diff --git a/codepot/src/codepot/controllers/code.php b/codepot/src/codepot/controllers/code.php
index 19945d7c..a997c1d5 100644
--- a/codepot/src/codepot/controllers/code.php
+++ b/codepot/src/codepot/controllers/code.php
@@ -557,6 +557,50 @@ class Code extends Controller
 		print $status;
 	}
 
+	function xhr_gettagrev ($projectid = '', $tag = '')
+	{
+		$this->load->model ('ProjectModel', 'projects');
+		$this->load->model ('SubversionModel', 'subversion');
+
+		$login = $this->login->getUser ();
+
+		$project = $this->projects->get ($projectid);
+		if ($project === FALSE)
+		{
+			$status = "error - failed to get the project {$projectid}";
+		}
+		else if ($project === NULL)
+		{
+			$status = "error - no such project {$projectid}";
+		}
+		else
+		{
+			if ($project->public !== 'Y' && $login['id'] == '')
+			{
+				// non-public projects require sign-in.
+				redirect ("main/signin/" . $this->converter->AsciiTohex(current_url()));
+			}
+
+			$tag = $this->converter->HexToAscii ($tag);
+
+			$rev = $this->subversion->findRevWithRevProp ($projectid, CODEPOT_SVN_TAG_PROPERTY, $tag);
+			if ($rev === FALSE)
+			{
+				$status = 'repoerr - ' . $this->subversion->getErrorMessage();
+			}
+			else if ($rev <= -1)
+			{
+				$status = 'noent';
+			}
+			else
+			{
+				$status = 'ok - ' . $rev;
+			}
+		}
+
+		print $status;
+	}
+
 	function enjson_save ($projectid = '', $path = '')
 	{
 		$this->load->model ('ProjectModel', 'projects');
@@ -1574,5 +1618,4 @@ class Code extends Controller
 			$this->graph->createGraph();
 		}
 	}
-
 }
diff --git a/codepot/src/codepot/models/subversionmodel.php b/codepot/src/codepot/models/subversionmodel.php
index a29749b2..51d05ded 100644
--- a/codepot/src/codepot/models/subversionmodel.php
+++ b/codepot/src/codepot/models/subversionmodel.php
@@ -1260,6 +1260,56 @@ class SubversionModel extends Model
 		return $result;
 	}
 
+	function mapRevPropToRev ($projectid, $revprop_name)
+	{
+		$url = 'file://'.$this->_canonical_path(CODEPOT_SVNREPO_DIR."/{$projectid}");
+
+		set_error_handler (array ($this, 'capture_error'));
+		$info = @svn_info ($url, FALSE);
+		restore_error_handler ();
+		if ($info == FALSE || count($info) != 1) return FALSE;
+
+		$props = array ();
+		$xi = $info[0];
+		for ($rev = $xi['revision']; $rev > 0; $rev--)
+		{
+			set_error_handler (array ($this, 'capture_error'));
+			$val = @svn_revprop_get ($url, $rev, $revprop_name);
+			restore_error_handler ();
+			if ($val != '')
+			{
+				$props[$val] = $rev;
+			}
+		}
+
+		return $props;
+	}
+
+	function findRevWithRevProp ($projectid, $revprop_name, $revprop_value)
+	{
+		$url = 'file://'.$this->_canonical_path(CODEPOT_SVNREPO_DIR."/{$projectid}");
+
+		set_error_handler (array ($this, 'capture_error'));
+		$info = @svn_info ($url, FALSE);
+		restore_error_handler ();
+		if ($info == FALSE || count($info) != 1) return FALSE;
+
+		$xi = $info[0];
+		for ($rev = $xi['revision']; $rev > 0; $rev--)
+		{
+			set_error_handler (array ($this, 'capture_error'));
+			$val = @svn_revprop_get ($url, $rev, $revprop_name);
+			restore_error_handler ();
+			if ($val != '' && $revprop_value == $val)
+			{
+				return $rev;
+			}
+		}
+
+		return -1;
+	}
+
+
 	function listProps ($projectid, $path, $rev)
 	{
 		$orgurl = 'file://'.$this->_canonical_path(CODEPOT_SVNREPO_DIR."/{$projectid}/{$path}");