coroutine-win32.c

   1 /*
   2  * Win32 coroutine initialization code
   3  *
   4  * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "qemu-common.h"
  26 #include "block/coroutine_int.h"
  27
  28 typedef struct
  29 {
  30     Coroutine base;
  31
  32     LPVOID fiber;
  33     CoroutineAction action;
  34 } CoroutineWin32;
  35
  36 static __thread CoroutineWin32 leader;
  37 static __thread Coroutine *current;
  38
  39 CoroutineAction qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
  40                                       CoroutineAction action)
  41 {
  42     CoroutineWin32 *from = DO_UPCAST(CoroutineWin32, base, from_);
  43     CoroutineWin32 *to = DO_UPCAST(CoroutineWin32, base, to_);
  44
  45     g_assert(current == from_);
  46     current = to_;
  47
  48     to->action = action;
  49     SwitchToFiber(to->fiber);
  50     return from->action;
  51 }
  52
  53 static void CALLBACK coroutine_trampoline(void *co_)
  54 {
  55     Coroutine *co = co_;
  56
  57     while (true) {
  58         co->entry(co->entry_arg);
  59         qemu_coroutine_switch(co, co->caller, COROUTINE_TERMINATE);
  60     }
  61 }
  62
  63 Coroutine *qemu_coroutine_new(void)
  64 {
  65     const size_t stack_size = 1 << 20;
  66     CoroutineWin32 *co;
  67
  68     co = g_malloc0(sizeof(*co));
  69     co->fiber = CreateFiber(stack_size, coroutine_trampoline, &co->base);
  70     return &co->base;
  71 }
  72
  73 void qemu_coroutine_delete(Coroutine *co_)
  74 {
  75     CoroutineWin32 *co = DO_UPCAST(CoroutineWin32, base, co_);
  76
  77     DeleteFiber(co->fiber);
  78     g_free(co);
  79 }
  80
  81 Coroutine *qemu_coroutine_self(void)
  82 {
  83     if (!current) {
  84         current = &leader.base;
  85         leader.fiber = ConvertThreadToFiber(NULL);
  86     }
  87     return current;
  88 }
  89
  90 bool qemu_in_coroutine(void)
  91 {
  92     return current && current->caller;
  93 }