Commit 1e960b46 authored by Markus Armbruster's avatar Markus Armbruster
Browse files

json: Eliminate lexer state IN_WHITESPACE, pseudo-token JSON_SKIP 



The lexer ignores whitespace like this:

         on whitespace      on non-ws   spontaneously
    IN_START --> IN_WHITESPACE --> JSON_SKIP --> IN_START
                    ^    |
                     \__/  on whitespace

This accumulates a whitespace token in state IN_WHITESPACE, only to
throw it away on the transition via JSON_SKIP to the start state.
Wasteful.  Go from IN_START to IN_START on whitespace directly,
dropping the whitespace character.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20180831075841.13363-7-armbru@redhat.com>
parent 2ce4ee64

qobject/json-lexer.c

+5 −17
Original line number Diff line number Diff line
@@ -115,7 +115,6 @@ enum json_lexer_state { 
    IN_SIGN,

    IN_KEYWORD,

    IN_INTERP,

    IN_WHITESPACE,

    IN_START,

    IN_START_INTERP,            /* must be IN_START + 1 */

};
@@ -228,15 +227,6 @@ static const uint8_t json_lexer[][256] = { 
        ['a' ... 'z'] = IN_KEYWORD,

    },



    /* whitespace */

    [IN_WHITESPACE] = {

        TERMINAL(JSON_SKIP),

        [' '] = IN_WHITESPACE,

        ['\t'] = IN_WHITESPACE,

        ['\r'] = IN_WHITESPACE,

        ['\n'] = IN_WHITESPACE,

    },



    /* interpolation */

    [IN_INTERP] = {

        TERMINAL(JSON_INTERP),
@@ -263,10 +253,10 @@ static const uint8_t json_lexer[][256] = { 
        [','] = JSON_COMMA,

        [':'] = JSON_COLON,

        ['a' ... 'z'] = IN_KEYWORD,

        [' '] = IN_WHITESPACE,

        ['\t'] = IN_WHITESPACE,

        ['\r'] = IN_WHITESPACE,

        ['\n'] = IN_WHITESPACE,

        [' '] = IN_START,

        ['\t'] = IN_START,

        ['\r'] = IN_START,

        ['\n'] = IN_START,

    },

    [IN_START_INTERP]['%'] = IN_INTERP,

};
@@ -323,10 +313,8 @@ static void json_lexer_feed_char(JSONLexer *lexer, char ch, bool flush) 
            json_message_process_token(lexer, lexer->token, new_state,

                                       lexer->x, lexer->y);

            /* fall through */

        case JSON_SKIP:

            g_string_truncate(lexer->token, 0);

            /* fall through */

        case IN_START:

            g_string_truncate(lexer->token, 0);

            new_state = lexer->start_state;

            break;

        case JSON_ERROR:

qobject/json-parser-int.h

+0 −1
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ typedef enum json_token_type { 
    JSON_KEYWORD,

    JSON_STRING,

    JSON_INTERP,

    JSON_SKIP,

    JSON_END_OF_INPUT,

    JSON_MAX = JSON_END_OF_INPUT

} JSONTokenType;