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vsh: Rework how option to complete is found

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The way that auto completion works currently is that user's input
is parsed, and then we try to find the first --option (in the
parsed structure) that has the same value as user's input around
where <TAB> was pressed. For instance, for the following input:

  virsh # command --arg1 hello --arg2 world<TAB>

we will see "world" as text that user is trying to autocomplete
(this is affected by rl_basic_word_break_characters which
readline uses internally to break user's input into individual
words) and find that it is --arg2 that user is trying to
autocomplete. So far so good, for this naive approach. But
consider the following example:

  virsh # command --arg1 world --arg2 world<TAB>

Here, both arguments have the same value and because we see
"world" as text that user is trying to autocomplete we would
think that it is --arg1 that user wants to autocomplete. This is
obviously wrong.

Fortunately, readline stores the current position of cursor (into
rl_point) and we can use that when parsing user's input: whenever
we reach a position that matches the cursor then we know that
that is the place where <TAB> was pressed and hence that is the
--option that user wants to autocomplete. Readline stores the
cursor position as offset (numbered from 1) from the beginning of
user's input. We store this input into @parser->pos initially,
but then advance it as we tokenize it. Therefore, what we need is
to store the original position too.

Thanks to Martin who helped me with this.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This commit is contained in:
Michal Privoznik 2021-01-26 09:51:27 +01:00
parent f61a4e91ef
commit 22904b5702
4 changed files with 49 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
tools/virsh.c
View File

@ -777,7 +777,7 @@ virshParseArgv(vshControl *ctl, int argc, char **argv)
ctl->imode = false;
if (argc - optind == 1) {
vshDebug(ctl, VSH_ERR_INFO, "commands: \"%s\"\n", argv[optind]);
return vshCommandStringParse(ctl, argv[optind], NULL);
return vshCommandStringParse(ctl, argv[optind], NULL, 0);
} else {
return vshCommandArgvParse(ctl, argc - optind, argv + optind);
}
@ -915,7 +915,7 @@ main(int argc, char **argv)
if (*ctl->cmdstr) {
vshReadlineHistoryAdd(ctl->cmdstr);
if (vshCommandStringParse(ctl, ctl->cmdstr, NULL))
if (vshCommandStringParse(ctl, ctl->cmdstr, NULL, 0))
vshCommandRun(ctl, ctl->cmd);
}
VIR_FREE(ctl->cmdstr);

4
tools/virt-admin.c
View File

@ -1364,7 +1364,7 @@ vshAdmParseArgv(vshControl *ctl, int argc, char **argv)
ctl->imode = false;
if (argc - optind == 1) {
vshDebug(ctl, VSH_ERR_INFO, "commands: \"%s\"\n", argv[optind]);
return vshCommandStringParse(ctl, argv[optind], NULL);
return vshCommandStringParse(ctl, argv[optind], NULL, 0);
} else {
return vshCommandArgvParse(ctl, argc - optind, argv + optind);
}
@ -1594,7 +1594,7 @@ main(int argc, char **argv)
if (*ctl->cmdstr) {
vshReadlineHistoryAdd(ctl->cmdstr);
if (vshCommandStringParse(ctl, ctl->cmdstr, NULL))
if (vshCommandStringParse(ctl, ctl->cmdstr, NULL, 0))
vshCommandRun(ctl, ctl->cmd);
}
VIR_FREE(ctl->cmdstr);

58
tools/vsh.c
View File

@ -1318,6 +1318,8 @@ struct _vshCommandParser {
char **, bool);
/* vshCommandStringGetArg() */
char *pos;
const char *originalLine;
size_t point;
/* vshCommandArgvGetArg() */
char **arg_pos;
char **arg_end;
@ -1426,6 +1428,10 @@ vshCommandParse(vshControl *ctl, vshCommandParser *parser, vshCmd **partial)
arg->data = tkdata;
tkdata = NULL;
arg->next = NULL;
if (parser->pos - parser->originalLine == parser->point - 1)
arg->completeThis = true;
if (!first)
first = arg;
if (last)
@ -1477,6 +1483,9 @@ vshCommandParse(vshControl *ctl, vshCommandParser *parser, vshCmd **partial)
arg->next = NULL;
tkdata = NULL;
if (parser->pos - parser->originalLine == parser->point)
arg->completeThis = true;
if (!first)
first = arg;
if (last)
@ -1588,7 +1597,7 @@ vshCommandArgvGetArg(vshControl *ctl G_GNUC_UNUSED,
bool
vshCommandArgvParse(vshControl *ctl, int nargs, char **argv)
{
vshCommandParser parser;
vshCommandParser parser = { 0 };
if (nargs <= 0)
return false;
@ -1675,15 +1684,38 @@ vshCommandStringGetArg(vshControl *ctl, vshCommandParser *parser, char **res,
return VSH_TK_ARG;
}
/**
* vshCommandStringParse:
* @ctl virsh control structure
* @cmdstr: string to parse
* @partial: store partially parsed command here
* @point: position of cursor (rl_point)
*
* Parse given string @cmdstr as a command and store it under
* @ctl->cmd. For readline completion, if @partial is not NULL on
* the input then errors in parsing are ignored (because user is
* still in progress of writing the command string) and partially
* parsed command is stored at *@partial (caller has to free it
* afterwards). Among with @partial, caller must set @point which
* is the position of cursor in @cmdstr (offset, numbered from 1).
* Parser will then set @completeThis attribute to true for the
* vshCmdOpt that appeared under the cursor.
*/
bool
vshCommandStringParse(vshControl *ctl, char *cmdstr, vshCmd **partial)
vshCommandStringParse(vshControl *ctl,
char *cmdstr,
vshCmd **partial,
size_t point)
{
vshCommandParser parser;
vshCommandParser parser = { 0 };
if (cmdstr == NULL || *cmdstr == '\0')
return false;
parser.pos = cmdstr;
parser.originalLine = cmdstr;
parser.point = point;
parser.getNextArg = vshCommandStringGetArg;
return vshCommandParse(ctl, &parser, partial);
}
@ -2634,28 +2666,20 @@ vshReadlineOptionsGenerator(const char *text,
static const vshCmdOptDef *
vshReadlineCommandFindOpt(const vshCmd *partial,
const char *text)
vshReadlineCommandFindOpt(const vshCmd *partial)
{
const vshCmd *tmp = partial;
while (tmp && tmp->next) {
if (tmp->def == tmp->next->def &&
!tmp->next->opts)
break;
tmp = tmp->next;
}
if (tmp && tmp->opts) {
while (tmp) {
const vshCmdOpt *opt = tmp->opts;
while (opt) {
if (STREQ_NULLABLE(opt->data, text) ||
STREQ_NULLABLE(opt->data, " "))
if (opt->completeThis)
return opt->def;
opt = opt->next;
}
tmp = tmp->next;
}
return NULL;
@ -2717,7 +2741,7 @@ vshReadlineParse(const char *text, int state)
*(line + rl_point) = '\0';
vshCommandStringParse(NULL, line, &partial);
vshCommandStringParse(NULL, line, &partial, rl_point);
if (partial) {
cmd = partial->def;
@ -2735,7 +2759,7 @@ vshReadlineParse(const char *text, int state)
cmd = NULL;
}
opt = vshReadlineCommandFindOpt(partial, text);
opt = vshReadlineCommandFindOpt(partial);
if (!cmd) {
list = vshReadlineCommandGenerator(text);

5
tools/vsh.h
View File

@ -152,6 +152,8 @@ struct _vshCmdOptDef {
struct _vshCmdOpt {
const vshCmdOptDef *def; /* non-NULL pointer to option definition */
char *data; /* allocated data, or NULL for bool option */
bool completeThis; /* true if this is the option user's wishing to
autocomplete */
vshCmdOpt *next;
};
@ -292,7 +294,8 @@ int vshBlockJobOptionBandwidth(vshControl *ctl,
unsigned long *bandwidth);
bool vshCommandOptBool(const vshCmd *cmd, const char *name);
bool vshCommandRun(vshControl *ctl, const vshCmd *cmd);
bool vshCommandStringParse(vshControl *ctl, char *cmdstr, vshCmd **partial);
bool vshCommandStringParse(vshControl *ctl, char *cmdstr,
vshCmd **partial, size_t point);
const vshCmdOpt *vshCommandOptArgv(vshControl *ctl, const vshCmd *cmd,
const vshCmdOpt *opt);