"word*word" => REGEX(word.*word)
*
*
* The full query syntax, in order of precedence, is roughly:
*
* The unary 'NOT' or '-' operator (they are equivalent) negates the
* following search clause.
*
* Search clauses may be joined with the (left-associative) binary operators
* 'AND' and 'OR'. (case-insensitive)
*
* Two adjoining search clauses are joined with an implicit 'AND'. This has
* lower precedence than either an explicit 'AND' or 'OR', so "a b OR c"
* parses as "a AND ( b OR c )", while "a AND b OR c" parses as
* "( a AND b ) OR c" (due to the left-associativity of 'AND' and 'OR'.)
*
* Search clauses can be grouped with parentheses.
*
* Phrases (or other things which don't look like words) can be forced to
* be interpreted as words by quoting them, either with single (') or double (")
* quotes. If you wan't to include the quote character within a quoted string,
* double-up on the quote character: 'I''m hungry' is equivalent to
* "I'm hungry".
*
* Force regex on "re:word" => posix-style, "/word/" => pcre-style
* or use regex='glob' to use file wildcard-like matching. (not yet)
*
* The parsed tree is then converted to the needed PCRE (highlight,
* simple backends) or SQL functions.
*
* @author: Jeff Dairiki
* @author: Reini Urban (case and regex detection, enhanced sql callbacks)
*/
// regex-style: 'auto', 'none', 'glob', 'posix', 'pcre', 'sql'
define ('TSQ_REGEX_NONE', 0);
define ('TSQ_REGEX_AUTO', 1);
define ('TSQ_REGEX_POSIX', 2);
define ('TSQ_REGEX_GLOB', 4);
define ('TSQ_REGEX_PCRE', 8);
define ('TSQ_REGEX_SQL', 16);
class TextSearchQuery {
/**
* Create a new query.
*
* @param $search_query string The query. Syntax is as described above.
* Note that an empty $search_query will match anything.
* @param $case_exact boolean
* @param $regex string one of 'auto', 'none', 'glob', 'posix', 'pcre', 'sql'
* @see TextSearchQuery
*/
function TextSearchQuery($search_query, $case_exact=false, $regex='auto') {
if ($regex == 'none' or !$regex)
$this->_regex = 0;
elseif (defined("TSQ_REGEX_".strtoupper($regex)))
$this->_regex = constant("TSQ_REGEX_".strtoupper($regex));
else {
trigger_error(fmt("Unsupported argument: %s=%s", 'regex', $regex));
$this->_regex = 0;
}
$this->_case_exact = $case_exact;
$parser = new TextSearchQuery_Parser;
$this->_tree = $parser->parse($search_query, $case_exact, $this->_regex);
//$this->_optimize(); // broken under certain circumstances: "word -word -word"
$this->_stoplist = '(A|An|And|But|By|For|From|In|Is|It|Of|On|Or|The|To|With)';
}
function _optimize() {
$this->_tree = $this->_tree->optimize();
}
/**
* Get a PCRE regexp which matches the query.
*/
function asRegexp() {
if (!isset($this->_regexp)) {
if ($this->_regex)
$this->_regexp = '/' . $this->_tree->regexp() . '/'.($this->_case_exact?'':'i').'sS';
else
$this->_regexp = '/^' . $this->_tree->regexp() . '/'.($this->_case_exact?'':'i').'sS';
}
return $this->_regexp;
}
/**
* Match query against string.
*
* @param $string string The string to match.
* @return boolean True if the string matches the query.
*/
function match($string) {
return preg_match($this->asRegexp(), $string);
}
/**
* Get a regular expression suitable for highlighting matched words.
*
* This returns a PCRE regular expression which matches any non-negated
* word in the query.
*
* @return string The PCRE regexp.
*/
function getHighlightRegexp() {
if (!isset($this->_hilight_regexp)) {
$words = array_unique($this->_tree->highlight_words());
if (!$words) {
$this->_hilight_regexp = false;
} else {
foreach ($words as $key => $word)
$words[$key] = preg_quote($word, '/');
$this->_hilight_regexp = '(?:' . join('|', $words) . ')';
}
}
return $this->_hilight_regexp;
}
/**
* Make an SQL clause which matches the query. (deprecated, use makeSqlClause instead)
*
* @param $make_sql_clause_cb WikiCallback
* A callback which takes a single word as an argument and
* returns an SQL clause which will match exactly those records
* containing the word. The word passed to the callback will always
* be in all lower case.
*
* TODO: support db-specific extensions, like MATCH AGAINST or REGEX
* mysql => 4.0.1 can also do Google: MATCH AGAINST IN BOOLEAN MODE
* How? WikiDB backend method?
*
* Old example usage:
*
* function sql_title_match($word) {
* return sprintf("LOWER(title) like '%s'",
* addslashes($word));
* }
*
* ...
*
* $query = new TextSearchQuery("wiki -page");
* $cb = new WikiFunctionCb('sql_title_match');
* $sql_clause = $query->makeSqlClause($cb);
*
* This will result in $sql_clause containing something like
* "(LOWER(title) like 'wiki') AND NOT (LOWER(title) like 'page')".
*
* @return string The SQL clause.
*/
function makeSqlClause($sql_clause_cb) {
$this->_sql_clause_cb = $sql_clause_cb;
return $this->_sql_clause($this->_tree);
}
// deprecated: use _sql_clause_obj now.
function _sql_clause($node) {
switch ($node->op) {
case 'WORD': // word => %word%
return $this->_sql_clause_cb->call($node->word);
case 'NOT':
return "NOT (" . $this->_sql_clause($node->leaves[0]) . ")";
case 'AND':
case 'OR':
$subclauses = array();
foreach ($node->leaves as $leaf)
$subclauses[] = "(" . $this->_sql_clause($leaf) . ")";
return join(" $node->op ", $subclauses);
default:
assert($node->op == VOID);
return '1=1';
}
}
/** Get away with the callback and use a db-specific search class instead.
* @see WikiDB_backend_PearDB_search
*/
function makeSqlClauseObj(&$sql_search_cb) {
$this->_sql_clause_cb = $sql_search_cb;
return $this->_sql_clause_obj($this->_tree);
}
function _sql_clause_obj($node) {
switch ($node->op) {
case 'NOT':
return "NOT (" . $this->_sql_clause_cb->call($node->leaves[0]) . ")";
case 'AND':
case 'OR':
$subclauses = array();
foreach ($node->leaves as $leaf)
$subclauses[] = "(" . $this->_sql_clause_obj($leaf) . ")";
return join(" $node->op ", $subclauses);
case 'VOID':
return '1=1';
default:
return $this->_sql_clause_cb->call($node);
}
}
function sql() { return '%'.$this->_sql_quote($this->word).'%'; }
/**
* Get printable representation of the parse tree.
*
* This is for debugging only.
* @return string Printable parse tree.
*/
function asString() {
return $this->_as_string($this->_tree);
}
function _as_string($node, $indent = '') {
switch ($node->op) {
case 'WORD':
return $indent . "WORD: $node->word";
case 'VOID':
return $indent . "VOID";
default:
$lines = array($indent . $node->op . ":");
$indent .= " ";
foreach ($node->leaves as $leaf)
$lines[] = $this->_as_string($leaf, $indent);
return join("\n", $lines);
}
}
}
/**
* This is a TextSearchQuery which matches nothing.
*/
class NullTextSearchQuery extends TextSearchQuery {
/**
* Create a new query.
*
* @see TextSearchQuery
*/
function NullTextSearchQuery() {}
function asRegexp() { return '/^(?!a)a/x'; }
function match($string) { return false; }
function getHighlightRegexp() { return ""; }
function makeSqlClause($make_sql_clause_cb) { return "(1 = 0)"; }
function asString() { return "NullTextSearchQuery"; }
};
////////////////////////////////////////////////////////////////
//
// Remaining classes are private.
//
////////////////////////////////////////////////////////////////
/**
* Virtual base class for nodes in a TextSearchQuery parse tree.
*
* Also servers as a 'VOID' (contentless) node.
*/
class TextSearchQuery_node
{
var $op = 'VOID';
/**
* Optimize this node.
* @return object Optimized node.
*/
function optimize() {
return $this;
}
/**
* @return regexp matching this node.
*/
function regexp() {
return '';
}
/**
* @param bool True if this node has been negated (higher in the parse tree.)
* @return array A list of all non-negated words contained by this node.
*/
function highlight_words($negated = false) {
return array();
}
function sql() { return $this->word; }
}
/**
* A word.
*/
class TextSearchQuery_node_word
extends TextSearchQuery_node
{
var $op = "WORD";
function TextSearchQuery_node_word($word) {
$this->word = $word;
}
function regexp() {
return '(?=.*' . preg_quote($this->word, '/') . ')';
}
function highlight_words($negated = false) {
return $negated ? array() : array($this->word);
}
function _sql_quote() {
$word = preg_replace('/(?=[%_\\\\])/', "\\", $this->word);
return $GLOBALS['request']->_dbi->qstr($word);
}
function sql() { return '%'.$this->_sql_quote($this->word).'%'; }
}
class TextSearchQuery_node_starts_with
extends TextSearchQuery_node_word {
var $op = "STARTS_WITH";
function regexp() { return '(?=.*\b' . preg_quote($this->word, '/') . ')'; }
function sql() { return $this->_sql_quote($this->word).'%'; }
}
class TextSearchQuery_node_ends_with
extends TextSearchQuery_node_word {
var $op = "ENDS_WITH";
function regexp() { return '(?=.*' . preg_quote($this->word, '/') . '\b)'; }
function sql() { return '%'.$this->_sql_quote($this->word); }
}
class TextSearchQuery_node_exact
extends TextSearchQuery_node_word {
var $op = "EXACT";
function regexp() { return '(?=\b' . preg_quote($this->word, '/') . '\b)'; }
function sql() { return $this->_sql_squote($this->word); }
}
class TextSearchQuery_node_regex // posix regex. FIXME!
extends TextSearchQuery_node_word {
var $op = "REGEX"; // using REGEXP or ~ extension
function regexp() { return '(?=.*\b' . $this->word . '\b)'; }
function sql() { return $this->_sql_quote($this->word); }
}
class TextSearchQuery_node_regex_glob
extends TextSearchQuery_node_regex {
var $op = "REGEX_GLOB";
function regexp() { return '(?=.*\b' . glob_to_pcre($this->word) . '\b)'; }
}
class TextSearchQuery_node_regex_pcre // how to handle pcre modifiers? /i
extends TextSearchQuery_node_regex {
var $op = "REGEX_PCRE";
function regexp() { return $this->word; }
}
class TextSearchQuery_node_regex_sql
extends TextSearchQuery_node_regex {
var $op = "REGEX_SQL"; // using LIKE
function regexp() { return str_replace(array("/%/","/_/"), array(".*","."), $this->word); }
function sql() { return $this->word; }
}
/**
* A negated clause.
*/
class TextSearchQuery_node_not
extends TextSearchQuery_node
{
var $op = "NOT";
function TextSearchQuery_node_not($leaf) {
$this->leaves = array($leaf);
}
function optimize() {
$leaf = &$this->leaves[0];
$leaf = $leaf->optimize();
if ($leaf->op == 'NOT')
return $leaf->leaves[0]; // ( NOT ( NOT x ) ) -> x
return $this;
}
function regexp() {
$leaf = &$this->leaves[0];
return '(?!' . $leaf->regexp() . ')';
}
function highlight_words($negated = false) {
return $this->leaves[0]->highlight_words(!$negated);
}
}
/**
* Virtual base class for 'AND' and 'OR conjoins.
*/
class TextSearchQuery_node_binop
extends TextSearchQuery_node
{
function TextSearchQuery_node_binop($leaves) {
$this->leaves = $leaves;
}
function _flatten() {
// This flattens e.g. (AND (AND a b) (OR c d) e)
// to (AND a b e (OR c d))
$flat = array();
foreach ($this->leaves as $leaf) {
$leaf = $leaf->optimize();
if ($this->op == $leaf->op)
$flat = array_merge($flat, $leaf->leaves);
else
$flat[] = $leaf;
}
$this->leaves = $flat;
}
function optimize() {
$this->_flatten();
assert(!empty($this->leaves));
if (count($this->leaves) == 1)
return $this->leaves[0]; // (AND x) -> x
return $this;
}
function highlight_words($negated = false) {
$words = array();
foreach ($this->leaves as $leaf)
array_splice($words,0,0,
$leaf->highlight_words($negated));
return $words;
}
}
/**
* A (possibly multi-argument) 'AND' conjoin.
*/
class TextSearchQuery_node_and
extends TextSearchQuery_node_binop
{
var $op = "AND";
function optimize() {
$this->_flatten();
// Convert (AND (NOT a) (NOT b) c d) into (AND (NOT (OR a b)) c d).
// Since OR's are more efficient for regexp matching:
// (?!.*a)(?!.*b) vs (?!.*(?:a|b))
// Suck out the negated leaves.
$nots = array();
foreach ($this->leaves as $key => $leaf) {
if ($leaf->op == 'NOT') {
$nots[] = $leaf->leaves[0];
unset($this->leaves[$key]);
}
}
// Combine the negated leaves into a single negated or.
if ($nots) {
$node = ( new TextSearchQuery_node_not
(new TextSearchQuery_node_or($nots)) );
array_unshift($this->leaves, $node->optimize());
}
assert(!empty($this->leaves));
if (count($this->leaves) == 1)
return $this->leaves[0]; // (AND x) -> x
return $this;
}
/* FIXME!
* Either we need all combinations of all words to be position independent,
* or we have to use multiple match calls for each AND
* (AND x y) => /(?(:x)(:y))|(?(:y)(:x))/
*/
function regexp() {
$regexp = '';
foreach ($this->leaves as $leaf)
$regexp .= $leaf->regexp();
return $regexp;
}
}
/**
* A (possibly multi-argument) 'OR' conjoin.
*/
class TextSearchQuery_node_or
extends TextSearchQuery_node_binop
{
var $op = "OR";
function regexp() {
// We will combine any of our direct descendents which are WORDs
// into a single (?=.*(?:word1|word2|...)) regexp.
$regexps = array();
$words = array();
foreach ($this->leaves as $leaf) {
if ($leaf->op == 'WORD')
$words[] = preg_quote($leaf->word, '/');
else
$regexps[] = $leaf->regexp();
}
if ($words)
array_unshift($regexps,
'(?=.*' . $this->_join($words) . ')');
return $this->_join($regexps);
}
function _join($regexps) {
assert(count($regexps) > 0);
if (count($regexps) > 1)
return '(?:' . join('|', $regexps) . ')';
else
return $regexps[0];
}
}
////////////////////////////////////////////////////////////////
//
// Parser:
// op's (and, or, not) are forced to lowercase in the tokenizer.
//
////////////////////////////////////////////////////////////////
define ('TSQ_TOK_BINOP', 1);
define ('TSQ_TOK_NOT', 2);
define ('TSQ_TOK_LPAREN', 4);
define ('TSQ_TOK_RPAREN', 8);
define ('TSQ_TOK_WORD', 16);
define ('TSQ_TOK_STARTS_WITH', 32);
define ('TSQ_TOK_ENDS_WITH', 64);
define ('TSQ_TOK_EXACT', 128);
define ('TSQ_TOK_REGEX', 256);
define ('TSQ_TOK_REGEX_GLOB', 512);
define ('TSQ_TOK_REGEX_PCRE', 1024);
define ('TSQ_TOK_REGEX_SQL', 2048);
// all bits from word to the last.
define ('TSQ_ALLWORDS', (2048*2)-1 - (16-1));
class TextSearchQuery_Parser
{
/*
* This is a simple recursive descent parser, based on the following grammar:
*
* toplist :
* | toplist expr
* ;
*
*
* list : expr
* | list expr
* ;
*
* expr : atom
* | expr BINOP atom
* ;
*
* atom : '(' list ')'
* | NOT atom
* | WORD
* ;
*
* The terminal tokens are:
*
*
* and|or BINOP
* -|not NOT
* ( LPAREN
* ) RPAREN
* /[^-()\s][^()\s]* WORD
* /"[^"]*"/ WORD
* /'[^']*'/ WORD
*
* ^WORD STARTS_WITH
* WORD* STARTS_WITH
* *WORD ENDS_WITH
* ^WORD$ EXACT
*/
function parse ($search_expr, $case_exact=false, $regex=TSQ_REGEX_AUTO) {
$this->lexer = new TextSearchQuery_Lexer($search_expr, $case_exact, $regex);
$this->_regex = $regex;
$tree = $this->get_list('toplevel');
assert($this->lexer->eof());
unset($this->lexer);
return $tree;
}
function get_list ($is_toplevel = false) {
$list = array();
// token types we'll accept as words (and thus expr's) for the
// purpose of error recovery:
$accept_as_words = TSQ_TOK_NOT | TSQ_TOK_BINOP;
if ($is_toplevel)
$accept_as_words |= TSQ_TOK_LPAREN | TSQ_TOK_RPAREN;
while ( ($expr = $this->get_expr())
|| ($expr = $this->get_word($accept_as_words)) ) {
$list[] = $expr;
}
if (!$list) {
if ($is_toplevel)
return new TextSearchQuery_node;
else
return false;
}
return new TextSearchQuery_node_and($list);
}
function get_expr () {
if ( !($expr = $this->get_atom()) )
return false;
$savedpos = $this->lexer->tell();
while ( ($op = $this->lexer->get(TSQ_TOK_BINOP)) ) {
if ( ! ($right = $this->get_atom()) ) {
break;
}
if ($op == 'and')
$expr = new TextSearchQuery_node_and(array($expr, $right));
else {
assert($op == 'or');
$expr = new TextSearchQuery_node_or(array($expr, $right));
}
$savedpos = $this->lexer->tell();
}
$this->lexer->seek($savedpos);
return $expr;
}
function get_atom() {
if ($word = $this->get_word(TSQ_ALLWORDS))
return $word;
$savedpos = $this->lexer->tell();
if ( $this->lexer->get(TSQ_TOK_LPAREN) ) {
if ( ($list = $this->get_list()) && $this->lexer->get(TSQ_TOK_RPAREN) )
return $list;
}
elseif ( $this->lexer->get(TSQ_TOK_NOT) ) {
if ( ($atom = $this->get_atom()) )
return new TextSearchQuery_node_not($atom);
}
$this->lexer->seek($savedpos);
return false;
}
function get_word($accept = TSQ_ALLWORDS) {
foreach (array("WORD","STARTS_WITH","ENDS_WITH","EXACT",
"REGEX","REGEX_GLOB","REGEX_PCRE") as $tok) {
$const = constant("TSQ_TOK_".$tok);
if ( $accept & $const and ($word = $this->lexer->get($const)) ) {
$classname = "TextSearchQuery_node_".strtolower($tok);
return new $classname($word);
}
}
return false;
}
}
class TextSearchQuery_Lexer {
function TextSearchQuery_Lexer ($query_str, $case_exact=false, $regex=TSQ_REGEX_AUTO) {
$this->tokens = $this->tokenize($query_str, $case_exact, $regex);
$this->pos = 0;
}
function tell() {
return $this->pos;
}
function seek($pos) {
$this->pos = $pos;
}
function eof() {
return $this->pos == count($this->tokens);
}
/**
* TODO: support more regex styles, esp. prefer the forced ones over auto
* re: and // stuff
*/
function tokenize($string, $case_exact=false, $regex=TSQ_REGEX_AUTO) {
$tokens = array();
$buf = $case_exact ? ltrim($string) : strtolower(ltrim($string));
while (!empty($buf)) {
if (preg_match('/^(and|or)\b\s*/i', $buf, $m)) {
$val = strtolower($m[1]);
$type = TSQ_TOK_BINOP;
}
elseif (preg_match('/^(-|not\b)\s*/i', $buf, $m)) {
$val = strtolower($m[1]);
$type = TSQ_TOK_NOT;
}
elseif (preg_match('/^([()])\s*/', $buf, $m)) {
$val = $m[1];
$type = $m[1] == '(' ? TSQ_TOK_LPAREN : TSQ_TOK_RPAREN;
}
// ^word
elseif ($regex & (TSQ_REGEX_AUTO|TSQ_REGEX_POSIX|TSQ_REGEX_PCRE)
and preg_match('/^\^([^-()][^()\s]*)\s*/', $buf, $m)) {
$val = $m[1];
$type = TSQ_TOK_STARTS_WITH;
}
// word*
elseif ($regex & (TSQ_REGEX_AUTO|TSQ_REGEX_POSIX|TSQ_REGEX_GLOB)
and preg_match('/^([^-()][^()\s]*)\*\s*/', $buf, $m)) {
$val = $m[1];
$type = TSQ_TOK_STARTS_WITH;
}
// *word
elseif ($regex & (TSQ_REGEX_AUTO|TSQ_REGEX_POSIX|TSQ_REGEX_GLOB)
and preg_match('/^\*([^-()][^()\s]*)\s*/', $buf, $m)) {
$val = $m[1];
$type = TSQ_TOK_ENDS_WITH;
}
// word$
elseif ($regex & (TSQ_REGEX_AUTO|TSQ_REGEX_POSIX|TSQ_REGEX_PCRE)
and preg_match('/^([^-()][^()\s]*)\$\s*/', $buf, $m)) {
$val = $m[1];
$type = TSQ_TOK_ENDS_WITH;
}
// ^word$
elseif ($regex & (TSQ_REGEX_AUTO|TSQ_REGEX_POSIX|TSQ_REGEX_PCRE)
and preg_match('/^\^([^-()][^()\s]*)\$\s*/', $buf, $m)) {
$val = $m[1];
$type = TSQ_TOK_EXACT;
}
// "words "
elseif (preg_match('/^ " ( (?: [^"]+ | "" )* ) " \s*/x', $buf, $m)) {
$val = str_replace('""', '"', $m[1]);
$type = TSQ_TOK_WORD;
}
// 'words '
elseif (preg_match("/^ ' ( (?:[^']+|'')* ) ' \s*/x", $buf, $m)) {
$val = str_replace("''", "'", $m[1]);
$type = TSQ_TOK_WORD;
}
// word
elseif (preg_match('/^([^-()][^()\s]*)\s*/', $buf, $m)) {
$val = $m[1];
$type = TSQ_TOK_WORD;
}
else {
assert(empty($buf));
break;
}
$buf = substr($buf, strlen($m[0]));
/* refine the simple parsing from above: bla*bla, bla?bla, ...
if ($regex and $type == TSQ_TOK_WORD) {
if (substr($val,0,1) == "^")
$type = TSQ_TOK_STARTS_WITH;
elseif (substr($val,0,1) == "*")
$type = TSQ_TOK_ENDS_WITH;
elseif (substr($val,-1,1) == "*")
$type = TSQ_TOK_STARTS_WITH;
}
*/
$tokens[] = array($type, $val);
}
return $tokens;
}
function get($accept) {
if ($this->pos >= count($this->tokens))
return false;
list ($type, $val) = $this->tokens[$this->pos];
if (($type & $accept) == 0)
return false;
$this->pos++;
return $val;
}
}
// Local Variables:
// mode: php
// tab-width: 8
// c-basic-offset: 4
// c-hanging-comment-ender-p: nil
// indent-tabs-mode: nil
// End:
?>