Simplify and standardize conversions between TEXT datums and ordinary C

strings.  This patch introduces four support functions cstring_to_text,
cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and
two macros CStringGetTextDatum and TextDatumGetCString.  A number of
existing macros that provided variants on these themes were removed.

Most of the places that need to make such conversions now require just one
function or macro call, in place of the multiple notational layers that used
to be needed.  There are no longer any direct calls of textout or textin,
and we got most of the places that were using handmade conversions via
memcpy (there may be a few still lurking, though).

This commit doesn't make any serious effort to eliminate transient memory
leaks caused by detoasting toasted text objects before they reach
text_to_cstring.  We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few
places where it was easy, but much more could be done.

Brendan Jurd and Tom Lane

1 files changed, 18 insertions, 19 deletions

diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c
index bfac89e4146..793f26ed583 100644
--- a/contrib/tablefunc/tablefunc.c
+++ b/contrib/tablefunc/tablefunc.c
@@ -95,8 +95,6 @@ typedef struct
 	char	   *lastrowid;		/* rowid of the last tuple sent */
 }	crosstab_fctx;
 
-#define GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
-#define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
 #define xpfree(var_) \
 	do { \
 		if (var_ != NULL) \
@@ -370,7 +368,7 @@ crosstab(PG_FUNCTION_ARGS)
 	/* stuff done only on the first call of the function */
 	if (SRF_IS_FIRSTCALL())
 	{
-		char	   *sql = GET_STR(PG_GETARG_TEXT_P(0));
+		char	   *sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
 		TupleDesc	tupdesc;
 		int			ret;
 		int			proc;
@@ -695,8 +693,8 @@ PG_FUNCTION_INFO_V1(crosstab_hash);
 Datum
 crosstab_hash(PG_FUNCTION_ARGS)
 {
-	char	   *sql = GET_STR(PG_GETARG_TEXT_P(0));
-	char	   *cats_sql = GET_STR(PG_GETARG_TEXT_P(1));
+	char	   *sql = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	   *cats_sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 	TupleDesc	tupdesc;
 	MemoryContext per_query_ctx;
@@ -1052,10 +1050,10 @@ PG_FUNCTION_INFO_V1(connectby_text);
 Datum
 connectby_text(PG_FUNCTION_ARGS)
 {
-	char	   *relname = GET_STR(PG_GETARG_TEXT_P(0));
-	char	   *key_fld = GET_STR(PG_GETARG_TEXT_P(1));
-	char	   *parent_key_fld = GET_STR(PG_GETARG_TEXT_P(2));
-	char	   *start_with = GET_STR(PG_GETARG_TEXT_P(3));
+	char	   *relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	   *key_fld = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	char	   *parent_key_fld = text_to_cstring(PG_GETARG_TEXT_PP(2));
+	char	   *start_with = text_to_cstring(PG_GETARG_TEXT_PP(3));
 	int			max_depth = PG_GETARG_INT32(4);
 	char	   *branch_delim = NULL;
 	bool		show_branch = false;
@@ -1079,7 +1077,7 @@ connectby_text(PG_FUNCTION_ARGS)
 
 	if (fcinfo->nargs == 6)
 	{
-		branch_delim = GET_STR(PG_GETARG_TEXT_P(5));
+		branch_delim = text_to_cstring(PG_GETARG_TEXT_PP(5));
 		show_branch = true;
 	}
 	else
@@ -1129,11 +1127,11 @@ PG_FUNCTION_INFO_V1(connectby_text_serial);
 Datum
 connectby_text_serial(PG_FUNCTION_ARGS)
 {
-	char	   *relname = GET_STR(PG_GETARG_TEXT_P(0));
-	char	   *key_fld = GET_STR(PG_GETARG_TEXT_P(1));
-	char	   *parent_key_fld = GET_STR(PG_GETARG_TEXT_P(2));
-	char	   *orderby_fld = GET_STR(PG_GETARG_TEXT_P(3));
-	char	   *start_with = GET_STR(PG_GETARG_TEXT_P(4));
+	char	   *relname = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	char	   *key_fld = text_to_cstring(PG_GETARG_TEXT_PP(1));
+	char	   *parent_key_fld = text_to_cstring(PG_GETARG_TEXT_PP(2));
+	char	   *orderby_fld = text_to_cstring(PG_GETARG_TEXT_PP(3));
+	char	   *start_with = text_to_cstring(PG_GETARG_TEXT_PP(4));
 	int			max_depth = PG_GETARG_INT32(5);
 	char	   *branch_delim = NULL;
 	bool		show_branch = false;
@@ -1158,7 +1156,7 @@ connectby_text_serial(PG_FUNCTION_ARGS)
 
 	if (fcinfo->nargs == 7)
 	{
-		branch_delim = GET_STR(PG_GETARG_TEXT_P(6));
+		branch_delim = text_to_cstring(PG_GETARG_TEXT_PP(6));
 		show_branch = true;
 	}
 	else
@@ -1645,9 +1643,10 @@ quote_literal_cstr(char *rawstr)
 	text	   *result_text;
 	char	   *result;
 
-	rawstr_text = DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(rawstr)));
-	result_text = DatumGetTextP(DirectFunctionCall1(quote_literal, PointerGetDatum(rawstr_text)));
-	result = DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(result_text)));
+	rawstr_text = cstring_to_text(rawstr);
+	result_text = DatumGetTextP(DirectFunctionCall1(quote_literal,
+													PointerGetDatum(rawstr_text)));
+	result = text_to_cstring(result_text);
 
 	return result;
 }