--- /dev/null
+/*
+ * 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"
+
+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_setg(&ctxt->err, "JSON parse error, %s", 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;
+ }
+
+ 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;
+ }
+
+ 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;
+ }
+ }
+ } else {
+ (void)parser_context_pop_token(ctxt);
+ }
+
+ 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, '[')) {
+ goto out;
+ }
+
+ 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;
+ }
+
+ 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;
+ }
+ }
+ } else {
+ (void)parser_context_pop_token(ctxt);
+ }
+
+ 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_bool(true));
+ } else if (token_is_keyword(token, "false")) {
+ ret = QOBJECT(qbool_from_bool(false));
+ } else if (token_is_keyword(token, "null")) {
+ ret = qnull();
+ } 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_bool(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;
+}
Code Review / kvmfornfv.git / blobdiff