PostgreSQL Source Code  git master
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros
pl_scanner.c
Go to the documentation of this file.
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 "plpgsql.h"
17 
18 #include "mb/pg_wchar.h"
19 #include "parser/scanner.h"
20 
21 #include "pl_gram.h" /* must be after parser/scanner.h */
22 
23 #define PG_KEYWORD(a,b,c) {a,b,c},
24 
25 
26 /* Klugy flag to tell scanner how to look up identifiers */
28 
29 /*
30  * A word about keywords:
31  *
32  * We keep reserved and unreserved keywords in separate arrays. The
33  * reserved keywords are passed to the core scanner, so they will be
34  * recognized before (and instead of) any variable name. Unreserved words
35  * are checked for separately, usually after determining that the identifier
36  * isn't a known variable name. If plpgsql_IdentifierLookup is DECLARE then
37  * no variable names will be recognized, so the unreserved words always work.
38  * (Note in particular that this helps us avoid reserving keywords that are
39  * only needed in DECLARE sections.)
40  *
41  * In certain contexts it is desirable to prefer recognizing an unreserved
42  * keyword over recognizing a variable name. In particular, at the start
43  * of a statement we should prefer unreserved keywords unless the statement
44  * looks like an assignment (i.e., first token is followed by ':=' or '[').
45  * This rule allows most statement-introducing keywords to be kept unreserved.
46  * (We still have to reserve initial keywords that might follow a block
47  * label, unfortunately, since the method used to determine if we are at
48  * start of statement doesn't recognize such cases. We'd also have to
49  * reserve any keyword that could legitimately be followed by ':=' or '['.)
50  * Some additional cases are handled in pl_gram.y using tok_is_keyword().
51  *
52  * We try to avoid reserving more keywords than we have to; but there's
53  * little point in not reserving a word if it's reserved in the core grammar.
54  * Currently, the following words are reserved here but not in the core:
55  * BEGIN BY DECLARE EXECUTE FOREACH IF LOOP STRICT WHILE
56  */
57 
58 /*
59  * Lists of keyword (name, token-value, category) entries.
60  *
61  * !!WARNING!!: These lists must be sorted by ASCII name, because binary
62  * search is used to locate entries.
63  *
64  * Be careful not to put the same word in both lists. Also be sure that
65  * pl_gram.y's unreserved_keyword production agrees with the second list.
66  */
67 
68 static const ScanKeyword reserved_keywords[] = {
69  PG_KEYWORD("all", K_ALL, RESERVED_KEYWORD)
70  PG_KEYWORD("begin", K_BEGIN, RESERVED_KEYWORD)
71  PG_KEYWORD("by", K_BY, RESERVED_KEYWORD)
72  PG_KEYWORD("case", K_CASE, RESERVED_KEYWORD)
73  PG_KEYWORD("declare", K_DECLARE, RESERVED_KEYWORD)
74  PG_KEYWORD("else", K_ELSE, RESERVED_KEYWORD)
75  PG_KEYWORD("end", K_END, RESERVED_KEYWORD)
76  PG_KEYWORD("execute", K_EXECUTE, RESERVED_KEYWORD)
77  PG_KEYWORD("for", K_FOR, RESERVED_KEYWORD)
78  PG_KEYWORD("foreach", K_FOREACH, RESERVED_KEYWORD)
79  PG_KEYWORD("from", K_FROM, RESERVED_KEYWORD)
80  PG_KEYWORD("if", K_IF, RESERVED_KEYWORD)
81  PG_KEYWORD("in", K_IN, RESERVED_KEYWORD)
82  PG_KEYWORD("into", K_INTO, RESERVED_KEYWORD)
83  PG_KEYWORD("loop", K_LOOP, RESERVED_KEYWORD)
84  PG_KEYWORD("not", K_NOT, RESERVED_KEYWORD)
85  PG_KEYWORD("null", K_NULL, RESERVED_KEYWORD)
86  PG_KEYWORD("or", K_OR, RESERVED_KEYWORD)
87  PG_KEYWORD("strict", K_STRICT, RESERVED_KEYWORD)
88  PG_KEYWORD("then", K_THEN, RESERVED_KEYWORD)
89  PG_KEYWORD("to", K_TO, RESERVED_KEYWORD)
90  PG_KEYWORD("using", K_USING, RESERVED_KEYWORD)
91  PG_KEYWORD("when", K_WHEN, RESERVED_KEYWORD)
92  PG_KEYWORD("while", K_WHILE, RESERVED_KEYWORD)
93 };
94 
95 static const int num_reserved_keywords = lengthof(reserved_keywords);
96 
97 static const ScanKeyword unreserved_keywords[] = {
98  PG_KEYWORD("absolute", K_ABSOLUTE, UNRESERVED_KEYWORD)
99  PG_KEYWORD("alias", K_ALIAS, UNRESERVED_KEYWORD)
100  PG_KEYWORD("array", K_ARRAY, UNRESERVED_KEYWORD)
101  PG_KEYWORD("assert", K_ASSERT, UNRESERVED_KEYWORD)
102  PG_KEYWORD("backward", K_BACKWARD, UNRESERVED_KEYWORD)
103  PG_KEYWORD("close", K_CLOSE, UNRESERVED_KEYWORD)
104  PG_KEYWORD("collate", K_COLLATE, UNRESERVED_KEYWORD)
105  PG_KEYWORD("column", K_COLUMN, UNRESERVED_KEYWORD)
106  PG_KEYWORD("column_name", K_COLUMN_NAME, UNRESERVED_KEYWORD)
107  PG_KEYWORD("constant", K_CONSTANT, UNRESERVED_KEYWORD)
108  PG_KEYWORD("constraint", K_CONSTRAINT, UNRESERVED_KEYWORD)
109  PG_KEYWORD("constraint_name", K_CONSTRAINT_NAME, UNRESERVED_KEYWORD)
110  PG_KEYWORD("continue", K_CONTINUE, UNRESERVED_KEYWORD)
111  PG_KEYWORD("current", K_CURRENT, UNRESERVED_KEYWORD)
112  PG_KEYWORD("cursor", K_CURSOR, UNRESERVED_KEYWORD)
113  PG_KEYWORD("datatype", K_DATATYPE, UNRESERVED_KEYWORD)
114  PG_KEYWORD("debug", K_DEBUG, UNRESERVED_KEYWORD)
115  PG_KEYWORD("default", K_DEFAULT, UNRESERVED_KEYWORD)
116  PG_KEYWORD("detail", K_DETAIL, UNRESERVED_KEYWORD)
117  PG_KEYWORD("diagnostics", K_DIAGNOSTICS, UNRESERVED_KEYWORD)
118  PG_KEYWORD("dump", K_DUMP, UNRESERVED_KEYWORD)
119  PG_KEYWORD("elseif", K_ELSIF, UNRESERVED_KEYWORD)
120  PG_KEYWORD("elsif", K_ELSIF, UNRESERVED_KEYWORD)
121  PG_KEYWORD("errcode", K_ERRCODE, UNRESERVED_KEYWORD)
122  PG_KEYWORD("error", K_ERROR, UNRESERVED_KEYWORD)
123  PG_KEYWORD("exception", K_EXCEPTION, UNRESERVED_KEYWORD)
124  PG_KEYWORD("exit", K_EXIT, UNRESERVED_KEYWORD)
125  PG_KEYWORD("fetch", K_FETCH, UNRESERVED_KEYWORD)
126  PG_KEYWORD("first", K_FIRST, UNRESERVED_KEYWORD)
127  PG_KEYWORD("forward", K_FORWARD, UNRESERVED_KEYWORD)
128  PG_KEYWORD("get", K_GET, UNRESERVED_KEYWORD)
129  PG_KEYWORD("hint", K_HINT, UNRESERVED_KEYWORD)
130  PG_KEYWORD("import", K_IMPORT, UNRESERVED_KEYWORD)
131  PG_KEYWORD("info", K_INFO, UNRESERVED_KEYWORD)
132  PG_KEYWORD("insert", K_INSERT, UNRESERVED_KEYWORD)
133  PG_KEYWORD("is", K_IS, UNRESERVED_KEYWORD)
134  PG_KEYWORD("last", K_LAST, UNRESERVED_KEYWORD)
135  PG_KEYWORD("log", K_LOG, UNRESERVED_KEYWORD)
136  PG_KEYWORD("message", K_MESSAGE, UNRESERVED_KEYWORD)
137  PG_KEYWORD("message_text", K_MESSAGE_TEXT, UNRESERVED_KEYWORD)
138  PG_KEYWORD("move", K_MOVE, UNRESERVED_KEYWORD)
139  PG_KEYWORD("next", K_NEXT, UNRESERVED_KEYWORD)
140  PG_KEYWORD("no", K_NO, UNRESERVED_KEYWORD)
141  PG_KEYWORD("notice", K_NOTICE, UNRESERVED_KEYWORD)
142  PG_KEYWORD("open", K_OPEN, UNRESERVED_KEYWORD)
143  PG_KEYWORD("option", K_OPTION, UNRESERVED_KEYWORD)
144  PG_KEYWORD("perform", K_PERFORM, UNRESERVED_KEYWORD)
145  PG_KEYWORD("pg_context", K_PG_CONTEXT, UNRESERVED_KEYWORD)
146  PG_KEYWORD("pg_datatype_name", K_PG_DATATYPE_NAME, UNRESERVED_KEYWORD)
147  PG_KEYWORD("pg_exception_context", K_PG_EXCEPTION_CONTEXT, UNRESERVED_KEYWORD)
148  PG_KEYWORD("pg_exception_detail", K_PG_EXCEPTION_DETAIL, UNRESERVED_KEYWORD)
149  PG_KEYWORD("pg_exception_hint", K_PG_EXCEPTION_HINT, UNRESERVED_KEYWORD)
150  PG_KEYWORD("print_strict_params", K_PRINT_STRICT_PARAMS, UNRESERVED_KEYWORD)
151  PG_KEYWORD("prior", K_PRIOR, UNRESERVED_KEYWORD)
152  PG_KEYWORD("query", K_QUERY, UNRESERVED_KEYWORD)
153  PG_KEYWORD("raise", K_RAISE, UNRESERVED_KEYWORD)
154  PG_KEYWORD("relative", K_RELATIVE, UNRESERVED_KEYWORD)
155  PG_KEYWORD("result_oid", K_RESULT_OID, UNRESERVED_KEYWORD)
156  PG_KEYWORD("return", K_RETURN, UNRESERVED_KEYWORD)
157  PG_KEYWORD("returned_sqlstate", K_RETURNED_SQLSTATE, UNRESERVED_KEYWORD)
158  PG_KEYWORD("reverse", K_REVERSE, UNRESERVED_KEYWORD)
159  PG_KEYWORD("row_count", K_ROW_COUNT, UNRESERVED_KEYWORD)
160  PG_KEYWORD("rowtype", K_ROWTYPE, UNRESERVED_KEYWORD)
161  PG_KEYWORD("schema", K_SCHEMA, UNRESERVED_KEYWORD)
162  PG_KEYWORD("schema_name", K_SCHEMA_NAME, UNRESERVED_KEYWORD)
163  PG_KEYWORD("scroll", K_SCROLL, UNRESERVED_KEYWORD)
164  PG_KEYWORD("slice", K_SLICE, UNRESERVED_KEYWORD)
165  PG_KEYWORD("sqlstate", K_SQLSTATE, UNRESERVED_KEYWORD)
166  PG_KEYWORD("stacked", K_STACKED, UNRESERVED_KEYWORD)
167  PG_KEYWORD("table", K_TABLE, UNRESERVED_KEYWORD)
168  PG_KEYWORD("table_name", K_TABLE_NAME, UNRESERVED_KEYWORD)
169  PG_KEYWORD("type", K_TYPE, UNRESERVED_KEYWORD)
170  PG_KEYWORD("use_column", K_USE_COLUMN, UNRESERVED_KEYWORD)
171  PG_KEYWORD("use_variable", K_USE_VARIABLE, UNRESERVED_KEYWORD)
172  PG_KEYWORD("variable_conflict", K_VARIABLE_CONFLICT, UNRESERVED_KEYWORD)
173  PG_KEYWORD("warning", K_WARNING, UNRESERVED_KEYWORD)
174 };
175 
176 static const int num_unreserved_keywords = lengthof(unreserved_keywords);
177 
178 /*
179  * This macro must recognize all tokens that can immediately precede a
180  * PL/pgSQL executable statement (that is, proc_sect or proc_stmt in the
181  * grammar). Fortunately, there are not very many, so hard-coding in this
182  * fashion seems sufficient.
183  */
184 #define AT_STMT_START(prev_token) \
185  ((prev_token) == ';' || \
186  (prev_token) == K_BEGIN || \
187  (prev_token) == K_THEN || \
188  (prev_token) == K_ELSE || \
189  (prev_token) == K_LOOP)
190 
191 
192 /* Auxiliary data about a token (other than the token type) */
193 typedef struct
194 {
195  YYSTYPE lval; /* semantic information */
196  YYLTYPE lloc; /* offset in scanbuf */
197  int leng; /* length in bytes */
198 } TokenAuxData;
199 
200 /*
201  * Scanner working state. At some point we might wish to fold all this
202  * into a YY_EXTRA struct. For the moment, there is no need for plpgsql's
203  * lexer to be re-entrant, and the notational burden of passing a yyscanner
204  * pointer around is great enough to not want to do it without need.
205  */
206 
207 /* The stuff the core lexer needs */
210 
211 /* The original input string */
212 static const char *scanorig;
213 
214 /* Current token's length (corresponds to plpgsql_yylval and plpgsql_yylloc) */
215 static int plpgsql_yyleng;
216 
217 /* Current token's code (corresponds to plpgsql_yylval and plpgsql_yylloc) */
218 static int plpgsql_yytoken;
219 
220 /* Token pushback stack */
221 #define MAX_PUSHBACKS 4
222 
223 static int num_pushbacks;
226 
227 /* State for plpgsql_location_to_lineno() */
228 static const char *cur_line_start;
229 static const char *cur_line_end;
230 static int cur_line_num;
231 
232 /* Internal functions */
233 static int internal_yylex(TokenAuxData *auxdata);
234 static void push_back_token(int token, TokenAuxData *auxdata);
235 static void location_lineno_init(void);
236 
237 
238 /*
239  * This is the yylex routine called from the PL/pgSQL grammar.
240  * It is a wrapper around the core lexer, with the ability to recognize
241  * PL/pgSQL variables and return them as special T_DATUM tokens. If a
242  * word or compound word does not match any variable name, or if matching
243  * is turned off by plpgsql_IdentifierLookup, it is returned as
244  * T_WORD or T_CWORD respectively, or as an unreserved keyword if it
245  * matches one of those.
246  */
247 int
249 {
250  int tok1;
251  TokenAuxData aux1;
252  const ScanKeyword *kw;
253 
254  tok1 = internal_yylex(&aux1);
255  if (tok1 == IDENT || tok1 == PARAM)
256  {
257  int tok2;
258  TokenAuxData aux2;
259 
260  tok2 = internal_yylex(&aux2);
261  if (tok2 == '.')
262  {
263  int tok3;
264  TokenAuxData aux3;
265 
266  tok3 = internal_yylex(&aux3);
267  if (tok3 == IDENT)
268  {
269  int tok4;
270  TokenAuxData aux4;
271 
272  tok4 = internal_yylex(&aux4);
273  if (tok4 == '.')
274  {
275  int tok5;
276  TokenAuxData aux5;
277 
278  tok5 = internal_yylex(&aux5);
279  if (tok5 == IDENT)
280  {
281  if (plpgsql_parse_tripword(aux1.lval.str,
282  aux3.lval.str,
283  aux5.lval.str,
284  &aux1.lval.wdatum,
285  &aux1.lval.cword))
286  tok1 = T_DATUM;
287  else
288  tok1 = T_CWORD;
289  }
290  else
291  {
292  /* not A.B.C, so just process A.B */
293  push_back_token(tok5, &aux5);
294  push_back_token(tok4, &aux4);
295  if (plpgsql_parse_dblword(aux1.lval.str,
296  aux3.lval.str,
297  &aux1.lval.wdatum,
298  &aux1.lval.cword))
299  tok1 = T_DATUM;
300  else
301  tok1 = T_CWORD;
302  }
303  }
304  else
305  {
306  /* not A.B.C, so just process A.B */
307  push_back_token(tok4, &aux4);
308  if (plpgsql_parse_dblword(aux1.lval.str,
309  aux3.lval.str,
310  &aux1.lval.wdatum,
311  &aux1.lval.cword))
312  tok1 = T_DATUM;
313  else
314  tok1 = T_CWORD;
315  }
316  }
317  else
318  {
319  /* not A.B, so just process A */
320  push_back_token(tok3, &aux3);
321  push_back_token(tok2, &aux2);
322  if (plpgsql_parse_word(aux1.lval.str,
323  core_yy.scanbuf + aux1.lloc,
324  &aux1.lval.wdatum,
325  &aux1.lval.word))
326  tok1 = T_DATUM;
327  else if (!aux1.lval.word.quoted &&
328  (kw = ScanKeywordLookup(aux1.lval.word.ident,
329  unreserved_keywords,
331  {
332  aux1.lval.keyword = kw->name;
333  tok1 = kw->value;
334  }
335  else
336  tok1 = T_WORD;
337  }
338  }
339  else
340  {
341  /* not A.B, so just process A */
342  push_back_token(tok2, &aux2);
343 
344  /*
345  * If we are at start of statement, prefer unreserved keywords
346  * over variable names, unless the next token is assignment or
347  * '[', in which case prefer variable names. (Note we need not
348  * consider '.' as the next token; that case was handled above,
349  * and we always prefer variable names in that case.) If we are
350  * not at start of statement, always prefer variable names over
351  * unreserved keywords.
352  */
354  !(tok2 == '=' || tok2 == COLON_EQUALS || tok2 == '['))
355  {
356  /* try for unreserved keyword, then for variable name */
357  if (core_yy.scanbuf[aux1.lloc] != '"' &&
358  (kw = ScanKeywordLookup(aux1.lval.str,
359  unreserved_keywords,
361  {
362  aux1.lval.keyword = kw->name;
363  tok1 = kw->value;
364  }
365  else if (plpgsql_parse_word(aux1.lval.str,
366  core_yy.scanbuf + aux1.lloc,
367  &aux1.lval.wdatum,
368  &aux1.lval.word))
369  tok1 = T_DATUM;
370  else
371  tok1 = T_WORD;
372  }
373  else
374  {
375  /* try for variable name, then for unreserved keyword */
376  if (plpgsql_parse_word(aux1.lval.str,
377  core_yy.scanbuf + aux1.lloc,
378  &aux1.lval.wdatum,
379  &aux1.lval.word))
380  tok1 = T_DATUM;
381  else if (!aux1.lval.word.quoted &&
382  (kw = ScanKeywordLookup(aux1.lval.word.ident,
383  unreserved_keywords,
385  {
386  aux1.lval.keyword = kw->name;
387  tok1 = kw->value;
388  }
389  else
390  tok1 = T_WORD;
391  }
392  }
393  }
394  else
395  {
396  /*
397  * Not a potential plpgsql variable name, just return the data.
398  *
399  * Note that we also come through here if the grammar pushed back a
400  * T_DATUM, T_CWORD, T_WORD, or unreserved-keyword token returned by a
401  * previous lookup cycle; thus, pushbacks do not incur extra lookup
402  * work, since we'll never do the above code twice for the same token.
403  * This property also makes it safe to rely on the old value of
404  * plpgsql_yytoken in the is-this-start-of-statement test above.
405  */
406  }
407 
408  plpgsql_yylval = aux1.lval;
409  plpgsql_yylloc = aux1.lloc;
410  plpgsql_yyleng = aux1.leng;
411  plpgsql_yytoken = tok1;
412  return tok1;
413 }
414 
415 /*
416  * Internal yylex function. This wraps the core lexer and adds one feature:
417  * a token pushback stack. We also make a couple of trivial single-token
418  * translations from what the core lexer does to what we want, in particular
419  * interfacing from the core_YYSTYPE to YYSTYPE union.
420  */
421 static int
423 {
424  int token;
425  const char *yytext;
426 
427  if (num_pushbacks > 0)
428  {
429  num_pushbacks--;
430  token = pushback_token[num_pushbacks];
431  *auxdata = pushback_auxdata[num_pushbacks];
432  }
433  else
434  {
435  token = core_yylex(&auxdata->lval.core_yystype,
436  &auxdata->lloc,
437  yyscanner);
438 
439  /* remember the length of yytext before it gets changed */
440  yytext = core_yy.scanbuf + auxdata->lloc;
441  auxdata->leng = strlen(yytext);
442 
443  /* Check for << >> and #, which the core considers operators */
444  if (token == Op)
445  {
446  if (strcmp(auxdata->lval.str, "<<") == 0)
447  token = LESS_LESS;
448  else if (strcmp(auxdata->lval.str, ">>") == 0)
449  token = GREATER_GREATER;
450  else if (strcmp(auxdata->lval.str, "#") == 0)
451  token = '#';
452  }
453 
454  /* The core returns PARAM as ival, but we treat it like IDENT */
455  else if (token == PARAM)
456  {
457  auxdata->lval.str = pstrdup(yytext);
458  }
459  }
460 
461  return token;
462 }
463 
464 /*
465  * Push back a token to be re-read by next internal_yylex() call.
466  */
467 static void
468 push_back_token(int token, TokenAuxData *auxdata)
469 {
471  elog(ERROR, "too many tokens pushed back");
472  pushback_token[num_pushbacks] = token;
473  pushback_auxdata[num_pushbacks] = *auxdata;
474  num_pushbacks++;
475 }
476 
477 /*
478  * Push back a single token to be re-read by next plpgsql_yylex() call.
479  *
480  * NOTE: this does not cause yylval or yylloc to "back up". Also, it
481  * is not a good idea to push back a token code other than what you read.
482  */
483 void
485 {
486  TokenAuxData auxdata;
487 
488  auxdata.lval = plpgsql_yylval;
489  auxdata.lloc = plpgsql_yylloc;
490  auxdata.leng = plpgsql_yyleng;
491  push_back_token(token, &auxdata);
492 }
493 
494 /*
495  * Tell whether a token is an unreserved keyword.
496  *
497  * (If it is, its lowercased form was returned as the token value, so we
498  * do not need to offer that data here.)
499  */
500 bool
502 {
503  int i;
504 
505  for (i = 0; i < num_unreserved_keywords; i++)
506  {
507  if (unreserved_keywords[i].value == token)
508  return true;
509  }
510  return false;
511 }
512 
513 /*
514  * Append the function text starting at startlocation and extending to
515  * (not including) endlocation onto the existing contents of "buf".
516  */
517 void
519  int startlocation, int endlocation)
520 {
521  Assert(startlocation <= endlocation);
522  appendBinaryStringInfo(buf, scanorig + startlocation,
523  endlocation - startlocation);
524 }
525 
526 /*
527  * Peek one token ahead in the input stream. Only the token code is
528  * made available, not any of the auxiliary info such as location.
529  *
530  * NB: no variable or unreserved keyword lookup is performed here, they will
531  * be returned as IDENT. Reserved keywords are resolved as usual.
532  */
533 int
535 {
536  int tok1;
537  TokenAuxData aux1;
538 
539  tok1 = internal_yylex(&aux1);
540  push_back_token(tok1, &aux1);
541  return tok1;
542 }
543 
544 /*
545  * Peek two tokens ahead in the input stream. The first token and its
546  * location in the query are returned in *tok1_p and *tok1_loc, second token
547  * and its location in *tok2_p and *tok2_loc.
548  *
549  * NB: no variable or unreserved keyword lookup is performed here, they will
550  * be returned as IDENT. Reserved keywords are resolved as usual.
551  */
552 void
553 plpgsql_peek2(int *tok1_p, int *tok2_p, int *tok1_loc, int *tok2_loc)
554 {
555  int tok1,
556  tok2;
557  TokenAuxData aux1,
558  aux2;
559 
560  tok1 = internal_yylex(&aux1);
561  tok2 = internal_yylex(&aux2);
562 
563  *tok1_p = tok1;
564  if (tok1_loc)
565  *tok1_loc = aux1.lloc;
566  *tok2_p = tok2;
567  if (tok2_loc)
568  *tok2_loc = aux2.lloc;
569 
570  push_back_token(tok2, &aux2);
571  push_back_token(tok1, &aux1);
572 }
573 
574 /*
575  * plpgsql_scanner_errposition
576  * Report an error cursor position, if possible.
577  *
578  * This is expected to be used within an ereport() call. The return value
579  * is a dummy (always 0, in fact).
580  *
581  * Note that this can only be used for messages emitted during initial
582  * parsing of a plpgsql function, since it requires the scanorig string
583  * to still be available.
584  */
585 int
587 {
588  int pos;
589 
590  if (location < 0 || scanorig == NULL)
591  return 0; /* no-op if location is unknown */
592 
593  /* Convert byte offset to character number */
594  pos = pg_mbstrlen_with_len(scanorig, location) + 1;
595  /* And pass it to the ereport mechanism */
596  (void) internalerrposition(pos);
597  /* Also pass the function body string */
598  return internalerrquery(scanorig);
599 }
600 
601 /*
602  * plpgsql_yyerror
603  * Report a lexer or grammar error.
604  *
605  * The message's cursor position refers to the current token (the one
606  * last returned by plpgsql_yylex()).
607  * This is OK for syntax error messages from the Bison parser, because Bison
608  * parsers report error as soon as the first unparsable token is reached.
609  * Beware of using yyerror for other purposes, as the cursor position might
610  * be misleading!
611  */
612 void
613 plpgsql_yyerror(const char *message)
614 {
615  char *yytext = core_yy.scanbuf + plpgsql_yylloc;
616 
617  if (*yytext == '\0')
618  {
619  ereport(ERROR,
620  (errcode(ERRCODE_SYNTAX_ERROR),
621  /* translator: %s is typically the translation of "syntax error" */
622  errmsg("%s at end of input", _(message)),
623  plpgsql_scanner_errposition(plpgsql_yylloc)));
624  }
625  else
626  {
627  /*
628  * If we have done any lookahead then flex will have restored the
629  * character after the end-of-token. Zap it again so that we report
630  * only the single token here. This modifies scanbuf but we no longer
631  * care about that.
632  */
633  yytext[plpgsql_yyleng] = '\0';
634 
635  ereport(ERROR,
636  (errcode(ERRCODE_SYNTAX_ERROR),
637  /* translator: first %s is typically the translation of "syntax error" */
638  errmsg("%s at or near \"%s\"", _(message), yytext),
639  plpgsql_scanner_errposition(plpgsql_yylloc)));
640  }
641 }
642 
643 /*
644  * Given a location (a byte offset in the function source text),
645  * return a line number.
646  *
647  * We expect that this is typically called for a sequence of increasing
648  * location values, so optimize accordingly by tracking the endpoints
649  * of the "current" line.
650  */
651 int
653 {
654  const char *loc;
655 
656  if (location < 0 || scanorig == NULL)
657  return 0; /* garbage in, garbage out */
658  loc = scanorig + location;
659 
660  /* be correct, but not fast, if input location goes backwards */
661  if (loc < cur_line_start)
663 
664  while (cur_line_end != NULL && loc > cur_line_end)
665  {
667  cur_line_num++;
668  cur_line_end = strchr(cur_line_start, '\n');
669  }
670 
671  return cur_line_num;
672 }
673 
674 /* initialize or reset the state for plpgsql_location_to_lineno */
675 static void
677 {
679  cur_line_num = 1;
680 
681  cur_line_end = strchr(cur_line_start, '\n');
682 }
683 
684 /* return the most recently computed lineno */
685 int
687 {
688  return cur_line_num;
689 }
690 
691 
692 /*
693  * Called before any actual parsing is done
694  *
695  * Note: the passed "str" must remain valid until plpgsql_scanner_finish().
696  * Although it is not fed directly to flex, we need the original string
697  * to cite in error messages.
698  */
699 void
700 plpgsql_scanner_init(const char *str)
701 {
702  /* Start up the core scanner */
703  yyscanner = scanner_init(str, &core_yy,
704  reserved_keywords, num_reserved_keywords);
705 
706  /*
707  * scanorig points to the original string, which unlike the scanner's
708  * scanbuf won't be modified on-the-fly by flex. Notice that although
709  * yytext points into scanbuf, we rely on being able to apply locations
710  * (offsets from string start) to scanorig as well.
711  */
712  scanorig = str;
713 
714  /* Other setup */
716  plpgsql_yytoken = 0;
717 
718  num_pushbacks = 0;
719 
721 }
722 
723 /*
724  * Called after parsing is done to clean up after plpgsql_scanner_init()
725  */
726 void
728 {
729  /* release storage */
731  /* avoid leaving any dangling pointers */
732  yyscanner = NULL;
733  scanorig = NULL;
734 }
#define MAX_PUSHBACKS
Definition: pl_scanner.c:221
int plpgsql_latest_lineno(void)
Definition: pl_scanner.c:686
static struct @76 value
static int cur_line_num
Definition: pl_scanner.c:230
bool plpgsql_parse_dblword(char *word1, char *word2, PLwdatum *wdatum, PLcword *cword)
Definition: pl_comp.c:1409
void * core_yyscan_t
Definition: scanner.h:116
static TokenAuxData pushback_auxdata[MAX_PUSHBACKS]
Definition: pl_scanner.c:225
const ScanKeyword * ScanKeywordLookup(const char *text, const ScanKeyword *keywords, int num_keywords)
Definition: keywords.c:64
IdentifierLookup
Definition: plpgsql.h:1011
char * pstrdup(const char *in)
Definition: mcxt.c:1165
YYLTYPE lloc
Definition: pl_scanner.c:196
void plpgsql_append_source_text(StringInfo buf, int startlocation, int endlocation)
Definition: pl_scanner.c:518
int errcode(int sqlerrcode)
Definition: elog.c:575
#define PG_KEYWORD(a, b, c)
Definition: pl_scanner.c:23
static const ScanKeyword reserved_keywords[]
Definition: pl_scanner.c:68
#define UNRESERVED_KEYWORD
Definition: keywords.h:18
#define lengthof(array)
Definition: c.h:558
static void location_lineno_init(void)
Definition: pl_scanner.c:676
static const int num_unreserved_keywords
Definition: pl_scanner.c:176
YYSTYPE lval
Definition: pl_scanner.c:195
static const char * cur_line_start
Definition: pl_scanner.c:228
void plpgsql_yyerror(const char *message)
Definition: pl_scanner.c:613
char * scanbuf
Definition: scanner.h:72
int pg_mbstrlen_with_len(const char *mbstr, int limit)
Definition: mbutils.c:805
int plpgsql_peek(void)
Definition: pl_scanner.c:534
bool plpgsql_token_is_unreserved_keyword(int token)
Definition: pl_scanner.c:501
void plpgsql_scanner_finish(void)
Definition: pl_scanner.c:727
#define ERROR
Definition: elog.h:43
static char * buf
Definition: pg_test_fsync.c:65
static int plpgsql_yytoken
Definition: pl_scanner.c:218
const char * name
Definition: keywords.h:26
#define YYLTYPE
Definition: scanner.h:44
static const ScanKeyword unreserved_keywords[]
Definition: pl_scanner.c:97
static int internal_yylex(TokenAuxData *auxdata)
Definition: pl_scanner.c:422
#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:1353
void plpgsql_peek2(int *tok1_p, int *tok2_p, int *tok1_loc, int *tok2_loc)
Definition: pl_scanner.c:553
static const char * scanorig
Definition: pl_scanner.c:212
IdentifierLookup plpgsql_IdentifierLookup
Definition: pl_scanner.c:27
static int num_pushbacks
Definition: pl_scanner.c:223
static int pushback_token[MAX_PUSHBACKS]
Definition: pl_scanner.c:224
#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:652
int internalerrquery(const char *query)
Definition: elog.c:1161
#define NULL
Definition: c.h:226
static core_yy_extra_type core_yy
Definition: pl_scanner.c:209
#define Assert(condition)
Definition: c.h:671
static int plpgsql_yyleng
Definition: pl_scanner.c:215
#define AT_STMT_START(prev_token)
Definition: pl_scanner.c:184
int plpgsql_scanner_errposition(int location)
Definition: pl_scanner.c:586
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:208
void plpgsql_scanner_init(const char *str)
Definition: pl_scanner.c:700
int errmsg(const char *fmt,...)
Definition: elog.c:797
static const char * cur_line_end
Definition: pl_scanner.c:229
bool plpgsql_parse_tripword(char *word1, char *word2, char *word3, PLwdatum *wdatum, PLcword *cword)
Definition: pl_comp.c:1529
int i
static const int num_reserved_keywords
Definition: pl_scanner.c:95
void scanner_finish(core_yyscan_t yyscanner)
#define elog
Definition: elog.h:219
int plpgsql_yylex(void)
Definition: pl_scanner.c:248
static void push_back_token(int token, TokenAuxData *auxdata)
Definition: pl_scanner.c:468
void plpgsql_push_back_token(int token)
Definition: pl_scanner.c:484
#define _(x)
Definition: elog.c:84
void appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
Definition: stringinfo.c:240
int internalerrposition(int cursorpos)
Definition: elog.c:1141