<?php
/**
 *      [PHPB2B] Copyright (C) 2007-2099, Ualink Inc. All Rights Reserved.
 *      The contents of this file are subject to the License; you may not use this file except in compliance with the License. 
 *
 */
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 = "yes"; ## "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;

	/* 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;



	/* public: constructor */
	function __construct($query = "") {
		$this->query($query);
	}

	/* public: some trivial reporting */
	function link_id() {
		return $this->Link_ID;
	}

	function query_id() {
		return $this->Query_ID;
	}

	/* public: connection management */
	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)) {
				$this->halt("Cannot use database ".$Database);
				return 0;
			}
		}

		return $this->Link_ID;
	}

	/* public: discard the query result */
	function free() {
		@mysql_free_result($this->Query_ID);
		$this->Query_ID = 0;
	}

	/* public: perform a query */
	function query($Query_String) {
		/* No empty queries, please, since PHP4 chokes on them. */
		if ($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();
		}

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

		$this->Query_ID = @mysql_query($Query_String,$this->Link_ID);
		$this->Row   = 0;
		$this->Errno = mysql_errno();
		$this->Error = mysql_error();
		if (!$this->Query_ID) {
			$this->halt("Invalid SQL: ".$Query_String);
		}

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

	/* public: walk result set */
	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();

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


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

	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 $this->num_rows();
	}
	function version() {
		if(empty($this->version)) {
			$this->version = mysql_get_server_info($this->Link_ID);
		}
		return $this->version;
	}

	function f($Name) {
		return $this->Record[$Name];
	}

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

	/* 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);
				$id = @mysql_query($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);
			$id = @mysql_query($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) {
		$count = 0;
		$id    = 0;
		$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.</div>");
	}

	function haltmsg($msg) {
		printf("<div style='font-family: Tahoma,Arial;'><b>Database error:</b> %s<br>\n", $msg);
		printf("<b>MySQL Error</b>: %s (%s)<br>\n",
		$this->Errno,
		$this->Error);
	}
	
	function error() {
		return (($this->Link_ID) ? mysql_error($this->Link_ID) : mysql_error());
	}
	
	function table_names() {
		$return = array();
		$this->query("SHOW TABLES");
		$i=0;
		while ($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;
	}
}
?>
