Index: modules/taxonomy/taxonomy.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/taxonomy/taxonomy.module,v
retrieving revision 1.316
diff -u -r1.316 taxonomy.module
--- modules/taxonomy/taxonomy.module	11 Sep 2006 08:18:24 -0000	1.316
+++ modules/taxonomy/taxonomy.module	14 Sep 2006 10:01:19 -0000
@@ -611,18 +611,7 @@
 function taxonomy_form_alter($form_id, &$form) {
   if (isset($form['type']) && $form['type']['#value'] .'_node_form' == $form_id) {
     $node = $form['#node'];
-
-    if (!isset($node->taxonomy)) {
-      if ($node->nid) {
-        $terms = taxonomy_node_get_terms($node->nid);
-      }
-      else {
-        $terms = array();
-      }
-    }
-    else {
-      $terms = $node->taxonomy;
-    }
+    $terms = isset($node->taxonomy) ? $node->taxonomy : array();
 
     $c = db_query(db_rewrite_sql("SELECT v.* FROM {vocabulary} v INNER JOIN {vocabulary_node_types} n ON v.vid = n.vid WHERE n.type = '%s' ORDER BY v.weight, v.name", 'v', 'vid'), $node->type);
 
@@ -706,17 +695,26 @@
 /**
  * Find all terms associated to the given node, ordered by vocabulary and term weight.
  */
-function taxonomy_node_get_terms($nid, $key = 'tid') {
+function taxonomy_node_get_terms(&$node, $key = 'tid') {
   static $terms;
 
-  if (!isset($terms[$nid])) {
-    $result = db_query(db_rewrite_sql('SELECT t.* FROM {term_node} r INNER JOIN {term_data} t ON r.tid = t.tid INNER JOIN {vocabulary} v ON t.vid = v.vid WHERE r.nid = %d ORDER BY v.weight, t.weight, t.name', 't', 'tid'), $nid);
-    $terms[$nid] = array();
-    while ($term = db_fetch_object($result)) {
-      $terms[$nid][$term->$key] = $term;
+  if (!isset($terms[$node->nid])) {
+    $vocabularies = taxonomy_get_vocabularies($node->type);
+    if (count($vocabularies)) {
+      $placeholder = array_fill(0, count($vocabularies), '%d');
+      $args = array_keys($vocabularies);
+      $args[] = $node->nid;
+      $result = db_query(db_rewrite_sql('SELECT t.* FROM {term_node} r INNER JOIN {term_data} t ON r.tid = t.tid INNER JOIN {vocabulary} v ON t.vid = v.vid AND v.vid IN ('. implode(',', $placeholder) .') WHERE r.nid = %d ORDER BY v.weight, t.weight, t.name', 't', 'tid'), $args);
+      $terms[$node->nid] = array();
+      while ($term = db_fetch_object($result)) {
+        $terms[$node->nid][$term->$key] = $term;
+      }
+    }
+    else {
+      $terms[$node->nid] = array();
     }
   }
-  return $terms[$nid];
+  return $terms[$node->nid];
 }
 
 /**
@@ -741,8 +739,11 @@
 /**
  * Save term associations for a given node.
  */
-function taxonomy_node_save($nid, $terms) {
-  taxonomy_node_delete($nid);
+function taxonomy_node_save($nid, $terms, $old_terms = FALSE) {
+  if ($old_terms === FALSE) {
+    $node = node_load($nid);
+    $old_terms = $node->taxonomy;
+  }
 
   // Free tagging vocabularies do not send their tids in the form,
   // so we'll detect them here and process them independently.
@@ -784,7 +785,7 @@
 
         // Defend against duplicate, different cased tags
         if (!isset($inserted[$typed_term_tid])) {
-          db_query('INSERT INTO {term_node} (nid, tid) VALUES (%d, %d)', $nid, $typed_term_tid);
+          _taxonomy_node_insert_tid($nid, $typed_term_tid, $old_terms);
           $inserted[$typed_term_tid] = TRUE;
         }
       }
@@ -796,18 +797,37 @@
       if (is_array($term)) {
         foreach ($term as $tid) {
           if ($tid) {
-            db_query('INSERT INTO {term_node} (nid, tid) VALUES (%d, %d)', $nid, $tid);
+            _taxonomy_node_insert_tid($nid, $tid, $old_terms);
           }
         }
       }
       else if (is_object($term)) {
-        db_query('INSERT INTO {term_node} (nid, tid) VALUES (%d, %d)', $nid, $term->tid);
+        _taxonomy_node_insert_tid($nid, $term->tid, $old_terms);
       }
       else if ($term) {
-        db_query('INSERT INTO {term_node} (nid, tid) VALUES (%d, %d)', $nid, $term);
+        _taxonomy_node_insert_tid($nid, $term, $old_terms);
       }
     }
   }
+  //delete removed terms
+  if (!empty($old_terms)) {
+    $placeholder = array_fill(0, count($old_terms), '%d');
+    $args = array($nid);
+    $args = array_merge($args, array_keys($old_terms));
+    db_query('DELETE FROM {term_node} WHERE nid = %d AND tid IN ('. implode(',', $placeholder) .')', $args);    
+  }
+}
+
+/*
+ * Helper function for taxonomy_node_save()
+ */
+function _taxonomy_node_insert_tid($nid, $tid, &$old_terms) {
+  if (!array_key_exists($tid, $old_terms)) {
+    db_query('INSERT INTO {term_node} (nid, tid) VALUES (%d, %d)', $nid, $tid);
+  }
+  else {
+    unset($old_terms[$tid]);
+  }
 }
 
 /**
@@ -1173,13 +1193,15 @@
 function taxonomy_nodeapi($node, $op, $arg = 0) {
   switch ($op) {
     case 'load':
-     $output['taxonomy'] = taxonomy_node_get_terms($node->nid);
+     $output['taxonomy'] = taxonomy_node_get_terms($node);
      return $output;
     case 'insert':
-      taxonomy_node_save($node->nid, $node->taxonomy);
+      taxonomy_node_save($node->nid, $node->taxonomy, array());
       break;
-    case 'update':
-      taxonomy_node_save($node->nid, $node->taxonomy);
+    case 'submit':
+      if ($node->nid) {
+        taxonomy_node_save($node->nid, $node->taxonomy);
+      }
       break;
     case 'delete':
       taxonomy_node_delete($node->nid);