Index: trunk/src/bp-xprofile/bp-xprofile-classes.php
===================================================================
--- trunk/src/bp-xprofile/bp-xprofile-classes.php	(revision 9084)
+++ trunk/src/bp-xprofile/bp-xprofile-classes.php	(revision 9178)
@@ -3263,2 +3263,533 @@
 	}
 }
+
+/**
+ * Class for generating SQL clauses to filter a user query by xprofile data.
+ *
+ * @since BuddyPress (2.2.0)
+ */
+class BP_XProfile_Query {
+	/**
+	 * Array of xprofile queries.
+	 *
+	 * See {@see WP_XProfile_Query::__construct()} for information on parameters.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 * @var    array
+	 */
+	public $queries = array();
+
+	/**
+	 * Database table that where the metadata's objects are stored (eg $wpdb->users).
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 * @var    string
+	 */
+	public $primary_table;
+
+	/**
+	 * Column in primary_table that represents the ID of the object.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 * @var    string
+	 */
+	public $primary_id_column;
+
+	/**
+	 * A flat list of table aliases used in JOIN clauses.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access protected
+	 * @var    array
+	 */
+	protected $table_aliases = array();
+
+	/**
+	 * Constructor.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 *
+	 * @param array $xprofile_query {
+	 *     Array of xprofile query clauses.
+	 *
+	 *     @type string $relation Optional. The MySQL keyword used to join the clauses of the query.
+	 *                            Accepts 'AND', or 'OR'. Default 'AND'.
+	 *     @type array {
+	 *         Optional. An array of first-order clause parameters, or another fully-formed xprofile query.
+	 *
+	 *         @type string|int $field   XProfile field to filter by. Accepts a field name or ID.
+	 *         @type string     $value   XProfile value to filter by.
+	 *         @type string     $compare MySQL operator used for comparing the $value. Accepts '=', '!=', '>',
+	 *                                   '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN', 'BETWEEN',
+	 *                                   'NOT BETWEEN', 'REGEXP', 'NOT REGEXP', or 'RLIKE'. Default is 'IN'
+	 *                                   when `$value` is an array, '=' otherwise.
+	 *         @type string     $type    MySQL data type that the `value` column will be CAST to for comparisons.
+	 *                                   Accepts 'NUMERIC', 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL',
+	 *                                   'SIGNED', 'TIME', or 'UNSIGNED'. Default is 'CHAR'.
+	 *     }
+	 * }
+	 */
+	public function __construct( $xprofile_query ) {
+		if ( empty( $xprofile_query ) ) {
+			return;
+		}
+
+		$this->queries = $this->sanitize_query( $xprofile_query );
+	}
+
+	/**
+	 * Ensure the `xprofile_query` argument passed to the class constructor is well-formed.
+	 *
+	 * Eliminates empty items and ensures that a 'relation' is set.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 *
+	 * @param  array $queries Array of query clauses.
+	 * @return array Sanitized array of query clauses.
+	 */
+	public function sanitize_query( $queries ) {
+		$clean_queries = array();
+
+		if ( ! is_array( $queries ) ) {
+			return $clean_queries;
+		}
+
+		foreach ( $queries as $key => $query ) {
+			if ( 'relation' === $key ) {
+				$relation = $query;
+
+			} else if ( ! is_array( $query ) ) {
+				continue;
+
+			// First-order clause.
+			} else if ( $this->is_first_order_clause( $query ) ) {
+				if ( isset( $query['value'] ) && array() === $query['value'] ) {
+					unset( $query['value'] );
+				}
+
+				$clean_queries[] = $query;
+
+			// Otherwise, it's a nested query, so we recurse.
+			} else {
+				$cleaned_query = $this->sanitize_query( $query );
+
+				if ( ! empty( $cleaned_query ) ) {
+					$clean_queries[] = $cleaned_query;
+				}
+			}
+		}
+
+		if ( empty( $clean_queries ) ) {
+			return $clean_queries;
+		}
+
+		// Sanitize the 'relation' key provided in the query.
+		if ( isset( $relation ) && 'OR' === strtoupper( $relation ) ) {
+			$clean_queries['relation'] = 'OR';
+
+		/*
+		 * If there is only a single clause, call the relation 'OR'.
+		 * This value will not actually be used to join clauses, but it
+		 * simplifies the logic around combining key-only queries.
+		 */
+		} else if ( 1 === count( $clean_queries ) ) {
+			$clean_queries['relation'] = 'OR';
+
+		// Default to AND.
+		} else {
+			$clean_queries['relation'] = 'AND';
+		}
+
+		return $clean_queries;
+	}
+
+	/**
+	 * Determine whether a query clause is first-order.
+	 *
+	 * A first-order query clause is one that has either a 'key' or a 'value' array key.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access protected
+	 *
+	 * @param  array $query XProfile query arguments.
+	 * @return bool  Whether the query clause is a first-order clause.
+	 */
+	protected function is_first_order_clause( $query ) {
+		return isset( $query['field'] ) || isset( $query['value'] );
+	}
+
+	/**
+	 * Return the appropriate alias for the given field type if applicable.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 *
+	 * @param  string $type MySQL type to cast `value`.
+	 * @return string MySQL type.
+	 */
+	public function get_cast_for_type( $type = '' ) {
+		if ( empty( $type ) )
+			return 'CHAR';
+
+		$meta_type = strtoupper( $type );
+
+		if ( ! preg_match( '/^(?:BINARY|CHAR|DATE|DATETIME|SIGNED|UNSIGNED|TIME|NUMERIC(?:\(\d+(?:,\s?\d+)?\))?|DECIMAL(?:\(\d+(?:,\s?\d+)?\))?)$/', $meta_type ) )
+			return 'CHAR';
+
+		if ( 'NUMERIC' == $meta_type )
+			$meta_type = 'SIGNED';
+
+		return $meta_type;
+	}
+
+	/**
+	 * Generate SQL clauses to be appended to a main query.
+	 *
+	 * Called by the public {@see BP_XProfile_Query::get_sql()}, this method is abstracted out to maintain parity
+	 * with WP's Query classes.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access protected
+	 *
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	protected function get_sql_clauses() {
+		/*
+		 * $queries are passed by reference to get_sql_for_query() for recursion.
+		 * To keep $this->queries unaltered, pass a copy.
+		 */
+		$queries = $this->queries;
+		$sql = $this->get_sql_for_query( $queries );
+
+		if ( ! empty( $sql['where'] ) ) {
+			$sql['where'] = ' AND ' . $sql['where'];
+		}
+
+		return $sql;
+	}
+
+	/**
+	 * Generate SQL clauses for a single query array.
+	 *
+	 * If nested subqueries are found, this method recurses the tree to produce the properly nested SQL.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access protected
+	 *
+	 * @param  array $query Query to parse.
+	 * @param  int   $depth Optional. Number of tree levels deep we currently are. Used to calculate indentation.
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to a single query array.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	protected function get_sql_for_query( &$query, $depth = 0 ) {
+		$sql_chunks = array(
+			'join'  => array(),
+			'where' => array(),
+		);
+
+		$sql = array(
+			'join'  => '',
+			'where' => '',
+		);
+
+		$indent = '';
+		for ( $i = 0; $i < $depth; $i++ ) {
+			$indent .= "  ";
+		}
+
+		foreach ( $query as $key => &$clause ) {
+			if ( 'relation' === $key ) {
+				$relation = $query['relation'];
+			} else if ( is_array( $clause ) ) {
+
+				// This is a first-order clause.
+				if ( $this->is_first_order_clause( $clause ) ) {
+					$clause_sql = $this->get_sql_for_clause( $clause, $query );
+
+					$where_count = count( $clause_sql['where'] );
+					if ( ! $where_count ) {
+						$sql_chunks['where'][] = '';
+					} else if ( 1 === $where_count ) {
+						$sql_chunks['where'][] = $clause_sql['where'][0];
+					} else {
+						$sql_chunks['where'][] = '( ' . implode( ' AND ', $clause_sql['where'] ) . ' )';
+					}
+
+					$sql_chunks['join'] = array_merge( $sql_chunks['join'], $clause_sql['join'] );
+				// This is a subquery, so we recurse.
+				} else {
+					$clause_sql = $this->get_sql_for_query( $clause, $depth + 1 );
+
+					$sql_chunks['where'][] = $clause_sql['where'];
+					$sql_chunks['join'][]  = $clause_sql['join'];
+				}
+			}
+		}
+
+		// Filter to remove empties.
+		$sql_chunks['join']  = array_filter( $sql_chunks['join'] );
+		$sql_chunks['where'] = array_filter( $sql_chunks['where'] );
+
+		if ( empty( $relation ) ) {
+			$relation = 'AND';
+		}
+
+		// Filter duplicate JOIN clauses and combine into a single string.
+		if ( ! empty( $sql_chunks['join'] ) ) {
+			$sql['join'] = implode( ' ', array_unique( $sql_chunks['join'] ) );
+		}
+
+		// Generate a single WHERE clause with proper brackets and indentation.
+		if ( ! empty( $sql_chunks['where'] ) ) {
+			$sql['where'] = '( ' . "\n  " . $indent . implode( ' ' . "\n  " . $indent . $relation . ' ' . "\n  " . $indent, $sql_chunks['where'] ) . "\n" . $indent . ')';
+		}
+
+		return $sql;
+	}
+
+	/**
+	 * Generates SQL clauses to be appended to a main query.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 *
+	 * @param string $primary_table     Database table where the object being filtered is stored (eg wp_users).
+	 * @param string $primary_id_column ID column for the filtered object in $primary_table.
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	public function get_sql( $primary_table, $primary_id_column, $context = null ) {
+		global $wpdb;
+
+		$this->primary_table     = $primary_table;
+		$this->primary_id_column = $primary_id_column;
+
+		$sql = $this->get_sql_clauses();
+
+		/*
+		 * If any JOINs are LEFT JOINs (as in the case of NOT EXISTS), then all JOINs should
+		 * be LEFT. Otherwise posts with no metadata will be excluded from results.
+		 */
+		if ( false !== strpos( $sql['join'], 'LEFT JOIN' ) ) {
+			$sql['join'] = str_replace( 'INNER JOIN', 'LEFT JOIN', $sql['join'] );
+		}
+
+		return $sql;
+	}
+
+	/**
+	 * Generate SQL JOIN and WHERE clauses for a first-order query clause.
+	 *
+	 * "First-order" means that it's an array with a 'field' or 'value'.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access public
+	 *
+	 * @param array $clause       Query clause.
+	 * @param array $parent_query Parent query array.
+	 * @return array {
+	 *     Array containing JOIN and WHERE SQL clauses to append to a first-order query.
+	 *
+	 *     @type string $join  SQL fragment to append to the main JOIN clause.
+	 *     @type string $where SQL fragment to append to the main WHERE clause.
+	 * }
+	 */
+	public function get_sql_for_clause( &$clause, $parent_query ) {
+		global $wpdb;
+
+		$sql_chunks = array(
+			'where' => array(),
+			'join' => array(),
+		);
+
+		if ( isset( $clause['compare'] ) ) {
+			$clause['compare'] = strtoupper( $clause['compare'] );
+		} else {
+			$clause['compare'] = isset( $clause['value'] ) && is_array( $clause['value'] ) ? 'IN' : '=';
+		}
+
+		if ( ! in_array( $clause['compare'], array(
+			'=', '!=', '>', '>=', '<', '<=',
+			'LIKE', 'NOT LIKE',
+			'IN', 'NOT IN',
+			'BETWEEN', 'NOT BETWEEN',
+			'EXISTS', 'NOT EXISTS',
+			'REGEXP', 'NOT REGEXP', 'RLIKE'
+		) ) ) {
+			$clause['compare'] = '=';
+		}
+
+		$field_compare = $clause['compare'];
+
+		// First build the JOIN clause, if one is required.
+		$join = '';
+
+		$data_table = buddypress()->profile->table_name_data;
+
+		// We prefer to avoid joins if possible. Look for an existing join compatible with this clause.
+		$alias = $this->find_compatible_table_alias( $clause, $parent_query );
+		if ( false === $alias ) {
+			$i = count( $this->table_aliases );
+			$alias = $i ? 'xpq' . $i : $data_table;
+
+			// JOIN clauses for NOT EXISTS have their own syntax.
+			if ( 'NOT EXISTS' === $field_compare ) {
+				$join .= " LEFT JOIN $data_table";
+				$join .= $i ? " AS $alias" : '';
+				$join .= $wpdb->prepare( " ON ($this->primary_table.$this->primary_id_column = $alias.user_id AND $alias.field_id = %d )", $clause['field'] );
+
+			// All other JOIN clauses.
+			} else {
+				$join .= " INNER JOIN $data_table";
+				$join .= $i ? " AS $alias" : '';
+				$join .= " ON ( $this->primary_table.$this->primary_id_column = $alias.user_id )";
+			}
+
+			$this->table_aliases[] = $alias;
+			$sql_chunks['join'][] = $join;
+		}
+
+		// Save the alias to this clause, for future siblings to find.
+		$clause['alias'] = $alias;
+
+		// Next, build the WHERE clause.
+		$where = '';
+
+		// field_id.
+		if ( array_key_exists( 'field', $clause ) ) {
+			// Convert field name to ID if necessary.
+			if ( ! is_numeric( $clause['field'] ) ) {
+				$clause['field'] = xprofile_get_field_id_from_name( $clause['field'] );
+			}
+
+			// NOT EXISTS has its own syntax.
+			if ( 'NOT EXISTS' === $field_compare ) {
+				$sql_chunks['where'][] = $alias . '.user_id IS NULL';
+			} else {
+				$sql_chunks['where'][] = $wpdb->prepare( "$alias.field_id = %d", $clause['field'] );
+			}
+		}
+
+		// value.
+		if ( array_key_exists( 'value', $clause ) ) {
+			$field_value = $clause['value'];
+			$field_type = $this->get_cast_for_type( isset( $clause['type'] ) ? $clause['type'] : '' );
+
+			if ( in_array( $field_compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ) ) ) {
+				if ( ! is_array( $field_value ) ) {
+					$field_value = preg_split( '/[,\s]+/', $field_value );
+				}
+			} else {
+				$field_value = trim( $field_value );
+			}
+
+			switch ( $field_compare ) {
+				case 'IN' :
+				case 'NOT IN' :
+					$field_compare_string = '(' . substr( str_repeat( ',%s', count( $field_value ) ), 1 ) . ')';
+					$where = $wpdb->prepare( $field_compare_string, $field_value );
+					break;
+
+				case 'BETWEEN' :
+				case 'NOT BETWEEN' :
+					$field_value = array_slice( $field_value, 0, 2 );
+					$where = $wpdb->prepare( '%s AND %s', $field_value );
+					break;
+
+				case 'LIKE' :
+				case 'NOT LIKE' :
+					$field_value = '%' . $wpdb->esc_like( $field_value ) . '%';
+					$where = $wpdb->prepare( '%s', $field_value );
+					break;
+
+				default :
+					$where = $wpdb->prepare( '%s', $field_value );
+					break;
+
+			}
+
+			if ( $where ) {
+				$sql_chunks['where'][] = "CAST($alias.value AS {$field_type}) {$field_compare} {$where}";
+			}
+		}
+
+		/*
+		 * Multiple WHERE clauses (`field` and `value` pairs) should be joined in parentheses.
+		 */
+		if ( 1 < count( $sql_chunks['where'] ) ) {
+			$sql_chunks['where'] = array( '( ' . implode( ' AND ', $sql_chunks['where'] ) . ' )' );
+		}
+
+		return $sql_chunks;
+	}
+
+	/**
+	 * Identify an existing table alias that is compatible with the current query clause.
+	 *
+	 * We avoid unnecessary table joins by allowing each clause to look for an existing table alias that is
+	 * compatible with the query that it needs to perform. An existing alias is compatible if (a) it is a
+	 * sibling of $clause (ie, it's under the scope of the same relation), and (b) the combination of
+	 * operator and relation between the clauses allows for a shared table join. In the case of BP_XProfile_Query,
+	 * this * only applies to IN clauses that are connected by the relation OR.
+	 *
+	 * @since  BuddyPress (2.2.0)
+	 * @access protected
+	 *
+	 * @param  array       $clause       Query clause.
+	 * @param  array       $parent_query Parent query of $clause.
+	 * @return string|bool Table alias if found, otherwise false.
+	 */
+	protected function find_compatible_table_alias( $clause, $parent_query ) {
+		$alias = false;
+
+		foreach ( $parent_query as $sibling ) {
+			// If the sibling has no alias yet, there's nothing to check.
+			if ( empty( $sibling['alias'] ) ) {
+				continue;
+			}
+
+			// We're only interested in siblings that are first-order clauses.
+			if ( ! is_array( $sibling ) || ! $this->is_first_order_clause( $sibling ) ) {
+				continue;
+			}
+
+			$compatible_compares = array();
+
+			// Clauses connected by OR can share joins as long as they have "positive" operators.
+			if ( 'OR' === $parent_query['relation'] ) {
+				$compatible_compares = array( '=', 'IN', 'BETWEEN', 'LIKE', 'REGEXP', 'RLIKE', '>', '>=', '<', '<=' );
+
+			// Clauses joined by AND with "negative" operators share a join only if they also share a key.
+			} else if ( isset( $sibling['field_id'] ) && isset( $clause['field_id'] ) && $sibling['field_id'] === $clause['field_id'] ) {
+				$compatible_compares = array( '!=', 'NOT IN', 'NOT LIKE' );
+			}
+
+			$clause_compare  = strtoupper( $clause['compare'] );
+			$sibling_compare = strtoupper( $sibling['compare'] );
+			if ( in_array( $clause_compare, $compatible_compares ) && in_array( $sibling_compare, $compatible_compares ) ) {
+				$alias = $sibling['alias'];
+				break;
+			}
+		}
+
+		return $alias;
+	}
+}
