From mboxrd@z Thu Jan 1 00:00:00 1970 From: Elena Zannoni To: tromey@redhat.com Cc: Elena Zannoni , gdb-patches@sources.redhat.com Subject: Re: PATCH: operate-and-get-next Date: Mon, 15 Oct 2001 09:13:00 -0000 Message-id: <15307.3296.609453.745678@krustylu.cygnus.com> References: <87r8skfh47.fsf@creche.redhat.com> <15300.61266.27769.906320@krustylu.cygnus.com> <87g08nzbho.fsf@creche.redhat.com> X-SW-Source: 2001-10/msg00216.html Tom Tromey writes: > >>>>> "Elena" == Elena Zannoni writes: > > Elena> It looks to me that prompt_just_set is always 1, after it is > Elena> set the very first time. So it doesn't really help. > > Quite right, sorry. > > Elena> Instead of having this global variable, could it be possible to > Elena> play with installing and un-installing the hook itself? And > Elena> then have rl_callback_read_char_wrapper do a check > > Ok, I implemented this. And it does make things cleaner. Thanks. > > I don't really like the hook name I chose but I was unable to think of > a better one. I can rename it to whatever you like. > > The new patch is appended. Ok, much claner. The only thing I wonder now about is, is it necessary to have operate_saved_history be checked in the gdb_rl_operate_and_get_next_completion () function. It looks like it would be always != -1 when that function is called, bacause of the way the hooks are installed. The hooks are not null while the var is not -1. It still needs to be a global, though. > > It has one very ugly thing, namely the call to > after_char_processing_hook in start_event_loop. Without this call, > if the user entered a command that caused an error, then the > C-o binding wouldn't work. > > For instance I tested it like this: > > output 1\n <- gives an error > p 1 > C-p C-p <- move up history > C-o <- re-accept the error line > > This would fail to put `p 1' into the editing buffer. > > The reason is that the error causes us to unwind past the call to > after_char_processing_hook. > > I tried calling the hook from a cleanup in rl_callback_read_char_wrapper, > but that didn't work. The problem is that the error unwinding leaves > the readline in a state that we can't anticipate -- the where_history() > value is wrong, so the operate-and-get-next completion code doesn't > work. > > What I'd really like is a hook which is called at the right point > after the prompt is printed. It doesn't need to be called for every > character (that is the conceptual problem, I think, with the appended). > Unfortunately calling the hook in display_gdb_prompt won't work, for > reasons mentioned in my first patch. > > I guess I could try to put an `after_prompt_hook' into start_event_loop. > This might work ok. What would you think of that? Or is there > another approach you'd like me to try? > I cannot think of another approach at the moment. But I agree that a different hook in start_event_loop could be used. The after_char_processing_hook seems a bit out of place there. Elena > Thanks, > Tom > > > Index: ChangeLog > from Tom Tromey > > * event-loop.c (start_event_loop): Call > after_char_processing_hook. > * event-top.h (after_char_processing_hook): Declare. > * event-top.c (rl_callback_read_char_wrapper): Call > after_char_processing_hook. > (after_char_processing_hook): New global. > * top.c (operate_saved_history): New global. > (gdb_rl_operate_and_get_next): New function. > (init_main): Add the operate-and-get-next defun. > (gdb_rl_operate_and_get_next_completion): New function. > > Index: event-loop.c > =================================================================== > RCS file: /cvs/src/src/gdb/event-loop.c,v > retrieving revision 1.16 > diff -u -r1.16 event-loop.c > --- event-loop.c 2001/03/27 20:36:23 1.16 > +++ event-loop.c 2001/10/13 17:11:13 > @@ -402,6 +402,14 @@ > interface specific, because interfaces can display the > prompt in their own way. */ > display_gdb_prompt (0); > + /* This call looks bizarre, but it is required. If the user > + entered a command that caused an error, > + after_char_processing_hook won't be called from > + rl_callback_read_char_wrapper. Using a cleanup there > + won't work, since we want this function to be called > + after a new prompt is printed. */ > + if (after_char_processing_hook) > + (*after_char_processing_hook) (); > /* Maybe better to set a flag to be checked somewhere as to > whether display the prompt or not. */ > } > Index: event-top.c > =================================================================== > RCS file: /cvs/src/src/gdb/event-top.c,v > retrieving revision 1.16 > diff -u -r1.16 event-top.c > --- event-top.c 2001/08/27 22:39:55 1.16 > +++ event-top.c 2001/10/13 17:11:15 > @@ -153,6 +153,10 @@ > char *linebuffer_ptr; > } > readline_input_state; > + > +/* This hook is called by rl_callback_read_char_wrapper after each > + character is processed. */ > +void (*after_char_processing_hook) (); > > > /* Wrapper function for calling into the readline library. The event > @@ -162,6 +166,8 @@ > rl_callback_read_char_wrapper (gdb_client_data client_data) > { > rl_callback_read_char (); > + if (after_char_processing_hook) > + (*after_char_processing_hook) (); > } > > /* Initialize all the necessary variables, start the event loop, > Index: event-top.h > =================================================================== > RCS file: /cvs/src/src/gdb/event-top.h,v > retrieving revision 1.3 > diff -u -r1.3 event-top.h > --- event-top.h 2001/04/20 14:25:59 1.3 > +++ event-top.h 2001/10/13 17:11:15 > @@ -108,3 +108,4 @@ > extern void (*call_readline) (void *); > extern void (*input_handler) (char *); > extern int input_fd; > +extern void (*after_char_processing_hook) (void); > Index: top.c > =================================================================== > RCS file: /cvs/src/src/gdb/top.c,v > retrieving revision 1.45 > diff -u -r1.45 top.c > --- top.c 2001/09/07 21:33:08 1.45 > +++ top.c 2001/10/13 17:11:17 > @@ -1032,6 +1032,55 @@ > #endif > } > > +/* The current saved history number from operate-and-get-next. > + This is -1 if not valid. */ > +static int operate_saved_history = -1; > + > +/* This is put on the appropriate hook and helps operate-and-get-next > + do its work. */ > + void > +gdb_rl_operate_and_get_next_completion () > +{ > + if (operate_saved_history != -1) > + { > + int delta = where_history () - operate_saved_history; > + /* The `key' argument to rl_get_previous_history is ignored. */ > + rl_get_previous_history (delta, 0); > + operate_saved_history = -1; > + > + /* readline doesn't automatically update the display for us. */ > + rl_redisplay (); > + > + after_char_processing_hook = NULL; > + rl_pre_input_hook = NULL; > + } > +} > + > +/* This is a gdb-local readline command handler. It accepts the > + current command line (like RET does) and, if this command was taken > + from the history, arranges for the next command in the history to > + appear on the command line when the prompt returns. > + We ignore the arguments. */ > +static int > +gdb_rl_operate_and_get_next (int count, int key) > +{ > + if (event_loop_p) > + { > + /* Use the async hook. */ > + after_char_processing_hook = gdb_rl_operate_and_get_next_completion; > + } > + else > + { > + /* This hook only works correctly when we are using the > + synchronous readline. */ > + rl_pre_input_hook = (Function *) gdb_rl_operate_and_get_next_completion; > + } > + > + /* Add 1 because we eventually want the next line. */ > + operate_saved_history = where_history () + 1; > + return rl_newline (1, key); > +} > + > /* Read one line from the command input stream `instream' > into the local static buffer `linebuffer' (whose current length > is `linelength'). > @@ -1881,6 +1930,10 @@ > get_gdb_completer_word_break_characters (); > rl_completer_quote_characters = get_gdb_completer_quote_characters (); > rl_readline_name = "gdb"; > + > + /* The name for this defun comes from Bash, where it originated. > + 15 is Control-o, the same binding this function has in Bash. */ > + rl_add_defun ("operate-and-get-next", gdb_rl_operate_and_get_next, 15); > > /* The set prompt command is different depending whether or not the > async version is run. NOTE: this difference is going to > Index: doc/ChangeLog > from Tom Tromey > > * gdb.texinfo (Command Syntax): Document C-o binding. > > Index: doc/gdb.texinfo > =================================================================== > RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v > retrieving revision 1.51 > diff -u -r1.51 gdb.texinfo > --- doc/gdb.texinfo 2001/09/12 19:49:52 1.51 > +++ doc/gdb.texinfo 2001/10/13 17:11:34 > @@ -1190,6 +1190,13 @@ > nothing. This is useful mainly in command files (@pxref{Command > Files,,Command files}). > > +@cindex repeating command sequences > +@kindex C-o @r{(operate-and-get-next)} > +The @kbd{C-o} binding is useful for repeating a complex sequence of > +commands. This command accepts the current line, like @kbd{RET}, and > +then fetches the next line relative to the current line from the history > +for editing. > + > @node Completion > @section Command completion >