feature #206: New Class to interface MySQL DBs

include/MySqlDB.h

@@ -0,0 +1,214 @@
+/* -------------------------------------------------------------------------- */
+/* Copyright 2002-2010, OpenNebula Project Leads (OpenNebula.org)             */
+/*                                                                            */
+/* Licensed under the Apache License, Version 2.0 (the "License"); you may    */
+/* not use this file except in compliance with the License. You may obtain    */
+/* a copy of the License at                                                   */
+/*                                                                            */
+/* http://www.apache.org/licenses/LICENSE-2.0                                 */
+/*                                                                            */
+/* Unless required by applicable law or agreed to in writing, software        */
+/* distributed under the License is distributed on an "AS IS" BASIS,          */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   */
+/* See the License for the specific language governing permissions and        */
+/* limitations under the License.                                             */
+/* -------------------------------------------------------------------------- */
+
+#ifndef MYSQL_DB_H_
+#define MYSQL_DB_H_
+
+#include <string>
+#include <sstream>
+#include <stdexcept>
+#include <mysql.h>
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "Log.h"
+#include "SqlDB.h"
+#include "ObjectSQL.h"
+
+using namespace std;
+
+/*********
+ * Doc: http://dev.mysql.com/doc/refman/5.5/en/c-api-function-overview.html
+ ********/
+
+/**
+ * SqliteDB class. Provides a wrapper to the mysql database interface.
+ */
+class MySqlDB : public SqlDB
+{
+public:
+
+    MySqlDB(
+            string server,
+            string user,
+            string password,
+            char * database,
+            Log::LogFunction _log = 0):log(_log)
+    {
+
+        // Initialize the MySQL library
+        mysql_library_init(0, NULL, NULL);
+
+        // Initialize a connection handler
+        db = mysql_init(NULL);
+
+        // Connect to the server
+        if (!mysql_real_connect(db, server.c_str(), user.c_str(),
+                                password.c_str(), database, 0, NULL, 0))
+        {
+            throw runtime_error("Could not open database.");
+        }
+    };
+
+    ~MySqlDB()
+    {
+        // Close the connection to the MySQL server
+        mysql_close(db);
+
+        // End use of the MySQL library
+        mysql_library_end();
+    };
+
+    /**
+     *  Wraps the mysql_query function call
+     *    @param cmd the SQL command
+     *    @param obj Callbackable obj to call if the query succeeds
+     *    @return 0 on success
+     */
+    int exec(ostringstream& cmd, Callbackable* obj=0)
+    {
+        int          rc;
+
+        const char * c_str;
+        string       str;
+
+
+        int   (*callback)(void*,int,char**,char**);
+        void * arg;
+
+        str   = cmd.str();
+        c_str = str.c_str();
+
+        callback = 0;
+        arg      = 0;
+
+
+        rc = mysql_query(db, c_str);
+
+        if (rc != 0)
+        {
+            if (log != 0)
+            {
+                ostringstream   oss;
+                const char *    err_msg = mysql_error(db);
+                int             err_num = mysql_errno(db);
+
+                oss << "SQL command was: " << c_str;
+                oss << ", error " << err_num << " : " << err_msg;
+
+                log("ONE",Log::ERROR,oss,0,Log::ERROR);
+            }
+
+            return -1;
+        }
+
+
+        if ( (obj != 0) && (obj->isCallBackSet()) )
+        {
+
+            MYSQL_RES *         result;
+            MYSQL_ROW           row;
+            MYSQL_FIELD *       fields;
+            unsigned int        num_fields;
+
+            // Retrieve the entire result set all at once
+            result = mysql_store_result(db);
+
+            if (result == NULL)
+            {
+                if (log != 0)
+                {
+                    ostringstream   oss;
+                    const char *    err_msg = mysql_error(db);
+                    int             err_num = mysql_errno(db);
+
+                    oss << "SQL command was: " << c_str;
+                    oss << ", error " << err_num << " : " << err_msg;
+
+                    log("ONE",Log::ERROR,oss,0,Log::ERROR);
+                }
+
+                return -1;
+            }
+
+            // Fetch the names of the fields
+            num_fields  = mysql_num_fields(result);
+            fields      = mysql_fetch_fields(result);
+
+            char ** names = new char*[num_fields];
+
+            for(unsigned int i = 0; i < num_fields; i++)
+            {
+                names[i] = fields[i].name;
+            }
+
+            // Fetch each row, and call-back the object waiting for them
+            while((row = mysql_fetch_row(result)))
+            {
+                obj->do_callback(num_fields, row, names);
+            }
+
+            // Free the result object
+            mysql_free_result(result);
+
+            delete[] names;
+        }
+
+        return 0;
+    };
+
+
+    /**
+     *  This function returns a legal SQL string that can be used in an SQL
+     *  statement. The string is encoded to an escaped SQL string, taking into
+     *  account the current character set of the connection.
+     *    @param str the string to be escaped
+     *    @return a valid SQL string or NULL in case of failure
+     */
+    char * escape_str(const string& str)
+    {
+        char * result = new char[str.size()*2+1];
+
+        mysql_real_escape_string(db, result, str.c_str(), str.size());
+
+        return result;
+    };
+
+    /**
+     *  Frees a previously scaped string
+     *    @param str pointer to the str
+     */
+    void free_str(char * str)
+    {
+        delete[] str;
+    };
+
+private:
+
+    /**
+     * The MySql connection handler
+     */
+    MYSQL *             db;
+
+    /**
+     *  Log facility
+     */
+    Log::LogFunction    log;
+};
+
+#endif /*MYSQL_DB_H_*/