Expose quote_literal_cstr() from core.

This eliminates the need for inefficient implementions of this
functionality in both contrib/dblink and contrib/tablefunc, so remove
them.  The upcoming patch implementing an in-core format() function
will also require this functionality.

In passing, add some regression tests.

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index ce868292100ec057a965d51b2b21b704942baf0c..30f1b0eab02b1555e6695600a6cc313c0ac4b5d5 100644 (file)
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -91,7 +91,6 @@ static char **get_text_array_contents(ArrayType *array, int *numitems);
 static char *get_sql_insert(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals);
 static char *get_sql_delete(Relation rel, int *pkattnums, int pknumatts, char **tgt_pkattvals);
 static char *get_sql_update(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals);
-static char *quote_literal_cstr(char *rawstr);
 static char *quote_ident_cstr(char *rawstr);
 static int     get_attnum_pk_pos(int *pkattnums, int pknumatts, int key);
 static HeapTuple get_tuple_of_interest(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals);
@@ -1893,25 +1892,6 @@ get_sql_update(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals
        return (buf.data);
 }
 
-/*
- * Return a properly quoted literal value.
- * Uses quote_literal in quote.c
- */
-static char *
-quote_literal_cstr(char *rawstr)
-{
-       text       *rawstr_text;
-       text       *result_text;
-       char       *result;
-
-       rawstr_text = cstring_to_text(rawstr);
-       result_text = DatumGetTextP(DirectFunctionCall1(quote_literal,
-                                                                                         PointerGetDatum(rawstr_text)));
-       result = text_to_cstring(result_text);
-
-       return result;
-}
-
 /*
  * Return a properly quoted identifier.
  * Uses quote_ident in quote.c

diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index ea2f2e15b0a3428a1dba73f93d10021a5618aadf..2e9ea1a626ef5a1ffc0af2be5cc234cb5a0c15c4 100644 (file)
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -85,7 +85,6 @@ static Tuplestorestate *build_tuplestore_recursively(char *key_fld,
                                                         MemoryContext per_query_ctx,
                                                         AttInMetadata *attinmeta,
                                                         Tuplestorestate *tupstore);
-static char *quote_literal_cstr(char *rawstr);
 
 typedef struct
 {
@@ -1564,22 +1563,3 @@ compatCrosstabTupleDescs(TupleDesc ret_tupdesc, TupleDesc sql_tupdesc)
        /* OK, the two tupdescs are compatible for our purposes */
        return true;
 }
-
-/*
- * Return a properly quoted literal value.
- * Uses quote_literal in quote.c
- */
-static char *
-quote_literal_cstr(char *rawstr)
-{
-       text       *rawstr_text;
-       text       *result_text;
-       char       *result;
-
-       rawstr_text = cstring_to_text(rawstr);
-       result_text = DatumGetTextP(DirectFunctionCall1(quote_literal,
-                                                                                         PointerGetDatum(rawstr_text)));
-       result = text_to_cstring(result_text);
-
-       return result;
-}

diff --git a/src/backend/utils/adt/quote.c b/src/backend/utils/adt/quote.c
index 70e98cad84b09be0d6ca7e5cac37bb0d3ad60398..af07443f7df065cc9dc938123a92d8615a6a7de4 100644 (file)
--- a/src/backend/utils/adt/quote.c
+++ b/src/backend/utils/adt/quote.c
@@ -33,8 +33,8 @@ quote_ident(PG_FUNCTION_ARGS)
 }
 
 /*
- * quote_literal -
- *       returns a properly quoted literal
+ * quote_literal_internal -
+ *       helper function for quote_literal and quote_literal_cstr
  *
  * NOTE: think not to make this function's behavior change with
  * standard_conforming_strings.  We don't know where the result
@@ -42,6 +42,37 @@ quote_ident(PG_FUNCTION_ARGS)
  * will work with either setting.  Take a look at what dblink
  * uses this for before thinking you know better.
  */
+static size_t
+quote_literal_internal(char *dst, char *src, size_t len)
+{
+       char       *s;
+       char       *savedst = dst;
+
+       for (s = src; s < src + len; s++)
+       {
+               if (*s == '\\')
+               {
+                       *dst++ = ESCAPE_STRING_SYNTAX;
+                       break;
+               }
+       }
+
+       *dst++ = '\'';
+       while (len-- > 0)
+       {
+               if (SQL_STR_DOUBLE(*src, true))
+                       *dst++ = *src;
+               *dst++ = *src++;
+       }
+       *dst++ = '\'';
+
+       return dst - savedst;
+}
+
+/*
+ * quote_literal -
+ *       returns a properly quoted literal
+ */
 Datum
 quote_literal(PG_FUNCTION_ARGS)
 {
@@ -58,30 +89,30 @@ quote_literal(PG_FUNCTION_ARGS)
        cp1 = VARDATA(t);
        cp2 = VARDATA(result);
 
-       for (; len-- > 0; cp1++)
-       {
-               if (*cp1 == '\\')
-               {
-                       *cp2++ = ESCAPE_STRING_SYNTAX;
-                       break;
-               }
-       }
+       SET_VARSIZE(result, VARHDRSZ + quote_literal_internal(cp2, cp1, len));
 
-       len = VARSIZE(t) - VARHDRSZ;
-       cp1 = VARDATA(t);
+       PG_RETURN_TEXT_P(result);
+}
 
-       *cp2++ = '\'';
-       while (len-- > 0)
-       {
-               if (SQL_STR_DOUBLE(*cp1, true))
-                       *cp2++ = *cp1;
-               *cp2++ = *cp1++;
-       }
-       *cp2++ = '\'';
+/*
+ * quote_literal_cstr -
+ *       returns a properly quoted literal
+ */
+char *
+quote_literal_cstr(char *rawstr)
+{
+       char       *result;
+       int                     len;
+       int                     newlen;
 
-       SET_VARSIZE(result, cp2 - ((char *) result));
+       len = strlen(rawstr);
+       /* We make a worst-case result area; wasting a little space is OK */
+       result = palloc(len * 2 + 3);
 
-       PG_RETURN_TEXT_P(result);
+       newlen = quote_literal_internal(result, rawstr, len);
+       result[newlen] = '\0';
+
+       return result;
 }
 
 /*

diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 7b1bb2353834337dcc53cdcf4528b34aaf351d0e..ae267ab17ad34945dd96f1756ce8abe2372a6eab 100644 (file)
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -977,6 +977,7 @@ extern int32 type_maximum_size(Oid type_oid, int32 typemod);
 /* quote.c */
 extern Datum quote_ident(PG_FUNCTION_ARGS);
 extern Datum quote_literal(PG_FUNCTION_ARGS);
+extern char *quote_literal_cstr(char *rawstr);
 extern Datum quote_nullable(PG_FUNCTION_ARGS);
 
 /* guc.c */

diff --git a/src/test/regress/expected/text.out b/src/test/regress/expected/text.out
index 84f4a5cda8b79bd033f76b6288228e220c4d74fd..0b0014a6e25ffe0246357e2d66b60434ee180968 100644 (file)
--- a/src/test/regress/expected/text.out
+++ b/src/test/regress/expected/text.out
@@ -118,3 +118,21 @@ select i, left('ahoj', i), right('ahoj', i) from generate_series(-5, 5) t(i) ord
   5 | ahoj | ahoj
 (11 rows)
 
+select quote_literal('');
+ quote_literal 
+---------------
+ ''
+(1 row)
+
+select quote_literal('abc''');
+ quote_literal 
+---------------
+ 'abc'''
+(1 row)
+
+select quote_literal(e'\\');
+ quote_literal 
+---------------
+ E'\\'
+(1 row)
+

diff --git a/src/test/regress/sql/text.sql b/src/test/regress/sql/text.sql
index a8768ee81aa5526112a22e843063f6f954312363..50c3033d9eb65e82996f628e16643fb6f1760189 100644 (file)
--- a/src/test/regress/sql/text.sql
+++ b/src/test/regress/sql/text.sql
@@ -41,3 +41,6 @@ select concat_ws('',10,20,null,30);
 select concat_ws(NULL,10,20,null,30) is null;
 select reverse('abcde');
 select i, left('ahoj', i), right('ahoj', i) from generate_series(-5, 5) t(i) order by i;
+select quote_literal('');
+select quote_literal('abc''');
+select quote_literal(e'\\');