Add connection to PostgreSQL

By Makefile you can now decide what driver to include in this program

7 files changed, 334 insertions, 136 deletions

diff --git a/database.c b/database.c
index f13e8a2..751e36d 100644
--- a/database.c
+++ b/database.c
@@ -14,49 +14,145 @@
 
     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 "database.h"
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-static int MAX_SIZE_DBMS_NAME  =   7; /* including \0 */
-static int MAX_SIZE_CONN_FIELD = 129; /* including \0 */
-
-static char *
-str_create(int size)
-{
-  char *str = (char *) malloc(sizeof (char) * size);
-  memset(str, '\0', size);
+#include "database.h"
+#include "utils.h"
+#ifdef PSQL
+#include "postgresql.h"
+#endif
 
-  return str;
-}
+static int MAX_SIZE_DBMS_NAME  =  15;
+static int MAX_SIZE_CONN_FIELD = 129; /* including \0 */
 
 qureje_conn	*
 qureje_conn_create()
 {
   qureje_conn *conn = (qureje_conn *) malloc (sizeof (qureje_conn));
 
-  conn->type     = str_create(MAX_SIZE_DBMS_NAME);
-  conn->host     = str_create(MAX_SIZE_CONN_FIELD);
-  conn->user     = str_create(MAX_SIZE_CONN_FIELD);
-  conn->password = str_create(MAX_SIZE_CONN_FIELD);
-  conn->dbname   = str_create(MAX_SIZE_CONN_FIELD);
+  conn->type     = NONE;
+  conn->host     = strcrt(MAX_SIZE_CONN_FIELD);
+  conn->user     = strcrt(MAX_SIZE_CONN_FIELD);
+  conn->password = strcrt(MAX_SIZE_CONN_FIELD);
+  conn->dbname   = strcrt(MAX_SIZE_CONN_FIELD);
 
   return conn;
 }
 
+static int
+opt_get_type(qureje_conn *conn, char *opt, char *optv)
+{
+  if (strcmp("-t", opt) == 0 || strcmp("--type", opt) == 0) {
+    if (strcmp("psql", optv) == 0) {
+      conn->type = POSTGRESQL;
+    } else if (strcmp("mariadb", optv) == 0) {
+      conn->type = MARIADB;
+    } else {
+      conn->type = NONE;
+    }
+
+    return 0;
+  }
+
+  return 1;
+}
+
+static int
+opt_get_user(qureje_conn *conn, char *opt, char *optv)
+{
+  if (strcmp("-u", opt) == 0 || strcmp("--username", opt) == 0) {
+    strncpy(conn->user, optv, MAX_SIZE_CONN_FIELD);
+    return 0;
+  }
+
+  return 1;
+}
+
+static void
+opt_get_dbname(qureje_conn *conn, char *opt)
+{
+  strncpy(conn->dbname, opt, MAX_SIZE_DBMS_NAME);
+}
+
 qureje_conn *
 qureje_conn_create_from_arguments(int argc, char **argv)
 {
+  int i, j;
   qureje_conn *conn = qureje_conn_create();
 
+  /*
+      Parameters:
+        -t, --type
+        -u, --username
+        -p, --password
+        -P, --no-password
+        -h, --hostname
+   */
+  for (i = 1, j = 2; i < argc; i++, j++) {
+    if (opt_get_type(conn, argv[i], argv[j]) == 0
+        || opt_get_user(conn, argv[i], argv[j]) == 0) {
+      i = j++;
+      continue;
+    }
+
+    /* this call must be the last one */
+    opt_get_dbname(conn, argv[i]);
+  }
 
   return conn;
 }
 
-void
-qureje_connect()
+int
+qureje_connect(qureje_conn *conn)
+{
+  #ifdef PSQL
+  if (conn->type == POSTGRESQL) {
+    printf("Establishing a PostgreSQL connection.\n");
+    return qureje_psql_connect(conn);
+  }
+  #endif
+
+  return 0;
+}
+
+char *
+qureje_get_type(qureje_conn *conn)
+{
+  int max_length = 11;
+  char *str_type = strcrt(max_length);
+
+  switch (conn->type) {
+    case POSTGRESQL:
+      #ifdef PSQL
+      strncpy(str_type, "PostgreSQL", max_length);
+      #else
+      printf("This program is not compiled with the support to PostgreSQL!\n");
+      exit(1);
+      #endif
+      break;
+    case MARIADB:
+      strncpy(str_type, "MariaDB", max_length);
+      break;
+    default:
+      strncpy(str_type, "None", max_length);
+      break;
+  }
+
+  return str_type;
+}
+
+char *
+qureje_get_user(qureje_conn *conn)
+{
+  return conn->user;
+}
+
+char *
+qureje_get_dbname(qureje_conn *conn)
 {
+  return conn->dbname;
 }
diff --git a/database.h b/database.h
index eeb3295..53edd43 100644
--- a/database.h
+++ b/database.h
@@ -14,21 +14,32 @@
 
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
-*/
+ */
 
 #ifndef __DATABASE_H__
 #define __DATABASE_H__
 
+typedef enum {
+  NONE,
+  POSTGRESQL,
+  MARIADB
+} qureje_dbtype;
+
 typedef struct {
-  char *type;
+  qureje_dbtype type;
   char *host;
   char *user;
   char *password;
   char *dbname;
+  void *conn; /* implementation based connection data */
 } qureje_conn;
 
-void		 qureje_connect();
+int			 qureje_connect(qureje_conn *);
 qureje_conn	*qureje_conn_create();
 qureje_conn	*qureje_conn_create_from_arguments(int, char **);
+char		*qureje_get_type(qureje_conn *);
+char		*qureje_get_user(qureje_conn *);
+char		*qureje_get_dbname(qureje_conn *);
+void		 qureje_free(qureje_conn *);
 
 #endif
diff --git a/main.c b/main.c
index 587b41e..7358551 100644
--- a/main.c
+++ b/main.c
@@ -16,131 +16,22 @@
     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"
 
-char		*qureje_parse_arguments(int, char **, qureje_conn *);
-char		*qureje_param(char *, char *);
-
 int main(int argc, char** argv)
 {
   qureje_conn *conn = qureje_conn_create_from_arguments(argc, argv);
-  PGconn *conn1;
-  /*PGresult *res;*/
-  /*int rowcount, colcount, i, j, firstcol;*/
-
-  char *conninfo = qureje_parse_arguments(argc, argv, conn);
-  printf("%s\n", conn->type);
-
-  /* parameter type should be guessed by PostgreSQL */
-  /*const Oid paramTypes[1] = { 0 };*/
-
-  /* parameter value */
-  /*const char * const paramValues[1] = { "pg_database" };*/
 
-  /*
-   * Using an empty connectstring will use default values for everything.
-   * If set, the environment variables PGHOST, PGDATABASE, PGPORT and
-   * PGUSER will be used.
-   */
-  conn1 = PQconnectdb(conninfo);
-
-  /*
-   * This can only happen if there is not enough memory
-   * to allocate the PGconn structure.
-   */
-  if (conn1 == NULL) {
-      fprintf(stderr, "Out of memory connecting to PostgreSQL.\n");
-      return 1;
+  if (qureje_connect(conn) != 0) {
+    fprintf(stderr, "Cannot establish connection with the database!\n");
+    return 1;
   }
 
-  /* check if the connection attempt worked */
-  if (PQstatus(conn1) != CONNECTION_OK) {
-      fprintf(stderr, "%s\n", PQerrorMessage(conn1));
-      /*
-       * Even if the connection failed, the PGconn structure has been
-       * allocated and must be freed.
-       */
-      PQfinish(conn1);
-      return 1;
-  }
-  printf("Hello, World!\n");
+  printf("Connection established.\n");
 
   return 0;
 }
-
-char *
-qureje_parse_arguments(int argc, char **argv, qureje_conn *conn)
-{
-  int i = 1, totsize = 0, paramc = 0, verbose = 0;
-  char *conninfo;
-  char **paramv;
-
-  if (argc <= 1) {
-    return "";
-  }
-
-  paramv = (char **) malloc(sizeof (char **) * argc);
-
-  if (strcmp ("-t", argv[i]) == 0 && i < argc) {
-    conn->type = argv[++i];
-  }
-
-  if (conn->type == NULL) {
-    puts("You must specify the database driver.");
-    exit(1);
-    return NULL;
-  }
-
-  while (i < argc) {
-    /* these are all options with a value */
-    if (strcmp ("-h", argv[i]) == 0) {
-      paramv[paramc++] = qureje_param("host", argv[++i]);
-    } else if (strcmp ("-U", argv[i]) == 0) {
-      paramv[paramc++] = qureje_param("user", argv[++i]);
-    } else if (strcmp ("-v", argv[i]) == 0) {
-      verbose = 1;
-    }
-
-    ++i;
-  }
-
-  for (i = 0; i < paramc; i++) {
-    totsize += strlen(paramv[i]);
-    if (i < paramc) totsize ++;
-  }
-
-  conninfo = (char *) malloc(sizeof (char *) * totsize);
-  memset (conninfo, '\0', totsize);
-
-  for (i = 0; i < paramc; i++) {
-    strcat(conninfo, paramv[i]);
-    if (i < argc - 1) strcat(conninfo, " ");
-  }
-
-  if (verbose == 1) {
-    printf("connection info:\n%s\n", conninfo);
-  }
-
-  return conninfo;
-}
-
-char *
-qureje_param(char *parname, char *src)
-{
-  /* the src's legth + the paraname length + '=' + '\0' */
-  int strc = strlen(src) + strlen(parname) + 2;
-  char *param = (char *) malloc(sizeof (char) * strc);
-  memset(param, '\0', strc);
-
-  strcat(param, parname);
-  strcat(param, "=");
-  strcat(param, src);
-
-  return param;
-}
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;
+}
diff --git a/postgresql.h b/postgresql.h
new file mode 100644
index 0000000..1e4df10
--- /dev/null
+++ b/postgresql.h
@@ -0,0 +1,24 @@
+/*
+    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/>.
+ */
+
+#ifndef __POSTGRESQL_H__
+#define __POSTGRESQL_H__
+
+int			 qureje_psql_connect();
+
+#endif
diff --git a/utils.c b/utils.c
new file mode 100644
index 0000000..af5f0e9
--- /dev/null
+++ b/utils.c
@@ -0,0 +1,29 @@
+/*
+    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 <stdlib.h>
+#include <string.h>
+
+char *
+strcrt(int size)
+{
+  char *str = (char *) malloc(sizeof (char) * size);
+  memset(str, '\0', size);
+
+  return str;
+}
diff --git a/utils.h b/utils.h
new file mode 100644
index 0000000..7e8c093
--- /dev/null
+++ b/utils.h
@@ -0,0 +1,24 @@
+/*
+    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/>.
+ */
+
+#ifndef __UTILS_H__
+#define __UTILS_H__
+
+char		*strcrt(int);
+
+#endif