<?php

/**
 * Session Management for PHP3
 *
 * Copyright (c) 1998-2000 NetUSE AG
 *                    Boris Erdmann, Kristian Koehntopp
 *
 * $Id: db_mysql.php,v 1.3 2005/03/05 16:27:30 said Exp $
 *
 */
class DB_Sql {
    /* public: connection parameters */

    var $Host = "";
    var $Database = "";
    var $User = "";
    var $Password = "";

    /* public: configuration parameters */
    var $Auto_Free = 0;     ## Set to 1 for automatic mysql_free_result()
    var $Debug = 0;     ## Set to 1 for debugging messages.
    var $Halt_On_Error = "no"; ## "yes" (halt with message), "no" (ignore errors quietly), "report" (ignore errror, but spit a warning)
    var $Seq_Table = "db_sequence";

    /* public: result array and current row number */
    var $Record = array();
    var $Row;
    var $num_rows;

    /* public: current error number and error text */
    var $Errno = 0;
    var $Error = "";

    /* public: this is an api revision, not a CVS revision. */
    var $type = "mysql";
    var $revision = "1.2";

    /* private: link and query handles */
    var $Link_ID = 0;
    var $Query_ID = 0;
    var $Query_String = "";

    /**
     * Constructor 
     */
    function DB_Sql($query = "") {
        $this->query($query);
    }

    /**
     * @return resource class variable Link_ID
     */
    function link_id() {
        return $this->Link_ID;
    }

    /**
     * @return integer class variable Query_ID
     */
    function query_id() {
        return $this->Query_ID;
    }

    /**
     * function for MySQL database connection management
     *
     * This function manages the connection to the MySQL database.
     *
     * @param $Database name of the database
     * @param $Host DNS of the MySQL hosting server
     * @param $User the user's name
     * @param $Password the user's password
     *
     * @return the class variable $Link_ID
     */
    function connect($Database = "", $Host = "", $User = "", $Password = "") {
        /* Handle defaults */
        if ("" == $Database) {
            $Database = $this->Database;
        }
        if ("" == $Host) {
            $Host = $this->Host;
        }
        if ("" == $User) {
            $User = $this->User;
        }
        if ("" == $Password) {
            $Password = $this->Password;
        }

        /* establish connection, select database */
        if (0 == $this->Link_ID) {

            $this->Link_ID = mysql_pconnect($Host, $User, $Password);
            if (!$this->Link_ID) {
                $this->halt("pconnect($Host, $User, \$Password) failed.");
                return 0;
            }

            if (!@mysql_select_db($Database, $this->Link_ID)) {
                $this->halt("cannot use database " . $this->Database);
                return 0;
            }
        }

        //persistent connection don't conserve database selection
        //if needed do a correct database selection
        $db_connected = @mysql_fetch_array(@mysql_query("SELECT DATABASE();", $this->Link_ID));
        if ($db_connected[0] != $this->Database)
            mysql_select_db($Database, $this->Link_ID);

        return $this->Link_ID;
    }

    /**
     * Discard the query result 
     *
     * This function discards the last query result.
     */
    function free() {
        @mysql_free_result($this->Query_ID);
        $this->Query_ID = 0;
    }

    /**
     * Perform a query 
     * 
     * This function performs the MySQL query described in the string parameter
     *
     * @param a string describing the MySQL query   
     * @return the $Query_ID class variable (null if fails)
     */
    function query($Query_String) {
        global $debug_alternc;

        /* No empty queries, please, since PHP4 chokes on them. */
        if ($Query_String == "") {
            /* The empty query string is passed on from the constructor,
             * when calling the class without a query, e.g. in situations
             * like these: '$db = new DB_Sql_Subclass;'
             */
            return 0;
        }

        if (!$this->connect()) {
            return 0; /* we already complained in connect() about that. */
        }

        # New query, discard previous result.
        if ($this->Query_ID) {
            $this->free();
            $this->Query_String = $Query_String;
        }

        if ($this->Debug) {
            printf("Debug: query = %s<br />\n", $Query_String);
        }

        $debug_chrono_start = microtime(true);
        $this->Query_ID = @mysql_query($Query_String, $this->Link_ID);
        $debug_chrono_start = (microtime(true) - $debug_chrono_start) * 1000;
        $this->Row = 0;
        $this->Errno = mysql_errno();
        $this->Error = mysql_error();
        if (0 != $this->Errno) {
            if (defined("THROW_EXCEPTIONS") && THROW_EXCEPTIONS) {
                throw new \Exception("Mysql query failed : $this->Error");
            }
            $this->halt("SQL Error: " . $Query_String);
            return FALSE;
        }
        if (!$this->Query_ID) {
            $this->halt("Invalid SQL: " . $Query_String);
        }

        if (isset($debug_alternc)) {
            $debug_alternc->add("SQL Query : (" . substr($debug_chrono_start, 0, 5) . " ms)\t $Query_String");
            $debug_alternc->nb_sql_query++;
            $debug_alternc->tps_sql_query += $debug_chrono_start;
        }

        # Will return nada if it fails. That's fine.
        return $this->Query_ID;
    }

    /**
     * walk result set 
     *
     * This function tests if a new record is available in the current
     * query result.
     *
     * @return TRUE if a new record is available
     */
    function next_record() {
        if (!$this->Query_ID) {
            $this->halt("next_record called with no query pending.");
            return 0;
        }

        $this->Record = @mysql_fetch_array($this->Query_ID);
        $this->Row += 1;
        $this->Errno = mysql_errno();
        $this->Error = mysql_error();

        $stat = is_array($this->Record);
        if (!$stat && $this->Auto_Free) {
            $this->free();
        }
        return $stat;
    }

    /**
     *
     * public: position in result set 
     */
    function seek($pos = 0) {
        $status = @mysql_data_seek($this->Query_ID, $pos);
        if ($status) {
            $this->Row = $pos;
        } else {
            $this->halt("seek($pos) failed: result has " . $this->num_rows() . " rows");

            /* half assed attempt to save the day, 
             * but do not consider this documented or even
             * desireable behaviour.
             */
            @mysql_data_seek($this->Query_ID, $this->num_rows());
            $this->Row = $this->num_rows;
            return 0;
        }

        return 1;
    }

    /** public: table locking */
    function lock($table, $mode = "write") {
        $this->connect();

        $query = "lock tables ";
        if (is_array($table)) {
            while (list($key, $value) = each($table)) {
                if ($key == "read" && $key != 0) {
                    $query.="$value read, ";
                } else {
                    $query.="$value $mode, ";
                }
            }
            $query = substr($query, 0, -2);
        } else {
            $query.="$table $mode";
        }
        $res = @mysql_query($query, $this->Link_ID);
        if (!$res) {
            $this->halt("lock($table, $mode) failed.");
            return 0;
        }
        return $res;
    }

    function unlock() {
        $this->connect();

        $res = @mysql_query("unlock tables", $this->Link_ID);
        if (!$res) {
            $this->halt("unlock() failed.");
            return 0;
        }
        return $res;
    }

    /** public: evaluate the result (size, width) */
    function affected_rows() {
        return @mysql_affected_rows($this->Link_ID);
    }

    function num_rows() {
        return @mysql_num_rows($this->Query_ID);
    }

    function num_fields() {
        return @mysql_num_fields($this->Query_ID);
    }

    /** public: shorthand notation */
    function nf() {
        return $this->num_rows();
    }

    function np() {
        print $this->num_rows();
    }

    /**
     * @param string $Name
     * @return integer
     */
    function f($Name) {
        if (isset($this->Record[$Name]))
            return $this->Record[$Name];
        else
            return false;
    }

    function p($Name) {
        print $this->Record[$Name];
    }

    function lastid() {
        return @mysql_insert_id($this->Link_ID);
    }

    /** public: sequence numbers */
    function nextid($seq_name) {
        $this->connect();

        if ($this->lock($this->Seq_Table)) {
            /* get sequence number (locked) and increment */
            $q = sprintf("select nextid from %s where seq_name = '%s'", $this->Seq_Table, $seq_name);
            $id = @mysql_query($q, $this->Link_ID);
            $res = @mysql_fetch_array($id);

            /* No current value, make one */
            if (!is_array($res)) {
                $currentid = 0;
                $q = sprintf("insert into %s values('%s', %s)", $this->Seq_Table, $seq_name, $currentid);
                @mysql_query($q, $this->Link_ID);
            } else {
                $currentid = $res["nextid"];
            }
            $nextid = $currentid + 1;
            $q = sprintf("update %s set nextid = '%s' where seq_name = '%s'", $this->Seq_Table, $nextid, $seq_name);
            @mysql_query($q, $this->Link_ID);
            $this->unlock();
        } else {
            $this->halt("cannot lock " . $this->Seq_Table . " - has it been created?");
            return 0;
        }
        return $nextid;
    }

    /** public: return table metadata */
    function metadata($table = '', $full = false) {
        $res = array();

        /*
         * Due to compatibility problems with Table we changed the behavior
         * of metadata();
         * depending on $full, metadata returns the following values:
         *
         * - full is false (default):
         * $result[]:
         *   [0]["table"]  table name
         *   [0]["name"]   field name
         *   [0]["type"]   field type
         *   [0]["len"]    field length
         *   [0]["flags"]  field flags
         *
         * - full is true
         * $result[]:
         *   ["num_fields"] number of metadata records
         *   [0]["table"]  table name
         *   [0]["name"]   field name
         *   [0]["type"]   field type
         *   [0]["len"]    field length
         *   [0]["flags"]  field flags
         *   ["meta"][field name]  index of field named "field name"
         *   The last one is used, if you have a field name, but no index.
         *   Test:  if (isset($result['meta']['myfield'])) { ...
         */

        // if no $table specified, assume that we are working with a query
        // result
        if ($table) {
            $this->connect();
            $id = @mysql_list_fields($this->Database, $table);
            if (!$id)
                $this->halt("Metadata query failed.");
        } else {
            $id = $this->Query_ID;
            if (!$id)
                $this->halt("No query specified.");
        }

        $count = @mysql_num_fields($id);

        // made this IF due to performance (one if is faster than $count if's)
        if (!$full) {
            for ($i = 0; $i < $count; $i++) {
                $res[$i]["table"] = @mysql_field_table($id, $i);
                $res[$i]["name"] = @mysql_field_name($id, $i);
                $res[$i]["type"] = @mysql_field_type($id, $i);
                $res[$i]["len"] = @mysql_field_len($id, $i);
                $res[$i]["flags"] = @mysql_field_flags($id, $i);
            }
        } else { // full
            $res["num_fields"] = $count;

            for ($i = 0; $i < $count; $i++) {
                $res[$i]["table"] = @mysql_field_table($id, $i);
                $res[$i]["name"] = @mysql_field_name($id, $i);
                $res[$i]["type"] = @mysql_field_type($id, $i);
                $res[$i]["len"] = @mysql_field_len($id, $i);
                $res[$i]["flags"] = @mysql_field_flags($id, $i);
                $res["meta"][$res[$i]["name"]] = $i;
            }
        }

        // free the result only if we were called on a table
        if ($table) {
            @mysql_free_result($id);
        }
        return $res;
    }

    /** private: error handling */
    function halt($msg) {
        $this->Error = @mysql_error($this->Link_ID);
        $this->Errno = @mysql_errno($this->Link_ID);
        if ($this->Halt_On_Error == "no")
            return;

        $this->haltmsg($msg);

        if ($this->Halt_On_Error != "report") {
            die("Session halted.");
        }
    }

    function haltmsg($msg) {
        printf("</td></tr></table><b>Database error:</b> %s<br />\n", $msg);
        printf("<b>MySQL Error</b>: %s (%s)<br />\n", $this->Errno, $this->Error);
    }

    function table_names() {
        $this->query("SHOW TABLES");
        $i = 0;
        $return = array();
        while ($info = mysql_fetch_row($this->Query_ID)) {
            $return[$i]["table_name"] = $info[0];
            $return[$i]["tablespace_name"] = $this->Database;
            $return[$i]["database"] = $this->Database;
            $i++;
        }
        return $return;
    }

}