Re: PATCH: PR tui/2173: Arrow keys no longer works in breakpoint command list

Jan Kratochvil
2006-12-26T06:00:53Z

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On Wed, 20 Dec 2006 00:19:26 +0100, Jan Kratochvil wrote:
> On Mon, 18 Dec 2006 21:09:19 +0100, Chet Ramey wrote:
> ...
> > Not exactly. The callback and traditional calling mechanisms are
> > orthogonal. It's just not safe to mix them. The longjmp leaves
> > readline in an inconsistent state, unless the calling application is
> > careful to undo what state-setting it has done. That's the part
> > readline can't know about: the appropriate application-specific part.
>
> OK, so going to provide callback based GDB reimplementation of
> gdb_readline_wrapper () (readline () call).

Here is one which forks for me but still it is more complicated than I expected.

I believe there may be side effects but unfortunately it can be expected the
interactive readline(3) usage is not well covered by the testsuite.
readline(3) call does a lot of various initializations currently omitted by the
callback-based gdb reimplementation.

Regards,
Jan

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2006-12-26 Jan Kratochvil <jan.kratochvil@redhat.com>

* gdb/Makefile.in (top.o): Updated dependencies.
* gdb/top.c: Include "event-loop.h"
(gdb_readline_wrapper_result): New variable.
(gdb_readline_wrapper_line): New function.
(gdb_readline_wrapper_cleanup): New struct.
(gdb_readline_wrapper_cleanup): New function.
(gdb_readline_wrapper): Replace `readline' by a `gdb_do_one_event loop'.

2006-12-26 Jan Kratochvil <jan.kratochvil@redhat.com>

* gdb.base/readline-callback-history.c,
gdb.base/readline-callback-history.exp: New files.

--- gdb/Makefile.in 17 Dec 2006 13:30:43 -0000 1.861
+++ gdb/Makefile.in 25 Dec 2006 22:46:41 -0000
@@ -2792,7 +2792,7 @@ top.o: top.c $(defs_h) $(gdbcmd_h) $(cal
$(annotate_h) $(completer_h) $(top_h) $(version_h) $(serial_h) \
$(doublest_h) $(gdb_assert_h) $(readline_h) $(readline_history_h) \
$(event_top_h) $(gdb_string_h) $(gdb_stat_h) $(ui_out_h) \
- $(cli_out_h) $(main_h)
+ $(cli_out_h) $(main_h) $(event_loop_h)
tracepoint.o: tracepoint.c $(defs_h) $(symtab_h) $(frame_h) $(gdbtypes_h) \
$(expression_h) $(gdbcmd_h) $(value_h) $(target_h) $(language_h) \
$(gdb_string_h) $(inferior_h) $(tracepoint_h) $(remote_h) \
--- gdb/top.c 21 Jul 2006 14:46:53 -0000 1.115
+++ gdb/top.c 25 Dec 2006 22:46:43 -0000
@@ -47,6 +47,7 @@
#include "doublest.h"
#include "gdb_assert.h"
#include "main.h"
+#include "event-loop.h"

/* readline include files */
#include "readline/readline.h"
@@ -721,17 +722,79 @@ The filename in which to record the comm
synchronous mode. So for operate-and-get-next to work in this
situation, we have to switch the hooks around. That is what
gdb_readline_wrapper is for. */
+
+static char *gdb_readline_wrapper_result;
+
+static void gdb_readline_wrapper_line (char *line)
+{
+ gdb_assert (gdb_readline_wrapper_result == NULL);
+ gdb_readline_wrapper_result = line;
+}
+
+struct gdb_readline_wrapper_cleanup
+ {
+ void (*handler_orig) (char *);
+ char *prompt_orig;
+ int already_prompted_orig;
+ };
+
+static void gdb_readline_wrapper_cleanup (struct gdb_readline_wrapper_cleanup *cleanup)
+{
+ gdb_assert (rl_already_prompted == 1);
+ rl_already_prompted = cleanup->already_prompted_orig;
+ set_prompt (cleanup->prompt_orig);
+ /* TODO: `cleanup->prompt_orig' leaks. */
+
+ gdb_assert (input_handler == gdb_readline_wrapper_line);
+ input_handler = cleanup->handler_orig;
+ gdb_readline_wrapper_result = NULL;
+
+ xfree (cleanup);
+}
+
char *
gdb_readline_wrapper (char *prompt)
{
+ struct cleanup *old_cleanups;
+ struct gdb_readline_wrapper_cleanup *cleanup;
+ char *retval;
+
+ /* `rl_initialize' not called as we are already called from the main loop. */
+
+ cleanup = xmalloc (sizeof (*cleanup));
+
/* Set the hook that works in this case. */
if (after_char_processing_hook)
{
rl_pre_input_hook = (Function *) after_char_processing_hook;
after_char_processing_hook = NULL;
}
+ cleanup->handler_orig = input_handler;
+ input_handler = gdb_readline_wrapper_line;
+
+ cleanup->prompt_orig = get_prompt ();
+ set_prompt (prompt);
+ cleanup->already_prompted_orig = rl_already_prompted;
+
+ old_cleanups = make_cleanup ((make_cleanup_ftype *)
+ gdb_readline_wrapper_cleanup, cleanup);
+
+ /* Install our `input_handler' and prevent double prompt display.
+ The second prompt would get otherwise displayed before
+ `gdb_readline_wrapper_cleanup' being called. */
+ display_gdb_prompt (NULL);
+ rl_already_prompted = 1;
+
+ /* gdb_do_one_event () argument is unused. */
+ while (gdb_do_one_event (NULL) >= 0)
+ if (gdb_readline_wrapper_result != NULL)
+ break;
+
+ retval = gdb_readline_wrapper_result;
+ gdb_assert (retval != NULL);
+ do_cleanups (old_cleanups);

- return readline (prompt);
+ return retval;
}

\f
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ./gdb/testsuite/gdb.base/readline-callback-history.c 25 Dec 2006 22:54:37 -0000
@@ -0,0 +1,25 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2006 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+ Please email any bugs, comments, and/or additions to this file to:
+ bug-gdb@prep.ai.mit.edu */
+
+int main()
+{
+ return 0;
+}
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ./gdb/testsuite/gdb.base/readline-callback-history.exp 25 Dec 2006 22:54:37 -0000
@@ -0,0 +1,55 @@
+# Copyright 2006 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+if $tracelevel then {
+ strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+set testfile start
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ untested "Couldn't compile test program"
+ return -1
+}
+
+# For: \033[A (up arrow)
+set env(TERM) vt100
+
+# Get things started.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# For C programs, "start" should stop in main().
+
+gdb_test "b main" \
+ "Breakpoint 1 at.*" \
+ "Breakpoint put"
+
+gdb_test "run" \
+ "Breakpoint 1, main (.*) at .*" \
+ "Stopped at the breakpoint"
+
+# \033[A (up arrow)
+gdb_test "command 1\n\033\[A\nend" \
+ "Type commands for when breakpoint 1 is hit.*\n>command 1.*" \
+ "History is available even from callback"