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+<?php
+/**
+ * SemanticScuttle - your social bookmark manager.
+ *
+ * PHP version 5.
+ *
+ * @category Bookmarking
+ * @package SemanticScuttle
+ * @author Christian Weiske <cweiske@cweiske.de>
+ * @license GPL http://www.gnu.org/licenses/gpl.html
+ * @link http://sourceforge.net/projects/semanticscuttle
+ */
+
+/**
+ * SemanticScuttle voting system.
+ *
+ * Each registered user in SemanticScuttle may vote
+ * for or against a bookmark, counting +1 or -1.
+ * The sum of all votes determines the "voting" of a bookmark.
+ * Every user is equal in voting. Each vote is tied to a user.
+ *
+ * @internal
+ * Votes are saved in a separate "votes" table.
+ * Additionally to that, the voting and number of votes
+ * of a bookmark is also stored in the bookmarks table.
+ * This is done to make sure lookups are really fast, since
+ * every bookmark in a list shows its voting.
+ *
+ * @category Bookmarking
+ * @package SemanticScuttle
+ * @author Christian Weiske <cweiske@cweiske.de>
+ * @license GPL http://www.gnu.org/licenses/gpl.html
+ * @link http://sourceforge.net/projects/semanticscuttle
+ */
+class SemanticScuttle_Service_Vote extends SemanticScuttle_DbService
+{
+ /**
+ * Returns the single service instance
+ *
+ * @param sql_db $db Database object
+ *
+ * @return SemanticScuttle_Service_Vote
+ */
+ public static function getInstance($db)
+ {
+ static $instance;
+ if (!isset($instance)) {
+ $instance = new self($db);
+ }
+ return $instance;
+ }
+
+
+
+ /**
+ * Create a new instance.
+ *
+ * @param sql_db $db Database object
+ */
+ protected function __construct($db)
+ {
+ $this->db = $db;
+ $this->tablename = $GLOBALS['tableprefix'] . 'votes';
+ }
+
+
+
+ /**
+ * Returns the sum of votes for the given bookmark.
+ *
+ * @internal
+ * Uses the "votes" table to retrieve the votes, which
+ * has high costs. It is more efficient to get the sum of
+ * all votes for a bookmark from the bookmarks table,
+ * field bVoting.
+ *
+ * @param integer $bookmark Bookmark ID
+ *
+ * @return integer Vote (can be positive, 0 or negative)
+ */
+ public function getVoting($bookmark)
+ {
+ $query = 'SELECT SUM(vote) as sum FROM ' . $this->getTableName()
+ . ' WHERE bid = "' . $this->db->sql_escape($bookmark) . '"';
+
+ if (!($dbres = $this->db->sql_query_limit($query, 1, 0))) {
+ message_die(
+ GENERAL_ERROR, 'Could not get voting',
+ '', __LINE__, __FILE__, $query, $this->db
+ );
+ //FIXME: throw exception
+ }
+
+ $row = $this->db->sql_fetchrow($dbres);
+ $this->db->sql_freeresult($dbres);
+
+ return (int)$row['sum'];
+ }//public function getVoting(..)
+
+
+
+ /**
+ * Returns the number of users that voted for or
+ * against the given bookmark.
+ *
+ * @internal
+ * This method uses the votes table to calculate the
+ * number of votes for a bookmark. In normal life, it
+ * is more efficient to use the "bVotes" field in the
+ * bookmarks table.
+ *
+ * @param integer $bookmark Bookmark ID
+ *
+ * @return integer Number of votes
+ */
+ public function getVotes($bookmark)
+ {
+ $query = 'SELECT COUNT(vote) as count FROM '
+ . $this->getTableName()
+ . ' WHERE bid = "' . $this->db->sql_escape($bookmark) . '"';
+
+ if (!($dbres = $this->db->sql_query_limit($query, 1, 0))) {
+ message_die(
+ GENERAL_ERROR, 'Could not get vote count',
+ '', __LINE__, __FILE__, $query, $this->db
+ );
+ //FIXME: throw exception
+ }
+
+ $row = $this->db->sql_fetchrow($dbres);
+ $this->db->sql_freeresult($dbres);
+
+ return (int)$row['count'];
+ }
+
+
+
+ /**
+ * Returns if the user has already voted for
+ * the given bookmark.
+ *
+ * @param integer $bookmark Bookmark ID
+ * @param integer $user User ID
+ *
+ * @return boolean True if the user has already voted
+ */
+ public function hasVoted($bookmark, $user)
+ {
+ $query = 'SELECT COUNT(vote) as count FROM '
+ . $this->getTableName()
+ . ' WHERE'
+ . ' bid = "' . $this->db->sql_escape($bookmark) . '"'
+ . ' AND uid = "' . $this->db->sql_escape($user) . '"';
+
+ if (!($dbres = $this->db->sql_query_limit($query, 1, 0))) {
+ message_die(
+ GENERAL_ERROR, 'Could not get vote count',
+ '', __LINE__, __FILE__, $query, $this->db
+ );
+ //FIXME: throw exception
+ }
+
+ $row = $this->db->sql_fetchrow($dbres);
+ $this->db->sql_freeresult($dbres);
+
+ return (int)$row['count'] == 1;
+ }
+
+
+
+ /**
+ * Returns the actual vote the given user
+ * gave the bookmark.
+ *
+ * @param integer $bookmark Bookmark ID
+ * @param integer $user User ID
+ *
+ * @return integer Either 1 or -1, null when not voted.
+ */
+ public function getVote($bookmark, $user)
+ {
+ $query = 'SELECT vote FROM ' . $this->getTableName()
+ . ' WHERE'
+ . ' bid = "' . $this->db->sql_escape($bookmark) . '"'
+ . ' AND uid = "' . $this->db->sql_escape($user) . '"';
+
+ if (!($dbres = $this->db->sql_query_limit($query, 1, 0))) {
+ message_die(
+ GENERAL_ERROR, 'Could not get vote count',
+ '', __LINE__, __FILE__, $query, $this->db
+ );
+ //FIXME: throw exception
+ }
+
+ $row = $this->db->sql_fetchrow($dbres);
+ $this->db->sql_freeresult($dbres);
+
+ if (!$row) {
+ return null;
+ }
+
+ return $row['vote'];
+ }
+
+
+
+ /**
+ * Let a user vote for the bookmark.
+ *
+ * @internal
+ * We check if voting is enabled or not,
+ * and if the user has already voted.
+ * It is up to the calling code to make sure
+ * the user is authorized to vote.
+ *
+ * @param integer $bookmark Bookmark ID
+ * @param integer $user User ID
+ * @param integer $vote 1 or -1
+ *
+ * @return boolean True if the vote was saved,
+ * false if there was a problem
+ * (i.e. already voted)
+ */
+ public function vote($bookmark, $user, $vote = 1)
+ {
+ if ($GLOBALS['enableVoting'] == false) {
+ return false;
+ }
+
+ if ($vote != -1 && $vote != 1) {
+ return false;
+ }
+
+ if ($this->hasVoted($bookmark, $user)) {
+ $this->removeVote($bookmark, $user);
+ }
+
+ $res = $this->db->sql_query(
+ 'INSERT INTO ' . $this->getTableName()
+ . ' SET'
+ . ' bid = ' . (int)$bookmark
+ . ',uid = ' . (int)$user
+ . ',vote = ' . (int)$vote
+ );
+ //FIXME: check for sql error
+ $this->db->sql_freeresult($res);
+
+ //update bookmark table
+ $bm = SemanticScuttle_Service_Factory::get('Bookmark');
+ $res = $this->db->sql_query(
+ $sql='UPDATE ' . $bm->getTableName()
+ . ' SET bVoting = bVoting + ' . (int)$vote
+ . ' , bVotes = bVotes + 1'
+ . ' WHERE bId = ' . (int)$bookmark
+ );
+ $this->db->sql_freeresult($res);
+
+ return true;
+ }
+
+
+
+ /**
+ * Removes a vote from the database
+ *
+ * @param integer $bookmark Bookmark ID
+ * @param integer $user User ID
+ *
+ * @return boolean True if all went well, false if not
+ */
+ protected function removeVote($bookmark, $user)
+ {
+ $vote = $this->getVote($bookmark, $user);
+ if ($vote === null) {
+ return false;
+ }
+
+ //remove from votes table
+ $query = 'DELETE FROM ' . $this->getTableName()
+ . ' WHERE bId = ' . (int)$bookmark
+ . ' AND uId = ' . (int)$user;
+ $this->db->sql_query($query);
+
+ //change voting sum in bookmarks table
+ $bm = SemanticScuttle_Service_Factory::get('Bookmark');
+ $res = $this->db->sql_query(
+ $sql='UPDATE ' . $bm->getTableName()
+ . ' SET bVoting = bVoting - ' . (int)$vote
+ . ' , bVotes = bVotes - 1'
+ . ' WHERE bId = ' . (int)$bookmark
+ );
+ $this->db->sql_freeresult($res);
+
+ return true;
+ }
+
+
+
+ /**
+ * Re-calculates all votings for all bookmarks
+ * and updates the voting values in the bookmarks
+ * table.
+ * This is mainly meant to be an administrative method
+ * to fix a broken database.
+ *
+ * @return void
+ */
+ public function rewriteVotings()
+ {
+ $bm = SemanticScuttle_Service_Factory::get('Bookmark');
+ $query = 'UPDATE ' . $bm->getTableName() . ' as B SET bVoting = '
+ . '(SELECT SUM(vote) FROM ' . $this->getTableName() . ' as V'
+ . ' WHERE V.bId = B.bId GROUP BY bid)'
+ . ', bVotes = '
+ . '(SELECT COUNT(vote) FROM ' . $this->getTableName() . ' as V'
+ . ' WHERE V.bId = B.bId GROUP BY bid)';
+ $this->db->sql_query($query);
+ }
+
+
+
+ /**
+ * Delete all votes from the database table.
+ * Used in unit tests.
+ *
+ * @return void
+ */
+ public function deleteAll()
+ {
+ $query = 'TRUNCATE TABLE `'. $this->getTableName() .'`';
+ $this->db->sql_query($query);
+ }
+
+
+}
+
+?> \ No newline at end of file
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-08 22:39:53 +0000