| /* |
| * JSON Parser |
| * |
| * Copyright IBM, Corp. 2009 |
| * |
| * Authors: |
| * Anthony Liguori <aliguori@us.ibm.com> |
| * |
| * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. |
| * See the COPYING.LIB file in the top-level directory. |
| * |
| */ |
| |
| #include <stdarg.h> |
| |
| #include "qemu-common.h" |
| #include "qapi/qmp/qstring.h" |
| #include "qapi/qmp/qint.h" |
| #include "qapi/qmp/qdict.h" |
| #include "qapi/qmp/qlist.h" |
| #include "qapi/qmp/qfloat.h" |
| #include "qapi/qmp/qbool.h" |
| #include "qapi/qmp/json-parser.h" |
| #include "qapi/qmp/json-lexer.h" |
| #include "qapi/qmp/qerror.h" |
| |
| typedef struct JSONParserContext |
| { |
| Error *err; |
| struct { |
| QObject **buf; |
| size_t pos; |
| size_t count; |
| } tokens; |
| } JSONParserContext; |
| |
| #define BUG_ON(cond) assert(!(cond)) |
| |
| /** |
| * TODO |
| * |
| * 0) make errors meaningful again |
| * 1) add geometry information to tokens |
| * 3) should we return a parsed size? |
| * 4) deal with premature EOI |
| */ |
| |
| static QObject *parse_value(JSONParserContext *ctxt, va_list *ap); |
| |
| /** |
| * Token manipulators |
| * |
| * tokens are dictionaries that contain a type, a string value, and geometry information |
| * about a token identified by the lexer. These are routines that make working with |
| * these objects a bit easier. |
| */ |
| static const char *token_get_value(QObject *obj) |
| { |
| return qdict_get_str(qobject_to_qdict(obj), "token"); |
| } |
| |
| static JSONTokenType token_get_type(QObject *obj) |
| { |
| return qdict_get_int(qobject_to_qdict(obj), "type"); |
| } |
| |
| static int token_is_operator(QObject *obj, char op) |
| { |
| const char *val; |
| |
| if (token_get_type(obj) != JSON_OPERATOR) { |
| return 0; |
| } |
| |
| val = token_get_value(obj); |
| |
| return (val[0] == op) && (val[1] == 0); |
| } |
| |
| static int token_is_keyword(QObject *obj, const char *value) |
| { |
| if (token_get_type(obj) != JSON_KEYWORD) { |
| return 0; |
| } |
| |
| return strcmp(token_get_value(obj), value) == 0; |
| } |
| |
| static int token_is_escape(QObject *obj, const char *value) |
| { |
| if (token_get_type(obj) != JSON_ESCAPE) { |
| return 0; |
| } |
| |
| return (strcmp(token_get_value(obj), value) == 0); |
| } |
| |
| /** |
| * Error handler |
| */ |
| static void GCC_FMT_ATTR(3, 4) parse_error(JSONParserContext *ctxt, |
| QObject *token, const char *msg, ...) |
| { |
| va_list ap; |
| char message[1024]; |
| va_start(ap, msg); |
| vsnprintf(message, sizeof(message), msg, ap); |
| va_end(ap); |
| if (ctxt->err) { |
| error_free(ctxt->err); |
| ctxt->err = NULL; |
| } |
| error_set(&ctxt->err, QERR_JSON_PARSE_ERROR, message); |
| } |
| |
| /** |
| * String helpers |
| * |
| * These helpers are used to unescape strings. |
| */ |
| static void wchar_to_utf8(uint16_t wchar, char *buffer, size_t buffer_length) |
| { |
| if (wchar <= 0x007F) { |
| BUG_ON(buffer_length < 2); |
| |
| buffer[0] = wchar & 0x7F; |
| buffer[1] = 0; |
| } else if (wchar <= 0x07FF) { |
| BUG_ON(buffer_length < 3); |
| |
| buffer[0] = 0xC0 | ((wchar >> 6) & 0x1F); |
| buffer[1] = 0x80 | (wchar & 0x3F); |
| buffer[2] = 0; |
| } else { |
| BUG_ON(buffer_length < 4); |
| |
| buffer[0] = 0xE0 | ((wchar >> 12) & 0x0F); |
| buffer[1] = 0x80 | ((wchar >> 6) & 0x3F); |
| buffer[2] = 0x80 | (wchar & 0x3F); |
| buffer[3] = 0; |
| } |
| } |
| |
| static int hex2decimal(char ch) |
| { |
| if (ch >= '0' && ch <= '9') { |
| return (ch - '0'); |
| } else if (ch >= 'a' && ch <= 'f') { |
| return 10 + (ch - 'a'); |
| } else if (ch >= 'A' && ch <= 'F') { |
| return 10 + (ch - 'A'); |
| } |
| |
| return -1; |
| } |
| |
| /** |
| * parse_string(): Parse a json string and return a QObject |
| * |
| * string |
| * "" |
| * " chars " |
| * chars |
| * char |
| * char chars |
| * char |
| * any-Unicode-character- |
| * except-"-or-\-or- |
| * control-character |
| * \" |
| * \\ |
| * \/ |
| * \b |
| * \f |
| * \n |
| * \r |
| * \t |
| * \u four-hex-digits |
| */ |
| static QString *qstring_from_escaped_str(JSONParserContext *ctxt, QObject *token) |
| { |
| const char *ptr = token_get_value(token); |
| QString *str; |
| int double_quote = 1; |
| |
| if (*ptr == '"') { |
| double_quote = 1; |
| } else { |
| double_quote = 0; |
| } |
| ptr++; |
| |
| str = qstring_new(); |
| while (*ptr && |
| ((double_quote && *ptr != '"') || (!double_quote && *ptr != '\''))) { |
| if (*ptr == '\\') { |
| ptr++; |
| |
| switch (*ptr) { |
| case '"': |
| qstring_append(str, "\""); |
| ptr++; |
| break; |
| case '\'': |
| qstring_append(str, "'"); |
| ptr++; |
| break; |
| case '\\': |
| qstring_append(str, "\\"); |
| ptr++; |
| break; |
| case '/': |
| qstring_append(str, "/"); |
| ptr++; |
| break; |
| case 'b': |
| qstring_append(str, "\b"); |
| ptr++; |
| break; |
| case 'f': |
| qstring_append(str, "\f"); |
| ptr++; |
| break; |
| case 'n': |
| qstring_append(str, "\n"); |
| ptr++; |
| break; |
| case 'r': |
| qstring_append(str, "\r"); |
| ptr++; |
| break; |
| case 't': |
| qstring_append(str, "\t"); |
| ptr++; |
| break; |
| case 'u': { |
| uint16_t unicode_char = 0; |
| char utf8_char[4]; |
| int i = 0; |
| |
| ptr++; |
| |
| for (i = 0; i < 4; i++) { |
| if (qemu_isxdigit(*ptr)) { |
| unicode_char |= hex2decimal(*ptr) << ((3 - i) * 4); |
| } else { |
| parse_error(ctxt, token, |
| "invalid hex escape sequence in string"); |
| goto out; |
| } |
| ptr++; |
| } |
| |
| wchar_to_utf8(unicode_char, utf8_char, sizeof(utf8_char)); |
| qstring_append(str, utf8_char); |
| } break; |
| default: |
| parse_error(ctxt, token, "invalid escape sequence in string"); |
| goto out; |
| } |
| } else { |
| char dummy[2]; |
| |
| dummy[0] = *ptr++; |
| dummy[1] = 0; |
| |
| qstring_append(str, dummy); |
| } |
| } |
| |
| return str; |
| |
| out: |
| QDECREF(str); |
| return NULL; |
| } |
| |
| static QObject *parser_context_pop_token(JSONParserContext *ctxt) |
| { |
| QObject *token; |
| g_assert(ctxt->tokens.pos < ctxt->tokens.count); |
| token = ctxt->tokens.buf[ctxt->tokens.pos]; |
| ctxt->tokens.pos++; |
| return token; |
| } |
| |
| /* Note: parser_context_{peek|pop}_token do not increment the |
| * token object's refcount. In both cases the references will continue |
| * to be tracked and cleaned up in parser_context_free(), so do not |
| * attempt to free the token object. |
| */ |
| static QObject *parser_context_peek_token(JSONParserContext *ctxt) |
| { |
| QObject *token; |
| g_assert(ctxt->tokens.pos < ctxt->tokens.count); |
| token = ctxt->tokens.buf[ctxt->tokens.pos]; |
| return token; |
| } |
| |
| static JSONParserContext parser_context_save(JSONParserContext *ctxt) |
| { |
| JSONParserContext saved_ctxt = {0}; |
| saved_ctxt.tokens.pos = ctxt->tokens.pos; |
| saved_ctxt.tokens.count = ctxt->tokens.count; |
| saved_ctxt.tokens.buf = ctxt->tokens.buf; |
| return saved_ctxt; |
| } |
| |
| static void parser_context_restore(JSONParserContext *ctxt, |
| JSONParserContext saved_ctxt) |
| { |
| ctxt->tokens.pos = saved_ctxt.tokens.pos; |
| ctxt->tokens.count = saved_ctxt.tokens.count; |
| ctxt->tokens.buf = saved_ctxt.tokens.buf; |
| } |
| |
| static void tokens_append_from_iter(QObject *obj, void *opaque) |
| { |
| JSONParserContext *ctxt = opaque; |
| g_assert(ctxt->tokens.pos < ctxt->tokens.count); |
| ctxt->tokens.buf[ctxt->tokens.pos++] = obj; |
| qobject_incref(obj); |
| } |
| |
| static JSONParserContext *parser_context_new(QList *tokens) |
| { |
| JSONParserContext *ctxt; |
| size_t count; |
| |
| if (!tokens) { |
| return NULL; |
| } |
| |
| count = qlist_size(tokens); |
| if (count == 0) { |
| return NULL; |
| } |
| |
| ctxt = g_malloc0(sizeof(JSONParserContext)); |
| ctxt->tokens.pos = 0; |
| ctxt->tokens.count = count; |
| ctxt->tokens.buf = g_malloc(count * sizeof(QObject *)); |
| qlist_iter(tokens, tokens_append_from_iter, ctxt); |
| ctxt->tokens.pos = 0; |
| |
| return ctxt; |
| } |
| |
| /* to support error propagation, ctxt->err must be freed separately */ |
| static void parser_context_free(JSONParserContext *ctxt) |
| { |
| int i; |
| if (ctxt) { |
| for (i = 0; i < ctxt->tokens.count; i++) { |
| qobject_decref(ctxt->tokens.buf[i]); |
| } |
| g_free(ctxt->tokens.buf); |
| g_free(ctxt); |
| } |
| } |
| |
| /** |
| * Parsing rules |
| */ |
| static int parse_pair(JSONParserContext *ctxt, QDict *dict, va_list *ap) |
| { |
| QObject *key = NULL, *token = NULL, *value, *peek; |
| JSONParserContext saved_ctxt = parser_context_save(ctxt); |
| |
| peek = parser_context_peek_token(ctxt); |
| if (peek == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| |
| key = parse_value(ctxt, ap); |
| if (!key || qobject_type(key) != QTYPE_QSTRING) { |
| parse_error(ctxt, peek, "key is not a string in object"); |
| goto out; |
| } |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| |
| if (!token_is_operator(token, ':')) { |
| parse_error(ctxt, token, "missing : in object pair"); |
| goto out; |
| } |
| |
| value = parse_value(ctxt, ap); |
| if (value == NULL) { |
| parse_error(ctxt, token, "Missing value in dict"); |
| goto out; |
| } |
| |
| qdict_put_obj(dict, qstring_get_str(qobject_to_qstring(key)), value); |
| |
| qobject_decref(key); |
| |
| return 0; |
| |
| out: |
| parser_context_restore(ctxt, saved_ctxt); |
| qobject_decref(key); |
| |
| return -1; |
| } |
| |
| static QObject *parse_object(JSONParserContext *ctxt, va_list *ap) |
| { |
| QDict *dict = NULL; |
| QObject *token, *peek; |
| JSONParserContext saved_ctxt = parser_context_save(ctxt); |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| goto out; |
| } |
| |
| if (!token_is_operator(token, '{')) { |
| goto out; |
| } |
| token = NULL; |
| |
| dict = qdict_new(); |
| |
| peek = parser_context_peek_token(ctxt); |
| if (peek == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| |
| if (!token_is_operator(peek, '}')) { |
| if (parse_pair(ctxt, dict, ap) == -1) { |
| goto out; |
| } |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| |
| while (!token_is_operator(token, '}')) { |
| if (!token_is_operator(token, ',')) { |
| parse_error(ctxt, token, "expected separator in dict"); |
| goto out; |
| } |
| token = NULL; |
| |
| if (parse_pair(ctxt, dict, ap) == -1) { |
| goto out; |
| } |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| } |
| token = NULL; |
| } else { |
| token = parser_context_pop_token(ctxt); |
| token = NULL; |
| } |
| |
| return QOBJECT(dict); |
| |
| out: |
| parser_context_restore(ctxt, saved_ctxt); |
| QDECREF(dict); |
| return NULL; |
| } |
| |
| static QObject *parse_array(JSONParserContext *ctxt, va_list *ap) |
| { |
| QList *list = NULL; |
| QObject *token, *peek; |
| JSONParserContext saved_ctxt = parser_context_save(ctxt); |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| goto out; |
| } |
| |
| if (!token_is_operator(token, '[')) { |
| token = NULL; |
| goto out; |
| } |
| token = NULL; |
| |
| list = qlist_new(); |
| |
| peek = parser_context_peek_token(ctxt); |
| if (peek == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| |
| if (!token_is_operator(peek, ']')) { |
| QObject *obj; |
| |
| obj = parse_value(ctxt, ap); |
| if (obj == NULL) { |
| parse_error(ctxt, token, "expecting value"); |
| goto out; |
| } |
| |
| qlist_append_obj(list, obj); |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| |
| while (!token_is_operator(token, ']')) { |
| if (!token_is_operator(token, ',')) { |
| parse_error(ctxt, token, "expected separator in list"); |
| goto out; |
| } |
| |
| token = NULL; |
| |
| obj = parse_value(ctxt, ap); |
| if (obj == NULL) { |
| parse_error(ctxt, token, "expecting value"); |
| goto out; |
| } |
| |
| qlist_append_obj(list, obj); |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| parse_error(ctxt, NULL, "premature EOI"); |
| goto out; |
| } |
| } |
| |
| token = NULL; |
| } else { |
| token = parser_context_pop_token(ctxt); |
| token = NULL; |
| } |
| |
| return QOBJECT(list); |
| |
| out: |
| parser_context_restore(ctxt, saved_ctxt); |
| QDECREF(list); |
| return NULL; |
| } |
| |
| static QObject *parse_keyword(JSONParserContext *ctxt) |
| { |
| QObject *token, *ret; |
| JSONParserContext saved_ctxt = parser_context_save(ctxt); |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| goto out; |
| } |
| |
| if (token_get_type(token) != JSON_KEYWORD) { |
| goto out; |
| } |
| |
| if (token_is_keyword(token, "true")) { |
| ret = QOBJECT(qbool_from_int(true)); |
| } else if (token_is_keyword(token, "false")) { |
| ret = QOBJECT(qbool_from_int(false)); |
| } else { |
| parse_error(ctxt, token, "invalid keyword `%s'", token_get_value(token)); |
| goto out; |
| } |
| |
| return ret; |
| |
| out: |
| parser_context_restore(ctxt, saved_ctxt); |
| |
| return NULL; |
| } |
| |
| static QObject *parse_escape(JSONParserContext *ctxt, va_list *ap) |
| { |
| QObject *token = NULL, *obj; |
| JSONParserContext saved_ctxt = parser_context_save(ctxt); |
| |
| if (ap == NULL) { |
| goto out; |
| } |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| goto out; |
| } |
| |
| if (token_is_escape(token, "%p")) { |
| obj = va_arg(*ap, QObject *); |
| } else if (token_is_escape(token, "%i")) { |
| obj = QOBJECT(qbool_from_int(va_arg(*ap, int))); |
| } else if (token_is_escape(token, "%d")) { |
| obj = QOBJECT(qint_from_int(va_arg(*ap, int))); |
| } else if (token_is_escape(token, "%ld")) { |
| obj = QOBJECT(qint_from_int(va_arg(*ap, long))); |
| } else if (token_is_escape(token, "%lld") || |
| token_is_escape(token, "%I64d")) { |
| obj = QOBJECT(qint_from_int(va_arg(*ap, long long))); |
| } else if (token_is_escape(token, "%s")) { |
| obj = QOBJECT(qstring_from_str(va_arg(*ap, const char *))); |
| } else if (token_is_escape(token, "%f")) { |
| obj = QOBJECT(qfloat_from_double(va_arg(*ap, double))); |
| } else { |
| goto out; |
| } |
| |
| return obj; |
| |
| out: |
| parser_context_restore(ctxt, saved_ctxt); |
| |
| return NULL; |
| } |
| |
| static QObject *parse_literal(JSONParserContext *ctxt) |
| { |
| QObject *token, *obj; |
| JSONParserContext saved_ctxt = parser_context_save(ctxt); |
| |
| token = parser_context_pop_token(ctxt); |
| if (token == NULL) { |
| goto out; |
| } |
| |
| switch (token_get_type(token)) { |
| case JSON_STRING: |
| obj = QOBJECT(qstring_from_escaped_str(ctxt, token)); |
| break; |
| case JSON_INTEGER: { |
| /* A possibility exists that this is a whole-valued float where the |
| * fractional part was left out due to being 0 (.0). It's not a big |
| * deal to treat these as ints in the parser, so long as users of the |
| * resulting QObject know to expect a QInt in place of a QFloat in |
| * cases like these. |
| * |
| * However, in some cases these values will overflow/underflow a |
| * QInt/int64 container, thus we should assume these are to be handled |
| * as QFloats/doubles rather than silently changing their values. |
| * |
| * strtoll() indicates these instances by setting errno to ERANGE |
| */ |
| int64_t value; |
| |
| errno = 0; /* strtoll doesn't set errno on success */ |
| value = strtoll(token_get_value(token), NULL, 10); |
| if (errno != ERANGE) { |
| obj = QOBJECT(qint_from_int(value)); |
| break; |
| } |
| /* fall through to JSON_FLOAT */ |
| } |
| case JSON_FLOAT: |
| /* FIXME dependent on locale */ |
| obj = QOBJECT(qfloat_from_double(strtod(token_get_value(token), NULL))); |
| break; |
| default: |
| goto out; |
| } |
| |
| return obj; |
| |
| out: |
| parser_context_restore(ctxt, saved_ctxt); |
| |
| return NULL; |
| } |
| |
| static QObject *parse_value(JSONParserContext *ctxt, va_list *ap) |
| { |
| QObject *obj; |
| |
| obj = parse_object(ctxt, ap); |
| if (obj == NULL) { |
| obj = parse_array(ctxt, ap); |
| } |
| if (obj == NULL) { |
| obj = parse_escape(ctxt, ap); |
| } |
| if (obj == NULL) { |
| obj = parse_keyword(ctxt); |
| } |
| if (obj == NULL) { |
| obj = parse_literal(ctxt); |
| } |
| |
| return obj; |
| } |
| |
| QObject *json_parser_parse(QList *tokens, va_list *ap) |
| { |
| return json_parser_parse_err(tokens, ap, NULL); |
| } |
| |
| QObject *json_parser_parse_err(QList *tokens, va_list *ap, Error **errp) |
| { |
| JSONParserContext *ctxt = parser_context_new(tokens); |
| QObject *result; |
| |
| if (!ctxt) { |
| return NULL; |
| } |
| |
| result = parse_value(ctxt, ap); |
| |
| error_propagate(errp, ctxt->err); |
| |
| parser_context_free(ctxt); |
| |
| return result; |
| } |
