=== modified file 'modules/search/search.install'
--- modules/search/search.install	2007-05-25 15:26:33 +0000
+++ modules/search/search.install	2007-06-21 16:24:24 +0000
@@ -19,3 +19,18 @@ function search_uninstall() {
   variable_del('minimum_word_size');
   variable_del('overlap_cjk');
 }
+
+/**
+ * Drop and recreate the search index.
+ */
+function search_update_1() {
+  $ret = array();
+  db_drop_table($ret, 'search_dataset');
+  db_drop_table($ret, 'search_index');
+  db_drop_table($ret, 'search_total');
+  drupal_install_schema('search');
+  return $ret;
+}
+
+// Note: if further schema changes are made before 6.0, update_1 should be
+// renamed to update_2, and a dummy update_1 should be provided.
\ No newline at end of file

=== modified file 'modules/search/search.module'
--- modules/search/search.module	2007-06-16 17:53:05 +0000
+++ modules/search/search.module	2007-06-21 16:36:55 +0000
@@ -293,9 +293,11 @@ function search_wipe($sid = NULL, $type 
   }
   else {
     db_query("DELETE FROM {search_dataset} WHERE sid = %d AND type = '%s'", $sid, $type);
-    db_query("DELETE FROM {search_index} WHERE fromsid = %d AND fromtype = '%s'", $sid, $type);
-    // When re-indexing, keep link references
-    db_query("DELETE FROM {search_index} WHERE sid = %d AND type = '%s'". ($reindex ? " AND fromsid = 0" : ''), $sid, $type);
+    db_query("DELETE FROM {search_index} WHERE sid = %d AND type = '%s'", $sid, $type);
+    // Don't remove links if re-indexing.
+    if (!$reindex) {
+      db_query("DELETE FROM {search_node_links} WHERE sid = %d AND type = '%s'", $sid, $type);
+    }
   }
 }
 
@@ -591,21 +593,24 @@ function search_index($sid, $type, $text
               $word = (int)ltrim($word, '-0');
             }
 
+            // Links score mainly for the target.
             if ($link) {
               if (!isset($results[$linknid])) {
                 $results[$linknid] = array();
               }
-              $results[$linknid][$word] += $score * $focus;
+              $results[$linknid][] = $word;
+              // Reduce score of the link caption in the source.
+              $focus *= 0.2;
             }
-            else {
-              if (!isset($results[0][$word])) {
-                $results[0][$word] = 0;
-              }
-              $results[0][$word] += $score * $focus;
-              // Focus is a decaying value in terms of the amount of unique words up to this point.
-              // From 100 words and more, it decays, to e.g. 0.5 at 500 words and 0.3 at 1000 words.
-              $focus = min(1, .01 + 3.5 / (2 + count($results[0]) * .015));
+            // Fall-through
+            if (!isset($results[0][$word])) {
+              $results[0][$word] = 0;
             }
+            $results[0][$word] += $score * $focus;
+
+            // Focus is a decaying value in terms of the amount of unique words up to this point.
+            // From 100 words and more, it decays, to e.g. 0.5 at 500 words and 0.3 at 1000 words.
+            $focus = min(1, .01 + 3.5 / (2 + count($results[0]) * .015));
           }
           $tagwords++;
           // Too many words inside a single tag probably mean a tag was accidentally left open.
@@ -631,13 +636,59 @@ function search_index($sid, $type, $text
   }
   unset($results[0]);
 
-  // Now insert links to nodes
+  // Get all previous links from this item.
+  $result = db_query("SELECT nid, caption FROM {search_node_links} WHERE sid = %d AND type = '%s'", $sid, $type);
+  $links = array();
+  while ($link = db_fetch_object($result)) {
+    $links[$link->nid] = $link->caption;
+  }
+
+  // Now store links to nodes.
   foreach ($results as $nid => $words) {
-    foreach ($words as $word => $score) {
-      db_query("INSERT INTO {search_index} (word, sid, type, fromsid, fromtype, score) VALUES ('%s', %d, '%s', %d, '%s', %f)", $word, $nid, 'node', $sid, $type, $score);
-      search_dirty($word);
+    $caption = implode(' ', $words);
+    if (isset($links[$nid])) {
+      if ($links[$nid] != $caption) {
+        // Update the existing link and mark the node for reindexing.
+        db_query("UPDATE {search_node_links} SET caption = '%s' WHERE sid = %d AND type = '%s' AND nid = %d", $caption, $sid, $type, $nid);
+        search_touch_node($nid);
+      }
+      // Unset the link to mark it as processed.
+      unset($links[$nid]);
+    }
+    else {
+      // Insert the existing link and mark the node for reindexing.
+      db_query("INSERT INTO {search_node_links} (caption, sid, type, nid) VALUES ('%s', %d, '%s', %d)", $caption, $sid, $type, $nid);
+      search_touch_node($nid);
     }
   }
+  // Any left-over links in $links no longer exist. Delete them and mark the nodes for reindexing.
+  foreach ($links as $nid) {
+    db_query("DELETE FROM {search_node_links} WHERE sid = %d AND type = '%s' AND nid = %d", $sid, $type, $nid);
+    search_touch_node($nid);
+  }
+}
+
+/**
+ * Change a node's changed timestamp to now to force reindexing.
+ */
+function search_touch_node($nid) {
+  db_query("UPDATE {node} SET changed = %d WHERE nid = %d", time(), $nid);
+}
+
+/**
+ * Implementation of hook_nodeapi().
+ */
+function search_nodeapi(&$node, $op, $teaser = NULL, $page = NULL) {
+  switch ($op) {
+    // Transplant links to a node into the target node.
+    case 'update index':
+      $result = db_query("SELECT caption FROM {search_node_links} WHERE nid = %d", $node->nid);
+      $output = array();
+      while ($link = db_fetch_object($result)) {
+        $output[] = $link->caption;
+      }
+      return '<a>('. implode(', ', $output) .')</a>';
+  }
 }
 
 /**

=== modified file 'modules/search/search.schema'
--- modules/search/search.schema	2007-06-15 21:27:10 +0000
+++ modules/search/search.schema	2007-06-21 16:18:43 +0000
@@ -5,25 +5,22 @@ function search_schema() {
   $schema['search_dataset'] = array(
     'fields' => array(
       'sid'  => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
-      'type' => array('type' => 'varchar', 'length' => 16, 'not null' => FALSE),
+      'type' => array('type' => 'varchar', 'length' => 16, 'not null' => TRUE, 'default' => ''),
       'data' => array('type' => 'text', 'not null' => TRUE, 'size' => 'medium')
     ),
-    'indexes' => array('sid_type' => array('sid', 'type')),
+    'primary key' => array('sid', 'type'),
   );
 
   $schema['search_index'] = array(
     'fields' => array(
       'word'     => array('type' => 'varchar', 'length' => 50, 'not null' => TRUE, 'default' => ''),
       'sid'      => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
-      'type'     => array('type' => 'varchar', 'length' => 16, 'not null' => FALSE),
-      'fromsid'  => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
-      'fromtype' => array('type' => 'varchar', 'length' => 16, 'not null' => FALSE),
+      'type'     => array('type' => 'varchar', 'length' => 16, 'not null' => TRUE, 'default' => ''),
       'score'    => array('type' => 'float', 'not null' => FALSE)
     ),
+    'primary key' => array('sid', 'type', 'word'),
     'indexes' => array(
-      'from_sid_type' => array('fromsid', 'fromtype'),
-      'sid_type'      => array('sid', 'type'),
-      'word'          => array('word')
+      'type_word' => array('type', 'word')
     ),
   );
 
@@ -35,6 +32,19 @@ function search_schema() {
     'primary key' => array('word'),
   );
 
+  $schema['search_node_links'] = array(
+    'fields' => array(
+      'sid'      => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
+      'type'     => array('type' => 'varchar', 'length' => 16, 'not null' => TRUE, 'default' => ''),
+      'nid'      => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
+      'caption'    => array('type' => 'text', 'size' => 'big', 'not null' => FALSE)
+    ),
+    'primary key' => array('sid', 'type', 'nid'),
+    'indexes' => array(
+      'nid' => array('nid')
+    ),
+  );
+
   return $schema;
 }