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.

9 files changed, 70 insertions, 68 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 591a114..febc377 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,36 @@
+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.
+
 2015-03-25  Gary Benson <gbenson@redhat.com>
 	    Pedro Alves  <palves@redhat.com>
 
diff --git a/gdb/inf-loop.c b/gdb/inf-loop.c
index 429cd73..eed881d 100644
--- a/gdb/inf-loop.c
+++ b/gdb/inf-loop.c
@@ -74,7 +74,7 @@ inferior_event_handler (enum inferior_event_type event_type,
 	     so that when the inferior is not running we don't get
 	     distracted by spurious inferior output.  */
 	  if (target_has_execution)
-	    target_async (NULL, 0);
+	    target_async (0);
 	}
 
       /* Do all continuations associated with the whole inferior (not
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);
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 5eb5cf4..240a8dc 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -278,17 +278,14 @@ record_btrace_close (struct target_ops *self)
 /* The to_async method of target record-btrace.  */
 
 static void
-record_btrace_async (struct target_ops *ops,
-		     void (*callback) (enum inferior_event_type event_type,
-				       void *context),
-		     void *context)
+record_btrace_async (struct target_ops *ops, int enable)
 {
-  if (callback != NULL)
+  if (enable)
     mark_async_event_handler (record_btrace_async_inferior_event_handler);
   else
     clear_async_event_handler (record_btrace_async_inferior_event_handler);
 
-  ops->beneath->to_async (ops->beneath, callback, context);
+  ops->beneath->to_async (ops->beneath, enable);
 }
 
 /* Adjusts the size and returns a human readable size suffix.  */
@@ -1789,7 +1786,7 @@ record_btrace_resume (struct target_ops *ops, ptid_t ptid, int step,
   /* Async support.  */
   if (target_can_async_p ())
     {
-      target_async (inferior_event_handler, 0);
+      target_async (1);
       mark_async_event_handler (record_btrace_async_inferior_event_handler);
     }
 }
diff --git a/gdb/record-full.c b/gdb/record-full.c
index 0fbb264..43e8be2 100644
--- a/gdb/record-full.c
+++ b/gdb/record-full.c
@@ -914,17 +914,14 @@ record_full_close (struct target_ops *self)
 /* "to_async" target method.  */
 
 static void
-record_full_async (struct target_ops *ops,
-		   void (*callback) (enum inferior_event_type event_type,
-				     void *context),
-		   void *context)
+record_full_async (struct target_ops *ops, int enable)
 {
-  if (callback != NULL)
+  if (enable)
     mark_async_event_handler (record_full_async_inferior_event_token);
   else
     clear_async_event_handler (record_full_async_inferior_event_token);
 
-  ops->beneath->to_async (ops->beneath, callback, context);
+  ops->beneath->to_async (ops->beneath, enable);
 }
 
 static int record_full_resume_step = 0;
@@ -1006,7 +1003,7 @@ record_full_resume (struct target_ops *ops, ptid_t ptid, int step,
   /* We are about to start executing the inferior (or simulate it),
      let's register it with the event loop.  */
   if (target_can_async_p ())
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 }
 
 static int record_full_get_sig = 0;
@@ -1978,7 +1975,7 @@ record_full_core_resume (struct target_ops *ops, ptid_t ptid, int step,
   /* We are about to start executing the inferior (or simulate it),
      let's register it with the event loop.  */
   if (target_can_async_p ())
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 }
 
 /* "to_kill" method for prec over corefile.  */
diff --git a/gdb/remote.c b/gdb/remote.c
index fd677fe..164231c 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -124,10 +124,7 @@ static int remote_can_async_p (struct target_ops *);
 
 static int remote_is_async_p (struct target_ops *);
 
-static void remote_async (struct target_ops *ops,
-			  void (*callback) (enum inferior_event_type event_type,
-					    void *context),
-			  void *context);
+static void remote_async (struct target_ops *ops, int enable);
 
 static void sync_remote_interrupt_twice (int signo);
 
@@ -356,10 +353,6 @@ struct remote_state
   int use_threadinfo_query;
   int use_threadextra_query;
 
-  void (*async_client_callback) (enum inferior_event_type event_type,
-				 void *context);
-  void *async_client_context;
-
   /* This is set to the data address of the access causing the target
      to stop for a watchpoint.  */
   CORE_ADDR remote_watch_data_address;
@@ -3661,7 +3654,7 @@ remote_start_remote (int from_tty, struct target_ops *target, int extended_p)
 	}
 
       if (target_can_async_p ())
-	target_async (inferior_event_handler, 0);
+	target_async (1);
 
       if (thread_count () == 0)
 	{
@@ -4590,7 +4583,7 @@ extended_remote_attach_1 (struct target_ops *target, const char *args,
 
 	  push_stop_reply ((struct stop_reply *) reply);
 
-	  target_async (inferior_event_handler, 0);
+	  target_async (1);
 	}
       else
 	{
@@ -4929,7 +4922,7 @@ remote_resume (struct target_ops *ops,
      into infcmd.c in order to allow inferior function calls to work
      NOT asynchronously.  */
   if (target_can_async_p ())
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 
   /* We've just told the target to resume.  The remote server will
      wait for the inferior to stop, and then send a stop reply.  In
@@ -8112,7 +8105,7 @@ extended_remote_create_inferior (struct target_ops *ops,
   /* If running asynchronously, register the target file descriptor
      with the event loop.  */
   if (target_can_async_p ())
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 
   /* Disable address space randomization if requested (and supported).  */
   if (extended_remote_supports_disable_randomization (ops))
@@ -11962,7 +11955,7 @@ remote_async_serial_handler (struct serial *scb, void *context)
 
   /* Don't propogate error information up to the client.  Instead let
      the client find out about the error by querying the target.  */
-  rs->async_client_callback (INF_REG_EVENT, rs->async_client_context);
+  inferior_event_handler (INF_REG_EVENT, NULL);
 }
 
 static void
@@ -11972,18 +11965,13 @@ remote_async_inferior_event_handler (gdb_client_data data)
 }
 
 static void
-remote_async (struct target_ops *ops,
-	      void (*callback) (enum inferior_event_type event_type,
-				void *context),
-	      void *context)
+remote_async (struct target_ops *ops, int enable)
 {
   struct remote_state *rs = get_remote_state ();
 
-  if (callback != NULL)
+  if (enable)
     {
       serial_async (rs->remote_desc, remote_async_serial_handler, rs);
-      rs->async_client_callback = callback;
-      rs->async_client_context = context;
 
       /* If there are pending events in the stop reply queue tell the
 	 event loop to process them.  */
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index 0c1309a..b29abaf 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -1692,29 +1692,27 @@ debug_is_async_p (struct target_ops *self)
 }
 
 static void
-delegate_async (struct target_ops *self, async_callback_ftype *arg1, void *arg2)
+delegate_async (struct target_ops *self, int arg1)
 {
   self = self->beneath;
-  self->to_async (self, arg1, arg2);
+  self->to_async (self, arg1);
 }
 
 static void
-tdefault_async (struct target_ops *self, async_callback_ftype *arg1, void *arg2)
+tdefault_async (struct target_ops *self, int arg1)
 {
   tcomplain ();
 }
 
 static void
-debug_async (struct target_ops *self, async_callback_ftype *arg1, void *arg2)
+debug_async (struct target_ops *self, int arg1)
 {
   fprintf_unfiltered (gdb_stdlog, "-> %s->to_async (...)\n", debug_target.to_shortname);
-  debug_target.to_async (&debug_target, arg1, arg2);
+  debug_target.to_async (&debug_target, arg1);
   fprintf_unfiltered (gdb_stdlog, "<- %s->to_async (", debug_target.to_shortname);
   target_debug_print_struct_target_ops_p (&debug_target);
   fputs_unfiltered (", ", gdb_stdlog);
-  target_debug_print_async_callback_ftype_p (arg1);
-  fputs_unfiltered (", ", gdb_stdlog);
-  target_debug_print_void_p (arg2);
+  target_debug_print_int (arg1);
   fputs_unfiltered (")\n", gdb_stdlog);
 }
 
diff --git a/gdb/target.h b/gdb/target.h
index 05dcd9f..19254d6 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -629,7 +629,7 @@ struct target_ops
       TARGET_DEFAULT_RETURN (0);
     int (*to_is_async_p) (struct target_ops *)
       TARGET_DEFAULT_RETURN (0);
-    void (*to_async) (struct target_ops *, async_callback_ftype *, void *)
+    void (*to_async) (struct target_ops *, int)
       TARGET_DEFAULT_NORETURN (tcomplain ());
     /* This method must be implemented in some situations.  See the
        comment on 'to_can_run'.  */
@@ -1686,9 +1686,9 @@ extern int target_async_permitted;
 /* Is the target in asynchronous execution mode?  */
 #define target_is_async_p() (current_target.to_is_async_p (&current_target))
 
-/* Put the target in async mode with the specified callback function.  */
-#define target_async(CALLBACK,CONTEXT) \
-     (current_target.to_async (&current_target, (CALLBACK), (CONTEXT)))
+/* Enables/disabled async target events.  */
+#define target_async(ENABLE) \
+     (current_target.to_async (&current_target, (ENABLE)))
 
 #define target_execution_direction() \
   (current_target.to_execution_direction (&current_target))
diff --git a/gdb/top.c b/gdb/top.c
index f746af8..b15c06b 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -806,7 +806,7 @@ gdb_readline_wrapper_cleanup (void *arg)
   saved_after_char_processing_hook = NULL;
 
   if (cleanup->target_is_async_orig)
-    target_async (inferior_event_handler, 0);
+    target_async (1);
 
   xfree (cleanup);
 }
@@ -829,7 +829,7 @@ gdb_readline_wrapper (const char *prompt)
   back_to = make_cleanup (gdb_readline_wrapper_cleanup, cleanup);
 
   if (cleanup->target_is_async_orig)
-    target_async (NULL, NULL);
+    target_async (0);
 
   /* Display our prompt and prevent double prompt display.  */
   display_gdb_prompt (prompt);