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config parser: recover after invalid input 

This is done by ignoring the rest of the current line and jumping to the
nearest <error> token.

fixes #879
This commit is contained in:
Michael Stapelberg 2012-11-20 17:09:03 +01:00
parent 6148136e7c
commit 3cb909fa62
5 changed files with 100 additions and 4 deletions
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1
generate-command-parser.pl
View File

@ -193,7 +193,6 @@ say $callfh ' default:';
say $callfh ' printf("BUG in the parser. state = %d\n", call_identifier);';
say $callfh ' assert(false);';
say $callfh ' }';
say $callfh ' state = result->next_state;';
say $callfh '}';
close($callfh);

3
parser-specs/config.spec
View File

@ -15,6 +15,7 @@ state INITIAL:
# We have an end token here for all the commands which just call some
# function without using an explicit 'end' token.
end ->
error ->
'#' -> IGNORE_LINE
'set' -> IGNORE_LINE
bindtype = 'bindsym', 'bindcode', 'bind' -> BINDING
@ -298,6 +299,7 @@ state MODEBRACE:
state MODE:
end ->
error ->
'#' -> MODE_IGNORE_LINE
'set' -> MODE_IGNORE_LINE
bindtype = 'bindsym', 'bindcode', 'bind'
@ -336,6 +338,7 @@ state BARBRACE:
state BAR:
end ->
error ->
'#' -> BAR_IGNORE_LINE
'set' -> BAR_IGNORE_LINE
'i3bar_command' -> BAR_BAR_COMMAND

1
src/commands_parser.c
View File

@ -190,6 +190,7 @@ static void next_state(const cmdp_token *token) {
subcommand_output.json_gen = command_output.json_gen;
subcommand_output.needs_tree_render = false;
GENERATED_call(token->extra.call_identifier, &subcommand_output);
state = subcommand_output.next_state;
/* If any subcommand requires a tree_render(), we need to make the
* whole parser result request a tree_render(). */
if (subcommand_output.needs_tree_render)

57
src/config_parser.c
View File

@ -21,6 +21,9 @@
* 3. config_parser recognizes \n and \r as 'end' token, while commands_parser
* ignores them.
*
* 4. config_parser skips the current line on invalid inputs and follows the
* nearest <error> token.
*
*/
#include <stdio.h>
#include <stdlib.h>
@ -221,23 +224,46 @@ static Match current_match;
static struct ConfigResult subcommand_output;
static struct ConfigResult command_output;
/* A list which contains the states that lead to the current state, e.g.
* INITIAL, WORKSPACE_LAYOUT.
* When jumping back to INITIAL, statelist_idx will simply be set to 1
* (likewise for other states, e.g. MODE or BAR).
* This list is used to process the nearest error token. */
static cmdp_state statelist[10] = { INITIAL };
/* NB: statelist_idx points to where the next entry will be inserted */
static int statelist_idx = 1;
#include "GENERATED_config_call.h"
static void next_state(const cmdp_token *token) {
cmdp_state _next_state = token->next_state;
//printf("token = name %s identifier %s\n", token->name, token->identifier);
//printf("next_state = %d\n", token->next_state);
if (token->next_state == __CALL) {
subcommand_output.json_gen = command_output.json_gen;
GENERATED_call(token->extra.call_identifier, &subcommand_output);
_next_state = subcommand_output.next_state;
clear_stack();
return;
}
state = token->next_state;
state = _next_state;
if (state == INITIAL) {
clear_stack();
}
/* See if we are jumping back to a state in which we were in previously
* (statelist contains INITIAL) and just move statelist_idx accordingly. */
for (int i = 0; i < statelist_idx; i++) {
if (statelist[i] != _next_state)
continue;
statelist_idx = i+1;
return;
}
/* Otherwise, the state is new and we add it to the list */
statelist[statelist_idx++] = _next_state;
}
/*
@ -284,6 +310,7 @@ struct ConfigResult *parse_config(const char *input, struct context *context) {
linecnt++;
}
state = INITIAL;
statelist_idx = 1;
/* A YAJL JSON generator used for formatting replies. */
#if YAJL_MAJOR >= 2
@ -450,6 +477,10 @@ struct ConfigResult *parse_config(const char *input, struct context *context) {
tokenwalk += strlen(token->name + 1);
*tokenwalk++ = '\'';
} else {
/* Skip error tokens in error messages, they are used
* internally only and might confuse users. */
if (strcmp(token->name, "error") == 0)
continue;
/* Any other token is copied to the error message enclosed
* with angle brackets. */
*tokenwalk++ = '<';
@ -531,10 +562,30 @@ struct ConfigResult *parse_config(const char *input, struct context *context) {
ystr(position);
y(map_close);
/* Skip the rest of this line, but continue parsing. */
while ((walk - input) <= len && *walk != '\n')
walk++;
free(position);
free(errormessage);
clear_stack();
break;
/* To figure out in which state to go (e.g. MODE or INITIAL),
* we find the nearest state which contains an <error> token
* and follow that one. */
bool error_token_found = false;
for (int i = statelist_idx-1; (i >= 0) && !error_token_found; i--) {
cmdp_token_ptr *errptr = &(tokens[statelist[i]]);
for (int j = 0; j < errptr->n; j++) {
if (strcmp(errptr->array[j].name, "error") != 0)
continue;
next_state(&(errptr->array[j]));
error_token_found = true;
break;
}
}
assert(error_token_found);
}
}

42
testcases/t/201-config-parser.t
View File

@ -362,6 +362,47 @@ is(parser_calls($config),
$expected,
'colors ok');
################################################################################
# Verify that errors don’t harm subsequent valid statements
################################################################################
$config = <<'EOT';
hide_edge_border both
client.focused #4c7899 #285577 #ffffff #2e9ef4
EOT
$expected = <<'EOT';
ERROR: CONFIG: Expected one of these tokens: <end>, '#', 'set', 'bindsym', 'bindcode', 'bind', 'bar', 'font', 'mode', 'floating_minimum_size', 'floating_maximum_size', 'floating_modifier', 'default_orientation', 'workspace_layout', 'new_window', 'new_float', 'hide_edge_borders', 'for_window', 'assign', 'focus_follows_mouse', 'force_focus_wrapping', 'force_xinerama', 'force-xinerama', 'workspace_auto_back_and_forth', 'fake_outputs', 'fake-outputs', 'force_display_urgency_hint', 'workspace', 'ipc_socket', 'ipc-socket', 'restart_state', 'popup_during_fullscreen', 'exec_always', 'exec', 'client.background', 'client.focused_inactive', 'client.focused', 'client.unfocused', 'client.urgent'
ERROR: CONFIG: (in file <stdin>)
ERROR: CONFIG: Line 1: hide_edge_border both
ERROR: CONFIG: ^^^^^^^^^^^^^^^^^^^^^
ERROR: CONFIG: Line 2: client.focused #4c7899 #285577 #ffffff #2e9ef4
cfg_color(client.focused, #4c7899, #285577, #ffffff, #2e9ef4)
EOT
is(parser_calls($config),
$expected,
'errors dont harm subsequent statements');
$config = <<'EOT';
hide_edge_borders FOOBAR
client.focused #4c7899 #285577 #ffffff #2e9ef4
EOT
$expected = <<'EOT';
ERROR: CONFIG: Expected one of these tokens: 'none', 'vertical', 'horizontal', 'both', '1', 'yes', 'true', 'on', 'enable', 'active'
ERROR: CONFIG: (in file <stdin>)
ERROR: CONFIG: Line 1: hide_edge_borders FOOBAR
ERROR: CONFIG: ^^^^^^
ERROR: CONFIG: Line 2: client.focused #4c7899 #285577 #ffffff #2e9ef4
cfg_color(client.focused, #4c7899, #285577, #ffffff, #2e9ef4)
EOT
is(parser_calls($config),
$expected,
'errors dont harm subsequent statements');
################################################################################
# Error message with 2+2 lines of context
################################################################################
@ -524,6 +565,7 @@ ERROR: CONFIG: Line 2: output LVDS-1
ERROR: CONFIG: Line 3: unknown qux
ERROR: CONFIG: ^^^^^^^^^^^
ERROR: CONFIG: Line 4: }
cfg_bar_finish()
EOT
is(parser_calls($config),