/*      $NetBSD: event_iocp.c,v 1.1.1.4 2021/04/07 02:43:14 christos Exp $      */
/*
* Copyright (c) 2009-2012 Niels Provos, Nick Mathewson
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "evconfig-private.h"

#ifndef _WIN32_WINNT
/* Minimum required for InitializeCriticalSectionAndSpinCount */
#define _WIN32_WINNT 0x0403
#endif
#include <winsock2.h>
#include <windows.h>
#include <process.h>
#include <stdio.h>
#include <mswsock.h>

#include "event2/util.h"
#include "util-internal.h"
#include "iocp-internal.h"
#include "log-internal.h"
#include "mm-internal.h"
#include "event-internal.h"
#include "evthread-internal.h"

#define NOTIFICATION_KEY ((ULONG_PTR)-1)

void
event_overlapped_init_(struct event_overlapped *o, iocp_callback cb)
{
       memset(o, 0, sizeof(struct event_overlapped));
       o->cb = cb;
}

static void
handle_entry(OVERLAPPED *o, ULONG_PTR completion_key, DWORD nBytes, int ok)
{
       struct event_overlapped *eo =
           EVUTIL_UPCAST(o, struct event_overlapped, overlapped);
       eo->cb(eo, completion_key, nBytes, ok);
}

static void
loop(void *port_)
{
       struct event_iocp_port *port = port_;
       long ms = port->ms;
       HANDLE p = port->port;

       if (ms <= 0)
               ms = INFINITE;

       while (1) {
               OVERLAPPED *overlapped=NULL;
               ULONG_PTR key=0;
               DWORD bytes=0;
               int ok = GetQueuedCompletionStatus(p, &bytes, &key,
                       &overlapped, ms);
               EnterCriticalSection(&port->lock);
               if (port->shutdown) {
                       if (--port->n_live_threads == 0)
                               ReleaseSemaphore(port->shutdownSemaphore, 1,
                                               NULL);
                       LeaveCriticalSection(&port->lock);
                       return;
               }
               LeaveCriticalSection(&port->lock);

               if (key != NOTIFICATION_KEY && overlapped)
                       handle_entry(overlapped, key, bytes, ok);
               else if (!overlapped)
                       break;
       }
       event_warnx("GetQueuedCompletionStatus exited with no event.");
       EnterCriticalSection(&port->lock);
       if (--port->n_live_threads == 0)
               ReleaseSemaphore(port->shutdownSemaphore, 1, NULL);
       LeaveCriticalSection(&port->lock);
}

int
event_iocp_port_associate_(struct event_iocp_port *port, evutil_socket_t fd,
   ev_uintptr_t key)
{
       HANDLE h;
       h = CreateIoCompletionPort((HANDLE)fd, port->port, key, port->n_threads);
       if (!h)
               return -1;
       return 0;
}

static void *
get_extension_function(SOCKET s, const GUID *which_fn)
{
       void *ptr = NULL;
       DWORD bytes=0;
       WSAIoctl(s, SIO_GET_EXTENSION_FUNCTION_POINTER,
           (GUID*)which_fn, sizeof(*which_fn),
           &ptr, sizeof(ptr),
           &bytes, NULL, NULL);

       /* No need to detect errors here: if ptr is set, then we have a good
          function pointer.  Otherwise, we should behave as if we had no
          function pointer.
       */
       return ptr;
}

/* Mingw doesn't have these in its mswsock.h.  The values are copied from
  wine.h.   Perhaps if we copy them exactly, the cargo will come again.
*/
#ifndef WSAID_ACCEPTEX
#define WSAID_ACCEPTEX \
       {0xb5367df1,0xcbac,0x11cf,{0x95,0xca,0x00,0x80,0x5f,0x48,0xa1,0x92}}
#endif
#ifndef WSAID_CONNECTEX
#define WSAID_CONNECTEX \
       {0x25a207b9,0xddf3,0x4660,{0x8e,0xe9,0x76,0xe5,0x8c,0x74,0x06,0x3e}}
#endif
#ifndef WSAID_GETACCEPTEXSOCKADDRS
#define WSAID_GETACCEPTEXSOCKADDRS \
       {0xb5367df2,0xcbac,0x11cf,{0x95,0xca,0x00,0x80,0x5f,0x48,0xa1,0x92}}
#endif

static int extension_fns_initialized = 0;

static void
init_extension_functions(struct win32_extension_fns *ext)
{
       const GUID acceptex = WSAID_ACCEPTEX;
       const GUID connectex = WSAID_CONNECTEX;
       const GUID getacceptexsockaddrs = WSAID_GETACCEPTEXSOCKADDRS;
       SOCKET s = socket(AF_INET, SOCK_STREAM, 0);
       if (s == EVUTIL_INVALID_SOCKET)
               return;
       ext->AcceptEx = get_extension_function(s, &acceptex);
       ext->ConnectEx = get_extension_function(s, &connectex);
       ext->GetAcceptExSockaddrs = get_extension_function(s,
           &getacceptexsockaddrs);
       closesocket(s);

       extension_fns_initialized = 1;
}

static struct win32_extension_fns the_extension_fns;

const struct win32_extension_fns *
event_get_win32_extension_fns_(void)
{
       return &the_extension_fns;
}

#define N_CPUS_DEFAULT 2

struct event_iocp_port *
event_iocp_port_launch_(int n_cpus)
{
       struct event_iocp_port *port;
       int i;

       if (!extension_fns_initialized)
               init_extension_functions(&the_extension_fns);

       if (!(port = mm_calloc(1, sizeof(struct event_iocp_port))))
               return NULL;

       if (n_cpus <= 0)
               n_cpus = N_CPUS_DEFAULT;
       port->n_threads = n_cpus * 2;
       port->threads = mm_calloc(port->n_threads, sizeof(HANDLE));
       if (!port->threads)
               goto err;

       port->port = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0,
                       n_cpus);
       port->ms = -1;
       if (!port->port)
               goto err;

       port->shutdownSemaphore = CreateSemaphore(NULL, 0, 1, NULL);
       if (!port->shutdownSemaphore)
               goto err;

       for (i=0; i<port->n_threads; ++i) {
               ev_uintptr_t th = _beginthread(loop, 0, port);
               if (th == (ev_uintptr_t)-1)
                       goto err;
               port->threads[i] = (HANDLE)th;
               ++port->n_live_threads;
       }

       InitializeCriticalSectionAndSpinCount(&port->lock, 1000);

       return port;
err:
       if (port->port)
               CloseHandle(port->port);
       if (port->threads)
               mm_free(port->threads);
       if (port->shutdownSemaphore)
               CloseHandle(port->shutdownSemaphore);
       mm_free(port);
       return NULL;
}

static void
event_iocp_port_unlock_and_free_(struct event_iocp_port *port)
{
       DeleteCriticalSection(&port->lock);
       CloseHandle(port->port);
       CloseHandle(port->shutdownSemaphore);
       mm_free(port->threads);
       mm_free(port);
}

static int
event_iocp_notify_all(struct event_iocp_port *port)
{
       int i, r, ok=1;
       for (i=0; i<port->n_threads; ++i) {
               r = PostQueuedCompletionStatus(port->port, 0, NOTIFICATION_KEY,
                   NULL);
               if (!r)
                       ok = 0;
       }
       return ok ? 0 : -1;
}

int
event_iocp_shutdown_(struct event_iocp_port *port, long waitMsec)
{
       DWORD ms = INFINITE;
       int n;

       EnterCriticalSection(&port->lock);
       port->shutdown = 1;
       LeaveCriticalSection(&port->lock);
       event_iocp_notify_all(port);

       if (waitMsec >= 0)
               ms = waitMsec;

       WaitForSingleObject(port->shutdownSemaphore, ms);
       EnterCriticalSection(&port->lock);
       n = port->n_live_threads;
       LeaveCriticalSection(&port->lock);
       if (n == 0) {
               event_iocp_port_unlock_and_free_(port);
               return 0;
       } else {
               return -1;
       }
}

int
event_iocp_activate_overlapped_(
   struct event_iocp_port *port, struct event_overlapped *o,
   ev_uintptr_t key, ev_uint32_t n)
{
       BOOL r;

       r = PostQueuedCompletionStatus(port->port, n, key, &o->overlapped);
       return (r==0) ? -1 : 0;
}

struct event_iocp_port *
event_base_get_iocp_(struct event_base *base)
{
#ifdef _WIN32
       return base->iocp;
#else
       return NULL;
#endif
}