Simplify starting the command event loop

All interpreter types (CLI/TUI/MI) print the prompt, and then call
start_event_loop.

Because we'll need an interpreter hook to display the
interpreter-specific prompt before going back to the event loop,
without actually starting an event loop, this patch moves the
start_event_loop call to common code, and replaces the command_loop
hook with a pre_command_look hook, that now just prints the prompt.

Turns out to be a cleanup on its own right anyway.

gdb/ChangeLog:
2016-06-21  Pedro Alves  <palves@redhat.com>

	* cli/cli-interp.c (cli_interpreter_pre_command_loop): New
	function.
	(cli_interp_procs): Install it instead of cli_command_loop.
	* cli/cli-interp.h (cli_interpreter_pre_command_loop): Declare.
	* event-top.c (cli_command_loop): Delete.
	* interps.c (interp_new): Remove reference to command_loop_proc.
	(current_interp_command_loop): Delete.
	(interp_pre_command_loop): New function.
	(interp_command_loop_ftype): Delete.
	* interps.h (interp_pre_command_loop_ftype): New typedef.
	(struct interp_procs) <command_loop_proc>: Delele field.
	<pre_command_loop_proc>: New field.
	(current_interp_command_loop): Delete declaration.
	(interp_pre_command_loop): New declaration.
	* main.c (captured_command_loop): Call interp_pre_command_loop
	instead of current_interp_command_loop and start an event loop.
	* mi/mi-interp.c (mi_command_loop): Delete.
	(mi_interpreter_pre_command_loop): New.
	(mi_interp_procs): Update.
	* tui/tui-interp.c (tui_interp_procs): Install
	cli_interpreter_pre_command_loop instead of cli_command_loop.

1 files changed, 6 insertions, 10 deletions

diff --git a/gdb/interps.c b/gdb/interps.c
index ab039ce..fdf1479 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -117,9 +117,6 @@ interp_new (const char *name, const struct interp_procs *procs, void *data)
   new_interp->procs = procs;
   new_interp->inited = 0;
 
-  /* Check for required procs.  */
-  gdb_assert (procs->command_loop_proc != NULL);
-
   return new_interp;
 }
 
@@ -411,16 +408,15 @@ command_interp (void)
     return ui_interp->current_interpreter;
 }
 
-/* Run the current command interpreter's main loop.  */
+/* See interps.h.  */
+
 void
-current_interp_command_loop (void)
+interp_pre_command_loop (struct interp *interp)
 {
-  struct ui_interp_info *ui_interp = get_current_interp_info ();
-  struct interp *interp = ui_interp->current_interpreter;
-
-  gdb_assert (ui_interp->current_interpreter != NULL);
+  gdb_assert (interp != NULL);
 
-  interp->procs->command_loop_proc (interp->data);
+  if (interp->procs->pre_command_loop_proc != NULL)
+    interp->procs->pre_command_loop_proc (interp);
 }
 
 /* See interp.h  */