Line data    Source code

       1              : /*-------------------------------------------------------------------------
       2              :  *
       3              :  * quote.c
       4              :  *    Functions for quoting identifiers and literals
       5              :  *
       6              :  * Portions Copyright (c) 2000-2026, PostgreSQL Global Development Group
       7              :  *
       8              :  *
       9              :  * IDENTIFICATION
      10              :  *    src/backend/utils/adt/quote.c
      11              :  *
      12              :  *-------------------------------------------------------------------------
      13              :  */
      14              : #include "postgres.h"
      15              : 
      16              : #include "utils/builtins.h"
      17              : #include "varatt.h"
      18              : 
      19              : 
      20              : /*
      21              :  * quote_ident -
      22              :  *    returns a properly quoted identifier
      23              :  */
      24              : Datum
      25         4372 : quote_ident(PG_FUNCTION_ARGS)
      26              : {
      27         4372 :     text       *t = PG_GETARG_TEXT_PP(0);
      28              :     const char *qstr;
      29              :     char       *str;
      30              : 
      31         4372 :     str = text_to_cstring(t);
      32         4372 :     qstr = quote_identifier(str);
      33         4372 :     PG_RETURN_TEXT_P(cstring_to_text(qstr));
      34              : }
      35              : 
      36              : /*
      37              :  * quote_literal_internal -
      38              :  *    helper function for quote_literal and quote_literal_cstr
      39              :  *
      40              :  * NOTE: This must produce output that will work in old servers with
      41              :  * standard_conforming_strings = off.  It's used for example by
      42              :  * dblink, which may send the result to another server.
      43              :  */
      44              : static size_t
      45         4793 : quote_literal_internal(char *dst, const char *src, size_t len)
      46              : {
      47              :     const char *s;
      48         4793 :     char       *savedst = dst;
      49              : 
      50       350422 :     for (s = src; s < src + len; s++)
      51              :     {
      52       345634 :         if (*s == '\\')
      53              :         {
      54            5 :             *dst++ = ESCAPE_STRING_SYNTAX;
      55            5 :             break;
      56              :         }
      57              :     }
      58              : 
      59         4793 :     *dst++ = '\'';
      60       350429 :     while (len-- > 0)
      61              :     {
      62       345636 :         if (SQL_STR_DOUBLE(*src, true))
      63           24 :             *dst++ = *src;
      64       345636 :         *dst++ = *src++;
      65              :     }
      66         4793 :     *dst++ = '\'';
      67              : 
      68         4793 :     return dst - savedst;
      69              : }
      70              : 
      71              : /*
      72              :  * quote_literal -
      73              :  *    returns a properly quoted literal
      74              :  */
      75              : Datum
      76         1769 : quote_literal(PG_FUNCTION_ARGS)
      77              : {
      78         1769 :     text       *t = PG_GETARG_TEXT_PP(0);
      79              :     text       *result;
      80              :     char       *cp1;
      81              :     char       *cp2;
      82              :     int         len;
      83              : 
      84         1769 :     len = VARSIZE_ANY_EXHDR(t);
      85              :     /* We make a worst-case result area; wasting a little space is OK */
      86         1769 :     result = (text *) palloc(len * 2 + 3 + VARHDRSZ);
      87              : 
      88         1769 :     cp1 = VARDATA_ANY(t);
      89         1769 :     cp2 = VARDATA(result);
      90              : 
      91         1769 :     SET_VARSIZE(result, VARHDRSZ + quote_literal_internal(cp2, cp1, len));
      92              : 
      93         1769 :     PG_RETURN_TEXT_P(result);
      94              : }
      95              : 
      96              : /*
      97              :  * quote_literal_cstr -
      98              :  *    returns a properly quoted literal
      99              :  */
     100              : char *
     101         3024 : quote_literal_cstr(const char *rawstr)
     102              : {
     103              :     char       *result;
     104              :     int         len;
     105              :     int         newlen;
     106              : 
     107         3024 :     len = strlen(rawstr);
     108              :     /* We make a worst-case result area; wasting a little space is OK */
     109         3024 :     result = palloc(
     110              :                     (len * 2)   /* doubling for every character if each one is
     111              :                                  * a quote */
     112              :                     + 3         /* two outer quotes + possibly 'E' if needed */
     113         3024 :                     + 1         /* null terminator */
     114              :         );
     115              : 
     116         3024 :     newlen = quote_literal_internal(result, rawstr, len);
     117         3024 :     result[newlen] = '\0';
     118              : 
     119         3024 :     return result;
     120              : }
     121              : 
     122              : /*
     123              :  * quote_nullable -
     124              :  *    Returns a properly quoted literal, with null values returned
     125              :  *    as the text string 'NULL'.
     126              :  */
     127              : Datum
     128          790 : quote_nullable(PG_FUNCTION_ARGS)
     129              : {
     130          790 :     if (PG_ARGISNULL(0))
     131           42 :         PG_RETURN_TEXT_P(cstring_to_text("NULL"));
     132              :     else
     133          748 :         PG_RETURN_DATUM(DirectFunctionCall1(quote_literal,
     134              :                                             PG_GETARG_DATUM(0)));
     135              : }