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- /* Notification to GDB.
- Copyright (C) 1989-2022 Free Software Foundation, Inc.
- This file is part of GDB.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /* Async notifications to GDB. When the state of remote target is
- changed or something interesting to GDB happened, async
- notifications are used to tell GDB.
- Each type of notification is represented by an object
- 'struct notif_server', in which there is a queue for events to GDB
- represented by 'struct notif_event'. GDBserver writes (by means of
- 'write' field) each event in the queue into the buffer and send the
- contents in buffer to GDB. The contents in buffer is specified in
- RSP. See more in the comments to field 'queue' of
- 'struct notif_server'.
- Here is the workflow of sending events and managing queue:
- 1. At any time, when something interesting FOO happens, a object
- of 'struct notif_event' or its sub-class EVENT is created for FOO.
- 2. Enque EVENT to the 'queue' field of 'struct notif_server' for
- FOO and send corresponding notification packet to GDB if EVENT is
- the first one.
- #1 and #2 are done by function 'notif_push'.
- 3. EVENT is not deque'ed until the ack of FOO from GDB arrives.
- Before ack of FOO arrives, FOO happens again, a new object of
- EVENT is created and enque EVENT silently.
- Once GDB has a chance to ack to FOO, it sends an ack to GDBserver,
- and GDBserver repeatedly sends events to GDB and gets ack of FOO,
- until queue is empty. Then, GDBserver sends 'OK' to GDB that all
- queued notification events are done.
- # 3 is done by function 'handle_notif_ack'. */
- #include "server.h"
- #include "notif.h"
- static struct notif_server *notifs[] =
- {
- ¬if_stop,
- };
- /* Write another event or an OK, if there are no more left, to
- OWN_BUF. */
- void
- notif_write_event (struct notif_server *notif, char *own_buf)
- {
- if (!notif->queue.empty ())
- {
- struct notif_event *event = notif->queue.front ();
- notif->write (event, own_buf);
- }
- else
- write_ok (own_buf);
- }
- /* Handle the ack in buffer OWN_BUF,and packet length is PACKET_LEN.
- Return 1 if the ack is handled, and return 0 if the contents
- in OWN_BUF is not a ack. */
- int
- handle_notif_ack (char *own_buf, int packet_len)
- {
- size_t i;
- struct notif_server *np;
- for (i = 0; i < ARRAY_SIZE (notifs); i++)
- {
- const char *ack_name = notifs[i]->ack_name;
- if (startswith (own_buf, ack_name)
- && packet_len == strlen (ack_name))
- break;
- }
- if (i == ARRAY_SIZE (notifs))
- return 0;
- np = notifs[i];
- /* If we're waiting for GDB to acknowledge a pending event,
- consider that done. */
- if (!np->queue.empty ())
- {
- struct notif_event *head = np->queue.front ();
- np->queue.pop_front ();
- remote_debug_printf ("%s: acking %d", np->ack_name,
- (int) np->queue.size ());
- delete head;
- }
- notif_write_event (np, own_buf);
- return 1;
- }
- /* Put EVENT to the queue of NOTIF. */
- void
- notif_event_enque (struct notif_server *notif,
- struct notif_event *event)
- {
- notif->queue.push_back (event);
- remote_debug_printf ("pending events: %s %d", notif->notif_name,
- (int) notif->queue.size ());
- }
- /* Push one event NEW_EVENT of notification NP into NP->queue. */
- void
- notif_push (struct notif_server *np, struct notif_event *new_event)
- {
- bool is_first_event = np->queue.empty ();
- /* Something interesting. Tell GDB about it. */
- notif_event_enque (np, new_event);
- /* If this is the first stop reply in the queue, then inform GDB
- about it, by sending a corresponding notification. */
- if (is_first_event)
- {
- char buf[PBUFSIZ];
- char *p = buf;
- xsnprintf (p, PBUFSIZ, "%s:", np->notif_name);
- p += strlen (p);
- np->write (new_event, p);
- putpkt_notif (buf);
- }
- }
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