MXS-1703 Use a common header for all mariadbmon files

The mariadb_common.hh file is now a header with only common definitions
such as module name. The QueryResult-class was moved to MariaDBServer.

server/modules/monitor/mariadbmon/mariadbserver.hh

@@ -12,13 +12,10 @@
  * of this software will be governed by version 2 or later of the General
  * Public License.
  */
-
-#include <maxscale/cppdefs.hh>
-
+#include "mariadbmon_common.hh"
 #include <string>
 #include <memory>
 #include <maxscale/monitor.h>
-#include "utilities.hh"
 #include "gtid.hh"
 
 enum mysql_server_version
@@ -34,6 +31,8 @@ enum print_repl_warnings_t
     WARNINGS_OFF
 };
 
+class QueryResult;
+
 // Contains data returned by one row of SHOW ALL SLAVES STATUS
 class SlaveStatusInfo
 {
@@ -163,3 +162,78 @@ public:
      */
     bool wait_until_gtid(const GtidList& target, int timeout, json_t** err_out);
 };
+
+/**
+ * Helper class for simplifying working with resultsets. Used in MariaDBServer.
+ */
+class QueryResult
+{
+    // These need to be banned to avoid premature destruction.
+    QueryResult(const QueryResult&) = delete;
+    QueryResult& operator = (const QueryResult&) = delete;
+
+public:
+    QueryResult(MYSQL_RES* resultset = NULL);
+    ~QueryResult();
+
+    /**
+     * Advance to next row. Affects all result returning functions.
+     *
+     * @return True if the next row has data, false if the current row was the last one.
+     */
+    bool next_row();
+
+    /**
+     * Get the index of the current row.
+     *
+     * @return Current row index, or -1 if no data or next_row() has not been called yet.
+     */
+    int64_t get_row_index() const;
+
+    /**
+     * How many columns the result set has.
+     *
+     * @return Column count, or -1 if no data.
+     */
+    int64_t get_column_count() const;
+
+    /**
+     * Get a numeric index for a column name. May give wrong results if column names are not unique.
+     *
+     * @param col_name Column name
+     * @return Index or -1 if not found.
+     */
+    int64_t get_col_index(const std::string& col_name) const;
+
+    /**
+     * Read a string value from the current row and given column. Empty string and (null) are both interpreted
+     * as the empty string.
+     *
+     * @param column_ind Column index
+     * @return Value as string
+     */
+    std::string get_string(int64_t column_ind) const;
+
+    /**
+     * Read a non-negative integer value from the current row and given column.
+     *
+     * @param column_ind Column index
+     * @return Value as integer. 0 or greater indicates success, -1 is returned on error.
+     */
+    int64_t get_uint(int64_t column_ind) const;
+
+    /**
+     * Read a boolean value from the current row and given column.
+     *
+     * @param column_ind Column index
+     * @return Value as boolean. Returns true if the text is either 'Y' or '1'.
+     */
+    bool get_bool(int64_t column_ind) const;
+
+private:
+    MYSQL_RES* m_resultset; // Underlying result set, freed at dtor.
+    std::tr1::unordered_map<std::string, int64_t> m_col_indexes; // Map of column name -> index
+    int64_t m_columns;     // How many columns does the data have. Usually equal to column index map size.
+    MYSQL_ROW m_rowdata;   // Data for current row
+    int64_t m_current_row; // Index of current row
+};