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allegro/src/win winput.c,1.1,1.2 wwnd.c,1.55,1.56
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From: <ebo...@us...> - 2002-09-08 16:42:52
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Update of /cvsroot/alleg/allegro/src/win
In directory usw-pr-cvs1:/tmp/cvs-serv5551/src/win
Modified Files:
winput.c wwnd.c
Log Message:
Fixed a race condition when registering input events
Index: winput.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/win/winput.c,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -d -r1.1 -r1.2
--- winput.c 27 May 2002 14:21:32 -0000 1.1
+++ winput.c 8 Sep 2002 16:42:48 -0000 1.2
@@ -29,19 +29,26 @@
#endif
-#define MAX_EVENTS 4
+#define MAX_EVENTS 8
+/* input thread event queue */
int input_events;
-HANDLE input_event_id[MAX_EVENTS]; /* event #0 is reserved */
+HANDLE input_event_id[MAX_EVENTS];
void (*input_event_handler[MAX_EVENTS])(void);
+/* pending event waiting for being processed */
+static HANDLE pending_event_id;
+static void (*pending_event_handler)(void);
+
+/* internal input thread management */
+static HANDLE ack_event = NULL;
+static int reserved_events = 0;
static int input_need_thread = FALSE;
static HANDLE input_thread = NULL;
-static int input_thread_suicide = FALSE;
-/* input_thread_proc:
+/* input_thread_proc: [input thread]
* Thread function that handles the input when there is
* no dedicated window thread because the library has
* been attached to an external window.
@@ -56,17 +63,10 @@
/* event loop */
while (TRUE) {
result = WaitForMultipleObjects(input_events, input_event_id, FALSE, INFINITE);
- if (result == WAIT_OBJECT_0) {
- /* we were instructed to unblock, make sure we can block again */
- _enter_critical();
- _exit_critical();
- if (input_thread_suicide)
- return;
- }
- else if ((result > WAIT_OBJECT_0) && (result < WAIT_OBJECT_0 + input_events)) {
- /* one of the registered events is in signaled state */
+ if (result == WAIT_OBJECT_0 + 2)
+ break; /* thread suicide */
+ else if ((result >= WAIT_OBJECT_0) && (result < WAIT_OBJECT_0 + input_events))
(*input_event_handler[result - WAIT_OBJECT_0])();
- }
}
_TRACE("input thread exits\n");
@@ -75,105 +75,148 @@
-/* input_register_event:
- * Adds an event to the input thread event queue.
+/* register_pending_event: [input thread]
+ * Registers effectively the pending event.
*/
-int input_register_event(HANDLE event_id, void (*event_handler)(void))
+static void register_pending_event(void)
{
- if (input_events == MAX_EVENTS)
- return -1;
+ /* add the pending event to the queue */
+ input_event_id[input_events] = pending_event_id;
+ input_event_handler[input_events] = pending_event_handler;
- _enter_critical();
+ /* adjust the size of the queue */
+ input_events++;
- /* unblock the input thread if any */
- if (!input_need_thread || input_thread)
- SetEvent(input_event_id[0]);
+ /* acknowledge the registration */
+ SetEvent(ack_event);
+}
- /* effectively add */
- input_event_id[input_events] = event_id;
- input_event_handler[input_events] = event_handler;
- /* adjust the size of the queue */
- input_events++;
- /* create input thread if none */
- if (input_need_thread && !input_thread) {
- input_thread = (HANDLE) _beginthread(input_thread_proc, 0, NULL);
- input_thread_suicide = FALSE;
+/* unregister_pending_event: [input thread]
+ * Unregisters effectively the pending event.
+ */
+static void unregister_pending_event(void)
+{
+ int i, found = -1;
+
+ /* look for the pending event in the event queue */
+ for (i=reserved_events; i<input_events; i++) {
+ if (input_event_id[i] == pending_event_id) {
+ found = i;
+ break;
+ }
}
- _exit_critical();
+ if (found >= 0) {
+ /* shift the queue to the left */
+ for (i=found; i<input_events-1; i++) {
+ input_event_id[i] = input_event_id[i+1];
+ input_event_handler[i] = input_event_handler[i+1];
+ }
- _TRACE("1 input event registered (total = %d)\n", input_events-1);
- return 0;
+ /* adjust the size of the queue */
+ input_events--;
+ }
+
+ /* acknowledge the unregistration */
+ SetEvent(ack_event);
}
-/* input_unregister_event:
- * Removes an event from the input thread event queue.
+/* input_register_event: [primary thread]
+ * Adds an event to the input thread event queue.
*/
-void input_unregister_event(HANDLE event_id)
+int input_register_event(HANDLE event_id, void (*event_handler)(void))
{
- int i, base;
-
- /* look for the requested event */
- for (i=1; i<input_events; i++) /* event #0 is reserved */
- if (input_event_id[i] == event_id) {
- base = i;
- goto Found;
- }
+ if (input_events == MAX_EVENTS)
+ return -1;
- return;
+ /* record the event */
+ pending_event_id = event_id;
+ pending_event_handler = event_handler;
- Found:
- _enter_critical();
+ /* create the input thread if none */
+ if (input_need_thread && !input_thread)
+ input_thread = (HANDLE) _beginthread(input_thread_proc, 0, NULL);
- /* unblock the input thread */
+ /* ask the input thread to register the pending event */
SetEvent(input_event_id[0]);
- /* shift the queue to the left if needed */
- for (i=base; i<input_events-1; i++) {
- input_event_id[i] = input_event_id[i+1];
- input_event_handler[i] = input_event_handler[i+1];
- }
+ /* wait for the input thread to acknowledge */
+ WaitForSingleObject(ack_event, INFINITE);
- /* adjust the size of the queue */
- input_events--;
+ _TRACE("1 input event registered (total = %d)\n", input_events-reserved_events);
+ return 0;
+}
- /* kill input thread if no more event */
- if ((input_events == 1) && input_thread) {
- input_thread_suicide = TRUE;
+
+
+/* input_unregister_event: [primary thread]
+ * Removes an event from the input thread event queue.
+ */
+void input_unregister_event(HANDLE event_id)
+{
+ /* record the event */
+ pending_event_id = event_id;
+
+ /* ask the input thread to unregister the pending event */
+ SetEvent(input_event_id[1]);
+
+ /* wait for the input thread to acknowledge */
+ WaitForSingleObject(ack_event, INFINITE);
+
+ /* kill the input thread if no more event */
+ if (input_need_thread && (input_events == reserved_events)) {
+ SetEvent(input_event_id[2]); /* thread suicide */
input_thread = NULL;
}
- _exit_critical();
-
- _TRACE("1 input event unregistered (total = %d)\n", input_events-1);
+ _TRACE("1 input event unregistered (total = %d)\n", input_events-reserved_events);
}
-/* input_init:
+/* input_init: [primary thread]
* Initializes the module.
*/
void input_init(int need_thread)
{
- input_need_thread = need_thread;
-
- /* event #0 is reserved by the module */
input_event_id[0] = CreateEvent(NULL, FALSE, FALSE, NULL);
- input_event_handler[0] = NULL;
- input_events = 1;
+ input_event_handler[0] = register_pending_event;
+ input_event_id[1] = CreateEvent(NULL, FALSE, FALSE, NULL);
+ input_event_handler[1] = unregister_pending_event;
+
+ if (need_thread) {
+ input_need_thread = TRUE;
+ input_event_id[2] = CreateEvent(NULL, FALSE, FALSE, NULL);
+ reserved_events = 3;
+ }
+ else {
+ input_need_thread = FALSE;
+ reserved_events = 2;
+ }
+
+ input_events = reserved_events;
+
+ ack_event = CreateEvent(NULL, FALSE, FALSE, NULL);
}
-/* input_exit:
+/* input_exit: [primary thread]
* Shuts down the module.
*/
void input_exit(void)
{
- CloseHandle(input_event_id[0]);
+ int i;
+
+ for (i=0; i<reserved_events; i++)
+ CloseHandle(input_event_id[i]);
+
+ input_events = 0;
+
+ CloseHandle(ack_event);
}
Index: wwnd.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/win/wwnd.c,v
retrieving revision 1.55
retrieving revision 1.56
diff -u -d -r1.55 -r1.56
--- wwnd.c 22 Aug 2002 13:35:03 -0000 1.55
+++ wwnd.c 8 Sep 2002 16:42:48 -0000 1.56
@@ -508,12 +508,7 @@
/* message loop */
while (TRUE) {
result = MsgWaitForMultipleObjects(input_events, input_event_id, FALSE, INFINITE, QS_ALLINPUT);
- if (result == WAIT_OBJECT_0) {
- /* we were instructed to unblock, make sure we can block again */
- _enter_critical();
- _exit_critical();
- }
- else if ((result > WAIT_OBJECT_0) && (result < WAIT_OBJECT_0 + input_events)) {
+ if ((result >= WAIT_OBJECT_0) && (result < WAIT_OBJECT_0 + input_events)) {
/* one of the registered events is in signaled state */
(*input_event_handler[result - WAIT_OBJECT_0])();
}
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