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Re: [Qemu-devel] [PATCH v3 for-2.5 09/12] qjson: Convert to parser to re
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v3 for-2.5 09/12] qjson: Convert to parser to recursive descent |
Date: |
Thu, 26 Nov 2015 09:37:37 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
Eric Blake <address@hidden> writes:
> On 11/25/2015 02:23 PM, Markus Armbruster wrote:
>> We backtrack in parse_value(), even though JSON is LL(1) and thus can
>> be parsed by straightforward recursive descent. Do exactly that.
>>
>> Based on an almost-correct patch from Paolo Bonzini.
>>
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>> qobject/json-parser.c | 165
>> ++++++++++++++------------------------------------
>> 1 file changed, 47 insertions(+), 118 deletions(-)
>>
>
>> static QObject *parse_value(JSONParserContext *ctxt, va_list *ap)
>> {
>> - QObject *obj;
>> + QObject *token;
>>
>> - 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);
>> + token = parser_context_peek_token(ctxt);
>> + if (token == NULL) {
>> + parse_error(ctxt, NULL, "premature EOI");
>
> Should we spell that out as 'end of input'?
>
> But that's cosmetic, and doesn't affect correctness of the conversion.
Doesn't matter, because we generally throw away these error messages,
then make up a useless one *boggle*. Once that's fixed, the
parse_error() could use some love.
> Reviewed-by: Eric Blake <address@hidden>
Thanks!
- Re: [Qemu-devel] [PATCH v3 for-2.5 07/12] qjson: Inline token_is_escape() and simplify, (continued)
- [Qemu-devel] [PATCH v3 for-2.5 03/12] check-qjson: Add test for JSON nesting depth limit, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 04/12] qjson: Spell out some silent assumptions, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 12/12] qjson: Limit number of tokens in addition to total size, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 08/12] qjson: replace QString in JSONLexer with GString, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 09/12] qjson: Convert to parser to recursive descent, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 02/12] qjson: Don't crash when input exceeds nesting limit, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 10/12] qjson: store tokens in a GQueue, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 11/12] qjson: surprise, allocating 6 QObjects per token is expensive, Markus Armbruster, 2015/11/25
- [Qemu-devel] [PATCH v3 for-2.5 05/12] qjson: Give each of the six structural chars its own token type, Markus Armbruster, 2015/11/25