMP void lock();

    _PPLXIMP void lock_read();

    _PPLXIMP void unlock();

private:
    // Windows slim reader writer lock
    void* _M_impl;

    // Slim reader writer lock doesn't have a general 'unlock' method.
    // We need to track how it was acquired and release accordingly.
    // true - lock exclusive
    // false - lock shared
    bool m_locked_exclusive;
};
#endif // _WIN32_WINNT >= _WIN32_WINNT_VISTA

/// <summary>
/// Recursive mutex
/// </summary>
class recursive_lock_impl
{
public:
    recursive_lock_impl() : _M_owner(-1), _M_recursionCount(0) {}

    ~recursive_lock_impl()
    {
        _ASSERTE(_M_owner == -1);
        _ASSERTE(_M_recursionCount == 0);
    }

    void lock()
    {
        auto id = ::pplx::details::platform::GetCurrentThreadId();

        if (_M_owner == id)
        {
            _M_recursionCount++;
        }
        else
        {
            _M_cs.lock();
            _M_owner = id;
            _M_recursionCount = 1;
        }
    }

    void unlock()
    {
        _ASSERTE(_M_owner == ::pplx::details::platform::GetCurrentThreadId());
        _ASSERTE(_M_recursionCount >= 1);

        _M_recursionCount--;

        if (_M_recursionCount == 0)
        {
            _M_owner = -1;
            _M_cs.unlock();
        }
    }

private:
    pplx::details::critical_section_impl _M_cs;
    long _M_recursionCount;
    volatile long _M_owner;
};

class windows_scheduler : public pplx::scheduler_interface
{
public:
    _PPLXIMP virtual void schedule(TaskProc_t proc, _In_ void* param);
};

} // namespace details

/// <summary>
///  A generic RAII wrapper for locks that implement the critical_section interface
///  std::lock_guard
/// </summary>
template<class _Lock>
class scoped_lock
{
public:
    explicit scoped_lock(_Lock& _Critical_section) : _M_critical_section(_Critical_section)
    {
        _M_critical_section.lock();
    }

    ~scoped_lock() { _M_critical_section.unlock(); }

private:
    _Lock& _M_critical_section;

    scoped_lock(const scoped_lock&);                  // no copy constructor
    scoped_lock const& operator=(const scoped_lock&); // no assignment operator
};

// The extensibility namespace contains the type definitions that are used internally
namespace extensibility
{
typedef ::pplx::details::event_impl event_t;

typedef ::pplx::details::critical_section_impl critical_section_t;
typedef scoped_lock<critical_section_t> scoped_critical_section_t;

#if _WIN32_WINNT >= _WIN32_WINNT_VISTA
typedef ::pplx::details::reader_writer_lock_impl reader_writer_lock_t;
typedef scoped_lock<reader_writer_lock_t> scoped_rw_lock_t;
typedef reader_writer_lock_t::scoped_lock_read scoped_read_lock_t;
#endif // _WIN32_WINNT >= _WIN32_WINNT_VISTA

typedef ::pplx::details::recursive_lock_impl recursive_lock_t;
typedef scoped_lock<recursive_lock_t> scoped_recursive_lock_t;
} // namespace extensibility

/// <summary>
/// Default scheduler type
/// </summary>
typedef details::windows_scheduler default_scheduler_t;

namespace details
{
/// <summary>
/// Terminate the process due to unhandled exception
/// </summary>

#ifndef _REPORT_PPLTASK_UNOBSERVED_EXCEPTION
#define _REPORT_PPLTASK_UNOBSERVED_EXCEPTION()                                                                         \
    do                                                                                                                 \
    {                                                                                                                  \
        __debugbreak();                                                                                                \
        std::terminate();                                                                                              \
    } while (false)
#endif // _REPORT_PPLTASK_UNOBSERVED_EXCEPTION

} // namespace details

} // namespace pplx

#endif