Changes in uspace/lib/c/generic/async.c [f302586:ab9f443] in mainline

File:

• uspace/lib/c/generic/async.c (modified) (16 diffs)

uspace/lib/c/generic/async.c

@@ -189 +189 @@
         /** If reply was received. */
         bool done;
+
+        /** If the message / reply should be discarded on arrival. */
+        bool forget;
+
+        /** If already destroyed. */
+        bool destroyed;
         
         /** Pointer to where the answer data is stored. */
@@ -240 +246 @@
 /** Identifier of the incoming connection handled by the current fibril. */
 static fibril_local connection_t *fibril_connection;
+
+static void to_event_initialize(to_event_t *to)
+{
+        struct timeval tv = { 0 };
+
+        to->inlist = false;
+        to->occurred = false;
+        link_initialize(&to->link);
+        to->expires = tv;
+}
+
+static void wu_event_initialize(wu_event_t *wu)
+{
+        wu->inlist = false;
+        link_initialize(&wu->link);
+}
+
+void awaiter_initialize(awaiter_t *aw)
+{
+        aw->fid = 0;
+        aw->active = false;
+        to_event_initialize(&aw->to_event);
+        wu_event_initialize(&aw->wu_event);
+}
+
+static amsg_t *amsg_create(void)
+{
+        amsg_t *msg;
+
+        msg = malloc(sizeof(amsg_t));
+        if (msg) {
+                msg->done = false;
+                msg->forget = false;
+                msg->destroyed = false;
+                msg->dataptr = NULL;
+                msg->retval = (sysarg_t) EINVAL;
+                awaiter_initialize(&msg->wdata);
+        }
+
+        return msg;
+}
+
+static void amsg_destroy(amsg_t *msg)
+{
+        assert(!msg->destroyed);
+        msg->destroyed = true;
+        free(msg);
+}
 
 static void *default_client_data_constructor(void)
@@ -1100 +1154 @@
         
         msg->done = true;
-        if (!msg->wdata.active) {
+
+        if (msg->forget) {
+                assert(msg->wdata.active);
+                amsg_destroy(msg);
+        } else if (!msg->wdata.active) {
                 msg->wdata.active = true;
                 fibril_add_ready(msg->wdata.fid);
         }
-        
+
         futex_up(&async_futex);
 }
@@ -1131 +1189 @@
                 return 0;
         
-        amsg_t *msg = malloc(sizeof(amsg_t));
+        amsg_t *msg = amsg_create();
         if (msg == NULL)
                 return 0;
         
-        msg->done = false;
         msg->dataptr = dataptr;
-        
-        msg->wdata.to_event.inlist = false;
-        
-        /*
-         * We may sleep in the next method,
-         * but it will use its own means
-         */
         msg->wdata.active = true;
         
@@ -1177 +1227 @@
                 return 0;
         
-        amsg_t *msg = malloc(sizeof(amsg_t));
-        
+        amsg_t *msg = amsg_create();
         if (msg == NULL)
                 return 0;
         
-        msg->done = false;
         msg->dataptr = dataptr;
-        
-        msg->wdata.to_event.inlist = false;
-        
-        /*
-         * We may sleep in the next method,
-         * but it will use its own means
-         */
         msg->wdata.active = true;
         
@@ -1213 +1254 @@
         
         futex_down(&async_futex);
+
+        assert(!msg->forget);
+        assert(!msg->destroyed);
+
         if (msg->done) {
                 futex_up(&async_futex);
@@ -1231 +1276 @@
                 *retval = msg->retval;
         
-        free(msg);
+        amsg_destroy(msg);
 }
 
 /** Wait for a message sent by the async framework, timeout variant.
+ *
+ * If the wait times out, the caller may choose to either wait again by calling
+ * async_wait_for() or async_wait_timeout(), or forget the message via
+ * async_forget().
  *
  * @param amsgid  Hash of the message to wait for.
@@ -1255 +1304 @@
         
         futex_down(&async_futex);
+
+        assert(!msg->forget);
+        assert(!msg->destroyed);
+
         if (msg->done) {
                 futex_up(&async_futex);
@@ -1279 +1332 @@
                 *retval = msg->retval;
         
-        free(msg);
+        amsg_destroy(msg);
         
         return 0;
 }
+ 
+/** Discard the message / reply on arrival.
+ *
+ * The message will be marked to be discarded once the reply arrives in
+ * reply_received(). It is not allowed to call async_wait_for() or
+ * async_wait_timeout() on this message after a call to this function.
+ *
+ * @param amsgid  Hash of the message to forget.
+ */
+void async_forget(aid_t amsgid)
+{
+        amsg_t *msg = (amsg_t *) amsgid;
+
+        assert(msg);
+        assert(!msg->forget);
+        assert(!msg->destroyed);
+
+        futex_down(&async_futex);
+        if (msg->done)
+                amsg_destroy(msg);
+        else 
+                msg->forget = true;
+        futex_up(&async_futex);
+}
 
 /** Wait for specified time.
@@ -1293 +1370 @@
 void async_usleep(suseconds_t timeout)
 {
-        amsg_t *msg = malloc(sizeof(amsg_t));
-        
+        amsg_t *msg = amsg_create();
         if (!msg)
                 return;
         
         msg->wdata.fid = fibril_get_id();
-        msg->wdata.active = false;
         
         gettimeofday(&msg->wdata.to_event.expires, NULL);
@@ -1313 +1388 @@
         /* Futex is up automatically after fibril_switch() */
         
-        free(msg);
+        amsg_destroy(msg);
 }
 
@@ -1584 +1659 @@
         ipc_call_t result;
         
-        amsg_t *msg = malloc(sizeof(amsg_t));
-        if (msg == NULL) {
+        amsg_t *msg = amsg_create();
+        if (!msg) {
                 free(sess);
                 errno = ENOMEM;
@@ -1591 +1666 @@
         }
         
-        msg->done = false;
         msg->dataptr = &result;
-        
-        msg->wdata.to_event.inlist = false;
-        
-        /*
-         * We may sleep in the next method,
-         * but it will use its own means
-         */
         msg->wdata.active = true;
         
@@ -1643 +1710 @@
         ipc_call_t result;
         
-        amsg_t *msg = malloc(sizeof(amsg_t));
-        if (msg == NULL)
+        amsg_t *msg = amsg_create();
+        if (!msg)
                 return ENOENT;
         
-        msg->done = false;
         msg->dataptr = &result;
-        
-        msg->wdata.to_event.inlist = false;
-        
-        /*
-         * We may sleep in the next method,
-         * but it will use its own means
-         */
         msg->wdata.active = true;
         
@@ -2251 +2310 @@
             IPC_FF_ROUTE_FROM_ME);
         if (retval != EOK) {
-                async_wait_for(msg, NULL);
+                async_forget(msg);
                 ipc_answer_0(callid, retval);
                 return retval;
@@ -2445 +2504 @@
             IPC_FF_ROUTE_FROM_ME);
         if (retval != EOK) {
-                async_wait_for(msg, NULL);
+                async_forget(msg);
                 ipc_answer_0(callid, retval);
                 return retval;