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vsh: Refactor logic in vshCommandParse
Refactor the existing logic using two nested loops with a jump into the middle of both with 3 separate places fetching next token to a single loop using a state machine with one centralized place to fetch next tokens and add explanation comments. Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This commit is contained in:
Peter Krempa
parent
c27070f738
commit
5540c3d241
368
tools/vsh.c
368
tools/vsh.c
@ -1476,171 +1476,255 @@ vshCmdNew(vshControl *ctl,
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}
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static bool
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vshCommandParse(vshControl *ctl, vshCommandParser *parser, vshCmd **partial)
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static int
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vshCmdOptAssignPositional(vshControl *ctl,
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vshCmd *cmd,
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const char *val,
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bool report)
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{
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g_autoptr(vshCmd) cmd = NULL;
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char *tkdata = NULL;
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vshCmd *clast = NULL;
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vshCmdOpt *opt;
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if (!partial) {
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if (!(opt = vshCmdGetNextPositionalOpt(cmd))) {
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/* ignore spurious arguments for 'help' command */
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if (STREQ(cmd->def->name, "help"))
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return 0;
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if (report)
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vshError(ctl, _("unexpected data '%1$s'"), val);
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return -1;
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}
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vshCmdOptAssign(ctl, cmd, opt, val, report);
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return 0;
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}
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typedef enum {
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VSH_CMD_PARSER_STATE_START,
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VSH_CMD_PARSER_STATE_COMMENT,
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VSH_CMD_PARSER_STATE_COMMAND,
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VSH_CMD_PARSER_STATE_ASSIGN_OPT,
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VSH_CMD_PARSER_STATE_POSITIONAL_ONLY,
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} vshCommandParserState;
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static bool
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vshCommandParse(vshControl *ctl,
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vshCommandParser *parser,
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vshCmd **partial)
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{
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g_autoptr(vshCmd) cmds = NULL; /* linked list of all parsed commands in this session */
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vshCmd *cmds_last = NULL;
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g_autoptr(vshCmd) cmd = NULL; /* currently parsed command */
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vshCommandParserState state = VSH_CMD_PARSER_STATE_START;
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vshCmdOpt *opt = NULL;
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g_autofree char *optionvalue = NULL;
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bool report = !partial;
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bool ret = false;
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if (partial) {
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g_clear_pointer(partial, vshCommandFree);
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} else {
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g_clear_pointer(&ctl->cmd, vshCommandFree);
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}
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while (1) {
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vshCommandToken tk;
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bool data_only = false;
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/* previous iteration might have already gotten a value. Store it as the
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* token in this iteration */
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g_autofree char *tkdata = g_steal_pointer(&optionvalue);
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if (partial) {
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g_clear_pointer(partial, vshCommandFree);
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/* If we have a value already or the option to fill is a boolean we
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* don't want to fetch a new token */
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if (!(tkdata ||
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(opt && opt->def->type == VSH_OT_BOOL))) {
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vshCommandToken tk;
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tk = parser->getNextArg(ctl, parser, &tkdata, report);
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switch (tk) {
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case VSH_TK_ARG:
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/* will be handled below */
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break;
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case VSH_TK_ERROR:
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goto out;
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case VSH_TK_END:
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case VSH_TK_SUBCMD_END:
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/* The last argument name expects a value, but it's missing */
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if (opt) {
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if (partial) {
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/* for completion to work we need to also store the
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* last token into the last 'opt' */
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vshCmdOptAssign(ctl, cmd, opt, tkdata, report);
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} else {
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if (opt->def->type == VSH_OT_INT)
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vshError(ctl, _("expected syntax: --%1$s <number>"),
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opt->def->name);
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else
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vshError(ctl, _("expected syntax: --%1$s <string>"),
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opt->def->name);
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goto out;
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}
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}
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/* command parsed -- allocate new struct for the command */
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if (cmd) {
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/* if we encountered --help, replace parsed command with 'help <cmdname>' */
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if (cmd->helpOptionSeen) {
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vshCmd *helpcmd = vshCmdNewHelp(cmd->def->name);
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vshCommandFree(cmd);
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cmd = helpcmd;
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}
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if (!partial &&
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vshCommandCheckOpts(ctl, cmd) < 0)
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goto out;
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if (!cmds)
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cmds = cmd;
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if (cmds_last)
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cmds_last->next = cmd;
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cmds_last = g_steal_pointer(&cmd);
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}
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/* everything parsed */
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if (tk == VSH_TK_END) {
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ret = true;
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goto out;
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}
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/* after processing the command we need to start over again to
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* fetch another token */
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state = VSH_CMD_PARSER_STATE_START;
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continue;
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}
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}
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while (1) {
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vshCmdOpt *opt = NULL;
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/* at this point we know that @tkdata is an argument */
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switch (state) {
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case VSH_CMD_PARSER_STATE_START:
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if (*tkdata == '#') {
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state = VSH_CMD_PARSER_STATE_COMMENT;
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} else {
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state = VSH_CMD_PARSER_STATE_COMMAND;
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tkdata = NULL;
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tk = parser->getNextArg(ctl, parser, &tkdata, true);
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if (!(cmd = vshCmdNew(ctl, tkdata, !partial)))
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goto out;
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}
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if (tk == VSH_TK_ERROR)
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goto syntaxError;
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if (tk != VSH_TK_ARG) {
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VIR_FREE(tkdata);
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break;
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case VSH_CMD_PARSER_STATE_COMMENT:
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/* continue eating tokens until end of line or end of input */
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state = VSH_CMD_PARSER_STATE_COMMENT;
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break;
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case VSH_CMD_PARSER_STATE_COMMAND: {
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/* parsing individual options for the command. There are following options:
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* --option
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* --option value
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* --option=value
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* --aliasoptionwithvalue (value is part of the alias definition)
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* value
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* -- (terminate accepting '--option', fill only positional args)
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*/
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const char *optionname = tkdata + 2;
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char *sep;
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if (!STRPREFIX(tkdata, "--")) {
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if (vshCmdOptAssignPositional(ctl, cmd, tkdata, report) < 0)
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goto out;
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break;
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}
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if (cmd == NULL) {
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/* first token must be command name or comment */
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if (*tkdata == '#') {
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do {
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VIR_FREE(tkdata);
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tk = parser->getNextArg(ctl, parser, &tkdata, false);
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} while (tk == VSH_TK_ARG);
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VIR_FREE(tkdata);
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if (STREQ(tkdata, "--")) {
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state = VSH_CMD_PARSER_STATE_POSITIONAL_ONLY;
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break;
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}
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if ((sep = strchr(optionname, '='))) {
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*(sep++) = '\0';
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/* 'optionvalue' has lifetime until next iteration */
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optionvalue = g_strdup(sep);
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}
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/* lookup the option. Note that vshCmdGetOption also resolves aliases
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* and thus the value possibly contained in the alias */
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if (!(opt = vshCmdGetOption(ctl, cmd, optionname, &optionvalue, report))) {
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if (STRNEQ(cmd->def->name, "help"))
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goto out;
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/* ignore spurious arguments for 'help' command */
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g_clear_pointer(&optionvalue, g_free);
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state = VSH_CMD_PARSER_STATE_COMMAND;
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} else {
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state = VSH_CMD_PARSER_STATE_ASSIGN_OPT;
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}
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}
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break;
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case VSH_CMD_PARSER_STATE_ASSIGN_OPT:
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/* Parameter for a boolean was passed via --boolopt=val */
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if (tkdata && opt->def->type == VSH_OT_BOOL) {
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if (report)
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vshError(ctl, _("invalid '=' after option --%1$s"),
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opt->def->name);
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goto out;
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}
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vshCmdOptAssign(ctl, cmd, opt, tkdata, report);
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opt = NULL;
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state = VSH_CMD_PARSER_STATE_COMMAND;
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break;
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case VSH_CMD_PARSER_STATE_POSITIONAL_ONLY:
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state = VSH_CMD_PARSER_STATE_POSITIONAL_ONLY;
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if (vshCmdOptAssignPositional(ctl, cmd, tkdata, report) < 0)
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goto out;
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break;
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}
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}
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out:
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if (partial) {
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/* When parsing a command for command completion, the last processed
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* command or the one being currently parsed */
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if (cmd) {
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*partial = g_steal_pointer(&cmd);
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} else if (cmds == cmds_last) {
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*partial = g_steal_pointer(&cmds);
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} else {
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/* break the last command out of the linked list and let the rest be freed */
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vshCmd *nc;
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for (nc = cmds; nc; nc = nc->next) {
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if (nc->next == cmds_last) {
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nc->next = NULL;
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break;
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}
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if (!(cmd = vshCmdNew(ctl, tkdata, !partial)))
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goto syntaxError;
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VIR_FREE(tkdata);
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} else if (data_only) {
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goto get_data;
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} else if (tkdata[0] == '-' && tkdata[1] == '-' &&
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g_ascii_isalnum(tkdata[2])) {
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char *optstr = strchr(tkdata + 2, '=');
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if (optstr) {
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*optstr = '\0'; /* convert the '=' to '\0' */
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optstr = g_strdup(optstr + 1);
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}
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/* Special case 'help' to ignore all spurious options */
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if (!(opt = vshCmdGetOption(ctl, cmd, tkdata + 2,
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&optstr, partial == NULL))) {
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VIR_FREE(optstr);
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if (STREQ(cmd->def->name, "help"))
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continue;
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goto syntaxError;
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}
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VIR_FREE(tkdata);
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if (opt->def->type != VSH_OT_BOOL) {
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/* option data */
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if (optstr)
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tkdata = optstr;
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else
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tk = parser->getNextArg(ctl, parser, &tkdata, partial == NULL);
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if (tk == VSH_TK_ERROR)
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goto syntaxError;
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if (tk != VSH_TK_ARG) {
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if (partial) {
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vshCmdOptAssign(ctl, cmd, opt, tkdata, !partial);
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VIR_FREE(tkdata);
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} else {
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vshError(ctl,
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_("expected syntax: --%1$s <%2$s>"),
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opt->def->name,
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opt->def->type ==
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VSH_OT_INT ? _("number") : _("string"));
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}
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goto syntaxError;
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}
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} else {
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tkdata = NULL;
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if (optstr) {
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if (!partial)
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vshError(ctl, _("invalid '=' after option --%1$s"),
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opt->def->name);
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VIR_FREE(optstr);
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goto syntaxError;
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}
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}
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} else if (tkdata[0] == '-' && tkdata[1] == '-' &&
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tkdata[2] == '\0') {
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VIR_FREE(tkdata);
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data_only = true;
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continue;
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} else {
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get_data:
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/* Special case 'help' to ignore spurious data */
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if (!(opt = vshCmdGetNextPositionalOpt(cmd)) &&
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STRNEQ(cmd->def->name, "help")) {
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if (!partial)
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vshError(ctl, _("unexpected data '%1$s'"), tkdata);
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goto syntaxError;
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}
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}
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if (opt) {
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vshCmdOptAssign(ctl, cmd, opt, tkdata, !partial);
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VIR_FREE(tkdata);
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}
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*partial = cmds_last;
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}
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/* command parsed -- allocate new struct for the command */
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if (cmd) {
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/* if we encountered --help, replace parsed command with 'help <cmdname>' */
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if (cmd->helpOptionSeen) {
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vshCmd *helpcmd = vshCmdNewHelp(cmd->def->name);
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vshCommandFree(cmd);
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cmd = helpcmd;
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}
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if (!partial &&
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vshCommandCheckOpts(ctl, cmd) < 0) {
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vshCommandFree(cmd);
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goto syntaxError;
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}
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if (partial) {
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vshCommandFree(*partial);
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*partial = g_steal_pointer(&cmd);
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} else {
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if (!ctl->cmd)
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ctl->cmd = cmd;
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if (clast)
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clast->next = cmd;
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clast = g_steal_pointer(&cmd);
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}
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}
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if (tk == VSH_TK_END)
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break;
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}
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return true;
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syntaxError:
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if (partial) {
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*partial = g_steal_pointer(&cmd);
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} else {
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g_clear_pointer(&ctl->cmd, vshCommandFree);
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/* for normal command parsing use the whole parsed command list, but
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* only on success */
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if (ret == true) {
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ctl->cmd = g_steal_pointer(&cmds);
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}
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}
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VIR_FREE(tkdata);
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return false;
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return ret;
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}
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/* --------------------
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* Command argv parsing
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* --------------------
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