Newer version of Bruce's pginterface library...

contrib/pginterface/pginterface.c

@@ -0,0 +1,212 @@
+/*
+ * pginterface.c
+ *
+*/
+
+#include <stdio.h>
+#include <signal.h>
+#include <string.h>
+#include <stdarg.h>
+
+#include <libpq-fe.h>
+#include "halt.h"
+#include "pginterface.h"
+
+static void sig_disconnect();
+static void set_signals();
+
+#define NUL '\0'
+
+/* GLOBAL VARIABLES */
+static PGconn* conn;
+static PGresult* res = NULL;
+
+#define ON_ERROR_STOP	0
+#define ON_ERROR_CONTINUE	1
+
+static int	on_error_state = ON_ERROR_STOP;
+
+/* LOCAL VARIABLES */
+static sigset_t block_sigs, unblock_sigs;
+static int tuple;
+
+/*
+**
+**	connectdb - returns PGconn structure
+**
+*/
+PGconn *connectdb(	char *dbName,
+					char *pghost,
+					char *pgport,
+					char *pgoptions,
+					char *pgtty)
+{
+	/* make a connection to the database */
+	conn = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);
+	if (PQstatus(conn) == CONNECTION_BAD)
+		halt("Connection to database '%s' failed.\n%s\n", dbName,
+			PQerrorMessage(conn));
+	set_signals();
+	return conn;
+}
+
+/*
+**
+**	disconnectdb
+**
+*/
+void disconnectdb()
+{
+	PQfinish(conn);
+}
+
+/*
+**
+**	doquery	- returns PGresult structure
+**
+*/
+PGresult *doquery(char *query)
+{
+	if (res != NULL)
+		PQclear(res);
+
+	sigprocmask(SIG_SETMASK,&block_sigs,NULL);
+	res = PQexec(conn, query);
+	sigprocmask(SIG_SETMASK,&unblock_sigs,NULL);
+
+	if (on_error_state == ON_ERROR_STOP &&
+		(res == NULL ||
+		 PQresultStatus(res) ==	PGRES_BAD_RESPONSE ||
+		 PQresultStatus(res) ==	PGRES_NONFATAL_ERROR ||
+		 PQresultStatus(res) ==	PGRES_FATAL_ERROR))
+	{
+		if (res != NULL)
+				fprintf(stderr,"query error:  %s\n",PQcmdStatus(res));
+		else	fprintf(stderr,"connection error:  %s\n",PQerrorMessage(conn));
+		PQfinish(conn);
+		halt("failed request:  %s\n", query);
+	}
+	tuple = 0;
+	return res;
+}
+
+/*
+**
+**	fetch - returns tuple number (starts at 0), or the value END_OF_TUPLES
+**			NULL pointers are skipped
+**
+*/
+int fetch(void *param, ...)
+{
+	va_list ap;
+	int arg, num_args;
+
+	num_args = PQnfields(res);
+
+	if (tuple >= PQntuples(res))
+		return END_OF_TUPLES;
+
+	va_start(ap, param);
+	for (arg = 0; arg < num_args; arg++)
+	{
+		if (param != NULL)
+		{
+			if (PQfsize(res, arg) == -1)
+			{
+				memcpy(param,PQgetvalue(res,tuple,arg),PQgetlength(res,tuple,arg));
+				((char *)param)[PQgetlength(res,tuple,arg)] = NUL;
+			}
+			else
+				memcpy(param,PQgetvalue(res,tuple,arg),PQfsize(res,arg));
+		}
+		param = va_arg(ap, char *);
+	}
+	va_end(ap);
+	return tuple++;
+}
+
+/*
+**
+**	fetchisnull - returns tuple number (starts at 0), or the value END_OF_TUPLES
+**				NULL pointers are skipped
+**				Returns true or false into null indicator variables
+*/
+int fetchisnull(void *param, ...)
+{
+	va_list ap;
+	int arg, num_args;
+
+	if (tuple == 0)
+		halt("pginterface:fetchisnull():  You must call fetch() first.\n");
+
+	num_args = PQnfields(res);
+
+	if (tuple-1 >= PQntuples(res))
+		return END_OF_TUPLES;
+	va_start(ap, param);
+	for (arg = 0; arg < num_args; arg++)
+	{
+		if (param != NULL)
+		{
+			if (PQgetisnull(res,tuple-1,arg) != 0)
+				*(int *)param = 1;
+			else
+				*(int *)param = 0;
+		}
+		param = va_arg(ap, char *);
+	}
+	va_end(ap);
+	return tuple-1;
+}
+
+/*
+**
+**	on_error_stop
+**
+*/
+void on_error_stop()
+{
+	on_error_state = ON_ERROR_STOP;
+}
+	
+/*
+**
+**	on_error_continue
+**
+*/
+void on_error_continue()
+{
+	on_error_state = ON_ERROR_CONTINUE;
+}
+	
+/*
+**
+**	sig_disconnect
+**
+*/
+static void sig_disconnect()
+{
+	fprintf(stderr,"exiting...\n");
+	PQfinish(conn);
+	exit(1);
+}
+
+/*
+**
+**	set_signals
+**
+*/
+static void set_signals()
+{
+	sigemptyset(&block_sigs);
+	sigemptyset(&unblock_sigs);
+	sigaddset(&block_sigs,SIGTERM);
+	sigaddset(&block_sigs,SIGHUP);
+	sigaddset(&block_sigs,SIGINT);
+/*	sigaddset(&block_sigs,SIGQUIT); no block */
+	sigprocmask(SIG_SETMASK,&unblock_sigs,NULL);
+	signal(SIGTERM,sig_disconnect);
+	signal(SIGHUP,sig_disconnect);
+	signal(SIGINT,sig_disconnect);
+	signal(SIGQUIT,sig_disconnect);
+}