MessageQueue.c

 
#include <winpr/config.h>
 
#include <winpr/crt.h>
#include <winpr/sysinfo.h>
#include <winpr/assert.h>
 
#include <winpr/collections.h>
 
struct s_wMessageQueue
{
  size_t head;
  size_t tail;
  size_t size;
  size_t capacity;
  BOOL closed;
  wMessage* array;
  CRITICAL_SECTION lock;
  HANDLE event;
 
  wObject object;
};
 
wObject* MessageQueue_Object(wMessageQueue* queue)
{
  WINPR_ASSERT(queue);
  return &queue->object;
}
 
HANDLE MessageQueue_Event(wMessageQueue* queue)
{
  WINPR_ASSERT(queue);
  return queue->event;
}
 
size_t MessageQueue_Size(wMessageQueue* queue)
{
  WINPR_ASSERT(queue);
  EnterCriticalSection(&queue->lock);
  const size_t ret = queue->size;
  LeaveCriticalSection(&queue->lock);
  return ret;
}
 
size_t MessageQueue_Capacity(wMessageQueue* queue)
{
  WINPR_ASSERT(queue);
  EnterCriticalSection(&queue->lock);
  const size_t ret = queue->capacity;
  LeaveCriticalSection(&queue->lock);
  return ret;
}
 
BOOL MessageQueue_Wait(wMessageQueue* queue)
{
  BOOL status = FALSE;
 
  WINPR_ASSERT(queue);
  if (WaitForSingleObject(queue->event, INFINITE) == WAIT_OBJECT_0)
    status = TRUE;
 
  return status;
}
 
static BOOL MessageQueue_EnsureCapacity(wMessageQueue* queue, size_t count)
{
  BOOL res = TRUE;
  const size_t increment = 128;
  WINPR_ASSERT(queue);
 
  const size_t required = queue->size + count;
  // check for overflow
  if ((required < queue->size) || (required < count) ||
      (required > (SIZE_MAX - increment) / sizeof(wMessage)))
    return FALSE;
 
  if (required > queue->capacity)
  {
    const size_t old_capacity = queue->capacity;
    const size_t new_capacity = required + increment;
 
    wMessage* new_arr = (wMessage*)realloc(queue->array, sizeof(wMessage) * new_capacity);
    if (!new_arr)
      return FALSE;
    queue->array = new_arr;
    queue->capacity = new_capacity;
    ZeroMemory(&(queue->array[old_capacity]), (new_capacity - old_capacity) * sizeof(wMessage));
 
    /* rearrange wrapped entries:
     * fill up the newly available space and move tail
     * back by the amount of elements that have been moved to the newly
     * allocated space.
     */
    if (queue->tail <= queue->head)
    {
      size_t tocopy = queue->tail;
      size_t slots = new_capacity - old_capacity;
      const size_t batch = (tocopy < slots) ? tocopy : slots;
      CopyMemory(&(queue->array[old_capacity]), queue->array, batch * sizeof(wMessage));
 
      /* Tail is decremented. if the whole thing is appended
       * just move the existing tail by old_capacity */
      if (tocopy < slots)
      {
        ZeroMemory(queue->array, batch * sizeof(wMessage));
        queue->tail += old_capacity;
      }
      else
      {
        const size_t remain = queue->tail - batch;
        const size_t movesize = remain * sizeof(wMessage);
        res = memmove_s(queue->array, queue->tail * sizeof(wMessage), &queue->array[batch],
                        movesize) >= 0;
 
        const size_t zerooffset = remain;
        const size_t zerosize = (queue->tail - remain) * sizeof(wMessage);
        ZeroMemory(&queue->array[zerooffset], zerosize);
        queue->tail -= batch;
      }
    }
  }
 
  return res;
}
 
BOOL MessageQueue_Dispatch(wMessageQueue* queue, const wMessage* message)
{
  wMessage* dst = nullptr;
  BOOL ret = FALSE;
  WINPR_ASSERT(queue);
 
  if (!message)
    return FALSE;
 
  WINPR_ASSERT(queue);
  EnterCriticalSection(&queue->lock);
 
  if (queue->closed)
    goto out;
 
  if (!MessageQueue_EnsureCapacity(queue, 1))
    goto out;
 
  dst = &(queue->array[queue->tail]);
  *dst = *message;
  dst->time = GetTickCount64();
 
  queue->tail = (queue->tail + 1) % queue->capacity;
  queue->size++;
 
  if (queue->size > 0)
    (void)SetEvent(queue->event);
 
  if (message->id == WMQ_QUIT)
    queue->closed = TRUE;
 
  ret = TRUE;
out:
  LeaveCriticalSection(&queue->lock);
  return ret;
}
 
BOOL MessageQueue_Post(wMessageQueue* queue, void* context, UINT32 type, void* wParam, void* lParam)
{
  wMessage message = WINPR_C_ARRAY_INIT;
 
  message.context = context;
  message.id = type;
  message.wParam = wParam;
  message.lParam = lParam;
  message.Free = nullptr;
 
  return MessageQueue_Dispatch(queue, &message);
}
 
BOOL MessageQueue_PostQuit(wMessageQueue* queue, int nExitCode)
{
  return MessageQueue_Post(queue, nullptr, WMQ_QUIT, (void*)(size_t)nExitCode, nullptr);
}
 
int MessageQueue_Get(wMessageQueue* queue, wMessage* message)
{
  int status = -1;
 
  if (!MessageQueue_Wait(queue))
    return status;
 
  EnterCriticalSection(&queue->lock);
 
  if (queue->size > 0)
  {
    CopyMemory(message, &(queue->array[queue->head]), sizeof(wMessage));
    ZeroMemory(&(queue->array[queue->head]), sizeof(wMessage));
    queue->head = (queue->head + 1) % queue->capacity;
    queue->size--;
 
    if (queue->size < 1)
      (void)ResetEvent(queue->event);
 
    status = (message->id != WMQ_QUIT) ? 1 : 0;
  }
 
  LeaveCriticalSection(&queue->lock);
 
  return status;
}
 
int MessageQueue_Peek(wMessageQueue* queue, wMessage* message, BOOL remove)
{
  int status = 0;
 
  WINPR_ASSERT(queue);
  EnterCriticalSection(&queue->lock);
 
  if (queue->size > 0)
  {
    CopyMemory(message, &(queue->array[queue->head]), sizeof(wMessage));
    status = 1;
 
    if (remove)
    {
      ZeroMemory(&(queue->array[queue->head]), sizeof(wMessage));
      queue->head = (queue->head + 1) % queue->capacity;
      queue->size--;
 
      if (queue->size < 1)
      {
        if (!ResetEvent(queue->event))
          status = -1;
      }
    }
  }
 
  LeaveCriticalSection(&queue->lock);
 
  return status;
}
 
wMessageQueue* MessageQueue_New(const wObject* callback)
{
  wMessageQueue* queue = nullptr;
 
  queue = (wMessageQueue*)calloc(1, sizeof(wMessageQueue));
  if (!queue)
    return nullptr;
 
  if (!InitializeCriticalSectionAndSpinCount(&queue->lock, 4000))
    goto fail;
 
  if (!MessageQueue_EnsureCapacity(queue, 32))
    goto fail;
 
  queue->event = CreateEvent(nullptr, TRUE, FALSE, nullptr);
  if (!queue->event)
    goto fail;
 
  if (callback)
    queue->object = *callback;
 
  return queue;
 
fail:
  WINPR_PRAGMA_DIAG_PUSH
  WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC
  MessageQueue_Free(queue);
  WINPR_PRAGMA_DIAG_POP
  return nullptr;
}
 
void MessageQueue_Free(wMessageQueue* queue)
{
  if (!queue)
    return;
 
  if (queue->event)
    MessageQueue_Clear(queue);
 
  (void)CloseHandle(queue->event);
  DeleteCriticalSection(&queue->lock);
 
  free(queue->array);
  free(queue);
}
 
int MessageQueue_Clear(wMessageQueue* queue)
{
  int status = 0;
 
  WINPR_ASSERT(queue);
  WINPR_ASSERT(queue->event);
 
  EnterCriticalSection(&queue->lock);
 
  while (queue->size > 0)
  {
    wMessage* msg = &(queue->array[queue->head]);
 
    /* Free resources of message. */
    if (queue->object.fnObjectUninit)
      queue->object.fnObjectUninit(msg);
    if (queue->object.fnObjectFree)
      queue->object.fnObjectFree(msg);
 
    ZeroMemory(msg, sizeof(wMessage));
 
    queue->head = (queue->head + 1) % queue->capacity;
    queue->size--;
  }
  if (!ResetEvent(queue->event))
    status = -1;
  queue->closed = FALSE;
 
  LeaveCriticalSection(&queue->lock);
 
  return status;
}