Tcl/Tk (used as the Insight GUI) delegates event handling to gdb and
requires file events monitoring to be masked with READ/WRITE/EXCEPTION
flags.
Currently, gdb only uses read events, but an unused and incomplete
provision exists for such flags.
This patch adds an event mask parameter to add_file_handler, allowing
to monitor non-read file events. Its value is always given as ored-in gdb
flags, whether effectively using poll or select. This parameter defaults to
GDB_READABLE | GDB_EXCEPTION, resulting in no change for existing calls.
To unify the semantics between select and poll, POLLRDHUP
(HANGUP-sensitiveness) is also included in read events on platforms
supporting it. This is the only change in this patch that may affect
bare gdb.
This patch benefits to Insight: the latter itself does not use non-read
file events. However these must be supported for Tcl/Tk internals.
It should be noted that gdb does not support write events on the mingw
platform but checks this condition with gdb_assert. This patch does not
change this.
Flags GDB_READABLE, GDB_WRITABLE and GDB_EXCEPTION are now made globally
available through the inclusion of event-loop.h.
---
gdbsupport/event-loop.cc | 43 +++++++++++++++++++++++-----------------
gdbsupport/event-loop.h | 11 ++++++++--
2 files changed, 34 insertions(+), 20 deletions(-)
@@ -28,6 +28,11 @@
#elif defined (HAVE_SYS_POLL_H)
#include <sys/poll.h>
#endif
+#if defined (POLLRDHUP)
+#define POLL_HANGUP POLLRDHUP
+#else
+#define POLL_HANGUP 0
+#endif
#endif
#include <sys/types.h>
@@ -40,13 +45,6 @@
debug_event_loop_kind debug_event_loop;
-/* 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)
-
/* Information about each file descriptor we register with the event
loop. */
@@ -269,8 +267,14 @@ gdb_do_one_event (int mstimeout)
void
add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
- std::string &&name, bool is_ui)
+ std::string &&name, bool is_ui, int mask)
{
+ /* If no event is monitored, remove an existing handler. */
+ if ((mask & (GDB_READABLE | GDB_WRITABLE | GDB_EXCEPTION)) == 0) {
+ delete_file_handler (fd);
+ return;
+ }
+
#ifdef HAVE_POLL
if (use_poll)
{
@@ -282,25 +286,28 @@ add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
On m68k-motorola-sysv, tty's are not stream-based and not
`poll'able. */
fds.fd = fd;
- fds.events = POLLIN;
+ fds.events = 0;
+ if (mask & GDB_READABLE)
+ fds.events |= POLLIN | POLL_HANGUP;
+ if (mask & GDB_WRITABLE)
+ fds.events |= POLLOUT;
+ if (mask & GDB_EXCEPTION)
+ fds.events |= POLLPRI;
if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL))
use_poll = false;
+ else
+ create_file_handler (fd, fds.events, proc, client_data,
+ std::move (name), is_ui);
}
- if (use_poll)
- {
- create_file_handler (fd, POLLIN, proc, client_data, std::move (name),
- is_ui);
- }
- else
+ if (!use_poll)
#endif /* HAVE_POLL */
- create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION,
- proc, client_data, std::move (name), is_ui);
+ create_file_handler (fd, mask, proc, client_data, std::move (name), is_ui);
}
/* Helper for add_file_handler.
For the poll case, MASK is a combination (OR) of POLLIN,
- POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM, POLLWRBAND:
+ POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM, POLLWRBAND, POLLRDHUP:
these are the events we are interested in. If any of them occurs,
proc should be called.
@@ -70,11 +70,17 @@
Corollary tasks are the creation and deletion of event sources. */
+/* Tell add_file_handler what events we are interested in. */
+
+#define GDB_READABLE (1<<1)
+#define GDB_WRITABLE (1<<2)
+#define GDB_EXCEPTION (1<<3)
+
typedef void *gdb_client_data;
typedef void (handler_func) (int, gdb_client_data);
typedef void (timer_handler_func) (gdb_client_data);
-/* Exported functions from event-loop.c */
+/* Exported functions from event-loop.cc */
extern int gdb_do_one_event (int mstimeout = -1);
extern void delete_file_handler (int fd);
@@ -90,7 +96,8 @@ extern void delete_file_handler (int fd);
extern void add_file_handler (int fd, handler_func *proc,
gdb_client_data client_data,
- std::string &&name, bool is_ui = false);
+ std::string &&name, bool is_ui = false,
+ int mask = GDB_READABLE | GDB_EXCEPTION);
extern int create_timer (int milliseconds,
timer_handler_func *proc,