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-rw-r--r--qobject/json-parser.c590
1 files changed, 590 insertions, 0 deletions
diff --git a/qobject/json-parser.c b/qobject/json-parser.c
new file mode 100644
index 000000000..008b326fb
--- /dev/null
+++ b/qobject/json-parser.c
@@ -0,0 +1,590 @@
+/*
+ * 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 "qemu/osdep.h"
+#include "qemu/ctype.h"
+#include "qemu/cutils.h"
+#include "qemu/unicode.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qbool.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qlist.h"
+#include "qapi/qmp/qnull.h"
+#include "qapi/qmp/qnum.h"
+#include "qapi/qmp/qstring.h"
+#include "json-parser-int.h"
+
+struct JSONToken {
+ JSONTokenType type;
+ int x;
+ int y;
+ char str[];
+};
+
+typedef struct JSONParserContext {
+ Error *err;
+ JSONToken *current;
+ GQueue *buf;
+ va_list *ap;
+} 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);
+
+/**
+ * Error handler
+ */
+static void GCC_FMT_ATTR(3, 4) parse_error(JSONParserContext *ctxt,
+ JSONToken *token, const char *msg, ...)
+{
+ va_list ap;
+ char message[1024];
+
+ if (ctxt->err) {
+ return;
+ }
+ va_start(ap, msg);
+ vsnprintf(message, sizeof(message), msg, ap);
+ va_end(ap);
+ error_setg(&ctxt->err, "JSON parse error, %s", message);
+}
+
+static int cvt4hex(const char *s)
+{
+ int cp, i;
+
+ cp = 0;
+ for (i = 0; i < 4; i++) {
+ if (!qemu_isxdigit(s[i])) {
+ return -1;
+ }
+ cp <<= 4;
+ if (s[i] >= '0' && s[i] <= '9') {
+ cp |= s[i] - '0';
+ } else if (s[i] >= 'a' && s[i] <= 'f') {
+ cp |= 10 + s[i] - 'a';
+ } else if (s[i] >= 'A' && s[i] <= 'F') {
+ cp |= 10 + s[i] - 'A';
+ } else {
+ return -1;
+ }
+ }
+ return cp;
+}
+
+/**
+ * parse_string(): Parse a JSON string
+ *
+ * From RFC 8259 "The JavaScript Object Notation (JSON) Data
+ * Interchange Format":
+ *
+ * char = unescaped /
+ * escape (
+ * %x22 / ; " quotation mark U+0022
+ * %x5C / ; \ reverse solidus U+005C
+ * %x2F / ; / solidus U+002F
+ * %x62 / ; b backspace U+0008
+ * %x66 / ; f form feed U+000C
+ * %x6E / ; n line feed U+000A
+ * %x72 / ; r carriage return U+000D
+ * %x74 / ; t tab U+0009
+ * %x75 4HEXDIG ) ; uXXXX U+XXXX
+ * escape = %x5C ; \
+ * quotation-mark = %x22 ; "
+ * unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
+ *
+ * Extensions over RFC 8259:
+ * - Extra escape sequence in strings:
+ * 0x27 (apostrophe) is recognized after escape, too
+ * - Single-quoted strings:
+ * Like double-quoted strings, except they're delimited by %x27
+ * (apostrophe) instead of %x22 (quotation mark), and can't contain
+ * unescaped apostrophe, but can contain unescaped quotation mark.
+ *
+ * Note:
+ * - Encoding is modified UTF-8.
+ * - Invalid Unicode characters are rejected.
+ * - Control characters \x00..\x1F are rejected by the lexer.
+ */
+static QString *parse_string(JSONParserContext *ctxt, JSONToken *token)
+{
+ const char *ptr = token->str;
+ GString *str;
+ char quote;
+ const char *beg;
+ int cp, trailing;
+ char *end;
+ ssize_t len;
+ char utf8_buf[5];
+
+ assert(*ptr == '"' || *ptr == '\'');
+ quote = *ptr++;
+ str = g_string_new(NULL);
+
+ while (*ptr != quote) {
+ assert(*ptr);
+ switch (*ptr) {
+ case '\\':
+ beg = ptr++;
+ switch (*ptr++) {
+ case '"':
+ g_string_append_c(str, '"');
+ break;
+ case '\'':
+ g_string_append_c(str, '\'');
+ break;
+ case '\\':
+ g_string_append_c(str, '\\');
+ break;
+ case '/':
+ g_string_append_c(str, '/');
+ break;
+ case 'b':
+ g_string_append_c(str, '\b');
+ break;
+ case 'f':
+ g_string_append_c(str, '\f');
+ break;
+ case 'n':
+ g_string_append_c(str, '\n');
+ break;
+ case 'r':
+ g_string_append_c(str, '\r');
+ break;
+ case 't':
+ g_string_append_c(str, '\t');
+ break;
+ case 'u':
+ cp = cvt4hex(ptr);
+ ptr += 4;
+
+ /* handle surrogate pairs */
+ if (cp >= 0xD800 && cp <= 0xDBFF
+ && ptr[0] == '\\' && ptr[1] == 'u') {
+ /* leading surrogate followed by \u */
+ cp = 0x10000 + ((cp & 0x3FF) << 10);
+ trailing = cvt4hex(ptr + 2);
+ if (trailing >= 0xDC00 && trailing <= 0xDFFF) {
+ /* followed by trailing surrogate */
+ cp |= trailing & 0x3FF;
+ ptr += 6;
+ } else {
+ cp = -1; /* invalid */
+ }
+ }
+
+ if (mod_utf8_encode(utf8_buf, sizeof(utf8_buf), cp) < 0) {
+ parse_error(ctxt, token,
+ "%.*s is not a valid Unicode character",
+ (int)(ptr - beg), beg);
+ goto out;
+ }
+ g_string_append(str, utf8_buf);
+ break;
+ default:
+ parse_error(ctxt, token, "invalid escape sequence in string");
+ goto out;
+ }
+ break;
+ case '%':
+ if (ctxt->ap) {
+ if (ptr[1] != '%') {
+ parse_error(ctxt, token, "can't interpolate into string");
+ goto out;
+ }
+ ptr++;
+ }
+ /* fall through */
+ default:
+ cp = mod_utf8_codepoint(ptr, 6, &end);
+ if (cp < 0) {
+ parse_error(ctxt, token, "invalid UTF-8 sequence in string");
+ goto out;
+ }
+ ptr = end;
+ len = mod_utf8_encode(utf8_buf, sizeof(utf8_buf), cp);
+ assert(len >= 0);
+ g_string_append(str, utf8_buf);
+ }
+ }
+
+ return qstring_from_gstring(str);
+
+out:
+ g_string_free(str, true);
+ return NULL;
+}
+
+/* Note: the token object returned by parser_context_peek_token or
+ * parser_context_pop_token is deleted as soon as parser_context_pop_token
+ * is called again.
+ */
+static JSONToken *parser_context_pop_token(JSONParserContext *ctxt)
+{
+ g_free(ctxt->current);
+ ctxt->current = g_queue_pop_head(ctxt->buf);
+ return ctxt->current;
+}
+
+static JSONToken *parser_context_peek_token(JSONParserContext *ctxt)
+{
+ return g_queue_peek_head(ctxt->buf);
+}
+
+/**
+ * Parsing rules
+ */
+static int parse_pair(JSONParserContext *ctxt, QDict *dict)
+{
+ QObject *key_obj = NULL;
+ QString *key;
+ QObject *value;
+ JSONToken *peek, *token;
+
+ peek = parser_context_peek_token(ctxt);
+ if (peek == NULL) {
+ parse_error(ctxt, NULL, "premature EOI");
+ goto out;
+ }
+
+ key_obj = parse_value(ctxt);
+ key = qobject_to(QString, key_obj);
+ if (!key) {
+ 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->type != JSON_COLON) {
+ parse_error(ctxt, token, "missing : in object pair");
+ goto out;
+ }
+
+ value = parse_value(ctxt);
+ if (value == NULL) {
+ parse_error(ctxt, token, "Missing value in dict");
+ goto out;
+ }
+
+ if (qdict_haskey(dict, qstring_get_str(key))) {
+ parse_error(ctxt, token, "duplicate key");
+ goto out;
+ }
+
+ qdict_put_obj(dict, qstring_get_str(key), value);
+
+ qobject_unref(key_obj);
+ return 0;
+
+out:
+ qobject_unref(key_obj);
+ return -1;
+}
+
+static QObject *parse_object(JSONParserContext *ctxt)
+{
+ QDict *dict = NULL;
+ JSONToken *token, *peek;
+
+ token = parser_context_pop_token(ctxt);
+ assert(token && token->type == JSON_LCURLY);
+
+ dict = qdict_new();
+
+ peek = parser_context_peek_token(ctxt);
+ if (peek == NULL) {
+ parse_error(ctxt, NULL, "premature EOI");
+ goto out;
+ }
+
+ if (peek->type != JSON_RCURLY) {
+ if (parse_pair(ctxt, dict) == -1) {
+ goto out;
+ }
+
+ token = parser_context_pop_token(ctxt);
+ if (token == NULL) {
+ parse_error(ctxt, NULL, "premature EOI");
+ goto out;
+ }
+
+ while (token->type != JSON_RCURLY) {
+ if (token->type != JSON_COMMA) {
+ parse_error(ctxt, token, "expected separator in dict");
+ goto out;
+ }
+
+ if (parse_pair(ctxt, dict) == -1) {
+ goto out;
+ }
+
+ token = parser_context_pop_token(ctxt);
+ if (token == NULL) {
+ parse_error(ctxt, NULL, "premature EOI");
+ goto out;
+ }
+ }
+ } else {
+ (void)parser_context_pop_token(ctxt);
+ }
+
+ return QOBJECT(dict);
+
+out:
+ qobject_unref(dict);
+ return NULL;
+}
+
+static QObject *parse_array(JSONParserContext *ctxt)
+{
+ QList *list = NULL;
+ JSONToken *token, *peek;
+
+ token = parser_context_pop_token(ctxt);
+ assert(token && token->type == JSON_LSQUARE);
+
+ list = qlist_new();
+
+ peek = parser_context_peek_token(ctxt);
+ if (peek == NULL) {
+ parse_error(ctxt, NULL, "premature EOI");
+ goto out;
+ }
+
+ if (peek->type != JSON_RSQUARE) {
+ QObject *obj;
+
+ obj = parse_value(ctxt);
+ 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->type != JSON_RSQUARE) {
+ if (token->type != JSON_COMMA) {
+ parse_error(ctxt, token, "expected separator in list");
+ goto out;
+ }
+
+ obj = parse_value(ctxt);
+ 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;
+ }
+ }
+ } else {
+ (void)parser_context_pop_token(ctxt);
+ }
+
+ return QOBJECT(list);
+
+out:
+ qobject_unref(list);
+ return NULL;
+}
+
+static QObject *parse_keyword(JSONParserContext *ctxt)
+{
+ JSONToken *token;
+
+ token = parser_context_pop_token(ctxt);
+ assert(token && token->type == JSON_KEYWORD);
+
+ if (!strcmp(token->str, "true")) {
+ return QOBJECT(qbool_from_bool(true));
+ } else if (!strcmp(token->str, "false")) {
+ return QOBJECT(qbool_from_bool(false));
+ } else if (!strcmp(token->str, "null")) {
+ return QOBJECT(qnull());
+ }
+ parse_error(ctxt, token, "invalid keyword '%s'", token->str);
+ return NULL;
+}
+
+static QObject *parse_interpolation(JSONParserContext *ctxt)
+{
+ JSONToken *token;
+
+ token = parser_context_pop_token(ctxt);
+ assert(token && token->type == JSON_INTERP);
+
+ if (!strcmp(token->str, "%p")) {
+ return va_arg(*ctxt->ap, QObject *);
+ } else if (!strcmp(token->str, "%i")) {
+ return QOBJECT(qbool_from_bool(va_arg(*ctxt->ap, int)));
+ } else if (!strcmp(token->str, "%d")) {
+ return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, int)));
+ } else if (!strcmp(token->str, "%ld")) {
+ return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, long)));
+ } else if (!strcmp(token->str, "%lld")) {
+ return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, long long)));
+ } else if (!strcmp(token->str, "%" PRId64)) {
+ return QOBJECT(qnum_from_int(va_arg(*ctxt->ap, int64_t)));
+ } else if (!strcmp(token->str, "%u")) {
+ return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned int)));
+ } else if (!strcmp(token->str, "%lu")) {
+ return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned long)));
+ } else if (!strcmp(token->str, "%llu")) {
+ return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, unsigned long long)));
+ } else if (!strcmp(token->str, "%" PRIu64)) {
+ return QOBJECT(qnum_from_uint(va_arg(*ctxt->ap, uint64_t)));
+ } else if (!strcmp(token->str, "%s")) {
+ return QOBJECT(qstring_from_str(va_arg(*ctxt->ap, const char *)));
+ } else if (!strcmp(token->str, "%f")) {
+ return QOBJECT(qnum_from_double(va_arg(*ctxt->ap, double)));
+ }
+ parse_error(ctxt, token, "invalid interpolation '%s'", token->str);
+ return NULL;
+}
+
+static QObject *parse_literal(JSONParserContext *ctxt)
+{
+ JSONToken *token;
+
+ token = parser_context_pop_token(ctxt);
+ assert(token);
+
+ switch (token->type) {
+ case JSON_STRING:
+ return QOBJECT(parse_string(ctxt, token));
+ case JSON_INTEGER: {
+ /*
+ * Represent JSON_INTEGER as QNUM_I64 if possible, else as
+ * QNUM_U64, else as QNUM_DOUBLE. Note that qemu_strtoi64()
+ * and qemu_strtou64() fail with ERANGE when it's not
+ * possible.
+ *
+ * qnum_get_int() will then work for any signed 64-bit
+ * JSON_INTEGER, qnum_get_uint() for any unsigned 64-bit
+ * integer, and qnum_get_double() both for any JSON_INTEGER
+ * and any JSON_FLOAT (with precision loss for integers beyond
+ * 53 bits)
+ */
+ int ret;
+ int64_t value;
+ uint64_t uvalue;
+
+ ret = qemu_strtoi64(token->str, NULL, 10, &value);
+ if (!ret) {
+ return QOBJECT(qnum_from_int(value));
+ }
+ assert(ret == -ERANGE);
+
+ if (token->str[0] != '-') {
+ ret = qemu_strtou64(token->str, NULL, 10, &uvalue);
+ if (!ret) {
+ return QOBJECT(qnum_from_uint(uvalue));
+ }
+ assert(ret == -ERANGE);
+ }
+ }
+ /* fall through to JSON_FLOAT */
+ case JSON_FLOAT:
+ /* FIXME dependent on locale; a pervasive issue in QEMU */
+ /* FIXME our lexer matches RFC 8259 in forbidding Inf or NaN,
+ * but those might be useful extensions beyond JSON */
+ return QOBJECT(qnum_from_double(strtod(token->str, NULL)));
+ default:
+ abort();
+ }
+}
+
+static QObject *parse_value(JSONParserContext *ctxt)
+{
+ JSONToken *token;
+
+ token = parser_context_peek_token(ctxt);
+ if (token == NULL) {
+ parse_error(ctxt, NULL, "premature EOI");
+ return NULL;
+ }
+
+ switch (token->type) {
+ case JSON_LCURLY:
+ return parse_object(ctxt);
+ case JSON_LSQUARE:
+ return parse_array(ctxt);
+ case JSON_INTERP:
+ return parse_interpolation(ctxt);
+ case JSON_INTEGER:
+ case JSON_FLOAT:
+ case JSON_STRING:
+ return parse_literal(ctxt);
+ case JSON_KEYWORD:
+ return parse_keyword(ctxt);
+ default:
+ parse_error(ctxt, token, "expecting value");
+ return NULL;
+ }
+}
+
+JSONToken *json_token(JSONTokenType type, int x, int y, GString *tokstr)
+{
+ JSONToken *token = g_malloc(sizeof(JSONToken) + tokstr->len + 1);
+
+ token->type = type;
+ memcpy(token->str, tokstr->str, tokstr->len);
+ token->str[tokstr->len] = 0;
+ token->x = x;
+ token->y = y;
+ return token;
+}
+
+QObject *json_parser_parse(GQueue *tokens, va_list *ap, Error **errp)
+{
+ JSONParserContext ctxt = { .buf = tokens, .ap = ap };
+ QObject *result;
+
+ result = parse_value(&ctxt);
+ assert(ctxt.err || g_queue_is_empty(ctxt.buf));
+
+ error_propagate(errp, ctxt.err);
+
+ while (!g_queue_is_empty(ctxt.buf)) {
+ parser_context_pop_token(&ctxt);
+ }
+ g_free(ctxt.current);
+
+ return result;
+}