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Commit530609a

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Remove jsonapi.c's lex_accept().
At first glance, this function seems useful, but it actually increasesthe amount of code required rather than decreasing it. Inline thelogic into the callers instead; most callers don't use the 'lexeme'argument for anything and as a result considerable simplification ispossible.Along the way, fix the header comment for the nearby functionlex_expect(), which mislabeled it as lex_accept().Patch by me, reviewed by David Steele, Mark Dilger, and AndrewDunstan.Discussion:http://postgr.es/m/CA+TgmoYfOXhd27MUDGioVh6QtpD0C1K-f6ObSA10AWiHBAL5bA@mail.gmail.com
1 parent11b5e3e commit530609a

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+51
-73
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1 file changed

+51
-73
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‎src/backend/utils/adt/jsonapi.c

Lines changed: 51 additions & 73 deletions
Original file line numberDiff line numberDiff line change
@@ -69,52 +69,17 @@ lex_peek(JsonLexContext *lex)
6969
}
7070

7171
/*
72-
* lex_accept
73-
*
74-
* accept the look_ahead token and move the lexer to the next token if the
75-
* look_ahead token matches the token parameter. In that case, and if required,
76-
* also hand back the de-escaped lexeme.
77-
*
78-
* returns true if the token matched, false otherwise.
79-
*/
80-
staticinlinebool
81-
lex_accept(JsonLexContext*lex,JsonTokenTypetoken,char**lexeme)
82-
{
83-
if (lex->token_type==token)
84-
{
85-
if (lexeme!=NULL)
86-
{
87-
if (lex->token_type==JSON_TOKEN_STRING)
88-
{
89-
if (lex->strval!=NULL)
90-
*lexeme=pstrdup(lex->strval->data);
91-
}
92-
else
93-
{
94-
intlen= (lex->token_terminator-lex->token_start);
95-
char*tokstr=palloc(len+1);
96-
97-
memcpy(tokstr,lex->token_start,len);
98-
tokstr[len]='\0';
99-
*lexeme=tokstr;
100-
}
101-
}
102-
json_lex(lex);
103-
return true;
104-
}
105-
return false;
106-
}
107-
108-
/*
109-
* lex_accept
72+
* lex_expect
11073
*
11174
* move the lexer to the next token if the current look_ahead token matches
11275
* the parameter token. Otherwise, report an error.
11376
*/
11477
staticinlinevoid
11578
lex_expect(JsonParseContextctx,JsonLexContext*lex,JsonTokenTypetoken)
11679
{
117-
if (!lex_accept(lex,token,NULL))
80+
if (lex_peek(lex)==token)
81+
json_lex(lex);
82+
else
11883
report_parse_error(ctx,lex);
11984
}
12085

@@ -260,12 +225,14 @@ json_count_array_elements(JsonLexContext *lex)
260225
lex_expect(JSON_PARSE_ARRAY_START,&copylex,JSON_TOKEN_ARRAY_START);
261226
if (lex_peek(&copylex)!=JSON_TOKEN_ARRAY_END)
262227
{
263-
do
228+
while (1)
264229
{
265230
count++;
266231
parse_array_element(&copylex,&nullSemAction);
232+
if (copylex.token_type!=JSON_TOKEN_COMMA)
233+
break;
234+
json_lex(&copylex);
267235
}
268-
while (lex_accept(&copylex,JSON_TOKEN_COMMA,NULL));
269236
}
270237
lex_expect(JSON_PARSE_ARRAY_NEXT,&copylex,JSON_TOKEN_ARRAY_END);
271238

@@ -286,35 +253,41 @@ parse_scalar(JsonLexContext *lex, JsonSemAction *sem)
286253
{
287254
char*val=NULL;
288255
json_scalar_actionsfunc=sem->scalar;
289-
char**valaddr;
290256
JsonTokenTypetok=lex_peek(lex);
291257

292-
valaddr=sfunc==NULL ?NULL :&val;
293-
294258
/* a scalar must be a string, a number, true, false, or null */
295-
switch (tok)
259+
if (tok!=JSON_TOKEN_STRING&&tok!=JSON_TOKEN_NUMBER&&
260+
tok!=JSON_TOKEN_TRUE&&tok!=JSON_TOKEN_FALSE&&
261+
tok!=JSON_TOKEN_NULL)
262+
report_parse_error(JSON_PARSE_VALUE,lex);
263+
264+
/* if no semantic function, just consume the token */
265+
if (sfunc==NULL)
296266
{
297-
caseJSON_TOKEN_TRUE:
298-
lex_accept(lex,JSON_TOKEN_TRUE,valaddr);
299-
break;
300-
caseJSON_TOKEN_FALSE:
301-
lex_accept(lex,JSON_TOKEN_FALSE,valaddr);
302-
break;
303-
caseJSON_TOKEN_NULL:
304-
lex_accept(lex,JSON_TOKEN_NULL,valaddr);
305-
break;
306-
caseJSON_TOKEN_NUMBER:
307-
lex_accept(lex,JSON_TOKEN_NUMBER,valaddr);
308-
break;
309-
caseJSON_TOKEN_STRING:
310-
lex_accept(lex,JSON_TOKEN_STRING,valaddr);
311-
break;
312-
default:
313-
report_parse_error(JSON_PARSE_VALUE,lex);
267+
json_lex(lex);
268+
return;
269+
}
270+
271+
/* extract the de-escaped string value, or the raw lexeme */
272+
if (lex_peek(lex)==JSON_TOKEN_STRING)
273+
{
274+
if(lex->strval!=NULL)
275+
val=pstrdup(lex->strval->data);
276+
}
277+
else
278+
{
279+
intlen= (lex->token_terminator-lex->token_start);
280+
281+
val=palloc(len+1);
282+
memcpy(val,lex->token_start,len);
283+
val[len]='\0';
314284
}
315285

316-
if (sfunc!=NULL)
317-
(*sfunc) (sem->semstate,val,tok);
286+
/* consume the token */
287+
json_lex(lex);
288+
289+
/* invoke the callback */
290+
(*sfunc) (sem->semstate,val,tok);
318291
}
319292

320293
staticvoid
@@ -330,14 +303,13 @@ parse_object_field(JsonLexContext *lex, JsonSemAction *sem)
330303
json_ofield_actionostart=sem->object_field_start;
331304
json_ofield_actionoend=sem->object_field_end;
332305
boolisnull;
333-
char**fnameaddr=NULL;
334306
JsonTokenTypetok;
335307

336-
if (ostart!=NULL||oend!=NULL)
337-
fnameaddr=&fname;
338-
339-
if (!lex_accept(lex,JSON_TOKEN_STRING,fnameaddr))
308+
if (lex_peek(lex)!=JSON_TOKEN_STRING)
340309
report_parse_error(JSON_PARSE_STRING,lex);
310+
if ((ostart!=NULL||oend!=NULL)&&lex->strval!=NULL)
311+
fname=pstrdup(lex->strval->data);
312+
json_lex(lex);
341313

342314
lex_expect(JSON_PARSE_OBJECT_LABEL,lex,JSON_TOKEN_COLON);
343315

@@ -387,16 +359,19 @@ parse_object(JsonLexContext *lex, JsonSemAction *sem)
387359
*/
388360
lex->lex_level++;
389361

390-
/* we know this will succeed, just clearing the token */
391-
lex_expect(JSON_PARSE_OBJECT_START,lex,JSON_TOKEN_OBJECT_START);
362+
Assert(lex_peek(lex)==JSON_TOKEN_OBJECT_START);
363+
json_lex(lex);
392364

393365
tok=lex_peek(lex);
394366
switch (tok)
395367
{
396368
caseJSON_TOKEN_STRING:
397369
parse_object_field(lex,sem);
398-
while (lex_accept(lex,JSON_TOKEN_COMMA,NULL))
370+
while (lex_peek(lex)==JSON_TOKEN_COMMA)
371+
{
372+
json_lex(lex);
399373
parse_object_field(lex,sem);
374+
}
400375
break;
401376
caseJSON_TOKEN_OBJECT_END:
402377
break;
@@ -473,8 +448,11 @@ parse_array(JsonLexContext *lex, JsonSemAction *sem)
473448

474449
parse_array_element(lex,sem);
475450

476-
while (lex_accept(lex,JSON_TOKEN_COMMA,NULL))
451+
while (lex_peek(lex)==JSON_TOKEN_COMMA)
452+
{
453+
json_lex(lex);
477454
parse_array_element(lex,sem);
455+
}
478456
}
479457

480458
lex_expect(JSON_PARSE_ARRAY_NEXT,lex,JSON_TOKEN_ARRAY_END);

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