1 files changed, 123 insertions, 0 deletions
diff --git a/postgresql.c b/postgresql.c
new file mode 100644
index 0000000..5f799bf
--- /dev/null
+++ b/postgresql.c
@@ -0,0 +1,123 @@
+/*
+    qureje is a database managment tool.
+    Copyright (C) 2022  Alessandro Iezzi <aiezzi AT alessandroiezzi PERIOD it>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <libpq-fe.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "database.h"
+#include "utils.h"
+
+static char *
+parameter(const char *key, char *value)
+{
+  int vsize = 0;
+  char *param = NULL;
+
+  if (value == NULL || (vsize = strlen(value)) <= 0) return NULL;
+
+  param = strcrt(strlen(key) + vsize + 2);
+  strcat(param, key);
+  strcat(param, "=");
+  strcat(param, value);
+  strcat(param, " ");
+
+  return param;
+}
+
+static void
+prmcat(char *conninfo, char *prm)
+{
+  if (prm != NULL) {
+    strcat(conninfo, prm);
+    free(prm);
+  }
+}
+
+static char *
+create_connection_info(qureje_conn *conn)
+{
+  int strsize = 0;
+  char *conninfo,
+    *prmusr = NULL,
+    *prmdb  = NULL;
+
+  if ((prmusr = parameter("user", conn->user)) != NULL) {
+    strsize += strlen(prmusr);
+  }
+
+  if ((prmdb = parameter("dbname", conn->dbname)) != NULL) {
+    strsize += strlen(prmdb);
+  }
+
+  conninfo = strcrt(strsize + 1);
+
+  prmcat(conninfo, prmusr);
+  prmcat(conninfo, prmdb );
+
+  return conninfo;
+}
+
+int
+qureje_psql_connect(qureje_conn *conn)
+{
+  char *conninfo = NULL;
+  PGconn *pgconn;
+
+  if (conn == NULL) return 1;
+
+  conninfo = create_connection_info(conn);
+  /*
+   * Using an empty connectstring will use default values for everything.
+   * If set, the environment variables PGHOST, PGDATABASE, PGPORT and
+   * PGUSER will be used.
+   */
+  pgconn = PQconnectdb(conninfo);
+
+  free(conninfo);
+
+  /*
+   * This can only happen if there is not enough memory
+   * to allocate the PGconn structure.
+   */
+  if (pgconn == NULL) {
+    fprintf(stderr, "Out of memory connecting to PostgreSQL.\n");
+
+    return 1;
+  }
+
+  /* check if the connection attempt worked */
+  if (PQstatus(pgconn) != CONNECTION_OK) {
+      fprintf(stderr, "%s\n", PQerrorMessage(pgconn));
+      /*
+       * Even if the connection failed, the PGconn structure has been
+       * allocated and must be freed.
+       */
+      PQfinish(pgconn);
+
+      return 1;
+  }
+
+  /* this program expects the database to return data in UTF-8 */
+  PQsetClientEncoding(pgconn, "UTF8");
+
+  conn->conn = pgconn;
+
+  return 0;
+}