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Diffstat (limited to 'json-parser.c')
-rw-r--r--json-parser.c230
1 files changed, 142 insertions, 88 deletions
diff --git a/json-parser.c b/json-parser.c
index 849e2156d..457291b16 100644
--- a/json-parser.c
+++ b/json-parser.c
@@ -27,6 +27,11 @@
typedef struct JSONParserContext
{
Error *err;
+ struct {
+ QObject **buf;
+ size_t pos;
+ size_t count;
+ } tokens;
} JSONParserContext;
#define BUG_ON(cond) assert(!(cond))
@@ -40,7 +45,7 @@ typedef struct JSONParserContext
* 4) deal with premature EOI
*/
-static QObject *parse_value(JSONParserContext *ctxt, QList **tokens, va_list *ap);
+static QObject *parse_value(JSONParserContext *ctxt, va_list *ap);
/**
* Token manipulators
@@ -270,27 +275,111 @@ out:
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, QList **tokens, va_list *ap)
+static int parse_pair(JSONParserContext *ctxt, QDict *dict, va_list *ap)
{
QObject *key = NULL, *token = NULL, *value, *peek;
- QList *working = qlist_copy(*tokens);
+ JSONParserContext saved_ctxt = parser_context_save(ctxt);
- peek = qlist_peek(working);
+ peek = parser_context_peek_token(ctxt);
if (peek == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
}
- key = parse_value(ctxt, &working, ap);
+ 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 = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
@@ -301,7 +390,7 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict, QList **tokens, va_l
goto out;
}
- value = parse_value(ctxt, &working, ap);
+ value = parse_value(ctxt, ap);
if (value == NULL) {
parse_error(ctxt, token, "Missing value in dict");
goto out;
@@ -309,28 +398,24 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict, QList **tokens, va_l
qdict_put_obj(dict, qstring_get_str(qobject_to_qstring(key)), value);
- qobject_decref(token);
qobject_decref(key);
- QDECREF(*tokens);
- *tokens = working;
return 0;
out:
- qobject_decref(token);
+ parser_context_restore(ctxt, saved_ctxt);
qobject_decref(key);
- QDECREF(working);
return -1;
}
-static QObject *parse_object(JSONParserContext *ctxt, QList **tokens, va_list *ap)
+static QObject *parse_object(JSONParserContext *ctxt, va_list *ap)
{
QDict *dict = NULL;
QObject *token, *peek;
- QList *working = qlist_copy(*tokens);
+ JSONParserContext saved_ctxt = parser_context_save(ctxt);
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
goto out;
}
@@ -338,23 +423,22 @@ static QObject *parse_object(JSONParserContext *ctxt, QList **tokens, va_list *a
if (!token_is_operator(token, '{')) {
goto out;
}
- qobject_decref(token);
token = NULL;
dict = qdict_new();
- peek = qlist_peek(working);
+ 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, &working, ap) == -1) {
+ if (parse_pair(ctxt, dict, ap) == -1) {
goto out;
}
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
@@ -365,59 +449,52 @@ static QObject *parse_object(JSONParserContext *ctxt, QList **tokens, va_list *a
parse_error(ctxt, token, "expected separator in dict");
goto out;
}
- qobject_decref(token);
token = NULL;
- if (parse_pair(ctxt, dict, &working, ap) == -1) {
+ if (parse_pair(ctxt, dict, ap) == -1) {
goto out;
}
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
}
}
- qobject_decref(token);
token = NULL;
} else {
- token = qlist_pop(working);
- qobject_decref(token);
+ token = parser_context_pop_token(ctxt);
token = NULL;
}
- QDECREF(*tokens);
- *tokens = working;
-
return QOBJECT(dict);
out:
- qobject_decref(token);
- QDECREF(working);
+ parser_context_restore(ctxt, saved_ctxt);
QDECREF(dict);
return NULL;
}
-static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap)
+static QObject *parse_array(JSONParserContext *ctxt, va_list *ap)
{
QList *list = NULL;
QObject *token, *peek;
- QList *working = qlist_copy(*tokens);
+ JSONParserContext saved_ctxt = parser_context_save(ctxt);
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
goto out;
}
if (!token_is_operator(token, '[')) {
+ token = NULL;
goto out;
}
- qobject_decref(token);
token = NULL;
list = qlist_new();
- peek = qlist_peek(working);
+ peek = parser_context_peek_token(ctxt);
if (peek == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
@@ -426,7 +503,7 @@ static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap
if (!token_is_operator(peek, ']')) {
QObject *obj;
- obj = parse_value(ctxt, &working, ap);
+ obj = parse_value(ctxt, ap);
if (obj == NULL) {
parse_error(ctxt, token, "expecting value");
goto out;
@@ -434,7 +511,7 @@ static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap
qlist_append_obj(list, obj);
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
@@ -446,10 +523,9 @@ static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap
goto out;
}
- qobject_decref(token);
token = NULL;
- obj = parse_value(ctxt, &working, ap);
+ obj = parse_value(ctxt, ap);
if (obj == NULL) {
parse_error(ctxt, token, "expecting value");
goto out;
@@ -457,39 +533,33 @@ static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap
qlist_append_obj(list, obj);
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
parse_error(ctxt, NULL, "premature EOI");
goto out;
}
}
- qobject_decref(token);
token = NULL;
} else {
- token = qlist_pop(working);
- qobject_decref(token);
+ token = parser_context_pop_token(ctxt);
token = NULL;
}
- QDECREF(*tokens);
- *tokens = working;
-
return QOBJECT(list);
out:
- qobject_decref(token);
- QDECREF(working);
+ parser_context_restore(ctxt, saved_ctxt);
QDECREF(list);
return NULL;
}
-static QObject *parse_keyword(JSONParserContext *ctxt, QList **tokens)
+static QObject *parse_keyword(JSONParserContext *ctxt)
{
QObject *token, *ret;
- QList *working = qlist_copy(*tokens);
+ JSONParserContext saved_ctxt = parser_context_save(ctxt);
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
goto out;
}
@@ -507,29 +577,24 @@ static QObject *parse_keyword(JSONParserContext *ctxt, QList **tokens)
goto out;
}
- qobject_decref(token);
- QDECREF(*tokens);
- *tokens = working;
-
return ret;
out:
- qobject_decref(token);
- QDECREF(working);
+ parser_context_restore(ctxt, saved_ctxt);
return NULL;
}
-static QObject *parse_escape(JSONParserContext *ctxt, QList **tokens, va_list *ap)
+static QObject *parse_escape(JSONParserContext *ctxt, va_list *ap)
{
QObject *token = NULL, *obj;
- QList *working = qlist_copy(*tokens);
+ JSONParserContext saved_ctxt = parser_context_save(ctxt);
if (ap == NULL) {
goto out;
}
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
goto out;
}
@@ -553,25 +618,20 @@ static QObject *parse_escape(JSONParserContext *ctxt, QList **tokens, va_list *a
goto out;
}
- qobject_decref(token);
- QDECREF(*tokens);
- *tokens = working;
-
return obj;
out:
- qobject_decref(token);
- QDECREF(working);
+ parser_context_restore(ctxt, saved_ctxt);
return NULL;
}
-static QObject *parse_literal(JSONParserContext *ctxt, QList **tokens)
+static QObject *parse_literal(JSONParserContext *ctxt)
{
QObject *token, *obj;
- QList *working = qlist_copy(*tokens);
+ JSONParserContext saved_ctxt = parser_context_save(ctxt);
- token = qlist_pop(working);
+ token = parser_context_pop_token(ctxt);
if (token == NULL) {
goto out;
}
@@ -591,35 +651,30 @@ static QObject *parse_literal(JSONParserContext *ctxt, QList **tokens)
goto out;
}
- qobject_decref(token);
- QDECREF(*tokens);
- *tokens = working;
-
return obj;
out:
- qobject_decref(token);
- QDECREF(working);
+ parser_context_restore(ctxt, saved_ctxt);
return NULL;
}
-static QObject *parse_value(JSONParserContext *ctxt, QList **tokens, va_list *ap)
+static QObject *parse_value(JSONParserContext *ctxt, va_list *ap)
{
QObject *obj;
- obj = parse_object(ctxt, tokens, ap);
+ obj = parse_object(ctxt, ap);
if (obj == NULL) {
- obj = parse_array(ctxt, tokens, ap);
+ obj = parse_array(ctxt, ap);
}
if (obj == NULL) {
- obj = parse_escape(ctxt, tokens, ap);
+ obj = parse_escape(ctxt, ap);
}
if (obj == NULL) {
- obj = parse_keyword(ctxt, tokens);
+ obj = parse_keyword(ctxt);
}
if (obj == NULL) {
- obj = parse_literal(ctxt, tokens);
+ obj = parse_literal(ctxt);
}
return obj;
@@ -632,19 +687,18 @@ QObject *json_parser_parse(QList *tokens, va_list *ap)
QObject *json_parser_parse_err(QList *tokens, va_list *ap, Error **errp)
{
- JSONParserContext ctxt = {};
- QList *working;
+ JSONParserContext *ctxt = parser_context_new(tokens);
QObject *result;
- if (!tokens) {
+ if (!ctxt) {
return NULL;
}
- working = qlist_copy(tokens);
- result = parse_value(&ctxt, &working, ap);
- QDECREF(working);
+ result = parse_value(ctxt, ap);
+
+ error_propagate(errp, ctxt->err);
- error_propagate(errp, ctxt.err);
+ parser_context_free(ctxt);
return result;
}