From 451b22f04ae4f2b6c165fc219be43951fe5dc37e Mon Sep 17 00:00:00 2001
From: dairiki <dairiki@96ab9672-09ca-45d6-a79d-3d69d39ca109>
Date: Sat, 18 Aug 2001 00:34:27 +0000
Subject: [PATCH] Added real back-link searches. The pgsql and msql backends
 are completely untested at this point, but they "should work".  (I.e.:
 they're probably broken now.)

The msql back-link search is a bit buggy, and will not find links
if they are split between two records ("lines") in the page store.
(The proper remedy for this is to implement the links table in
the msql back end.)


git-svn-id: svn://svn.code.sf.net/p/phpwiki/code/branches/release-1_2-branch@535 96ab9672-09ca-45d6-a79d-3d69d39ca109
---
 lib/msql.php | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 65 insertions(+), 1 deletion(-)

diff --git a/lib/msql.php b/lib/msql.php
index c7537fb6f..e2e92c854 100644
--- a/lib/msql.php
+++ b/lib/msql.php
@@ -1,4 +1,4 @@
-<!-- $Id: msql.php,v 1.6 2001-02-01 04:24:26 wainstead Exp $ -->
+<!-- $Id: msql.php,v 1.6.2.1 2001-08-18 00:34:27 dairiki Exp $ -->
 <?php
 
    /*
@@ -15,6 +15,9 @@
       TitleSearchNextMatch($dbi, &$pos)
       InitFullSearch($dbi, $search)
       FullSearchNextMatch($dbi, &$pos)
+      MakeBackLinkSearchRegexp($pagename)
+      InitBackLinkSearch($dbi, $pagename) 
+      BackLinkSearchNextMatch($dbi, &$pos) 
       GetAllWikiPageNames($dbi)
    */
 
@@ -388,6 +391,67 @@
    ////////////////////////
    // new database features
 
+   // Compute PCRE suitable for searching for links to the given page.
+   function MakeBackLinkSearchRegexp($pagename) {
+      global $WikiNameRegexp;
+
+      // Note that in (at least some) PHP 3.x's, preg_quote only takes
+      // (at most) one argument.  Also it doesn't quote '/'s.
+      // It does quote '='s, so we'll use that for the delimeter.
+      $quoted_pagename = preg_quote($pagename);
+      if (preg_match("/^$WikiNameRegexp\$/", $pagename)) {
+	 # FIXME: This may need modification for non-standard (non-english) $WikiNameRegexp.
+	 return "=(?<![A-Za-z0-9!])$quoted_pagename(?![A-Za-z0-9])=";
+      }
+      else {
+	 // Note from author: Sorry. :-/
+	 return ( '='
+		  . '(?<!\[)\[(?!\[)' // Single, isolated '['
+		  . '([^]|]*\|)?'     // Optional stuff followed by '|'
+	          . '\s*'             // Optional space
+		  . $quoted_pagename  // Pagename
+		  . '\s*\]=' );	      // Optional space, followed by ']'
+	 // FIXME: the above regexp is still not quite right.
+	 // Consider the text: " [ [ test page ]".  This is a link to a page
+	 // named '[ test page'.  The above regexp will recognize this
+	 // as a link either to '[ test page' (good) or to 'test page' (wrong).
+      } 
+   }
+
+   // setup for back-link search
+   function InitBackLinkSearch($dbi, $pagename) {
+      global $WikiLinksStore;
+     
+      $topage = addslashes($pagename);
+
+      // FIXME: this is buggy.  If a [multiword link] is split accross
+      // multiple lines int the page_table, we wont find it.
+      // (Probably the best fix is to implement the link table, and use it.)
+      $res['regexp'] = MakeBackLinkSearchRegexp($pagename);
+      $res['res'] = msql_query( "SELECT pagename, line FROM $dbi[page_table]"
+				. " WHERE line LIKE '%$topage%'"
+				. " ORDER BY pagename",
+				$dbi["dbc"]);
+      $res['lastpage'] = '';
+      
+      return $res;
+   }
+
+
+   // iterating through database
+   function BackLinkSearchNextMatch($dbi, $res) {
+      while (true) {
+	 if ( ! ($o = msql_fetch_object($res['res']))) {
+	    return 0;
+	 }
+	 if ( $res['lastpage'] == $o->pagename )
+	    continue;
+	 if ( ! preg_match($res['regexp'], $a->line) )
+	    continue;
+	 $res['lastpage'] = $o->pagename;
+	 return $o->pagename;
+      }
+   }
 
    function IncreaseHitCount($dbi, $pagename) {
 
-- 
2.45.0