granicus.if.org Git - postgresql/blob - src/backend/utils/adt/quote.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * quote.c
   4  *        Functions for quoting identifiers and literals
   5  *
   6  * Portions Copyright (c) 2000-2014, 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 quote_ident(PG_FUNCTION_ARGS)
  25 {
  26         text       *t = PG_GETARG_TEXT_PP(0);
  27         const char *qstr;
  28         char       *str;
  29
  30         str = text_to_cstring(t);
  31         qstr = quote_identifier(str);
  32         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 quote_literal_internal(char *dst, const char *src, size_t len)
  47 {
  48         const char *s;
  49         char       *savedst = dst;
  50
  51         for (s = src; s < src + len; s++)
  52         {
  53                 if (*s == '\\')
  54                 {
  55                         *dst++ = ESCAPE_STRING_SYNTAX;
  56                         break;
  57                 }
  58         }
  59
  60         *dst++ = '\'';
  61         while (len-- > 0)
  62         {
  63                 if (SQL_STR_DOUBLE(*src, true))
  64                         *dst++ = *src;
  65                 *dst++ = *src++;
  66         }
  67         *dst++ = '\'';
  68
  69         return dst - savedst;
  70 }
  71
  72 /*
  73  * quote_literal -
  74  *        returns a properly quoted literal
  75  */
  76 Datum
  77 quote_literal(PG_FUNCTION_ARGS)
  78 {
  79         text       *t = PG_GETARG_TEXT_P(0);
  80         text       *result;
  81         char       *cp1;
  82         char       *cp2;
  83         int                     len;
  84
  85         len = VARSIZE(t) - VARHDRSZ;
  86         /* We make a worst-case result area; wasting a little space is OK */
  87         result = (text *) palloc(len * 2 + 3 + VARHDRSZ);
  88
  89         cp1 = VARDATA(t);
  90         cp2 = VARDATA(result);
  91
  92         SET_VARSIZE(result, VARHDRSZ + quote_literal_internal(cp2, cp1, len));
  93
  94         PG_RETURN_TEXT_P(result);
  95 }
  96
  97 /*
  98  * quote_literal_cstr -
  99  *        returns a properly quoted literal
 100  */
 101 char *
 102 quote_literal_cstr(const char *rawstr)
 103 {
 104         char       *result;
 105         int                     len;
 106         int                     newlen;
 107
 108         len = strlen(rawstr);
 109         /* We make a worst-case result area; wasting a little space is OK */
 110         result = palloc(len * 2 + 3);
 111
 112         newlen = quote_literal_internal(result, rawstr, len);
 113         result[newlen] = '\0';
 114
 115         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 quote_nullable(PG_FUNCTION_ARGS)
 125 {
 126         if (PG_ARGISNULL(0))
 127                 PG_RETURN_TEXT_P(cstring_to_text("NULL"));
 128         else
 129                 PG_RETURN_DATUM(DirectFunctionCall1(quote_literal,
 130                                                                                         PG_GETARG_DATUM(0)));
 131 }