dlls/netapi32/nbcmdqueue.c

   1 /* Copyright (c) 2003 Juan Lang
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16  */
  17 #include "config.h"
  18 #include "wine/debug.h"
  19 #include "nbcmdqueue.h"
  20
  21 WINE_DEFAULT_DEBUG_CHANNEL(netbios);
  22
  23 struct NBCmdQueue
  24 {
  25     HANDLE           heap;
  26     CRITICAL_SECTION cs;
  27     PNCB             head;
  28 };
  29
  30 #define CANCEL_EVENT_PTR(ncb) (PHANDLE)((ncb)->ncb_reserve)
  31 #define NEXT_PTR(ncb) (PNCB *)((ncb)->ncb_reserve + sizeof(HANDLE))
  32
  33 /* The reserved area of an ncb will be used for the following data:
  34  * - a cancelled flag (BOOL, 4 bytes??)
  35  * - a handle to an event that's set by a cancelled command on completion
  36  *   (HANDLE, 4 bytes)
  37  * These members are used in the following way
  38  * - on cancel, set the event member of the reserved field (with create event)
  39  * - NBCmdComplete will delete the ncb from the queue of there's no event;
  40  *   otherwise it will set the event and not delete the ncb
  41  * - cancel must lock the queue before finding the ncb in it, and can unlock it
  42  *   once it's set the event (and the cancelled flag)
  43  * - NBCmdComplete must lock the queue before attempting to remove the ncb or
  44  *   check the event
  45  * - NBCmdQueueCancelAll will lock the queue, and cancel all ncb's in the queue.
  46  *   It'll then unlock the queue, and wait on the event in the head of the queue
  47  *   until there's no more ncb's in the queue.
  48  * Space optimization: use the handle as a boolean.  NULL == 0 => not cancelled.
  49  * Non-NULL == valid handle => cancelled.  This allows storing a next pointer
  50  * in the ncb's reserved field as well, avoiding a memory alloc for a new
  51  * command (cool).
  52  */
  53
  54 struct NBCmdQueue *NBCmdQueueCreate(HANDLE heap)
  55 {
  56     struct NBCmdQueue *queue;
  57
  58     if (heap == NULL)
  59         heap = GetProcessHeap();
  60     queue = (struct NBCmdQueue *)HeapAlloc(heap, 0, sizeof(struct NBCmdQueue));
  61     if (queue)
  62     {
  63         queue->heap = heap;
  64         InitializeCriticalSection(&queue->cs);
  65         queue->head = NULL;
  66     }
  67     return queue;
  68 }
  69
  70 UCHAR NBCmdQueueAdd(struct NBCmdQueue *queue, PNCB ncb)
  71 {
  72     UCHAR ret;
  73
  74     TRACE(": queue %p, ncb %p\n", queue, ncb);
  75
  76     if (!queue)
  77         return NRC_BADDR;
  78     if (!ncb)
  79         return NRC_INVADDRESS;
  80
  81     *CANCEL_EVENT_PTR(ncb) = NULL;
  82     EnterCriticalSection(&queue->cs);
  83     *NEXT_PTR(ncb) = queue->head;
  84     queue->head = ncb;
  85     ret = NRC_GOODRET;
  86     LeaveCriticalSection(&queue->cs);
  87     TRACE("returning 0x%02x\n", ret);
  88     return ret;
  89 }
  90
  91 static PNCB *NBCmdQueueFindNBC(struct NBCmdQueue *queue, PNCB ncb)
  92 {
  93     PNCB *ret;
  94
  95     if (!queue || !ncb)
  96         ret = NULL;
  97     else
  98     {
  99         ret = &queue->head;
 100         while (ret && *ret != ncb)
 101             ret = NEXT_PTR(*ret);
 102     }
 103     return ret;
 104 }
 105
 106 UCHAR NBCmdQueueCancel(struct NBCmdQueue *queue, PNCB ncb)
 107 {
 108     UCHAR ret;
 109     PNCB *spot;
 110
 111     TRACE(": queue %p, ncb %p\n", queue, ncb);
 112
 113     if (!queue)
 114         return NRC_BADDR;
 115     if (!ncb)
 116         return NRC_INVADDRESS;
 117
 118     EnterCriticalSection(&queue->cs);
 119     spot = NBCmdQueueFindNBC(queue, ncb);
 120     if (spot)
 121     {
 122         *CANCEL_EVENT_PTR(*spot) = CreateEventW(NULL, FALSE, FALSE, NULL);
 123         WaitForSingleObject(*CANCEL_EVENT_PTR(*spot), INFINITE);
 124         CloseHandle(*CANCEL_EVENT_PTR(*spot));
 125         *spot = *NEXT_PTR(*spot);
 126         if (ncb->ncb_retcode == NRC_CMDCAN)
 127             ret = NRC_CMDCAN;
 128         else
 129             ret = NRC_CANOCCR;
 130     }
 131     else
 132         ret = NRC_INVADDRESS;
 133     LeaveCriticalSection(&queue->cs);
 134     TRACE("returning 0x%02x\n", ret);
 135     return ret;
 136 }
 137
 138 UCHAR NBCmdQueueComplete(struct NBCmdQueue *queue, PNCB ncb, UCHAR retcode)
 139 {
 140     UCHAR ret;
 141     PNCB *spot;
 142
 143     TRACE(": queue %p, ncb %p\n", queue, ncb);
 144
 145     if (!queue)
 146         return NRC_BADDR;
 147     if (!ncb)
 148         return NRC_INVADDRESS;
 149
 150     EnterCriticalSection(&queue->cs);
 151     spot = NBCmdQueueFindNBC(queue, ncb);
 152     if (spot)
 153     {
 154         if (*CANCEL_EVENT_PTR(*spot))
 155             SetEvent(*CANCEL_EVENT_PTR(*spot));
 156         else
 157             *spot = *NEXT_PTR(*spot);
 158         ret = NRC_GOODRET;
 159     }
 160     else
 161         ret = NRC_INVADDRESS;
 162     LeaveCriticalSection(&queue->cs);
 163     TRACE("returning 0x%02x\n", ret);
 164     return ret;
 165 }
 166
 167 UCHAR NBCmdQueueCancelAll(struct NBCmdQueue *queue)
 168 {
 169     UCHAR ret;
 170
 171     TRACE(": queue %p\n", queue);
 172
 173     if (!queue)
 174         return NRC_BADDR;
 175
 176     EnterCriticalSection(&queue->cs);
 177     while (queue->head)
 178     {
 179         TRACE(": waiting for ncb %p (command 0x%02x)\n", queue->head,
 180          queue->head->ncb_command);
 181         NBCmdQueueCancel(queue, queue->head);
 182     }
 183     LeaveCriticalSection(&queue->cs);
 184     ret = NRC_GOODRET;
 185     TRACE("returning 0x%02x\n", ret);
 186     return ret;
 187 }
 188
 189 void NBCmdQueueDestroy(struct NBCmdQueue *queue)
 190 {
 191     TRACE(": queue %p\n", queue);
 192
 193     if (queue)
 194     {
 195         NBCmdQueueCancelAll(queue);
 196         DeleteCriticalSection(&queue->cs);
 197         HeapFree(queue->heap, 0, queue);
 198     }
 199 }