Command line input handling TLC

I didn't manage to usefully split this further into smaller
independent pieces, so:

 - Use "struct buffer" more.

 - Split out the responsibility of composing a complete command line
   from multiple input lines split with backslash

    (
    E.g.:

       (gdb) print \
       1 + \
       2
       $1 = 3
       (gdb)
    )

   to a separate function.  Note we don't need the separate
   readline_input_state and more_to_come globals at all.  They were
   just obfuscating the logic.

 - Factor out the tricky mostly duplicated code in
   command_line_handler and command_line_input.

gdb/ChangeLog
2016-03-09  Pedro Alves  <palves@redhat.com>

	* event-top.c (more_to_come): Delete.
	(struct readline_input_state): Delete.
	(readline_input_state): Delete.
	(get_command_line_buffer): New function.
	(command_handler): Update comments.  Don't handle NULL commands
	here.  Do not execute commented lines.
	(command_line_append_input_line): New function.
	(handle_line_of_input): New function, partly based on
	command_line_handler and command_line_input.
	(command_line_handler): Rewrite.
	* event-top.h (command_handler): New declaration.
	(command_loop): Defer command execution to command_handler.
	(command_line_input): Update comments.  Simplify, using struct
	buffer and handle_line_of_input.
	* top.h (struct buffer): New forward declaration.
	(handle_line_of_input): New declaration.

1 files changed, 6 insertions, 0 deletions

diff --git a/gdb/top.h b/gdb/top.h
index f3b080b..a498f39 100644
--- a/gdb/top.h
+++ b/gdb/top.h
@@ -20,6 +20,8 @@
 #ifndef TOP_H
 #define TOP_H
 
+struct buffer;
+
 /* From top.c.  */
 extern char *saved_command_line;
 extern FILE *instream;
@@ -97,4 +99,8 @@ extern void set_verbose (char *, int, struct cmd_list_element *);
 
 extern void do_restore_instream_cleanup (void *stream);
 
+extern char *handle_line_of_input (struct buffer *cmd_line_buffer,
+				   char *rl, int repeat,
+				   char *annotation_suffix);
+
 #endif