Simplify target_async hook interface

All callers of target_async pass it the same callback
(inferior_event_handler).  Since both common code and target backends
need to be able to put the target in and out of target async mode at
any given time, there's really no way that a different callback could
be passed.  This commit simplifies things, and removes the indirection
altogether.  Bonus: with this, gdb's target_async method ends up with
the same signature as gdbserver's.

Tested on x86_64 Fedora 20, native and gdbserver.

gdb/ChangeLog:
2015-03-25  Pedro Alves  <palves@redhat.com>

	* target.h <to_async>: Replace 'callback' and 'context' parameters
	with boolean 'enable' parameter.
	(target_async): Replace CALLBACK and CONTEXT parameters with
	boolean ENABLE parameter.
	* inf-loop.c (inferior_event_handler): Adjust.
	* linux-nat.c (linux_nat_attach, linux_nat_resume)
	(linux_nat_resume): Adjust.
	(async_client_callback, async_client_context): Delete.
	(handle_target_event): Call inferior_event_handler directly.
	(linux_nat_async): Replace 'callback' and 'context' parameters
	with boolean 'enable' parameter.  Adjust.  Remove references to
	async_client_callback and async_client_context.
	(linux_nat_close): Adjust.
	* record-btrace.c (record_btrace_async): Replace 'callback' and
	'context' parameters with boolean 'enable' parameter.  Adjust.
	(record_btrace_resume): Adjust.
	* record-full.c (record_full_async): Replace 'callback' and
	'context' parameters with boolean 'enable' parameter.  Adjust.
	(record_full_resume, record_full_core_resume): Adjust.
	* remote.c (struct remote_state) <async_client_callback,
	async_client_context>: Delete fields.
	(remote_start_remote, extended_remote_attach_1, remote_resume)
	(extended_remote_create_inferior): Adjust.
	(remote_async_serial_handler): Call inferior_event_handler
	directly.
	(remote_async): Replace 'callback' and 'context' parameters with
	boolean 'enable' parameter.  Adjust.
	* top.c (gdb_readline_wrapper_cleanup, gdb_readline_wrapper):
	Adjust.
	* target-delegates.c: Regenerate.

1 files changed, 7 insertions, 18 deletions

diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 660dc8f..0376299 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1341,7 +1341,7 @@ linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
 				  attach_proc_task_lwp_callback);
 
   if (target_can_async_p ())
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 }
 
 /* Get pending status of LP.  */
@@ -1789,7 +1789,7 @@ linux_nat_resume (struct target_ops *ops,
 
       if (target_can_async_p ())
 	{
-	  target_async (inferior_event_handler, 0);
+	  target_async (1);
 	  /* Tell the event loop we have something to process.  */
 	  async_file_mark ();
 	}
@@ -1810,7 +1810,7 @@ linux_nat_resume (struct target_ops *ops,
   linux_resume_one_lwp (lp, step, signo);
 
   if (target_can_async_p ())
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 }
 
 /* Send a signal to an LWP.  */
@@ -4625,10 +4625,6 @@ linux_nat_terminal_ours (struct target_ops *self)
   async_terminal_is_ours = 1;
 }
 
-static void (*async_client_callback) (enum inferior_event_type event_type,
-				      void *context);
-static void *async_client_context;
-
 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
    so we notice when any child changes state, and notify the
    event-loop; it allows us to use sigsuspend in linux_nat_wait_1
@@ -4656,7 +4652,7 @@ sigchld_handler (int signo)
 static void
 handle_target_event (int error, gdb_client_data client_data)
 {
-  (*async_client_callback) (INF_REG_EVENT, async_client_context);
+  inferior_event_handler (INF_REG_EVENT, NULL);
 }
 
 /* Create/destroy the target events pipe.  Returns previous state.  */
@@ -4700,15 +4696,10 @@ linux_async_pipe (int enable)
 /* target_async implementation.  */
 
 static void
-linux_nat_async (struct target_ops *ops,
-		 void (*callback) (enum inferior_event_type event_type,
-				   void *context),
-		 void *context)
+linux_nat_async (struct target_ops *ops, int enable)
 {
-  if (callback != NULL)
+  if (enable)
     {
-      async_client_callback = callback;
-      async_client_context = context;
       if (!linux_async_pipe (1))
 	{
 	  add_file_handler (linux_nat_event_pipe[0],
@@ -4720,8 +4711,6 @@ linux_nat_async (struct target_ops *ops,
     }
   else
     {
-      async_client_callback = callback;
-      async_client_context = context;
       delete_file_handler (linux_nat_event_pipe[0]);
       linux_async_pipe (0);
     }
@@ -4789,7 +4778,7 @@ linux_nat_close (struct target_ops *self)
 {
   /* Unregister from the event loop.  */
   if (linux_nat_is_async_p (self))
-    linux_nat_async (self, NULL, NULL);
+    linux_nat_async (self, 0);
 
   if (linux_ops->to_close)
     linux_ops->to_close (linux_ops);