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, 8 insertions, 4 deletions

diff --git a/gdb/interps.h b/gdb/interps.h
index eba3387..4ac0845 100644
--- a/gdb/interps.h
+++ b/gdb/interps.h
@@ -46,7 +46,7 @@ typedef int (interp_resume_ftype) (void *data);
 typedef int (interp_suspend_ftype) (void *data);
 typedef struct gdb_exception (interp_exec_ftype) (void *data,
 						  const char *command);
-typedef void (interp_command_loop_ftype) (void *data);
+typedef void (interp_pre_command_loop_ftype) (struct interp *self);
 typedef struct ui_out *(interp_ui_out_ftype) (struct interp *self);
 
 typedef int (interp_set_logging_ftype) (struct interp *self, int start_log,
@@ -73,7 +73,9 @@ struct interp_procs
      disabled.  */
   interp_set_logging_ftype *set_logging_proc;
 
-  interp_command_loop_ftype *command_loop_proc;
+  /* Called before starting an event loop, to give the interpreter a
+     chance to e.g., print a prompt.  */
+  interp_pre_command_loop_ftype *pre_command_loop_proc;
 
   /* Returns true if this interpreter supports using the readline
      library; false if it uses GDB's own simplified readline
@@ -100,8 +102,6 @@ extern struct interp *interp_set_temp (const char *name);
 
 extern int current_interp_named_p (const char *name);
 
-extern void current_interp_command_loop (void);
-
 /* Call this function to give the current interpreter an opportunity
    to do any special handling of streams when logging is enabled or
    disabled.  START_LOG is 1 when logging is starting, 0 when it ends,
@@ -127,6 +127,10 @@ extern void clear_interpreter_hooks (void);
    if it uses GDB's own simplified form of readline.  */
 extern int interp_supports_command_editing (struct interp *interp);
 
+/* Called before starting an event loop, to give the interpreter a
+   chance to e.g., print a prompt.  */
+extern void interp_pre_command_loop (struct interp *interp);
+
 /* well-known interpreters */
 #define INTERP_CONSOLE		"console"
 #define INTERP_MI1             "mi1"