Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * quote.c
       4             :  *    Functions for quoting identifiers and literals
       5             :  *
       6             :  * Portions Copyright (c) 2000-2017, 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             : 
      18             : 
      19             : /*
      20             :  * quote_ident -
      21             :  *    returns a properly quoted identifier
      22             :  */
      23             : Datum
      24         206 : quote_ident(PG_FUNCTION_ARGS)
      25             : {
      26         206 :     text       *t = PG_GETARG_TEXT_PP(0);
      27             :     const char *qstr;
      28             :     char       *str;
      29             : 
      30         206 :     str = text_to_cstring(t);
      31         206 :     qstr = quote_identifier(str);
      32         206 :     PG_RETURN_TEXT_P(cstring_to_text(qstr));
      33             : }
      34             : 
      35             : /*
      36             :  * quote_literal_internal -
      37             :  *    helper function for quote_literal and quote_literal_cstr
      38             :  *
      39             :  * NOTE: think not to make this function's behavior change with
      40             :  * standard_conforming_strings.  We don't know where the result
      41             :  * literal will be used, and so we must generate a result that
      42             :  * will work with either setting.  Take a look at what dblink
      43             :  * uses this for before thinking you know better.
      44             :  */
      45             : static size_t
      46         698 : quote_literal_internal(char *dst, const char *src, size_t len)
      47             : {
      48             :     const char *s;
      49         698 :     char       *savedst = dst;
      50             : 
      51        3720 :     for (s = src; s < src + len; s++)
      52             :     {
      53        3023 :         if (*s == '\\')
      54             :         {
      55           1 :             *dst++ = ESCAPE_STRING_SYNTAX;
      56           1 :             break;
      57             :         }
      58             :     }
      59             : 
      60         698 :     *dst++ = '\'';
      61        4419 :     while (len-- > 0)
      62             :     {
      63        3023 :         if (SQL_STR_DOUBLE(*src, true))
      64           2 :             *dst++ = *src;
      65        3023 :         *dst++ = *src++;
      66             :     }
      67         698 :     *dst++ = '\'';
      68             : 
      69         698 :     return dst - savedst;
      70             : }
      71             : 
      72             : /*
      73             :  * quote_literal -
      74             :  *    returns a properly quoted literal
      75             :  */
      76             : Datum
      77         445 : quote_literal(PG_FUNCTION_ARGS)
      78             : {
      79         445 :     text       *t = PG_GETARG_TEXT_PP(0);
      80             :     text       *result;
      81             :     char       *cp1;
      82             :     char       *cp2;
      83             :     int         len;
      84             : 
      85         445 :     len = VARSIZE_ANY_EXHDR(t);
      86             :     /* We make a worst-case result area; wasting a little space is OK */
      87         445 :     result = (text *) palloc(len * 2 + 3 + VARHDRSZ);
      88             : 
      89         445 :     cp1 = VARDATA_ANY(t);
      90         445 :     cp2 = VARDATA(result);
      91             : 
      92         445 :     SET_VARSIZE(result, VARHDRSZ + quote_literal_internal(cp2, cp1, len));
      93             : 
      94         445 :     PG_RETURN_TEXT_P(result);
      95             : }
      96             : 
      97             : /*
      98             :  * quote_literal_cstr -
      99             :  *    returns a properly quoted literal
     100             :  */
     101             : char *
     102         253 : quote_literal_cstr(const char *rawstr)
     103             : {
     104             :     char       *result;
     105             :     int         len;
     106             :     int         newlen;
     107             : 
     108         253 :     len = strlen(rawstr);
     109             :     /* We make a worst-case result area; wasting a little space is OK */
     110         253 :     result = palloc(len * 2 + 3 + 1);
     111             : 
     112         253 :     newlen = quote_literal_internal(result, rawstr, len);
     113         253 :     result[newlen] = '\0';
     114             : 
     115         253 :     return result;
     116             : }
     117             : 
     118             : /*
     119             :  * quote_nullable -
     120             :  *    Returns a properly quoted literal, with null values returned
     121             :  *    as the text string 'NULL'.
     122             :  */
     123             : Datum
     124         254 : quote_nullable(PG_FUNCTION_ARGS)
     125             : {
     126         254 :     if (PG_ARGISNULL(0))
     127          14 :         PG_RETURN_TEXT_P(cstring_to_text("NULL"));
     128             :     else
     129         240 :         PG_RETURN_DATUM(DirectFunctionCall1(quote_literal,
     130             :                                             PG_GETARG_DATUM(0)));
     131             : }