Switch various builtin functions to use pg_lsn instead of text.

The functions in slotfuncs.c don't exist in any released version,
but the changes to xlogfuncs.c represent backward-incompatibilities.
Per discussion, we're hoping that the queries using these functions
are few enough and simple enough that this won't cause too much
breakage for users.

Michael Paquier, reviewed by Andres Freund and further modified
by me.

1 files changed, 15 insertions, 138 deletions

diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 9133179a954..5f8d65514c1 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -30,11 +30,10 @@
 #include "utils/builtins.h"
 #include "utils/numeric.h"
 #include "utils/guc.h"
+#include "utils/pg_lsn.h"
 #include "utils/timestamp.h"
 #include "storage/fd.h"
 
-static void validate_xlog_location(char *str);
-
 
 /*
  * pg_start_backup: set up for taking an on-line backup dump
@@ -52,7 +51,6 @@ pg_start_backup(PG_FUNCTION_ARGS)
 	bool		fast = PG_GETARG_BOOL(1);
 	char	   *backupidstr;
 	XLogRecPtr	startpoint;
-	char		startxlogstr[MAXFNAMELEN];
 
 	backupidstr = text_to_cstring(backupid);
 
@@ -63,9 +61,7 @@ pg_start_backup(PG_FUNCTION_ARGS)
 
 	startpoint = do_pg_start_backup(backupidstr, fast, NULL, NULL);
 
-	snprintf(startxlogstr, sizeof(startxlogstr), "%X/%X",
-			 (uint32) (startpoint >> 32), (uint32) startpoint);
-	PG_RETURN_TEXT_P(cstring_to_text(startxlogstr));
+	PG_RETURN_LSN(startpoint);
 }
 
 /*
@@ -85,7 +81,6 @@ Datum
 pg_stop_backup(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	stoppoint;
-	char		stopxlogstr[MAXFNAMELEN];
 
 	if (!superuser() && !has_rolreplication(GetUserId()))
 		ereport(ERROR,
@@ -94,9 +89,7 @@ pg_stop_backup(PG_FUNCTION_ARGS)
 
 	stoppoint = do_pg_stop_backup(NULL, true, NULL);
 
-	snprintf(stopxlogstr, sizeof(stopxlogstr), "%X/%X",
-			 (uint32) (stoppoint >> 32), (uint32) stoppoint);
-	PG_RETURN_TEXT_P(cstring_to_text(stopxlogstr));
+	PG_RETURN_LSN(stoppoint);
 }
 
 /*
@@ -106,7 +99,6 @@ Datum
 pg_switch_xlog(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	switchpoint;
-	char		location[MAXFNAMELEN];
 
 	if (!superuser())
 		ereport(ERROR,
@@ -124,9 +116,7 @@ pg_switch_xlog(PG_FUNCTION_ARGS)
 	/*
 	 * As a convenience, return the WAL location of the switch record
 	 */
-	snprintf(location, sizeof(location), "%X/%X",
-			 (uint32) (switchpoint >> 32), (uint32) switchpoint);
-	PG_RETURN_TEXT_P(cstring_to_text(location));
+	PG_RETURN_LSN(switchpoint);
 }
 
 /*
@@ -138,7 +128,6 @@ pg_create_restore_point(PG_FUNCTION_ARGS)
 	text	   *restore_name = PG_GETARG_TEXT_P(0);
 	char	   *restore_name_str;
 	XLogRecPtr	restorepoint;
-	char		location[MAXFNAMELEN];
 
 	if (!superuser())
 		ereport(ERROR,
@@ -169,9 +158,7 @@ pg_create_restore_point(PG_FUNCTION_ARGS)
 	/*
 	 * As a convenience, return the WAL location of the restore point record
 	 */
-	snprintf(location, sizeof(location), "%X/%X",
-			 (uint32) (restorepoint >> 32), (uint32) restorepoint);
-	PG_RETURN_TEXT_P(cstring_to_text(location));
+	PG_RETURN_LSN(restorepoint);
 }
 
 /*
@@ -185,7 +172,6 @@ Datum
 pg_current_xlog_location(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	current_recptr;
-	char		location[MAXFNAMELEN];
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -195,9 +181,7 @@ pg_current_xlog_location(PG_FUNCTION_ARGS)
 
 	current_recptr = GetXLogWriteRecPtr();
 
-	snprintf(location, sizeof(location), "%X/%X",
-			 (uint32) (current_recptr >> 32), (uint32) current_recptr);
-	PG_RETURN_TEXT_P(cstring_to_text(location));
+	PG_RETURN_LSN(current_recptr);
 }
 
 /*
@@ -209,7 +193,6 @@ Datum
 pg_current_xlog_insert_location(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	current_recptr;
-	char		location[MAXFNAMELEN];
 
 	if (RecoveryInProgress())
 		ereport(ERROR,
@@ -219,9 +202,7 @@ pg_current_xlog_insert_location(PG_FUNCTION_ARGS)
 
 	current_recptr = GetXLogInsertRecPtr();
 
-	snprintf(location, sizeof(location), "%X/%X",
-			 (uint32) (current_recptr >> 32), (uint32) current_recptr);
-	PG_RETURN_TEXT_P(cstring_to_text(location));
+	PG_RETURN_LSN(current_recptr);
 }
 
 /*
@@ -234,16 +215,13 @@ Datum
 pg_last_xlog_receive_location(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	recptr;
-	char		location[MAXFNAMELEN];
 
 	recptr = GetWalRcvWriteRecPtr(NULL, NULL);
 
 	if (recptr == 0)
 		PG_RETURN_NULL();
 
-	snprintf(location, sizeof(location), "%X/%X",
-			 (uint32) (recptr >> 32), (uint32) recptr);
-	PG_RETURN_TEXT_P(cstring_to_text(location));
+	PG_RETURN_LSN(recptr);
 }
 
 /*
@@ -256,16 +234,13 @@ Datum
 pg_last_xlog_replay_location(PG_FUNCTION_ARGS)
 {
 	XLogRecPtr	recptr;
-	char		location[MAXFNAMELEN];
 
 	recptr = GetXLogReplayRecPtr(NULL);
 
 	if (recptr == 0)
 		PG_RETURN_NULL();
 
-	snprintf(location, sizeof(location), "%X/%X",
-			 (uint32) (recptr >> 32), (uint32) recptr);
-	PG_RETURN_TEXT_P(cstring_to_text(location));
+	PG_RETURN_LSN(recptr);
 }
 
 /*
@@ -279,13 +254,9 @@ pg_last_xlog_replay_location(PG_FUNCTION_ARGS)
 Datum
 pg_xlogfile_name_offset(PG_FUNCTION_ARGS)
 {
-	text	   *location = PG_GETARG_TEXT_P(0);
-	char	   *locationstr;
-	uint32		hi,
-				lo;
 	XLogSegNo	xlogsegno;
 	uint32		xrecoff;
-	XLogRecPtr	locationpoint;
+	XLogRecPtr	locationpoint = PG_GETARG_LSN(0);
 	char		xlogfilename[MAXFNAMELEN];
 	Datum		values[2];
 	bool		isnull[2];
@@ -300,20 +271,6 @@ pg_xlogfile_name_offset(PG_FUNCTION_ARGS)
 				 errhint("pg_xlogfile_name_offset() cannot be executed during recovery.")));
 
 	/*
-	 * Read input and parse
-	 */
-	locationstr = text_to_cstring(location);
-
-	validate_xlog_location(locationstr);
-
-	if (sscanf(locationstr, "%X/%X", &hi, &lo) != 2)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("could not parse transaction log location \"%s\"",
-						locationstr)));
-	locationpoint = ((uint64) hi) << 32 | lo;
-
-	/*
 	 * Construct a tuple descriptor for the result row.  This must match this
 	 * function's pg_proc entry!
 	 */
@@ -359,12 +316,8 @@ pg_xlogfile_name_offset(PG_FUNCTION_ARGS)
 Datum
 pg_xlogfile_name(PG_FUNCTION_ARGS)
 {
-	text	   *location = PG_GETARG_TEXT_P(0);
-	char	   *locationstr;
-	uint32		hi,
-				lo;
 	XLogSegNo	xlogsegno;
-	XLogRecPtr	locationpoint;
+	XLogRecPtr	locationpoint = PG_GETARG_LSN(0);
 	char		xlogfilename[MAXFNAMELEN];
 
 	if (RecoveryInProgress())
@@ -373,17 +326,6 @@ pg_xlogfile_name(PG_FUNCTION_ARGS)
 				 errmsg("recovery is in progress"),
 		 errhint("pg_xlogfile_name() cannot be executed during recovery.")));
 
-	locationstr = text_to_cstring(location);
-
-	validate_xlog_location(locationstr);
-
-	if (sscanf(locationstr, "%X/%X", &hi, &lo) != 2)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("could not parse transaction log location \"%s\"",
-						locationstr)));
-	locationpoint = ((uint64) hi) << 32 | lo;
-
 	XLByteToPrevSeg(locationpoint, xlogsegno);
 	XLogFileName(xlogfilename, ThisTimeLineID, xlogsegno);
 
@@ -482,81 +424,16 @@ pg_is_in_recovery(PG_FUNCTION_ARGS)
 }
 
 /*
- * Validate the text form of a transaction log location.
- * (Just using sscanf() input allows incorrect values such as
- * negatives, so we have to be a bit more careful about that).
- */
-static void
-validate_xlog_location(char *str)
-{
-#define MAXLSNCOMPONENT		8
-
-	int			len1,
-				len2;
-
-	len1 = strspn(str, "0123456789abcdefABCDEF");
-	if (len1 < 1 || len1 > MAXLSNCOMPONENT || str[len1] != '/')
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-				 errmsg("invalid input syntax for transaction log location: \"%s\"", str)));
-
-	len2 = strspn(str + len1 + 1, "0123456789abcdefABCDEF");
-	if (len2 < 1 || len2 > MAXLSNCOMPONENT || str[len1 + 1 + len2] != '\0')
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
-				 errmsg("invalid input syntax for transaction log location: \"%s\"", str)));
-}
-
-/*
  * Compute the difference in bytes between two WAL locations.
  */
 Datum
 pg_xlog_location_diff(PG_FUNCTION_ARGS)
 {
-	text	   *location1 = PG_GETARG_TEXT_P(0);
-	text	   *location2 = PG_GETARG_TEXT_P(1);
-	char	   *str1,
-			   *str2;
-	XLogRecPtr	loc1,
-				loc2;
-	Numeric		result;
-	uint64		bytes1,
-				bytes2;
-	uint32		hi,
-				lo;
-
-	/*
-	 * Read and parse input
-	 */
-	str1 = text_to_cstring(location1);
-	str2 = text_to_cstring(location2);
-
-	validate_xlog_location(str1);
-	validate_xlog_location(str2);
+	Datum	result;
 
-	if (sscanf(str1, "%X/%X", &hi, &lo) != 2)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-		   errmsg("could not parse transaction log location \"%s\"", str1)));
-	loc1 = ((uint64) hi) << 32 | lo;
-
-	if (sscanf(str2, "%X/%X", &hi, &lo) != 2)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-		   errmsg("could not parse transaction log location \"%s\"", str2)));
-	loc2 = ((uint64) hi) << 32 | lo;
-
-	bytes1 = (uint64) loc1;
-	bytes2 = (uint64) loc2;
-
-	/*
-	 * result = bytes1 - bytes2.
-	 *
-	 * XXX: this won't handle values higher than 2^63 correctly.
-	 */
-	result = DatumGetNumeric(DirectFunctionCall2(numeric_sub,
-			DirectFunctionCall1(int8_numeric, Int64GetDatum((int64) bytes1)),
-		  DirectFunctionCall1(int8_numeric, Int64GetDatum((int64) bytes2))));
+	result = DirectFunctionCall2(pg_lsn_mi,
+								 PG_GETARG_DATUM(0),
+								 PG_GETARG_DATUM(1));
 
 	PG_RETURN_NUMERIC(result);
 }