class DatabaseSchema_mysql

class DatabaseSchema_mysql extends DatabaseSchema {
    
    /**
     * Maximum length of a table comment in MySQL.
     */
    const COMMENT_MAX_TABLE = 60;
    
    /**
     * Maximum length of a column comment in MySQL.
     */
    const COMMENT_MAX_COLUMN = 255;
    
    /**
     * Get information about the table and database name from the prefix.
     *
     * @return
     *   A keyed array with information about the database, table name and prefix.
     */
    protected function getPrefixInfo($table = 'default', $add_prefix = TRUE) {
        $info = array(
            'prefix' => $this->connection
                ->tablePrefix($table),
        );
        if ($add_prefix) {
            $table = $info['prefix'] . $table;
        }
        if (($pos = strpos($table, '.')) !== FALSE) {
            $info['database'] = substr($table, 0, $pos);
            $info['table'] = substr($table, ++$pos);
        }
        else {
            $db_info = $this->connection
                ->getConnectionOptions();
            $info['database'] = $db_info['database'];
            $info['table'] = $table;
        }
        return $info;
    }
    
    /**
     * Build a condition to match a table name against a standard information_schema.
     *
     * MySQL uses databases like schemas rather than catalogs so when we build
     * a condition to query the information_schema.tables, we set the default
     * database as the schema unless specified otherwise, and exclude table_catalog
     * from the condition criteria.
     */
    protected function buildTableNameCondition($table_name, $operator = '=', $add_prefix = TRUE) {
        $info = $this->connection
            ->getConnectionOptions();
        // Ensure the table name is not surrounded with quotes as that is not
        // appropriate for schema queries.
        $quote_char = variable_get('mysql_identifier_quote_character', MYSQL_IDENTIFIER_QUOTE_CHARACTER_DEFAULT);
        $table_name = str_replace($quote_char, '', $table_name);
        $table_info = $this->getPrefixInfo($table_name, $add_prefix);
        $condition = new DatabaseCondition('AND');
        $condition->condition('table_schema', $table_info['database']);
        $condition->condition('table_name', $table_info['table'], $operator);
        return $condition;
    }
    
    /**
     * Generate SQL to create a new table from a Drupal schema definition.
     *
     * @param $name
     *   The name of the table to create.
     * @param $table
     *   A Schema API table definition array.
     * @return
     *   An array of SQL statements to create the table.
     */
    protected function createTableSql($name, $table) {
        $info = $this->connection
            ->getConnectionOptions();
        // Provide defaults if needed.
        $table += array(
            'mysql_engine' => 'InnoDB',
            // Allow the default charset to be overridden in settings.php.
'mysql_character_set' => $this->connection
                ->utf8mb4IsActive() ? 'utf8mb4' : 'utf8',
        );
        $sql = "CREATE TABLE {" . $name . "} (\n";
        // Add the SQL statement for each field.
        foreach ($table['fields'] as $field_name => $field) {
            $sql .= $this->createFieldSql($field_name, $this->processField($field)) . ", \n";
        }
        // Process keys & indexes.
        $keys = $this->createKeysSql($table);
        if (count($keys)) {
            $sql .= implode(", \n", $keys) . ", \n";
        }
        // Remove the last comma and space.
        $sql = substr($sql, 0, -3) . "\n) ";
        $sql .= 'ENGINE = ' . $table['mysql_engine'] . ' DEFAULT CHARACTER SET ' . $table['mysql_character_set'];
        // By default, MySQL uses the default collation for new tables, which is
        // 'utf8_general_ci' for utf8. If an alternate collation has been set, it
        // needs to be explicitly specified.
        // @see DatabaseConnection_mysql
        if (!empty($info['collation'])) {
            $sql .= ' COLLATE ' . $info['collation'];
        }
        // The row format needs to be either DYNAMIC or COMPRESSED in order to allow
        // for the innodb_large_prefix setting to take effect, see
        // https://dev.mysql.com/doc/refman/5.6/en/create-table.html
        if ($this->connection
            ->utf8mb4IsActive()) {
            $sql .= ' ROW_FORMAT=DYNAMIC';
        }
        // Add table comment.
        if (!empty($table['description'])) {
            $sql .= ' COMMENT ' . $this->prepareComment($table['description'], self::COMMENT_MAX_TABLE);
        }
        return array(
            $sql,
        );
    }
    
    /**
     * Create an SQL string for a field to be used in table creation or alteration.
     *
     * Before passing a field out of a schema definition into this function it has
     * to be processed by _db_process_field().
     *
     * @param $name
     *   Name of the field.
     * @param $spec
     *   The field specification, as per the schema data structure format.
     */
    protected function createFieldSql($name, $spec) {
        $sql = "`" . $name . "` " . $spec['mysql_type'];
        if (in_array($spec['mysql_type'], array(
            'VARCHAR',
            'CHAR',
            'TINYTEXT',
            'MEDIUMTEXT',
            'LONGTEXT',
            'TEXT',
        ))) {
            if (isset($spec['length'])) {
                $sql .= '(' . $spec['length'] . ')';
            }
            if (!empty($spec['binary'])) {
                $sql .= ' BINARY';
            }
        }
        elseif (isset($spec['precision']) && isset($spec['scale'])) {
            $sql .= '(' . $spec['precision'] . ', ' . $spec['scale'] . ')';
        }
        if (!empty($spec['unsigned'])) {
            $sql .= ' unsigned';
        }
        if (isset($spec['not null'])) {
            if ($spec['not null']) {
                $sql .= ' NOT NULL';
            }
            else {
                $sql .= ' NULL';
            }
        }
        if (!empty($spec['auto_increment'])) {
            $sql .= ' auto_increment';
        }
        // $spec['default'] can be NULL, so we explicitly check for the key here.
        if (array_key_exists('default', $spec)) {
            if (is_string($spec['default'])) {
                $spec['default'] = "'" . $spec['default'] . "'";
            }
            elseif (!isset($spec['default'])) {
                $spec['default'] = 'NULL';
            }
            $sql .= ' DEFAULT ' . $spec['default'];
        }
        if (empty($spec['not null']) && !isset($spec['default'])) {
            $sql .= ' DEFAULT NULL';
        }
        // Add column comment.
        if (!empty($spec['description'])) {
            $sql .= ' COMMENT ' . $this->prepareComment($spec['description'], self::COMMENT_MAX_COLUMN);
        }
        return $sql;
    }
    
    /**
     * Set database-engine specific properties for a field.
     *
     * @param $field
     *   A field description array, as specified in the schema documentation.
     */
    protected function processField($field) {
        if (!isset($field['size'])) {
            $field['size'] = 'normal';
        }
        // Set the correct database-engine specific datatype.
        // In case one is already provided, force it to uppercase.
        if (isset($field['mysql_type'])) {
            $field['mysql_type'] = drupal_strtoupper($field['mysql_type']);
        }
        else {
            $map = $this->getFieldTypeMap();
            $field['mysql_type'] = $map[$field['type'] . ':' . $field['size']];
        }
        if (isset($field['type']) && $field['type'] == 'serial') {
            $field['auto_increment'] = TRUE;
        }
        return $field;
    }
    public function getFieldTypeMap() {
        // Put :normal last so it gets preserved by array_flip. This makes
        // it much easier for modules (such as schema.module) to map
        // database types back into schema types.
        // $map does not use drupal_static as its value never changes.
        static $map = array(
            'varchar:normal' => 'VARCHAR',
            'char:normal' => 'CHAR',
            'text:tiny' => 'TINYTEXT',
            'text:small' => 'TINYTEXT',
            'text:medium' => 'MEDIUMTEXT',
            'text:big' => 'LONGTEXT',
            'text:normal' => 'TEXT',
            'serial:tiny' => 'TINYINT',
            'serial:small' => 'SMALLINT',
            'serial:medium' => 'MEDIUMINT',
            'serial:big' => 'BIGINT',
            'serial:normal' => 'INT',
            'int:tiny' => 'TINYINT',
            'int:small' => 'SMALLINT',
            'int:medium' => 'MEDIUMINT',
            'int:big' => 'BIGINT',
            'int:normal' => 'INT',
            'float:tiny' => 'FLOAT',
            'float:small' => 'FLOAT',
            'float:medium' => 'FLOAT',
            'float:big' => 'DOUBLE',
            'float:normal' => 'FLOAT',
            'numeric:normal' => 'DECIMAL',
            'blob:big' => 'LONGBLOB',
            'blob:normal' => 'BLOB',
        );
        return $map;
    }
    protected function createKeysSql($spec) {
        $keys = array();
        if (!empty($spec['primary key'])) {
            $keys[] = 'PRIMARY KEY (' . $this->createKeysSqlHelper($spec['primary key']) . ')';
        }
        if (!empty($spec['unique keys'])) {
            foreach ($spec['unique keys'] as $key => $fields) {
                $keys[] = 'UNIQUE KEY `' . $key . '` (' . $this->createKeysSqlHelper($fields) . ')';
            }
        }
        if (!empty($spec['indexes'])) {
            foreach ($spec['indexes'] as $index => $fields) {
                $keys[] = 'INDEX `' . $index . '` (' . $this->createKeysSqlHelper($fields) . ')';
            }
        }
        return $keys;
    }
    protected function createKeySql($fields) {
        $return = array();
        foreach ($fields as $field) {
            if (is_array($field)) {
                $return[] = '`' . $field[0] . '`(' . $field[1] . ')';
            }
            else {
                $return[] = '`' . $field . '`';
            }
        }
        return implode(', ', $return);
    }
    protected function createKeysSqlHelper($fields) {
        $return = array();
        foreach ($fields as $field) {
            if (is_array($field)) {
                $return[] = '`' . $field[0] . '`(' . $field[1] . ')';
            }
            else {
                $return[] = '`' . $field . '`';
            }
        }
        return implode(', ', $return);
    }
    public function renameTable($table, $new_name) {
        if (!$this->tableExists($table)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot rename @table to @table_new: table @table doesn't exist.", array(
                '@table' => $table,
                '@table_new' => $new_name,
            )));
        }
        if ($this->tableExists($new_name)) {
            throw new DatabaseSchemaObjectExistsException(t("Cannot rename @table to @table_new: table @table_new already exists.", array(
                '@table' => $table,
                '@table_new' => $new_name,
            )));
        }
        $info = $this->getPrefixInfo($new_name);
        return $this->connection
            ->query('ALTER TABLE {' . $table . '} RENAME TO `' . $info['table'] . '`');
    }
    public function dropTable($table) {
        if (!$this->tableExists($table)) {
            return FALSE;
        }
        $this->connection
            ->query('DROP TABLE {' . $table . '}');
        return TRUE;
    }
    public function addField($table, $field, $spec, $keys_new = array()) {
        if (!$this->tableExists($table)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add field @table.@field: table doesn't exist.", array(
                '@field' => $field,
                '@table' => $table,
            )));
        }
        if ($this->fieldExists($table, $field)) {
            throw new DatabaseSchemaObjectExistsException(t("Cannot add field @table.@field: field already exists.", array(
                '@field' => $field,
                '@table' => $table,
            )));
        }
        $fixnull = FALSE;
        if (!empty($spec['not null']) && !isset($spec['default'])) {
            $fixnull = TRUE;
            $spec['not null'] = FALSE;
        }
        $query = 'ALTER TABLE {' . $table . '} ADD ';
        $query .= $this->createFieldSql($field, $this->processField($spec));
        if ($keys_sql = $this->createKeysSql($keys_new)) {
            $query .= ', ADD ' . implode(', ADD ', $keys_sql);
        }
        $this->connection
            ->query($query);
        if (isset($spec['initial'])) {
            $this->connection
                ->update($table)
                ->fields(array(
                $field => $spec['initial'],
            ))
                ->execute();
        }
        if ($fixnull) {
            $spec['not null'] = TRUE;
            $this->changeField($table, $field, $field, $spec);
        }
    }
    public function dropField($table, $field) {
        if (!$this->fieldExists($table, $field)) {
            return FALSE;
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} DROP `' . $field . '`');
        return TRUE;
    }
    public function fieldSetDefault($table, $field, $default) {
        if (!$this->fieldExists($table, $field)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot set default value of field @table.@field: field doesn't exist.", array(
                '@table' => $table,
                '@field' => $field,
            )));
        }
        if (!isset($default)) {
            $default = 'NULL';
        }
        else {
            $default = is_string($default) ? "'{$default}'" : $default;
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} ALTER COLUMN `' . $field . '` SET DEFAULT ' . $default);
    }
    public function fieldSetNoDefault($table, $field) {
        if (!$this->fieldExists($table, $field)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot remove default value of field @table.@field: field doesn't exist.", array(
                '@table' => $table,
                '@field' => $field,
            )));
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} ALTER COLUMN `' . $field . '` DROP DEFAULT');
    }
    public function indexExists($table, $name) {
        // Returns one row for each column in the index. Result is string or FALSE.
        // Details at http://dev.mysql.com/doc/refman/5.0/en/show-index.html
        $row = $this->connection
            ->query('SHOW INDEX FROM {' . $table . "} WHERE key_name = '{$name}'")
            ->fetchAssoc();
        return isset($row['Key_name']);
    }
    public function addPrimaryKey($table, $fields) {
        if (!$this->tableExists($table)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add primary key to table @table: table doesn't exist.", array(
                '@table' => $table,
            )));
        }
        if ($this->indexExists($table, 'PRIMARY')) {
            throw new DatabaseSchemaObjectExistsException(t("Cannot add primary key to table @table: primary key already exists.", array(
                '@table' => $table,
            )));
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} ADD PRIMARY KEY (' . $this->createKeySql($fields) . ')');
    }
    public function dropPrimaryKey($table) {
        if (!$this->indexExists($table, 'PRIMARY')) {
            return FALSE;
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} DROP PRIMARY KEY');
        return TRUE;
    }
    public function addUniqueKey($table, $name, $fields) {
        if (!$this->tableExists($table)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add unique key @name to table @table: table doesn't exist.", array(
                '@table' => $table,
                '@name' => $name,
            )));
        }
        if ($this->indexExists($table, $name)) {
            throw new DatabaseSchemaObjectExistsException(t("Cannot add unique key @name to table @table: unique key already exists.", array(
                '@table' => $table,
                '@name' => $name,
            )));
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} ADD UNIQUE KEY `' . $name . '` (' . $this->createKeySql($fields) . ')');
    }
    public function dropUniqueKey($table, $name) {
        if (!$this->indexExists($table, $name)) {
            return FALSE;
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} DROP KEY `' . $name . '`');
        return TRUE;
    }
    public function addIndex($table, $name, $fields) {
        if (!$this->tableExists($table)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add index @name to table @table: table doesn't exist.", array(
                '@table' => $table,
                '@name' => $name,
            )));
        }
        if ($this->indexExists($table, $name)) {
            throw new DatabaseSchemaObjectExistsException(t("Cannot add index @name to table @table: index already exists.", array(
                '@table' => $table,
                '@name' => $name,
            )));
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} ADD INDEX `' . $name . '` (' . $this->createKeySql($fields) . ')');
    }
    public function dropIndex($table, $name) {
        if (!$this->indexExists($table, $name)) {
            return FALSE;
        }
        $this->connection
            ->query('ALTER TABLE {' . $table . '} DROP INDEX `' . $name . '`');
        return TRUE;
    }
    public function changeField($table, $field, $field_new, $spec, $keys_new = array()) {
        if (!$this->fieldExists($table, $field)) {
            throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot change the definition of field @table.@name: field doesn't exist.", array(
                '@table' => $table,
                '@name' => $field,
            )));
        }
        if ($field != $field_new && $this->fieldExists($table, $field_new)) {
            throw new DatabaseSchemaObjectExistsException(t("Cannot rename field @table.@name to @name_new: target field already exists.", array(
                '@table' => $table,
                '@name' => $field,
                '@name_new' => $field_new,
            )));
        }
        $sql = 'ALTER TABLE {' . $table . '} CHANGE `' . $field . '` ' . $this->createFieldSql($field_new, $this->processField($spec));
        if ($keys_sql = $this->createKeysSql($keys_new)) {
            $sql .= ', ADD ' . implode(', ADD ', $keys_sql);
        }
        $this->connection
            ->query($sql);
    }
    public function prepareComment($comment, $length = NULL) {
        // Work around a bug in some versions of PDO, see http://bugs.php.net/bug.php?id=41125
        $comment = str_replace("'", '’', $comment);
        // Truncate comment to maximum comment length.
        if (isset($length)) {
            // Add table prefixes before truncating.
            $comment = truncate_utf8($this->connection
                ->prefixTables($comment), $length, TRUE, TRUE);
        }
        return $this->connection
            ->quote($comment);
    }
    
    /**
     * Retrieve a table or column comment.
     */
    public function getComment($table, $column = NULL) {
        $condition = $this->buildTableNameCondition($table);
        if (isset($column)) {
            $condition->condition('column_name', $column);
            $condition->compile($this->connection, $this);
            // Don't use {} around information_schema.columns table.
            return $this->connection
                ->query("SELECT column_comment AS column_comment FROM information_schema.columns WHERE " . (string) $condition, $condition->arguments())
                ->fetchField();
        }
        $condition->compile($this->connection, $this);
        // Don't use {} around information_schema.tables table.
        $comment = $this->connection
            ->query("SELECT table_comment AS table_comment FROM information_schema.tables WHERE " . (string) $condition, $condition->arguments())
            ->fetchField();
        // Work-around for MySQL 5.0 bug http://bugs.mysql.com/bug.php?id=11379
        return preg_replace('/; InnoDB free:.*$/', '', $comment);
    }
    public function tableExists($table) {
        // The information_schema table is very slow to query under MySQL 5.0.
        // Instead, we try to select from the table in question.  If it fails,
        // the most likely reason is that it does not exist. That is dramatically
        // faster than using information_schema.
        // @link http://bugs.mysql.com/bug.php?id=19588
        // @todo: This override should be removed once we require a version of MySQL
        // that has that bug fixed.
        try {
            $this->connection
                ->queryRange("SELECT 1 FROM {" . $table . "}", 0, 1);
            return TRUE;
        } catch (Exception $e) {
            return FALSE;
        }
    }
    public function fieldExists($table, $column) {
        // The information_schema table is very slow to query under MySQL 5.0.
        // Instead, we try to select from the table and field in question. If it
        // fails, the most likely reason is that it does not exist. That is
        // dramatically faster than using information_schema.
        // @link http://bugs.mysql.com/bug.php?id=19588
        // @todo: This override should be removed once we require a version of MySQL
        // that has that bug fixed.
        try {
            $this->connection
                ->queryRange("SELECT {$column} FROM {" . $table . "}", 0, 1);
            return TRUE;
        } catch (Exception $e) {
            return FALSE;
        }
    }

}