some dblink refactoring

From 2e1fc0b0c50452bac91461a2317c28a8718fe89f Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Sun, 25 Dec 2016 12:00:00 -0500
Subject: [PATCH v2 1/2] dblink: Replace some macros by static functions

Also remove some unused code and the no longer useful dblink.h file.
---
 contrib/dblink/dblink.c | 290 +++++++++++++++++++++++-------------------------
 contrib/dblink/dblink.h |  39 -------
 2 files changed, 137 insertions(+), 192 deletions(-)
 delete mode 100644 contrib/dblink/dblink.h

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index e0d6778a08..67d6699066 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -61,8 +61,6 @@
 #include "utils/tqual.h"
 #include "utils/varlena.h"
 
-#include "dblink.h"
-
 PG_MODULE_MAGIC;
 
 typedef struct remoteConn
@@ -146,98 +144,102 @@ typedef struct remoteConnHashEnt
 /* initial number of connection hashes */
 #define NUMCONN 16
 
-/* general utility */
-#define xpfree(var_) \
-	do { \
-		if (var_ != NULL) \
-		{ \
-			pfree(var_); \
-			var_ = NULL; \
-		} \
-	} while (0)
-
-#define xpstrdup(var_c, var_) \
-	do { \
-		if (var_ != NULL) \
-			var_c = pstrdup(var_); \
-		else \
-			var_c = NULL; \
-	} while (0)
-
-#define DBLINK_RES_INTERNALERROR(p2) \
-	do { \
-			msg = pchomp(PQerrorMessage(conn)); \
-			if (res) \
-				PQclear(res); \
-			elog(ERROR, "%s: %s", p2, msg); \
-	} while (0)
-
-#define DBLINK_CONN_NOT_AVAIL \
-	do { \
-		if(conname) \
-			ereport(ERROR, \
-					(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), \
-					 errmsg("connection \"%s\" not available", conname))); \
-		else \
-			ereport(ERROR, \
-					(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), \
-					 errmsg("connection not available"))); \
-	} while (0)
-
-#define DBLINK_GET_CONN \
-	do { \
-			char *conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0)); \
-			rconn = getConnectionByName(conname_or_str); \
-			if (rconn) \
-			{ \
-				conn = rconn->conn; \
-				conname = conname_or_str; \
-			} \
-			else \
-			{ \
-				connstr = get_connect_string(conname_or_str); \
-				if (connstr == NULL) \
-				{ \
-					connstr = conname_or_str; \
-				} \
-				dblink_connstr_check(connstr); \
-				conn = PQconnectdb(connstr); \
-				if (PQstatus(conn) == CONNECTION_BAD) \
-				{ \
-					msg = pchomp(PQerrorMessage(conn)); \
-					PQfinish(conn); \
-					ereport(ERROR, \
-							(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION), \
-							 errmsg("could not establish connection"), \
-							 errdetail_internal("%s", msg))); \
-				} \
-				dblink_security_check(conn, rconn); \
-				if (PQclientEncoding(conn) != GetDatabaseEncoding()) \
-					PQsetClientEncoding(conn, GetDatabaseEncodingName()); \
-				freeconn = true; \
-			} \
-	} while (0)
-
-#define DBLINK_GET_NAMED_CONN \
-	do { \
-			conname = text_to_cstring(PG_GETARG_TEXT_PP(0)); \
-			rconn = getConnectionByName(conname); \
-			if (rconn) \
-				conn = rconn->conn; \
-			else \
-				DBLINK_CONN_NOT_AVAIL; \
-	} while (0)
-
-#define DBLINK_INIT \
-	do { \
-			if (!pconn) \
-			{ \
-				pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn)); \
-				pconn->conn = NULL; \
-				pconn->openCursorCount = 0; \
-				pconn->newXactForCursor = FALSE; \
-			} \
-	} while (0)
+static char *
+xpstrdup(const char *in)
+{
+	if (in == NULL)
+		return NULL;
+	return pstrdup(in);
+}
+
+static void
+dblink_res_internalerror(PGconn *conn, PGresult *res, const char *p2)
+{
+	char	   *msg = pchomp(PQerrorMessage(conn));
+	if (res)
+		PQclear(res);
+	elog(ERROR, "%s: %s", p2, msg);
+}
+
+static void pg_attribute_noreturn()
+dblink_conn_not_avail(const char *conname)
+{
+	if (conname)
+		ereport(ERROR,
+				(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
+				 errmsg("connection \"%s\" not available", conname)));
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
+				 errmsg("connection not available")));
+}
+
+static void
+dblink_get_conn(char *conname_or_str,
+				PGconn * volatile *conn_p, char **conname_p, volatile bool *freeconn_p)
+{
+	remoteConn *rconn = getConnectionByName(conname_or_str);
+	PGconn	   *conn;
+	char	   *conname;
+	bool		freeconn;
+
+	if (rconn)
+	{
+		conn = rconn->conn;
+		conname = conname_or_str;
+		freeconn = false;
+	}
+	else
+	{
+		const char *connstr;
+
+		connstr = get_connect_string(conname_or_str);
+		if (connstr == NULL)
+			connstr = conname_or_str;
+		dblink_connstr_check(connstr);
+		conn = PQconnectdb(connstr);
+		if (PQstatus(conn) == CONNECTION_BAD)
+		{
+			char	   *msg = pchomp(PQerrorMessage(conn));
+			PQfinish(conn);
+			ereport(ERROR,
+					(errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
+					 errmsg("could not establish connection"),
+					 errdetail_internal("%s", msg)));
+		}
+		dblink_security_check(conn, rconn);
+		if (PQclientEncoding(conn) != GetDatabaseEncoding())
+			PQsetClientEncoding(conn, GetDatabaseEncodingName());
+		freeconn = true;
+		conname = NULL;
+	}
+
+	*conn_p = conn;
+	*conname_p = conname;
+	*freeconn_p = freeconn;
+}
+
+static PGconn *
+dblink_get_named_conn(const char *conname)
+{
+	remoteConn *rconn = getConnectionByName(conname);
+	if (rconn)
+		return rconn->conn;
+	else
+		dblink_conn_not_avail(conname);
+}
+
+static void
+dblink_init(void)
+{
+	if (!pconn)
+	{
+		pconn = (remoteConn *) MemoryContextAlloc(TopMemoryContext, sizeof(remoteConn));
+		pconn->conn = NULL;
+		pconn->openCursorCount = 0;
+		pconn->newXactForCursor = FALSE;
+	}
+}
 
 /*
  * Create a persistent connection to another database
@@ -253,7 +255,7 @@ dblink_connect(PG_FUNCTION_ARGS)
 	PGconn	   *conn = NULL;
 	remoteConn *rconn = NULL;
 
-	DBLINK_INIT;
+	dblink_init();
 
 	if (PG_NARGS() == 2)
 	{
@@ -318,7 +320,7 @@ dblink_disconnect(PG_FUNCTION_ARGS)
 	remoteConn *rconn = NULL;
 	PGconn	   *conn = NULL;
 
-	DBLINK_INIT;
+	dblink_init();
 
 	if (PG_NARGS() == 1)
 	{
@@ -331,7 +333,7 @@ dblink_disconnect(PG_FUNCTION_ARGS)
 		conn = pconn->conn;
 
 	if (!conn)
-		DBLINK_CONN_NOT_AVAIL;
+		dblink_conn_not_avail(conname);
 
 	PQfinish(conn);
 	if (rconn)
@@ -352,7 +354,6 @@ PG_FUNCTION_INFO_V1(dblink_open);
 Datum
 dblink_open(PG_FUNCTION_ARGS)
 {
-	char	   *msg;
 	PGresult   *res = NULL;
 	PGconn	   *conn = NULL;
 	char	   *curname = NULL;
@@ -362,7 +363,7 @@ dblink_open(PG_FUNCTION_ARGS)
 	remoteConn *rconn = NULL;
 	bool		fail = true;	/* default to backward compatible behavior */
 
-	DBLINK_INIT;
+	dblink_init();
 	initStringInfo(&buf);
 
 	if (PG_NARGS() == 2)
@@ -401,7 +402,7 @@ dblink_open(PG_FUNCTION_ARGS)
 	}
 
 	if (!rconn || !rconn->conn)
-		DBLINK_CONN_NOT_AVAIL;
+		dblink_conn_not_avail(conname);
 	else
 		conn = rconn->conn;
 
@@ -410,7 +411,7 @@ dblink_open(PG_FUNCTION_ARGS)
 	{
 		res = PQexec(conn, "BEGIN");
 		if (PQresultStatus(res) != PGRES_COMMAND_OK)
-			DBLINK_RES_INTERNALERROR("begin error");
+			dblink_res_internalerror(conn, res, "begin error");
 		PQclear(res);
 		rconn->newXactForCursor = TRUE;
 
@@ -450,11 +451,10 @@ dblink_close(PG_FUNCTION_ARGS)
 	char	   *curname = NULL;
 	char	   *conname = NULL;
 	StringInfoData buf;
-	char	   *msg;
 	remoteConn *rconn = NULL;
 	bool		fail = true;	/* default to backward compatible behavior */
 
-	DBLINK_INIT;
+	dblink_init();
 	initStringInfo(&buf);
 
 	if (PG_NARGS() == 1)
@@ -489,7 +489,7 @@ dblink_close(PG_FUNCTION_ARGS)
 	}
 
 	if (!rconn || !rconn->conn)
-		DBLINK_CONN_NOT_AVAIL;
+		dblink_conn_not_avail(conname);
 	else
 		conn = rconn->conn;
 
@@ -517,7 +517,7 @@ dblink_close(PG_FUNCTION_ARGS)
 
 			res = PQexec(conn, "COMMIT");
 			if (PQresultStatus(res) != PGRES_COMMAND_OK)
-				DBLINK_RES_INTERNALERROR("commit error");
+				dblink_res_internalerror(conn, res, "commit error");
 			PQclear(res);
 		}
 	}
@@ -543,7 +543,7 @@ dblink_fetch(PG_FUNCTION_ARGS)
 
 	prepTuplestoreResult(fcinfo);
 
-	DBLINK_INIT;
+	dblink_init();
 
 	if (PG_NARGS() == 4)
 	{
@@ -587,7 +587,7 @@ dblink_fetch(PG_FUNCTION_ARGS)
 	}
 
 	if (!conn)
-		DBLINK_CONN_NOT_AVAIL;
+		dblink_conn_not_avail(conname);
 
 	initStringInfo(&buf);
 	appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
@@ -633,15 +633,13 @@ PG_FUNCTION_INFO_V1(dblink_send_query);
 Datum
 dblink_send_query(PG_FUNCTION_ARGS)
 {
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	char	   *sql = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
+	char	   *sql;
 	int			retval;
 
 	if (PG_NARGS() == 2)
 	{
-		DBLINK_GET_NAMED_CONN;
+		conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 		sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 	}
 	else
@@ -671,15 +669,12 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 
 	prepTuplestoreResult(fcinfo);
 
-	DBLINK_INIT;
+	dblink_init();
 
 	PG_TRY();
 	{
-		char	   *msg;
-		char	   *connstr = NULL;
 		char	   *sql = NULL;
 		char	   *conname = NULL;
-		remoteConn *rconn = NULL;
 		bool		fail = true;	/* default to backward compatible */
 
 		if (!is_async)
@@ -687,7 +682,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 			if (PG_NARGS() == 3)
 			{
 				/* text,text,bool */
-				DBLINK_GET_CONN;
+				dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), &conn, &conname, &freeconn);
 				sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 				fail = PG_GETARG_BOOL(2);
 			}
@@ -702,7 +697,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 				}
 				else
 				{
-					DBLINK_GET_CONN;
+					dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), &conn, &conname, &freeconn);
 					sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 				}
 			}
@@ -722,13 +717,13 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 			if (PG_NARGS() == 2)
 			{
 				/* text,bool */
-				DBLINK_GET_NAMED_CONN;
+				conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 				fail = PG_GETARG_BOOL(1);
 			}
 			else if (PG_NARGS() == 1)
 			{
 				/* text */
-				DBLINK_GET_NAMED_CONN;
+				conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 			}
 			else
 				/* shouldn't happen */
@@ -736,7 +731,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async)
 		}
 
 		if (!conn)
-			DBLINK_CONN_NOT_AVAIL;
+			dblink_conn_not_avail(conname);
 
 		if (!is_async)
 		{
@@ -1297,12 +1292,10 @@ PG_FUNCTION_INFO_V1(dblink_is_busy);
 Datum
 dblink_is_busy(PG_FUNCTION_ARGS)
 {
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
 
-	DBLINK_INIT;
-	DBLINK_GET_NAMED_CONN;
+	dblink_init();
+	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 
 	PQconsumeInput(conn);
 	PG_RETURN_INT32(PQisBusy(conn));
@@ -1323,15 +1316,13 @@ PG_FUNCTION_INFO_V1(dblink_cancel_query);
 Datum
 dblink_cancel_query(PG_FUNCTION_ARGS)
 {
-	int			res = 0;
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	int			res;
+	PGconn	   *conn;
 	PGcancel   *cancel;
 	char		errbuf[256];
 
-	DBLINK_INIT;
-	DBLINK_GET_NAMED_CONN;
+	dblink_init();
+	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 	cancel = PQgetCancel(conn);
 
 	res = PQcancel(cancel, errbuf, 256);
@@ -1359,12 +1350,10 @@ Datum
 dblink_error_message(PG_FUNCTION_ARGS)
 {
 	char	   *msg;
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
 
-	DBLINK_INIT;
-	DBLINK_GET_NAMED_CONN;
+	dblink_init();
+	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 
 	msg = PQerrorMessage(conn);
 	if (msg == NULL || msg[0] == '\0')
@@ -1384,22 +1373,19 @@ dblink_exec(PG_FUNCTION_ARGS)
 	PGconn	   *volatile conn = NULL;
 	volatile bool freeconn = false;
 
-	DBLINK_INIT;
+	dblink_init();
 
 	PG_TRY();
 	{
-		char	   *msg;
 		PGresult   *res = NULL;
-		char	   *connstr = NULL;
 		char	   *sql = NULL;
 		char	   *conname = NULL;
-		remoteConn *rconn = NULL;
 		bool		fail = true;	/* default to backward compatible behavior */
 
 		if (PG_NARGS() == 3)
 		{
 			/* must be text,text,bool */
-			DBLINK_GET_CONN;
+			dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), &conn, &conname, &freeconn);
 			sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 			fail = PG_GETARG_BOOL(2);
 		}
@@ -1414,7 +1400,7 @@ dblink_exec(PG_FUNCTION_ARGS)
 			}
 			else
 			{
-				DBLINK_GET_CONN;
+				dblink_get_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)), &conn, &conname, &freeconn);
 				sql = text_to_cstring(PG_GETARG_TEXT_PP(1));
 			}
 		}
@@ -1429,7 +1415,7 @@ dblink_exec(PG_FUNCTION_ARGS)
 			elog(ERROR, "wrong number of arguments");
 
 		if (!conn)
-			DBLINK_CONN_NOT_AVAIL;
+			dblink_conn_not_avail(conname);
 
 		res = PQexec(conn, sql);
 		if (!res ||
@@ -1880,9 +1866,7 @@ PG_FUNCTION_INFO_V1(dblink_get_notify);
 Datum
 dblink_get_notify(PG_FUNCTION_ARGS)
 {
-	char	   *conname = NULL;
-	PGconn	   *conn = NULL;
-	remoteConn *rconn = NULL;
+	PGconn	   *conn;
 	PGnotify   *notify;
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
 	TupleDesc	tupdesc;
@@ -1892,9 +1876,9 @@ dblink_get_notify(PG_FUNCTION_ARGS)
 
 	prepTuplestoreResult(fcinfo);
 
-	DBLINK_INIT;
+	dblink_init();
 	if (PG_NARGS() == 1)
-		DBLINK_GET_NAMED_CONN;
+		conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
 	else
 		conn = pconn->conn;
 
@@ -2698,10 +2682,10 @@ dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
 	else
 		sqlstate = ERRCODE_CONNECTION_FAILURE;
 
-	xpstrdup(message_primary, pg_diag_message_primary);
-	xpstrdup(message_detail, pg_diag_message_detail);
-	xpstrdup(message_hint, pg_diag_message_hint);
-	xpstrdup(message_context, pg_diag_context);
+	message_primary = xpstrdup(pg_diag_message_primary);
+	message_detail = xpstrdup(pg_diag_message_detail);
+	message_hint = xpstrdup(pg_diag_message_hint);
+	message_context = xpstrdup(pg_diag_context);
 
 	/*
 	 * If we don't get a message from the PGresult, try the PGconn.  This
diff --git a/contrib/dblink/dblink.h b/contrib/dblink/dblink.h
deleted file mode 100644
index c96dbe28a8..0000000000
--- a/contrib/dblink/dblink.h
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
- * dblink.h
- *
- * Functions returning results from a remote database
- *
- * Joe Conway <mail@joeconway.com>
- * And contributors:
- * Darko Prenosil <Darko.Prenosil@finteh.hr>
- * Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
- *
- * contrib/dblink/dblink.h
- * Copyright (c) 2001-2017, PostgreSQL Global Development Group
- * ALL RIGHTS RESERVED;
- *
- * Permission to use, copy, modify, and distribute this software and its
- * documentation for any purpose, without fee, and without a written agreement
- * is hereby granted, provided that the above copyright notice and this
- * paragraph and the following two paragraphs appear in all copies.
- *
- * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
- * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
- * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
- * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
- * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
- * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
- *
- */
-
-#ifndef DBLINK_H
-#define DBLINK_H
-
-#include "fmgr.h"
-
-#endif   /* DBLINK_H */
-- 
2.12.0