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pl_scanner.c
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1 /*-------------------------------------------------------------------------
2  *
3  * pl_scanner.c
4  * lexical scanning for PL/pgSQL
5  *
6  *
7  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  *
11  * IDENTIFICATION
12  * src/pl/plpgsql/src/pl_scanner.c
13  *
14  *-------------------------------------------------------------------------
15  */
16 #include "postgres.h"
17 
18 #include "mb/pg_wchar.h"
19 #include "parser/scanner.h"
20 
21 #include "plpgsql.h"
22 #include "pl_gram.h" /* must be after parser/scanner.h */
23 
24 
25 #define PG_KEYWORD(a,b,c) {a,b,c},
26 
27 
28 /* Klugy flag to tell scanner how to look up identifiers */
30 
31 /*
32  * A word about keywords:
33  *
34  * We keep reserved and unreserved keywords in separate arrays. The
35  * reserved keywords are passed to the core scanner, so they will be
36  * recognized before (and instead of) any variable name. Unreserved words
37  * are checked for separately, usually after determining that the identifier
38  * isn't a known variable name. If plpgsql_IdentifierLookup is DECLARE then
39  * no variable names will be recognized, so the unreserved words always work.
40  * (Note in particular that this helps us avoid reserving keywords that are
41  * only needed in DECLARE sections.)
42  *
43  * In certain contexts it is desirable to prefer recognizing an unreserved
44  * keyword over recognizing a variable name. In particular, at the start
45  * of a statement we should prefer unreserved keywords unless the statement
46  * looks like an assignment (i.e., first token is followed by ':=' or '[').
47  * This rule allows most statement-introducing keywords to be kept unreserved.
48  * (We still have to reserve initial keywords that might follow a block
49  * label, unfortunately, since the method used to determine if we are at
50  * start of statement doesn't recognize such cases. We'd also have to
51  * reserve any keyword that could legitimately be followed by ':=' or '['.)
52  * Some additional cases are handled in pl_gram.y using tok_is_keyword().
53  *
54  * We try to avoid reserving more keywords than we have to; but there's
55  * little point in not reserving a word if it's reserved in the core grammar.
56  * Currently, the following words are reserved here but not in the core:
57  * BEGIN BY DECLARE EXECUTE FOREACH IF LOOP STRICT WHILE
58  */
59 
60 /*
61  * Lists of keyword (name, token-value, category) entries.
62  *
63  * !!WARNING!!: These lists must be sorted by ASCII name, because binary
64  * search is used to locate entries.
65  *
66  * Be careful not to put the same word in both lists. Also be sure that
67  * pl_gram.y's unreserved_keyword production agrees with the second list.
68  */
69 
70 static const ScanKeyword reserved_keywords[] = {
71  PG_KEYWORD("all", K_ALL, RESERVED_KEYWORD)
72  PG_KEYWORD("begin", K_BEGIN, RESERVED_KEYWORD)
73  PG_KEYWORD("by", K_BY, RESERVED_KEYWORD)
74  PG_KEYWORD("case", K_CASE, RESERVED_KEYWORD)
75  PG_KEYWORD("declare", K_DECLARE, RESERVED_KEYWORD)
76  PG_KEYWORD("else", K_ELSE, RESERVED_KEYWORD)
77  PG_KEYWORD("end", K_END, RESERVED_KEYWORD)
78  PG_KEYWORD("execute", K_EXECUTE, RESERVED_KEYWORD)
79  PG_KEYWORD("for", K_FOR, RESERVED_KEYWORD)
80  PG_KEYWORD("foreach", K_FOREACH, RESERVED_KEYWORD)
81  PG_KEYWORD("from", K_FROM, RESERVED_KEYWORD)
82  PG_KEYWORD("if", K_IF, RESERVED_KEYWORD)
83  PG_KEYWORD("in", K_IN, RESERVED_KEYWORD)
84  PG_KEYWORD("into", K_INTO, RESERVED_KEYWORD)
85  PG_KEYWORD("loop", K_LOOP, RESERVED_KEYWORD)
86  PG_KEYWORD("not", K_NOT, RESERVED_KEYWORD)
87  PG_KEYWORD("null", K_NULL, RESERVED_KEYWORD)
88  PG_KEYWORD("or", K_OR, RESERVED_KEYWORD)
89  PG_KEYWORD("strict", K_STRICT, RESERVED_KEYWORD)
90  PG_KEYWORD("then", K_THEN, RESERVED_KEYWORD)
91  PG_KEYWORD("to", K_TO, RESERVED_KEYWORD)
92  PG_KEYWORD("using", K_USING, RESERVED_KEYWORD)
93  PG_KEYWORD("when", K_WHEN, RESERVED_KEYWORD)
94  PG_KEYWORD("while", K_WHILE, RESERVED_KEYWORD)
95 };
96 
97 static const int num_reserved_keywords = lengthof(reserved_keywords);
98 
99 static const ScanKeyword unreserved_keywords[] = {
100  PG_KEYWORD("absolute", K_ABSOLUTE, UNRESERVED_KEYWORD)
101  PG_KEYWORD("alias", K_ALIAS, UNRESERVED_KEYWORD)
102  PG_KEYWORD("array", K_ARRAY, UNRESERVED_KEYWORD)
103  PG_KEYWORD("assert", K_ASSERT, UNRESERVED_KEYWORD)
104  PG_KEYWORD("backward", K_BACKWARD, UNRESERVED_KEYWORD)
105  PG_KEYWORD("close", K_CLOSE, UNRESERVED_KEYWORD)
106  PG_KEYWORD("collate", K_COLLATE, UNRESERVED_KEYWORD)
107  PG_KEYWORD("column", K_COLUMN, UNRESERVED_KEYWORD)
108  PG_KEYWORD("column_name", K_COLUMN_NAME, UNRESERVED_KEYWORD)
109  PG_KEYWORD("constant", K_CONSTANT, UNRESERVED_KEYWORD)
110  PG_KEYWORD("constraint", K_CONSTRAINT, UNRESERVED_KEYWORD)
111  PG_KEYWORD("constraint_name", K_CONSTRAINT_NAME, UNRESERVED_KEYWORD)
112  PG_KEYWORD("continue", K_CONTINUE, UNRESERVED_KEYWORD)
113  PG_KEYWORD("current", K_CURRENT, UNRESERVED_KEYWORD)
114  PG_KEYWORD("cursor", K_CURSOR, UNRESERVED_KEYWORD)
115  PG_KEYWORD("datatype", K_DATATYPE, UNRESERVED_KEYWORD)
116  PG_KEYWORD("debug", K_DEBUG, UNRESERVED_KEYWORD)
117  PG_KEYWORD("default", K_DEFAULT, UNRESERVED_KEYWORD)
118  PG_KEYWORD("detail", K_DETAIL, UNRESERVED_KEYWORD)
119  PG_KEYWORD("diagnostics", K_DIAGNOSTICS, UNRESERVED_KEYWORD)
120  PG_KEYWORD("dump", K_DUMP, UNRESERVED_KEYWORD)
121  PG_KEYWORD("elseif", K_ELSIF, UNRESERVED_KEYWORD)
122  PG_KEYWORD("elsif", K_ELSIF, UNRESERVED_KEYWORD)
123  PG_KEYWORD("errcode", K_ERRCODE, UNRESERVED_KEYWORD)
124  PG_KEYWORD("error", K_ERROR, UNRESERVED_KEYWORD)
125  PG_KEYWORD("exception", K_EXCEPTION, UNRESERVED_KEYWORD)
126  PG_KEYWORD("exit", K_EXIT, UNRESERVED_KEYWORD)
127  PG_KEYWORD("fetch", K_FETCH, UNRESERVED_KEYWORD)
128  PG_KEYWORD("first", K_FIRST, UNRESERVED_KEYWORD)
129  PG_KEYWORD("forward", K_FORWARD, UNRESERVED_KEYWORD)
130  PG_KEYWORD("get", K_GET, UNRESERVED_KEYWORD)
131  PG_KEYWORD("hint", K_HINT, UNRESERVED_KEYWORD)
132  PG_KEYWORD("import", K_IMPORT, UNRESERVED_KEYWORD)
133  PG_KEYWORD("info", K_INFO, UNRESERVED_KEYWORD)
134  PG_KEYWORD("insert", K_INSERT, UNRESERVED_KEYWORD)
135  PG_KEYWORD("is", K_IS, UNRESERVED_KEYWORD)
136  PG_KEYWORD("last", K_LAST, UNRESERVED_KEYWORD)
137  PG_KEYWORD("log", K_LOG, UNRESERVED_KEYWORD)
138  PG_KEYWORD("message", K_MESSAGE, UNRESERVED_KEYWORD)
139  PG_KEYWORD("message_text", K_MESSAGE_TEXT, UNRESERVED_KEYWORD)
140  PG_KEYWORD("move", K_MOVE, UNRESERVED_KEYWORD)
141  PG_KEYWORD("next", K_NEXT, UNRESERVED_KEYWORD)
142  PG_KEYWORD("no", K_NO, UNRESERVED_KEYWORD)
143  PG_KEYWORD("notice", K_NOTICE, UNRESERVED_KEYWORD)
144  PG_KEYWORD("open", K_OPEN, UNRESERVED_KEYWORD)
145  PG_KEYWORD("option", K_OPTION, UNRESERVED_KEYWORD)
146  PG_KEYWORD("perform", K_PERFORM, UNRESERVED_KEYWORD)
147  PG_KEYWORD("pg_context", K_PG_CONTEXT, UNRESERVED_KEYWORD)
148  PG_KEYWORD("pg_datatype_name", K_PG_DATATYPE_NAME, UNRESERVED_KEYWORD)
149  PG_KEYWORD("pg_exception_context", K_PG_EXCEPTION_CONTEXT, UNRESERVED_KEYWORD)
150  PG_KEYWORD("pg_exception_detail", K_PG_EXCEPTION_DETAIL, UNRESERVED_KEYWORD)
151  PG_KEYWORD("pg_exception_hint", K_PG_EXCEPTION_HINT, UNRESERVED_KEYWORD)
152  PG_KEYWORD("print_strict_params", K_PRINT_STRICT_PARAMS, UNRESERVED_KEYWORD)
153  PG_KEYWORD("prior", K_PRIOR, UNRESERVED_KEYWORD)
154  PG_KEYWORD("query", K_QUERY, UNRESERVED_KEYWORD)
155  PG_KEYWORD("raise", K_RAISE, UNRESERVED_KEYWORD)
156  PG_KEYWORD("relative", K_RELATIVE, UNRESERVED_KEYWORD)
157  PG_KEYWORD("result_oid", K_RESULT_OID, UNRESERVED_KEYWORD)
158  PG_KEYWORD("return", K_RETURN, UNRESERVED_KEYWORD)
159  PG_KEYWORD("returned_sqlstate", K_RETURNED_SQLSTATE, UNRESERVED_KEYWORD)
160  PG_KEYWORD("reverse", K_REVERSE, UNRESERVED_KEYWORD)
161  PG_KEYWORD("row_count", K_ROW_COUNT, UNRESERVED_KEYWORD)
162  PG_KEYWORD("rowtype", K_ROWTYPE, UNRESERVED_KEYWORD)
163  PG_KEYWORD("schema", K_SCHEMA, UNRESERVED_KEYWORD)
164  PG_KEYWORD("schema_name", K_SCHEMA_NAME, UNRESERVED_KEYWORD)
165  PG_KEYWORD("scroll", K_SCROLL, UNRESERVED_KEYWORD)
166  PG_KEYWORD("slice", K_SLICE, UNRESERVED_KEYWORD)
167  PG_KEYWORD("sqlstate", K_SQLSTATE, UNRESERVED_KEYWORD)
168  PG_KEYWORD("stacked", K_STACKED, UNRESERVED_KEYWORD)
169  PG_KEYWORD("table", K_TABLE, UNRESERVED_KEYWORD)
170  PG_KEYWORD("table_name", K_TABLE_NAME, UNRESERVED_KEYWORD)
171  PG_KEYWORD("type", K_TYPE, UNRESERVED_KEYWORD)
172  PG_KEYWORD("use_column", K_USE_COLUMN, UNRESERVED_KEYWORD)
173  PG_KEYWORD("use_variable", K_USE_VARIABLE, UNRESERVED_KEYWORD)
174  PG_KEYWORD("variable_conflict", K_VARIABLE_CONFLICT, UNRESERVED_KEYWORD)
175  PG_KEYWORD("warning", K_WARNING, UNRESERVED_KEYWORD)
176 };
177 
178 static const int num_unreserved_keywords = lengthof(unreserved_keywords);
179 
180 /*
181  * This macro must recognize all tokens that can immediately precede a
182  * PL/pgSQL executable statement (that is, proc_sect or proc_stmt in the
183  * grammar). Fortunately, there are not very many, so hard-coding in this
184  * fashion seems sufficient.
185  */
186 #define AT_STMT_START(prev_token) \
187  ((prev_token) == ';' || \
188  (prev_token) == K_BEGIN || \
189  (prev_token) == K_THEN || \
190  (prev_token) == K_ELSE || \
191  (prev_token) == K_LOOP)
192 
193 
194 /* Auxiliary data about a token (other than the token type) */
195 typedef struct
196 {
197  YYSTYPE lval; /* semantic information */
198  YYLTYPE lloc; /* offset in scanbuf */
199  int leng; /* length in bytes */
200 } TokenAuxData;
201 
202 /*
203  * Scanner working state. At some point we might wish to fold all this
204  * into a YY_EXTRA struct. For the moment, there is no need for plpgsql's
205  * lexer to be re-entrant, and the notational burden of passing a yyscanner
206  * pointer around is great enough to not want to do it without need.
207  */
208 
209 /* The stuff the core lexer needs */
210 static core_yyscan_t yyscanner = NULL;
212 
213 /* The original input string */
214 static const char *scanorig;
215 
216 /* Current token's length (corresponds to plpgsql_yylval and plpgsql_yylloc) */
217 static int plpgsql_yyleng;
218 
219 /* Current token's code (corresponds to plpgsql_yylval and plpgsql_yylloc) */
220 static int plpgsql_yytoken;
221 
222 /* Token pushback stack */
223 #define MAX_PUSHBACKS 4
224 
225 static int num_pushbacks;
228 
229 /* State for plpgsql_location_to_lineno() */
230 static const char *cur_line_start;
231 static const char *cur_line_end;
232 static int cur_line_num;
233 
234 /* Internal functions */
235 static int internal_yylex(TokenAuxData *auxdata);
236 static void push_back_token(int token, TokenAuxData *auxdata);
237 static void location_lineno_init(void);
238 
239 
240 /*
241  * This is the yylex routine called from the PL/pgSQL grammar.
242  * It is a wrapper around the core lexer, with the ability to recognize
243  * PL/pgSQL variables and return them as special T_DATUM tokens. If a
244  * word or compound word does not match any variable name, or if matching
245  * is turned off by plpgsql_IdentifierLookup, it is returned as
246  * T_WORD or T_CWORD respectively, or as an unreserved keyword if it
247  * matches one of those.
248  */
249 int
251 {
252  int tok1;
253  TokenAuxData aux1;
254  const ScanKeyword *kw;
255 
256  tok1 = internal_yylex(&aux1);
257  if (tok1 == IDENT || tok1 == PARAM)
258  {
259  int tok2;
260  TokenAuxData aux2;
261 
262  tok2 = internal_yylex(&aux2);
263  if (tok2 == '.')
264  {
265  int tok3;
266  TokenAuxData aux3;
267 
268  tok3 = internal_yylex(&aux3);
269  if (tok3 == IDENT)
270  {
271  int tok4;
272  TokenAuxData aux4;
273 
274  tok4 = internal_yylex(&aux4);
275  if (tok4 == '.')
276  {
277  int tok5;
278  TokenAuxData aux5;
279 
280  tok5 = internal_yylex(&aux5);
281  if (tok5 == IDENT)
282  {
283  if (plpgsql_parse_tripword(aux1.lval.str,
284  aux3.lval.str,
285  aux5.lval.str,
286  &aux1.lval.wdatum,
287  &aux1.lval.cword))
288  tok1 = T_DATUM;
289  else
290  tok1 = T_CWORD;
291  }
292  else
293  {
294  /* not A.B.C, so just process A.B */
295  push_back_token(tok5, &aux5);
296  push_back_token(tok4, &aux4);
297  if (plpgsql_parse_dblword(aux1.lval.str,
298  aux3.lval.str,
299  &aux1.lval.wdatum,
300  &aux1.lval.cword))
301  tok1 = T_DATUM;
302  else
303  tok1 = T_CWORD;
304  }
305  }
306  else
307  {
308  /* not A.B.C, so just process A.B */
309  push_back_token(tok4, &aux4);
310  if (plpgsql_parse_dblword(aux1.lval.str,
311  aux3.lval.str,
312  &aux1.lval.wdatum,
313  &aux1.lval.cword))
314  tok1 = T_DATUM;
315  else
316  tok1 = T_CWORD;
317  }
318  }
319  else
320  {
321  /* not A.B, so just process A */
322  push_back_token(tok3, &aux3);
323  push_back_token(tok2, &aux2);
324  if (plpgsql_parse_word(aux1.lval.str,
325  core_yy.scanbuf + aux1.lloc,
326  &aux1.lval.wdatum,
327  &aux1.lval.word))
328  tok1 = T_DATUM;
329  else if (!aux1.lval.word.quoted &&
330  (kw = ScanKeywordLookup(aux1.lval.word.ident,
331  unreserved_keywords,
333  {
334  aux1.lval.keyword = kw->name;
335  tok1 = kw->value;
336  }
337  else
338  tok1 = T_WORD;
339  }
340  }
341  else
342  {
343  /* not A.B, so just process A */
344  push_back_token(tok2, &aux2);
345 
346  /*
347  * If we are at start of statement, prefer unreserved keywords
348  * over variable names, unless the next token is assignment or
349  * '[', in which case prefer variable names. (Note we need not
350  * consider '.' as the next token; that case was handled above,
351  * and we always prefer variable names in that case.) If we are
352  * not at start of statement, always prefer variable names over
353  * unreserved keywords.
354  */
356  !(tok2 == '=' || tok2 == COLON_EQUALS || tok2 == '['))
357  {
358  /* try for unreserved keyword, then for variable name */
359  if (core_yy.scanbuf[aux1.lloc] != '"' &&
360  (kw = ScanKeywordLookup(aux1.lval.str,
361  unreserved_keywords,
363  {
364  aux1.lval.keyword = kw->name;
365  tok1 = kw->value;
366  }
367  else if (plpgsql_parse_word(aux1.lval.str,
368  core_yy.scanbuf + aux1.lloc,
369  &aux1.lval.wdatum,
370  &aux1.lval.word))
371  tok1 = T_DATUM;
372  else
373  tok1 = T_WORD;
374  }
375  else
376  {
377  /* try for variable name, then for unreserved keyword */
378  if (plpgsql_parse_word(aux1.lval.str,
379  core_yy.scanbuf + aux1.lloc,
380  &aux1.lval.wdatum,
381  &aux1.lval.word))
382  tok1 = T_DATUM;
383  else if (!aux1.lval.word.quoted &&
384  (kw = ScanKeywordLookup(aux1.lval.word.ident,
385  unreserved_keywords,
387  {
388  aux1.lval.keyword = kw->name;
389  tok1 = kw->value;
390  }
391  else
392  tok1 = T_WORD;
393  }
394  }
395  }
396  else
397  {
398  /*
399  * Not a potential plpgsql variable name, just return the data.
400  *
401  * Note that we also come through here if the grammar pushed back a
402  * T_DATUM, T_CWORD, T_WORD, or unreserved-keyword token returned by a
403  * previous lookup cycle; thus, pushbacks do not incur extra lookup
404  * work, since we'll never do the above code twice for the same token.
405  * This property also makes it safe to rely on the old value of
406  * plpgsql_yytoken in the is-this-start-of-statement test above.
407  */
408  }
409 
410  plpgsql_yylval = aux1.lval;
411  plpgsql_yylloc = aux1.lloc;
412  plpgsql_yyleng = aux1.leng;
413  plpgsql_yytoken = tok1;
414  return tok1;
415 }
416 
417 /*
418  * Internal yylex function. This wraps the core lexer and adds one feature:
419  * a token pushback stack. We also make a couple of trivial single-token
420  * translations from what the core lexer does to what we want, in particular
421  * interfacing from the core_YYSTYPE to YYSTYPE union.
422  */
423 static int
425 {
426  int token;
427  const char *yytext;
428 
429  if (num_pushbacks > 0)
430  {
431  num_pushbacks--;
432  token = pushback_token[num_pushbacks];
433  *auxdata = pushback_auxdata[num_pushbacks];
434  }
435  else
436  {
437  token = core_yylex(&auxdata->lval.core_yystype,
438  &auxdata->lloc,
439  yyscanner);
440 
441  /* remember the length of yytext before it gets changed */
442  yytext = core_yy.scanbuf + auxdata->lloc;
443  auxdata->leng = strlen(yytext);
444 
445  /* Check for << >> and #, which the core considers operators */
446  if (token == Op)
447  {
448  if (strcmp(auxdata->lval.str, "<<") == 0)
449  token = LESS_LESS;
450  else if (strcmp(auxdata->lval.str, ">>") == 0)
451  token = GREATER_GREATER;
452  else if (strcmp(auxdata->lval.str, "#") == 0)
453  token = '#';
454  }
455 
456  /* The core returns PARAM as ival, but we treat it like IDENT */
457  else if (token == PARAM)
458  {
459  auxdata->lval.str = pstrdup(yytext);
460  }
461  }
462 
463  return token;
464 }
465 
466 /*
467  * Push back a token to be re-read by next internal_yylex() call.
468  */
469 static void
470 push_back_token(int token, TokenAuxData *auxdata)
471 {
473  elog(ERROR, "too many tokens pushed back");
474  pushback_token[num_pushbacks] = token;
475  pushback_auxdata[num_pushbacks] = *auxdata;
476  num_pushbacks++;
477 }
478 
479 /*
480  * Push back a single token to be re-read by next plpgsql_yylex() call.
481  *
482  * NOTE: this does not cause yylval or yylloc to "back up". Also, it
483  * is not a good idea to push back a token code other than what you read.
484  */
485 void
487 {
488  TokenAuxData auxdata;
489 
490  auxdata.lval = plpgsql_yylval;
491  auxdata.lloc = plpgsql_yylloc;
492  auxdata.leng = plpgsql_yyleng;
493  push_back_token(token, &auxdata);
494 }
495 
496 /*
497  * Tell whether a token is an unreserved keyword.
498  *
499  * (If it is, its lowercased form was returned as the token value, so we
500  * do not need to offer that data here.)
501  */
502 bool
504 {
505  int i;
506 
507  for (i = 0; i < num_unreserved_keywords; i++)
508  {
509  if (unreserved_keywords[i].value == token)
510  return true;
511  }
512  return false;
513 }
514 
515 /*
516  * Append the function text starting at startlocation and extending to
517  * (not including) endlocation onto the existing contents of "buf".
518  */
519 void
521  int startlocation, int endlocation)
522 {
523  Assert(startlocation <= endlocation);
524  appendBinaryStringInfo(buf, scanorig + startlocation,
525  endlocation - startlocation);
526 }
527 
528 /*
529  * Peek one token ahead in the input stream. Only the token code is
530  * made available, not any of the auxiliary info such as location.
531  *
532  * NB: no variable or unreserved keyword lookup is performed here, they will
533  * be returned as IDENT. Reserved keywords are resolved as usual.
534  */
535 int
537 {
538  int tok1;
539  TokenAuxData aux1;
540 
541  tok1 = internal_yylex(&aux1);
542  push_back_token(tok1, &aux1);
543  return tok1;
544 }
545 
546 /*
547  * Peek two tokens ahead in the input stream. The first token and its
548  * location in the query are returned in *tok1_p and *tok1_loc, second token
549  * and its location in *tok2_p and *tok2_loc.
550  *
551  * NB: no variable or unreserved keyword lookup is performed here, they will
552  * be returned as IDENT. Reserved keywords are resolved as usual.
553  */
554 void
555 plpgsql_peek2(int *tok1_p, int *tok2_p, int *tok1_loc, int *tok2_loc)
556 {
557  int tok1,
558  tok2;
559  TokenAuxData aux1,
560  aux2;
561 
562  tok1 = internal_yylex(&aux1);
563  tok2 = internal_yylex(&aux2);
564 
565  *tok1_p = tok1;
566  if (tok1_loc)
567  *tok1_loc = aux1.lloc;
568  *tok2_p = tok2;
569  if (tok2_loc)
570  *tok2_loc = aux2.lloc;
571 
572  push_back_token(tok2, &aux2);
573  push_back_token(tok1, &aux1);
574 }
575 
576 /*
577  * plpgsql_scanner_errposition
578  * Report an error cursor position, if possible.
579  *
580  * This is expected to be used within an ereport() call. The return value
581  * is a dummy (always 0, in fact).
582  *
583  * Note that this can only be used for messages emitted during initial
584  * parsing of a plpgsql function, since it requires the scanorig string
585  * to still be available.
586  */
587 int
589 {
590  int pos;
591 
592  if (location < 0 || scanorig == NULL)
593  return 0; /* no-op if location is unknown */
594 
595  /* Convert byte offset to character number */
596  pos = pg_mbstrlen_with_len(scanorig, location) + 1;
597  /* And pass it to the ereport mechanism */
598  (void) internalerrposition(pos);
599  /* Also pass the function body string */
600  return internalerrquery(scanorig);
601 }
602 
603 /*
604  * plpgsql_yyerror
605  * Report a lexer or grammar error.
606  *
607  * The message's cursor position refers to the current token (the one
608  * last returned by plpgsql_yylex()).
609  * This is OK for syntax error messages from the Bison parser, because Bison
610  * parsers report error as soon as the first unparsable token is reached.
611  * Beware of using yyerror for other purposes, as the cursor position might
612  * be misleading!
613  */
614 void
615 plpgsql_yyerror(const char *message)
616 {
617  char *yytext = core_yy.scanbuf + plpgsql_yylloc;
618 
619  if (*yytext == '\0')
620  {
621  ereport(ERROR,
622  (errcode(ERRCODE_SYNTAX_ERROR),
623  /* translator: %s is typically the translation of "syntax error" */
624  errmsg("%s at end of input", _(message)),
625  plpgsql_scanner_errposition(plpgsql_yylloc)));
626  }
627  else
628  {
629  /*
630  * If we have done any lookahead then flex will have restored the
631  * character after the end-of-token. Zap it again so that we report
632  * only the single token here. This modifies scanbuf but we no longer
633  * care about that.
634  */
635  yytext[plpgsql_yyleng] = '\0';
636 
637  ereport(ERROR,
638  (errcode(ERRCODE_SYNTAX_ERROR),
639  /* translator: first %s is typically the translation of "syntax error" */
640  errmsg("%s at or near \"%s\"", _(message), yytext),
641  plpgsql_scanner_errposition(plpgsql_yylloc)));
642  }
643 }
644 
645 /*
646  * Given a location (a byte offset in the function source text),
647  * return a line number.
648  *
649  * We expect that this is typically called for a sequence of increasing
650  * location values, so optimize accordingly by tracking the endpoints
651  * of the "current" line.
652  */
653 int
655 {
656  const char *loc;
657 
658  if (location < 0 || scanorig == NULL)
659  return 0; /* garbage in, garbage out */
660  loc = scanorig + location;
661 
662  /* be correct, but not fast, if input location goes backwards */
663  if (loc < cur_line_start)
665 
666  while (cur_line_end != NULL && loc > cur_line_end)
667  {
669  cur_line_num++;
670  cur_line_end = strchr(cur_line_start, '\n');
671  }
672 
673  return cur_line_num;
674 }
675 
676 /* initialize or reset the state for plpgsql_location_to_lineno */
677 static void
679 {
681  cur_line_num = 1;
682 
683  cur_line_end = strchr(cur_line_start, '\n');
684 }
685 
686 /* return the most recently computed lineno */
687 int
689 {
690  return cur_line_num;
691 }
692 
693 
694 /*
695  * Called before any actual parsing is done
696  *
697  * Note: the passed "str" must remain valid until plpgsql_scanner_finish().
698  * Although it is not fed directly to flex, we need the original string
699  * to cite in error messages.
700  */
701 void
702 plpgsql_scanner_init(const char *str)
703 {
704  /* Start up the core scanner */
705  yyscanner = scanner_init(str, &core_yy,
706  reserved_keywords, num_reserved_keywords);
707 
708  /*
709  * scanorig points to the original string, which unlike the scanner's
710  * scanbuf won't be modified on-the-fly by flex. Notice that although
711  * yytext points into scanbuf, we rely on being able to apply locations
712  * (offsets from string start) to scanorig as well.
713  */
714  scanorig = str;
715 
716  /* Other setup */
718  plpgsql_yytoken = 0;
719 
720  num_pushbacks = 0;
721 
723 }
724 
725 /*
726  * Called after parsing is done to clean up after plpgsql_scanner_init()
727  */
728 void
730 {
731  /* release storage */
733  /* avoid leaving any dangling pointers */
734  yyscanner = NULL;
735  scanorig = NULL;
736 }
#define MAX_PUSHBACKS
Definition: pl_scanner.c:223
int plpgsql_latest_lineno(void)
Definition: pl_scanner.c:688
static int cur_line_num
Definition: pl_scanner.c:232
bool plpgsql_parse_dblword(char *word1, char *word2, PLwdatum *wdatum, PLcword *cword)
Definition: pl_comp.c:1416
void * core_yyscan_t
Definition: scanner.h:116
static TokenAuxData pushback_auxdata[MAX_PUSHBACKS]
Definition: pl_scanner.c:227
const ScanKeyword * ScanKeywordLookup(const char *text, const ScanKeyword *keywords, int num_keywords)
Definition: keywords.c:64
IdentifierLookup
Definition: plpgsql.h:1010
char * pstrdup(const char *in)
Definition: mcxt.c:1076
YYLTYPE lloc
Definition: pl_scanner.c:198
void plpgsql_append_source_text(StringInfo buf, int startlocation, int endlocation)
Definition: pl_scanner.c:520
int errcode(int sqlerrcode)
Definition: elog.c:575
#define PG_KEYWORD(a, b, c)
Definition: pl_scanner.c:25
static const ScanKeyword reserved_keywords[]
Definition: pl_scanner.c:70
#define UNRESERVED_KEYWORD
Definition: keywords.h:18
#define lengthof(array)
Definition: c.h:556
static void location_lineno_init(void)
Definition: pl_scanner.c:678
static const int num_unreserved_keywords
Definition: pl_scanner.c:178
YYSTYPE lval
Definition: pl_scanner.c:197
static const char * cur_line_start
Definition: pl_scanner.c:230
void plpgsql_yyerror(const char *message)
Definition: pl_scanner.c:615
char * scanbuf
Definition: scanner.h:72
int pg_mbstrlen_with_len(const char *mbstr, int limit)
Definition: mbutils.c:794
int plpgsql_peek(void)
Definition: pl_scanner.c:536
bool plpgsql_token_is_unreserved_keyword(int token)
Definition: pl_scanner.c:503
void plpgsql_scanner_finish(void)
Definition: pl_scanner.c:729
#define ERROR
Definition: elog.h:43
static struct @121 value
static char * buf
Definition: pg_test_fsync.c:67
static int plpgsql_yytoken
Definition: pl_scanner.c:220
const char * name
Definition: keywords.h:26
#define YYLTYPE
Definition: scanner.h:44
static const ScanKeyword unreserved_keywords[]
Definition: pl_scanner.c:99
static int internal_yylex(TokenAuxData *auxdata)
Definition: pl_scanner.c:424
#define ereport(elevel, rest)
Definition: elog.h:122
bool plpgsql_parse_word(char *word1, const char *yytxt, PLwdatum *wdatum, PLword *word)
Definition: pl_comp.c:1360
void plpgsql_peek2(int *tok1_p, int *tok2_p, int *tok1_loc, int *tok2_loc)
Definition: pl_scanner.c:555
static const char * scanorig
Definition: pl_scanner.c:214
IdentifierLookup plpgsql_IdentifierLookup
Definition: pl_scanner.c:29
static int num_pushbacks
Definition: pl_scanner.c:225
static int pushback_token[MAX_PUSHBACKS]
Definition: pl_scanner.c:226
#define RESERVED_KEYWORD
Definition: keywords.h:21
int core_yylex(core_YYSTYPE *lvalp, YYLTYPE *llocp, core_yyscan_t yyscanner)
int16 value
Definition: keywords.h:27
int plpgsql_location_to_lineno(int location)
Definition: pl_scanner.c:654
int internalerrquery(const char *query)
Definition: elog.c:1161
static core_yy_extra_type core_yy
Definition: pl_scanner.c:211
#define Assert(condition)
Definition: c.h:681
static int plpgsql_yyleng
Definition: pl_scanner.c:217
#define AT_STMT_START(prev_token)
Definition: pl_scanner.c:186
int plpgsql_scanner_errposition(int location)
Definition: pl_scanner.c:588
core_yyscan_t scanner_init(const char *str, core_yy_extra_type *yyext, const ScanKeyword *keywords, int num_keywords)
static core_yyscan_t yyscanner
Definition: pl_scanner.c:210
void plpgsql_scanner_init(const char *str)
Definition: pl_scanner.c:702
int errmsg(const char *fmt,...)
Definition: elog.c:797
static const char * cur_line_end
Definition: pl_scanner.c:231
bool plpgsql_parse_tripword(char *word1, char *word2, char *word3, PLwdatum *wdatum, PLcword *cword)
Definition: pl_comp.c:1536
int i
static const int num_reserved_keywords
Definition: pl_scanner.c:97
void scanner_finish(core_yyscan_t yyscanner)
#define elog
Definition: elog.h:219
int plpgsql_yylex(void)
Definition: pl_scanner.c:250
static void push_back_token(int token, TokenAuxData *auxdata)
Definition: pl_scanner.c:470
void plpgsql_push_back_token(int token)
Definition: pl_scanner.c:486
#define _(x)
Definition: elog.c:84
void appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
Definition: stringinfo.c:208
int internalerrposition(int cursorpos)
Definition: elog.c:1141