Add previous_saved_command_line to allow a command to repeat a previous command.

Currently, a previous command can be repeated when the user types an
empty line.  This is implemented in handle_line_of_input by
returning saved_command_line in case an empty line has been input.

If we want a command to repeat the previous command, we need to save
the previous saved_command_line, as when a command runs, the saved_command_line
already contains the current command line of the command being executed.

As suggested by Tom, the previous_saved_command_line is made static.
At the same time, saved_command_line is also made static.
The support functions/variables for the repeat command logic are now all
located inside top.c.

gdb/ChangeLog
2019-05-31  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* top.h (saved_command_line): Remove declaration.
	* top.c (previous_saved_command_line, previous_repeat_arguments):
	New variables.
	(saved_command_line): Make static, define together with other
	'repeat variables'.
	(dont_repeat): Clear repeat_arguments.
	(repeat_previous, get_saved_command_line, save_command_line):
	New functions.
	(gdb_init): Initialize saved_command_line
	and previous_saved_command_line.
	* main.c (captured_main_1): Remove saved_command_line initialization.
	* event-top.c (handle_line_of_input): Update to use
	the new 'repeat' related functions instead of direct access to
	saved_command_line.
	* command.h (repeat_previous, get_saved_command_line,
	save_command_line): New declarations.
	(dont_repeat): Add comment.

1 files changed, 35 insertions, 1 deletions

diff --git a/gdb/command.h b/gdb/command.h
index 35006cc..26e4029 100644
--- a/gdb/command.h
+++ b/gdb/command.h
@@ -448,7 +448,29 @@ extern void cmd_show_list (struct cmd_list_element *, int, const char *);
 
 extern void error_no_arg (const char *) ATTRIBUTE_NORETURN;
 
-extern void dont_repeat (void);
+
+/* Command line saving and repetition.
+   Each input line executed is saved to possibly be repeated either
+   when the user types an empty line, or be repeated by a command
+   that wants to repeat the previously executed command.  The below
+   functions control command repetition.  */
+
+/* Commands call dont_repeat if they do not want to be repeated by null
+   lines or by repeat_previous ().  */
+
+extern void dont_repeat ();
+
+/* Commands call repeat_previous if they want to repeat the previous command.
+   Such commands that repeat the previous command must indicate
+   to not repeat themselves, to avoid recursive repeat.
+   repeat_previous will mark the current command as not repeating,
+   and will ensure get_saved_command_line returns the previous command,
+   so that the currently executing command can repeat it.  */
+
+extern void repeat_previous ();
+
+/* Prevent dont_repeat from working, and return a cleanup that
+   restores the previous state.  */
 
 extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
 
@@ -457,6 +479,18 @@ extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
 
 extern void set_repeat_arguments (const char *args);
 
+/* Returns the saved command line to repeat.
+   When a command is being executed, this is the currently executing
+   command line, unless the currently executing command has called
+   repeat_previous (): in this case, get_saved_command_line returns
+   the previously saved command line.  */
+
+extern char *get_saved_command_line ();
+
+/* Takes a copy of CMD, for possible repetition.  */
+
+extern void save_command_line (const char *cmd);
+
 /* Used to mark commands that don't do anything.  If we just leave the
    function field NULL, the command is interpreted as a help topic, or
    as a class of commands.  */