gdb/gdbserver/

2012-12-15  Yao Qi  <yao@codesourcery.com>

	* Makefile.in (OBS): Add notif.o.
	* notif.c, notif.h: New.
	* server.c: Include "notif.h".
	(struct vstop_notif) <next>: Remove.
	<base>: New field.
	(queue_stop_reply): Update.
	(push_event, send_next_stop_reply): Remove.
	(discard_queued_stop_replies): Update.
	(notif_stop): New variable.
	(handle_v_stopped): Remove.
	(handle_v_requests): Don't call handle_v_stopped.  Call
	handle_ack_notif instead.
	(queue_stop_reply_callback): Call notif_event_enque instead
	of queue_stop_reply.
	(handle_status): Don't call send_next_stop_reply, call
	notif_write_event instead.
	(kill_inferior_callback): Likewise.
	(detach_or_kill_inferior_callback): Likewise.
	(main): Call initialize_notif.
	(process_serial_event): Call QUEUE_is_empty.
	(handle_target_event): Call notif_push instead of push event.
	* server.h (push_event): Remove declaration.

1 files changed, 168 insertions, 0 deletions

diff --git a/gdb/gdbserver/notif.c b/gdb/gdbserver/notif.c
new file mode 100644
index 0000000..0713b36
--- /dev/null
+++ b/gdb/gdbserver/notif.c
@@ -0,0 +1,168 @@
+/* Notification to GDB.
+   Copyright (C) 1989, 1993-1995, 1997-2000, 2002-2012 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 "notif.h"
+
+static struct notif_server *notifs[] =
+{
+  &notif_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 (!QUEUE_is_empty (notif_event_p, notif->queue))
+    {
+      struct notif_event *event
+	= QUEUE_peek (notif_event_p, notif->queue);
+
+      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)
+{
+  int i = 0;
+  struct notif_server *np = NULL;
+
+  for (i = 0; i < ARRAY_SIZE (notifs); i++)
+    {
+      np = notifs[i];
+      if (strncmp (own_buf, np->ack_name, strlen (np->ack_name)) == 0
+	  && packet_len == strlen (np->ack_name))
+	break;
+    }
+
+  if (np == NULL)
+    return 0;
+
+  /* If we're waiting for GDB to acknowledge a pending event,
+     consider that done.  */
+  if (!QUEUE_is_empty (notif_event_p, np->queue))
+    {
+      struct notif_event *head
+	= QUEUE_deque (notif_event_p, np->queue);
+
+      if (remote_debug)
+	fprintf (stderr, "%s: acking %d\n", np->ack_name,
+		 QUEUE_length (notif_event_p, np->queue));
+
+      xfree (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)
+{
+  QUEUE_enque (notif_event_p, notif->queue, event);
+
+  if (remote_debug)
+    fprintf (stderr, "pending events: %s %d\n", notif->notif_name,
+	     QUEUE_length (notif_event_p, notif->queue));
+
+}
+
+/* Push one event NEW_EVENT of notification NP into NP->queue.  */
+
+void
+notif_push (struct notif_server *np, struct notif_event *new_event)
+{
+  int is_first_event = QUEUE_is_empty (notif_event_p, np->queue);
+
+  /* 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);
+    }
+}
+
+static void
+notif_event_xfree (struct notif_event *event)
+{
+  xfree (event);
+}
+
+void
+initialize_notif (void)
+{
+  int i = 0;
+
+  for (i = 0; i < ARRAY_SIZE (notifs); i++)
+    notifs[i]->queue
+      = QUEUE_alloc (notif_event_p, notif_event_xfree);
+}