[RFC 12/17] Add the ability to stop the event loop

[Tom Tromey <tom@tromey.com>]

gdbserver needs a way to stop the event loop.  This patch adds it.

gdb/ChangeLog
2019-02-24  Tom Tromey  <tom@tromey.com>

	* common/event-loop.h (stop_event_loop): Declare.
	* common/event-loop.c (event_looping): New global.
	(start_event_loop): Check it.
	(stop_event_loop): New function.
---
 gdb/ChangeLog           |  7 +++++++
 gdb/common/event-loop.c | 13 ++++++++++++-
 gdb/common/event-loop.h |  5 +++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/gdb/common/event-loop.c b/gdb/common/event-loop.c
index a2563414dfd..b8d5b007163 100644
--- a/gdb/common/event-loop.c
+++ b/gdb/common/event-loop.c
@@ -256,6 +256,8 @@ gdb_do_one_event (void)
   return 1;
 }
 
+static bool event_looping = true;
+
 /* Start up the event loop.  This is the entry point to the event loop
    from the command loop.  */
 
@@ -266,7 +268,8 @@ start_event_loop ()
      the event loop engine.  gdb_do_one_event will process one event
      for each invocation.  It blocks waiting for an event and then
      processes it.  */
-  while (1)
+  event_looping = true;
+  while (event_looping)
     {
       int result = 0;
 
@@ -288,6 +291,14 @@ start_event_loop ()
      to listen to.  So we exit GDB.  */
   return;
 }
+
+/* See event-loop.h.  */
+
+void
+stop_event_loop ()
+{
+  event_looping = false;
+}
 \f
 
 /* Wrapper function for create_file_handler, so that the caller
diff --git a/gdb/common/event-loop.h b/gdb/common/event-loop.h
index 1eec1ed2cd9..9ace0c46f6c 100644
--- a/gdb/common/event-loop.h
+++ b/gdb/common/event-loop.h
@@ -79,6 +79,11 @@ typedef void (timer_handler_func) (gdb_client_data);
 /* Exported functions from event-loop.c */
 
 extern void start_event_loop ();
+
+/* Request that the event loop stop.  */
+
+extern void stop_event_loop ();
+
 extern int gdb_do_one_event (void);
 extern void delete_file_handler (int fd);
 extern void add_file_handler (int fd, handler_func *proc, 
-- 
2.17.2