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[/] [openrisc/] [trunk/] [gnu-old/] [gdb-7.1/] [gdb/] [event-loop.h] - Blame information for rev 842

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1 227 jeremybenn
/* Definitions used by the GDB event loop.
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   Copyright (C) 1999, 2000, 2007, 2008, 2009, 2010
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   Free Software Foundation, Inc.
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   Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
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   This file is part of GDB.
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   This program is free software; you can redistribute it and/or modify
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   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3 of the License, or
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   (at your option) any later version.
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   This program is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
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   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
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/* An event loop listens for events from multiple event sources. When
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   an event arrives, it is queued and processed by calling the
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   appropriate event handler. The event loop then continues to listen
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   for more events. An event loop completes when there are no event
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   sources to listen on.  External event sources can be plugged into
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   the loop.
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   There are 4 main components:
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   - a list of file descriptors to be monitored, GDB_NOTIFIER.
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   - a list of asynchronous event sources to be monitored,
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     ASYNC_EVENT_HANDLER_LIST.
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   - a list of events that have occurred, EVENT_QUEUE.
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   - a list of signal handling functions, SIGHANDLER_LIST.
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   GDB_NOTIFIER keeps track of the file descriptor based event
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   sources.  ASYNC_EVENT_HANDLER_LIST keeps track of asynchronous
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   event sources that are signalled by some component of gdb, usually
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   a target_ops instance.  Event sources for gdb are currently the UI
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   and the target.  Gdb communicates with the command line user
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   interface via the readline library and usually communicates with
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   remote targets via a serial port.  Serial ports are represented in
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   GDB as file descriptors and select/poll calls.  For native targets
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   instead, the communication varies across operating system debug
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   APIs, but usually consists of calls to ptrace and waits (via
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   signals) or calls to poll/select (via file descriptors).  In the
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   current gdb, the code handling events related to the target resides
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   in wait_for_inferior for synchronous targets; or, for asynchronous
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   capable targets, by having the target register either a target
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   controlled file descriptor and/or an asynchronous event source in
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   the event loop, with the fetch_inferior_event function as the event
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   callback.  In both the synchronous and asynchronous cases, usually
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   the target event is collected through the target_wait interface.
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   The target is free to install other event sources in the event loop
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   if it so requires.
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   EVENT_QUEUE keeps track of the events that have happened during the
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   last iteration of the event loop, and need to be processed.  An
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   event is represented by a procedure to be invoked in order to
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   process the event.  The queue is scanned head to tail.  If the
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   event of interest is a change of state in a file descriptor, then a
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   call to poll or select will be made to detect it.
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   If the events generate signals, they are also queued by special
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   functions that are invoked through traditional signal handlers.
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   The actions to be taken is response to such events will be executed
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   when the SIGHANDLER_LIST is scanned, the next time through the
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   infinite loop.
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   Corollary tasks are the creation and deletion of event sources. */
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typedef void *gdb_client_data;
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struct async_signal_handler;
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struct async_event_handler;
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typedef void (handler_func) (int, gdb_client_data);
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typedef void (sig_handler_func) (gdb_client_data);
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typedef void (async_event_handler_func) (gdb_client_data);
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typedef void (timer_handler_func) (gdb_client_data);
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/* Where to add an event onto the event queue, by queue_event. */
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typedef enum
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  {
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    /* Add at tail of queue. It will be processed in first in first
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       out order. */
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    TAIL,
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    /* Add at head of queue. It will be processed in last in first out
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       order. */
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    HEAD
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  }
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queue_position;
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/* Tell create_file_handler what events we are interested in.
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   This is used by the select version of the event loop. */
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#define GDB_READABLE    (1<<1)
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#define GDB_WRITABLE    (1<<2)
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#define GDB_EXCEPTION   (1<<3)
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/* Exported functions from event-loop.c */
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extern void start_event_loop (void);
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extern int gdb_do_one_event (void *data);
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extern void delete_file_handler (int fd);
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extern void add_file_handler (int fd, handler_func * proc, gdb_client_data client_data);
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extern struct async_signal_handler *
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  create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_data);
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extern void delete_async_signal_handler (struct async_signal_handler **async_handler_ptr);
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extern int create_timer (int milliseconds, timer_handler_func * proc, gdb_client_data client_data);
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extern void delete_timer (int id);
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/* Call the handler from HANDLER immediately.  This function
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   runs signal handlers when returning to the event loop would be too
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   slow.  Do not call this directly; use gdb_call_async_signal_handler,
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   below, with IMMEDIATE_P == 1.  */
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void call_async_signal_handler (struct async_signal_handler *handler);
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/* Call the handler from HANDLER the next time through the event loop.
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   Do not call this directly; use gdb_call_async_signal_handler,
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   below, with IMMEDIATE_P == 0.  */
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void mark_async_signal_handler (struct async_signal_handler *handler);
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/* Wrapper for the body of signal handlers.  Call this function from
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   any SIGINT handler which needs to access GDB data structures or
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   escape via longjmp.  If IMMEDIATE_P is set, this triggers either
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   immediately (for POSIX platforms), or from gdb_select (for
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   MinGW).  If IMMEDIATE_P is clear, the handler will run the next
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   time we return to the event loop and any current select calls
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   will be interrupted.  */
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void gdb_call_async_signal_handler (struct async_signal_handler *handler,
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                                    int immediate_p);
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/* Create and register an asynchronous event source in the event loop,
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   and set PROC as its callback.  CLIENT_DATA is passed as argument to
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   PROC upon its invocation.  Returns a pointer to an opaque structure
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   used to mark as ready and to later delete this event source from
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   the event loop.  */
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extern struct async_event_handler *
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  create_async_event_handler (async_event_handler_func *proc,
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                              gdb_client_data client_data);
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/* Remove the event source pointed by HANDLER_PTR created by
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   CREATE_ASYNC_EVENT_HANDLER from the event loop, and release it.  */
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extern void
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  delete_async_event_handler (struct async_event_handler **handler_ptr);
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/* Call the handler from HANDLER the next time through the event
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   loop.  */
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extern void mark_async_event_handler (struct async_event_handler *handler);

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