/* Definitions used by the GDB event loop.
- Copyright 1999 Free Software Foundation, Inc.
+ Copyright (C) 1999-2020 Free Software Foundation, Inc.
Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
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 2 of the License, or
+ 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,
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, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
-/* An event loop listens for events from multiple event sources. When
+#ifndef EVENT_LOOP_H
+#define EVENT_LOOP_H
+
+/* An event loop listens for events from multiple event sources. When
an event arrives, it is queued and processed by calling the
- appropriate event handler. The event loop then continues to listen
- for more events. An event loop completes when there are no event
+ appropriate event handler. The event loop then continues to listen
+ for more events. An event loop completes when there are no event
sources to listen on. External event sources can be plugged into
the loop.
- There are 3 main components:
- - a list of file descriptors to be monitored, GDB_NOTIFIER.
- - a list of events that have occurred, EVENT_QUEUE.
+ There are 4 main components:
+ - a list of file descriptors to be monitored, GDB_NOTIFIER.
+ - a list of asynchronous event sources to be monitored,
+ ASYNC_EVENT_HANDLER_LIST.
+ - a list of events that have occurred, EVENT_QUEUE.
- a list of signal handling functions, SIGHANDLER_LIST.
- GDB_NOTIFIER keeps track of the event sources. Event sources for
- gdb are currently the UI and the target. Gdb communicates with the
- command line user interface via the readline library and usually
- communicates with remote targets via a serial port. Serial ports
- are represented in GDB as file descriptors and select/poll calls.
- For native targets instead, the communication consists of calls to
- ptrace and waits (via signals) or calls to poll/select (via file
- descriptors). In the current gdb, the code handling events related
- to the target resides in the wait_for_inferior function and in
- various target specific files (*-tdep.c).
+ GDB_NOTIFIER keeps track of the file descriptor based event
+ sources. ASYNC_EVENT_HANDLER_LIST keeps track of asynchronous
+ event sources that are signalled by some component of gdb, usually
+ a target_ops instance. Event sources for gdb are currently the UI
+ and the target. Gdb communicates with the command line user
+ interface via the readline library and usually communicates with
+ remote targets via a serial port. Serial ports are represented in
+ GDB as file descriptors and select/poll calls. For native targets
+ instead, the communication varies across operating system debug
+ APIs, but usually consists of calls to ptrace and waits (via
+ signals) or calls to poll/select (via file descriptors). In the
+ current gdb, the code handling events related to the target resides
+ in wait_for_inferior for synchronous targets; or, for asynchronous
+ capable targets, by having the target register either a target
+ controlled file descriptor and/or an asynchronous event source in
+ the event loop, with the fetch_inferior_event function as the event
+ callback. In both the synchronous and asynchronous cases, usually
+ the target event is collected through the target_wait interface.
+ The target is free to install other event sources in the event loop
+ if it so requires.
EVENT_QUEUE keeps track of the events that have happened during the
last iteration of the event loop, and need to be processed. An
functions that are invoked through traditional signal handlers.
The actions to be taken is response to such events will be executed
when the SIGHANDLER_LIST is scanned, the next time through the
- infinite loop.
+ infinite loop.
- Corollary tasks are the creation and deletion of event sources. */
+ Corollary tasks are the creation and deletion of event sources. */
typedef void *gdb_client_data;
-struct async_signal_handler;
typedef void (handler_func) (int, gdb_client_data);
-typedef void (sig_handler_func) (gdb_client_data);
typedef void (timer_handler_func) (gdb_client_data);
-/* Where to add an event onto the event queue, by queue_event. */
-typedef enum
- {
- /* Add at tail of queue. It will be processed in first in first
- out order. */
- TAIL,
- /* Add at head of queue. It will be processed in last in first out
- order. */
- HEAD
- }
-queue_position;
-
-/* Tell create_file_handler what events we are interested in.
- This is used by the select version of the event loop. */
-
-#define GDB_READABLE (1<<1)
-#define GDB_WRITABLE (1<<2)
-#define GDB_EXCEPTION (1<<3)
-
/* Exported functions from event-loop.c */
-extern void start_event_loop (void);
+extern int gdb_do_one_event (void);
extern void delete_file_handler (int fd);
-extern void add_file_handler (int fd, handler_func * proc, gdb_client_data client_data);
-extern void mark_async_signal_handler (struct async_signal_handler *async_handler_ptr);
-extern struct async_signal_handler *
- create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_data);
-extern void delete_async_signal_handler (struct async_signal_handler **async_handler_ptr);
-extern int create_timer (int milliseconds, timer_handler_func * proc, gdb_client_data client_data);
+extern void add_file_handler (int fd, handler_func *proc,
+ gdb_client_data client_data);
+extern int create_timer (int milliseconds,
+ timer_handler_func *proc,
+ gdb_client_data client_data);
extern void delete_timer (int id);
+
+/* Must be defined by client. */
+
+extern void handle_event_loop_exception (const gdb_exception &);
+
+/* Must be defined by client. Returns true if any signal handler was
+ ready. */
+
+extern int invoke_async_signal_handlers ();
+
+/* Must be defined by client. Returns true if any event handler was
+ ready. */
+
+extern int check_async_event_handlers ();
+
+#endif /* EVENT_LOOP_H */
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