The R13B03 release.OTP_R13B03

1 files changed, 224 insertions, 0 deletions

diff --git a/erts/example/pg_async.c b/erts/example/pg_async.c
new file mode 100644
index 0000000000..7ffb4bb1f3
--- /dev/null
+++ b/erts/example/pg_async.c
@@ -0,0 +1,224 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 2006-2009. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ */
+/*
+ * Purpose: A driver using libpq to connect to Postgres
+ * from erlang, a sample for the driver documentation
+ */
+
+#include <erl_driver.h>
+
+#include <libpq-fe.h>
+
+#include <ei.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "pg_encode.h"
+
+/* Driver interface declarations */
+static ErlDrvData start(ErlDrvPort port, char *command);
+static void stop(ErlDrvData drv_data);
+static int control(ErlDrvData drv_data, unsigned int command, char *buf, 
+		   int len, char **rbuf, int rlen); 
+static void ready_io(ErlDrvData drv_data, ErlDrvEvent event);
+
+static ErlDrvEntry pq_driver_entry = {
+    NULL,			/* init */
+    start, 
+    stop, 
+    NULL,			/* output */
+    ready_io,			/* ready_input */
+    ready_io,			/* ready_output */ 
+    "pg_async",                 /* the name of the driver */
+    NULL,			/* finish */
+    NULL,			/* handle */
+    control, 
+    NULL,			/* timeout */
+    NULL,			/* outputv */
+    NULL,			/* ready_async */
+    NULL,			/* flush */
+    NULL,			/* call */
+    NULL			/* event */
+};
+
+typedef struct our_data_t {
+    PGconn* conn;
+    ErlDrvPort port;
+    int socket;
+    int connecting;
+} our_data_t;
+
+/* Keep the following definitions in alignment with the FUNC_LIST
+ * in erl_pq_sync.erl
+ */
+
+#define DRV_CONNECT             'C'
+#define DRV_DISCONNECT          'D'
+#define DRV_SELECT              'S'
+
+/* #define L     fprintf(stderr, "%d\r\n", __LINE__) */
+
+/* INITIALIZATION AFTER LOADING */
+
+/* 
+ * This is the init function called after this driver has been loaded.
+ * It must *not* be declared static. Must return the address to 
+ * the driver entry.
+ */
+DRIVER_INIT(pq_drv)
+{
+    return &pq_driver_entry;
+}
+
+static char* get_s(const char* buf, int len);
+static int do_connect(const char *s, our_data_t* data);
+static int do_disconnect(our_data_t* data);
+static int do_select(const char* s, our_data_t* data);
+
+/* DRIVER INTERFACE */
+static ErlDrvData start(ErlDrvPort port, char *command)
+{ 
+    our_data_t* data = driver_alloc(sizeof(our_data_t));
+    data->port = port;
+    data->conn = NULL;
+    return (ErlDrvData)data;
+}
+
+static void stop(ErlDrvData drv_data)
+{
+    do_disconnect((our_data_t*)drv_data);
+}
+
+static int control(ErlDrvData drv_data, unsigned int command, char *buf,
+		   int len, char **rbuf, int rlen)
+{
+    int r;
+    char* s = get_s(buf, len);
+    our_data_t* data = (our_data_t*)drv_data;
+    switch (command) {
+    case DRV_CONNECT:     r = do_connect(s, data);  break;
+    case DRV_DISCONNECT:  r = do_disconnect(data);  break;
+    case DRV_SELECT:      r = do_select(s, data);   break;
+    default:              r = -1;	break;
+    }
+    driver_free(s);
+    return r;
+}
+
+static int do_connect(const char *s, our_data_t* data)
+{
+    PGconn* conn = PQconnectStart(s);
+    if (PQstatus(conn) == CONNECTION_BAD) {
+	ei_x_buff x;
+	ei_x_new_with_version(&x);
+        encode_error(&x, conn);
+	PQfinish(conn);
+	conn = NULL;
+	driver_output(data->port, x.buff, x.index);
+	ei_x_free(&x);
+    }
+    PQconnectPoll(conn);
+    int socket = PQsocket(conn);
+    data->socket = socket;
+    driver_select(data->port, (ErlDrvEvent)socket, DO_READ, 1);
+    driver_select(data->port, (ErlDrvEvent)socket, DO_WRITE, 1);
+    data->conn = conn;
+    data->connecting = 1;
+    return 0;
+}
+
+static int do_disconnect(our_data_t* data)
+{
+    ei_x_buff x;
+    driver_select(data->port, (ErlDrvEvent)data->socket, DO_READ, 0);
+    driver_select(data->port, (ErlDrvEvent)data->socket, DO_WRITE, 0);
+    PQfinish(data->conn);
+    data->conn = NULL;
+    ei_x_new_with_version(&x);
+    encode_ok(&x);
+    driver_output(data->port, x.buff, x.index);
+    ei_x_free(&x);
+    return 0;
+}
+
+static int do_select(const char* s, our_data_t* data)
+{
+    data->connecting = 0;
+    PGconn* conn = data->conn;
+    /* if there's an error return it now */
+    if (PQsendQuery(conn, s) == 0) {
+	ei_x_buff x;
+	ei_x_new_with_version(&x);
+	encode_error(&x, conn);
+	driver_output(data->port, x.buff, x.index);
+	ei_x_free(&x);
+    }
+    /* else wait for ready_output to get results */
+    return 0;
+}
+
+static void ready_io(ErlDrvData drv_data, ErlDrvEvent event)
+{
+    PGresult* res = NULL;
+    our_data_t* data = (our_data_t*)drv_data;
+    PGconn* conn = data->conn;
+    ei_x_buff x;
+    ei_x_new_with_version(&x);
+    if (data->connecting) {
+	ConnStatusType status;
+	PQconnectPoll(conn);
+	status = PQstatus(conn);
+	if (status == CONNECTION_OK)
+	    encode_ok(&x);
+	else if (status == CONNECTION_BAD)
+	    encode_error(&x, conn);
+    } else {
+	PQconsumeInput(conn);
+	if (PQisBusy(conn))
+	    return;
+	res = PQgetResult(conn);
+	encode_result(&x, res, conn);
+	PQclear(res);
+	for (;;) {
+	    res = PQgetResult(conn);
+	    if (res == NULL)
+		break;
+	    PQclear(res);
+	}
+    }
+    if (x.index > 1) {
+	driver_output(data->port, x.buff, x.index);
+	if (data->connecting) 
+	    driver_select(data->port, (ErlDrvEvent)data->socket, DO_WRITE, 0);
+    }
+    ei_x_free(&x);
+}
+
+/* utilities */
+static char* get_s(const char* buf, int len)
+{
+    char* result;
+    if (len < 1 || len > 1000) return NULL;
+    result = driver_alloc(len+1);
+    memcpy(result, buf, len);
+    result[len] = '\0';
+    return result;
+}