diff options
Diffstat (limited to 'util/keyval.c')
| -rw-r--r-- | util/keyval.c | 103 |
1 files changed, 76 insertions, 27 deletions
diff --git a/util/keyval.c b/util/keyval.c index 13def4af54..7f625ad33c 100644 --- a/util/keyval.c +++ b/util/keyval.c @@ -14,10 +14,11 @@ * KEY=VALUE,... syntax: * * key-vals = [ key-val { ',' key-val } [ ',' ] ] - * key-val = key '=' val + * key-val = key '=' val | help * key = key-fragment { '.' key-fragment } - * key-fragment = / [^=,.]* / - * val = { / [^,]* / | ',,' } + * key-fragment = / [^=,.]+ / + * val = { / [^,]+ / | ',,' } + * help = 'help' | '?' * * Semantics defined by reduction to JSON: * @@ -54,6 +55,9 @@ * * The length of any key-fragment must be between 1 and 127. * + * If any key-val is help, the object is to be treated as a help + * request. + * * Design flaw: there is no way to denote an empty array or non-root * object. While interpreting "key absent" as empty seems natural * (removing a key-val from the input string removes the member when @@ -71,12 +75,16 @@ * Awkward. Note that we carefully restrict alternate types to avoid * similar ambiguity. * - * Additional syntax for use with an implied key: + * Alternative syntax for use with an implied key: + * + * key-vals = [ key-val-1st { ',' key-val } [ ',' ] ] + * key-val-1st = val-no-key | key-val + * val-no-key = / [^=,]+ / - help * - * key-vals-ik = val-no-key [ ',' key-vals ] - * val-no-key = / [^=,]* / + * where val-no-key is syntactic sugar for implied-key=val-no-key. * - * where no-key is syntactic sugar for implied-key=val-no-key. + * Note that you can't use the sugared form when the value contains + * '=' or ','. */ #include "qemu/osdep.h" @@ -85,6 +93,7 @@ #include "qapi/qmp/qlist.h" #include "qapi/qmp/qstring.h" #include "qemu/cutils.h" +#include "qemu/help_option.h" #include "qemu/option.h" /* @@ -158,18 +167,23 @@ static QObject *keyval_parse_put(QDict *cur, } /* - * Parse one KEY=VALUE from @params, store result in @qdict. + * Parse one parameter from @params. + * + * If we're looking at KEY=VALUE, store result in @qdict. * The first fragment of KEY applies to @qdict. Subsequent fragments * apply to nested QDicts, which are created on demand. @implied_key * is as in keyval_parse(). - * On success, return a pointer to the next KEY=VALUE, or else to '\0'. + * + * If we're looking at "help" or "?", set *help to true. + * + * On success, return a pointer to the next parameter, or else to '\0'. * On failure, return NULL. */ static const char *keyval_parse_one(QDict *qdict, const char *params, - const char *implied_key, + const char *implied_key, bool *help, Error **errp) { - const char *key, *key_end, *s, *end; + const char *key, *key_end, *val_end, *s, *end; size_t len; char key_in_cur[128]; QDict *cur; @@ -178,11 +192,23 @@ static const char *keyval_parse_one(QDict *qdict, const char *params, QString *val; key = params; + val_end = NULL; len = strcspn(params, "=,"); - if (implied_key && len && key[len] != '=') { - /* Desugar implied key */ - key = implied_key; - len = strlen(implied_key); + if (len && key[len] != '=') { + if (starts_with_help_option(key) == len) { + *help = true; + s = key + len; + if (*s == ',') { + s++; + } + return s; + } + if (implied_key) { + /* Desugar implied key */ + key = implied_key; + val_end = params + len; + len = strlen(implied_key); + } } key_end = key + len; @@ -237,7 +263,11 @@ static const char *keyval_parse_one(QDict *qdict, const char *params, if (key == implied_key) { assert(!*s); - s = params; + val = qstring_from_substr(params, 0, val_end - params); + s = val_end; + if (*s == ',') { + s++; + } } else { if (*s != '=') { error_setg(errp, "Expected '=' after parameter '%.*s'", @@ -245,19 +275,19 @@ static const char *keyval_parse_one(QDict *qdict, const char *params, return NULL; } s++; - } - val = qstring_new(); - for (;;) { - if (!*s) { - break; - } else if (*s == ',') { - s++; - if (*s != ',') { + val = qstring_new(); + for (;;) { + if (!*s) { break; + } else if (*s == ',') { + s++; + if (*s != ',') { + break; + } } + qstring_append_chr(val, *s++); } - qstring_append_chr(val, *s++); } if (!keyval_parse_put(cur, key_in_cur, val, key, key_end, errp)) { @@ -388,21 +418,32 @@ static QObject *keyval_listify(QDict *cur, GSList *key_of_cur, Error **errp) /* * Parse @params in QEMU's traditional KEY=VALUE,... syntax. + * * If @implied_key, the first KEY= can be omitted. @implied_key is * implied then, and VALUE can't be empty or contain ',' or '='. + * + * A parameter "help" or "?" without a value isn't added to the + * resulting dictionary, but instead is interpreted as help request. + * All other options are parsed and returned normally so that context + * specific help can be printed. + * + * If @p_help is not NULL, store whether help is requested there. + * If @p_help is NULL and help is requested, fail. + * * On success, return a dictionary of the parsed keys and values. * On failure, store an error through @errp and return NULL. */ QDict *keyval_parse(const char *params, const char *implied_key, - Error **errp) + bool *p_help, Error **errp) { QDict *qdict = qdict_new(); QObject *listified; const char *s; + bool help = false; s = params; while (*s) { - s = keyval_parse_one(qdict, s, implied_key, errp); + s = keyval_parse_one(qdict, s, implied_key, &help, errp); if (!s) { qobject_unref(qdict); return NULL; @@ -410,6 +451,14 @@ QDict *keyval_parse(const char *params, const char *implied_key, implied_key = NULL; } + if (p_help) { + *p_help = help; + } else if (help) { + error_setg(errp, "Help is not available for this option"); + qobject_unref(qdict); + return NULL; + } + listified = keyval_listify(qdict, NULL, errp); if (!listified) { qobject_unref(qdict); |