This is the mail archive of the
gdb-prs@sources.redhat.com
mailing list for the GDB project.
pending/1382: [RFA] error-catching mechanism for scripts (fwd)
- From: Don Howard <dhoward at redhat dot com>
- To: Andrew Cagney <ac131313 at redhat dot com>
- Cc: gdb-gnats at sources dot redhat dot com
- Date: Thu, 18 Sep 2003 14:29:12 -0700 (PDT)
- Subject: pending/1382: [RFA] error-catching mechanism for scripts (fwd)
>Number: 1382
>Category: pending
>Synopsis: [RFA] error-catching mechanism for scripts (fwd)
>Confidential: yes
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: change-request
>Submitter-Id: unknown
>Arrival-Date: Thu Sep 18 21:28:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:
>Release:
>Organization:
>Environment:
>Description:
I don't know if this will apply against current gdb, but here's the state
of things from when I last looked at this.
--
dhoward@redhat.com
sustaining engineering
---------- Forwarded message ----------
Date: Tue, 18 Dec 2001 15:48:18 -0800 (PST)
From: Don Howard <dhoward@redhat.com>
To: gdb-patches@sources.redhat.com
Subject: [RFA] error-catching mechanism for scripts
Here is an implementation of the error-catcher that I mentioned a few
weeks ago. I chose "try" and "except" as the keywords:
try
some commands that might error
end
-- or --
try
some commands that might error
except
some commands to recover from error
(errors in this block will not be caught)
end
I've included a quick write-up for the gdb manual. I'll submit new tests
for the testsuite shortly.
2001-12-18 Don Howard <dhoward@redhat.com>
* cli/cli-script.h: New function.
* cli/cli-script.c (build_command_line): Add support for try
command.
(print_command_lines): Ditto.
(print_command_line): Ditto.
(execute_control_command): Ditto.
(read_next_line): Ditto.
(recurse_read_control_structure): Ditto.
(captured_execute_control_command): New function.
(try_command): Ditto.
* cli/cli-cmds.c (init_cli_cmds): Add try command.
* defs.h (enum misc_command_type): Added enum except_command.
(enum command_control_type): Exclude zero from the range of
command_control_type. Added enum try_control.
2001-12-18 Don Howard <dhoward@redhat.com>
* gdb.texinfo (User-defined commands): New section, documenting
try/except feature.
Index: defs.h
===================================================================
RCS file: /cvs/src/src/gdb/defs.h,v
retrieving revision 1.68
diff -p -u -w -r1.68 defs.h
--- defs.h 2001/12/15 16:53:22 1.68
+++ defs.h 2001/12/18 23:45:33
@@ -811,16 +811,18 @@ enum misc_command_type
ok_command,
end_command,
else_command,
+ except_command,
nop_command
};
enum command_control_type
{
- simple_control,
+ simple_control = 1,
break_control,
continue_control,
while_control,
if_control,
+ try_control,
invalid_control
};
Index: cli/cli-cmds.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-cmds.c,v
retrieving revision 1.10
diff -p -u -w -r1.10 cli-cmds.c
--- cli-cmds.c 2001/09/01 21:38:05 1.10
+++ cli-cmds.c 2001/12/18 23:45:34
@@ -721,6 +721,12 @@ The conditional expression must follow t
followed by a new line. The nested commands must be entered one per line,\n\
and should be terminated by the word `end'.");
+ add_com ("try", class_support, try_command,
+"Execute nested commands. On error, terminate execution of the 'try' block\n\
+and execute the optional 'except' block. Commands must be entered one per line,\n\
+terminating with the word 'end'.");
+
+
add_com ("if", class_support, if_command,
"Execute nested commands once IF the conditional expression is non zero.\n\
The conditional expression must follow the word `if' and must in turn be\n\
Index: cli/cli-script.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-script.c,v
retrieving revision 1.8
diff -p -u -w -r1.8 cli-script.c
--- cli-script.c 2001/12/13 22:42:23 1.8
+++ cli-script.c 2001/12/18 23:45:34
@@ -83,7 +83,7 @@ build_command_line (enum command_control
{
struct command_line *cmd;
- if (args == NULL)
+ if (args == NULL && type != try_control)
error ("if/while commands require arguments.\n");
cmd = (struct command_line *) xmalloc (sizeof (struct command_line));
@@ -95,7 +95,12 @@ build_command_line (enum command_control
= (struct command_line **) xmalloc (sizeof (struct command_line *)
* cmd->body_count);
memset (cmd->body_list, 0, sizeof (struct command_line *) * cmd->body_count);
+
+ if (type != try_control)
cmd->line = savestring (args, strlen (args));
+ else
+ cmd->line = savestring ("", strlen (""));
+
return cmd;
}
@@ -208,6 +213,33 @@ print_command_lines (struct ui_out *uiou
continue;
}
+ /* A try command. Recursively print the try and catch blocks
+ before continuing. */
+ if (list->control_type == try_control)
+ {
+ ui_out_field_string (uiout, NULL, "try");
+ ui_out_text (uiout, "\n");
+ /* The true arm. */
+ print_command_lines (uiout, list->body_list[0], depth + 1);
+
+ /* Show the except arm if it exists. */
+ if (list->body_count == 2)
+ {
+ if (depth)
+ ui_out_spaces (uiout, 2 * depth);
+ ui_out_field_string (uiout, NULL, "except");
+ ui_out_text (uiout, "\n");
+ print_command_lines (uiout, list->body_list[1], depth + 1);
+ }
+
+ if (depth)
+ ui_out_spaces (uiout, 2 * depth);
+ ui_out_field_string (uiout, NULL, "end");
+ ui_out_text (uiout, "\n");
+ list = list->next;
+ continue;
+ }
+
/* ignore illegal command type and try next */
list = list->next;
} /* while (list) */
@@ -290,7 +322,33 @@ print_command_line (struct command_line
}
fputs_filtered ("end\n", stream);
}
+
+ /* A try command. Recursively print both try and catch blocks. */
+ if (cmd->control_type == try_control)
+ {
+ fputs_filtered ("try\n", stream);
+ /* The true arm. */
+ print_command_line (cmd->body_list[0], depth + 1, stream);
+
+ /* Show the catch block if it exists. */
+ if (cmd->body_count == 2)
+ {
+ if (depth)
+ {
+ for (i = 0; i < depth; i++)
+ fputs_filtered (" ", stream);
+ }
+ fputs_filtered ("except\n", stream);
+ print_command_line (cmd->body_list[1], depth + 1, stream);
+ }
+ if (depth)
+ {
+ for (i = 0; i < depth; i++)
+ fputs_filtered (" ", stream);
}
+ fputs_filtered ("end\n", stream);
+ }
+}
#endif
/* Execute the command in CMD. */
@@ -326,6 +384,13 @@ execute_user_command (struct cmd_list_el
do_cleanups (old_chain);
}
+static int
+captured_execute_control_command (PTR arg)
+{
+ struct command_line * cmd = (struct command_line *) arg;
+ return execute_control_command (cmd);
+}
+
enum command_control_type
execute_control_command (struct command_line *cmd)
{
@@ -459,6 +524,30 @@ execute_control_command (struct command_
break;
}
+ case try_control:
+ {
+ current = cmd->body_list[0];
+
+ while (current)
+ {
+ ret = catch_errors (captured_execute_control_command, current,
+ "", RETURN_MASK_ALL);
+
+ if (ret == 0 || ret == invalid_control)
+ {
+ if (cmd->body_count == 2)
+ current = cmd->body_list[1];
+ else
+ current = NULL;
+ }
+ else
+ {
+ current = current->next;
+ }
+ }
+ break;
+ }
+
default:
warning ("Invalid control type in command structure.");
return invalid_control;
@@ -506,6 +595,21 @@ if_command (char *arg, int from_tty)
free_command_lines (&command);
}
+void
+try_command (char *block, int from_tty)
+{
+ struct command_line *command = NULL;
+
+ control_level = 1;
+ command = get_command_line (try_control, block);
+
+ if (command == NULL)
+ return;
+
+ execute_control_command (command);
+ free_command_lines (&command);
+}
+
/* Cleanup */
static void
arg_cleanup (void *ignore)
@@ -758,12 +862,18 @@ read_next_line (struct command_line **co
if (p1 - p == 4 && !strncmp (p, "else", 4))
return else_command;
+ /* Is the except clause of an if try structure? */
+ if (p1 - p == 6 && !strncmp (p, "except", 6))
+ return except_command;
+
/* Check for while, if, break, continue, etc and build a new command
line structure for them. */
if (p1 - p > 5 && !strncmp (p, "while", 5))
*command = build_command_line (while_control, p + 6);
else if (p1 - p > 2 && !strncmp (p, "if", 2))
*command = build_command_line (if_control, p + 3);
+ else if (p1 - p == 3 && !strncmp (p, "try", 3))
+ *command = build_command_line (try_control, p + 4);
else if (p1 - p == 10 && !strncmp (p, "loop_break", 10))
{
*command = (struct command_line *)
@@ -845,7 +955,8 @@ recurse_read_control_structure (struct c
if (val == end_command)
{
if (current_cmd->control_type == while_control
- || current_cmd->control_type == if_control)
+ || current_cmd->control_type == if_control
+ || current_cmd->control_type == try_control)
{
/* Success reading an entire control structure. */
ret = simple_control;
@@ -876,6 +987,23 @@ recurse_read_control_structure (struct c
}
}
+ if (val == except_command)
+ {
+ if (current_cmd->control_type == try_control
+ && current_body == 1)
+ {
+ realloc_body_list (current_cmd, 2);
+ current_body = 2;
+ child_tail = NULL;
+ continue;
+ }
+ else
+ {
+ ret = invalid_control;
+ break;
+ }
+ }
+
if (child_tail)
{
child_tail->next = next;
@@ -895,7 +1023,8 @@ recurse_read_control_structure (struct c
/* If the latest line is another control structure, then recurse
on it. */
if (next->control_type == while_control
- || next->control_type == if_control)
+ || next->control_type == if_control
+ || next->control_type == try_control)
{
control_level++;
ret = recurse_read_control_structure (next);
@@ -962,7 +1091,8 @@ read_command_lines (char *prompt_arg, in
}
if (next->control_type == while_control
- || next->control_type == if_control)
+ || next->control_type == if_control
+ || next->control_type == try_control)
{
control_level++;
ret = recurse_read_control_structure (next);
Index: cli/cli-script.h
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-script.h,v
retrieving revision 1.2
diff -p -u -w -r1.2 cli-script.h
--- cli-script.h 2001/03/06 08:21:20 1.2
+++ cli-script.h 2001/12/18 23:45:34
@@ -31,6 +31,8 @@ extern void while_command (char *arg, in
extern void if_command (char *arg, int from_tty);
+extern void try_command (char *block, int from_tty);
+
extern void show_user_1 (struct cmd_list_element *c, struct ui_file *stream);
/* Exported to gdb/breakpoint.c */
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.59
diff -p -u -w -r1.59 gdb.texinfo
--- gdb.texinfo 2001/11/30 23:03:09 1.59
+++ gdb.texinfo 2001/12/18 23:45:47
@@ -13323,6 +13323,17 @@ execute, one per line, terminated by an
The commands are executed repeatedly as long as the expression
evaluates to true.
+@kindex try
+@kindex except
+@item try
+Takes no arguments and must be followed by a series of commands to be
+executed, one per line. Errors in the series of commands will terminate
+execution of the series, but not the entire script. There can be and
+optional @code{except} line, which must also be followed by a series of
+commands, one per line. Commands in the @code{except} block are
+executed if an error is encountered in the corresponding @code{try}
+block.
+
@kindex document
@item document @var{commandname}
Document the user-defined command @var{commandname}, so that it can be
--
dhoward@redhat.com
gdb engineering
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: