Merge branch 'jn/gitweb-per-request-config'

* jn/gitweb-per-request-config:
  gitweb: document $per_request_config better
  gitweb: selectable configurations that change with each request

gitweb/README

@@ -177,13 +177,15 @@ not include variables usually directly set during build):
  * $my_url, $my_uri
    Full URL and absolute URL of gitweb script;
    in earlier versions of gitweb you might have need to set those
-   variables, now there should be no need to do it.
+   variables, now there should be no need to do it.  See
+   $per_request_config if you need to set them still.
  * $base_url
    Base URL for relative URLs in pages generated by gitweb,
    (e.g. $logo, $favicon, @stylesheets if they are relative URLs),
    needed and used only for URLs with nonempty PATH_INFO via
    <base href="$base_url">.  Usually gitweb sets its value correctly,
    and there is no need to set this variable, e.g. to $my_uri or "/".
+   See $per_request_config if you need to set it anyway.
  * $home_link
    Target of the home link on top of all pages (the first part of view
    "breadcrumbs").  By default set to absolute URI of a page ($my_uri).
@@ -246,6 +248,16 @@ not include variables usually directly set during build):
    http://www.andre-simon.de due to assumptions about parameters and output).
    Useful if highlight is not installed on your webserver's PATH.
    [Default: highlight]
+ * $per_request_config
+   If set to code reference, it would be run once per each request.  You can
+   set parts of configuration that change per session, e.g. by setting it to
+     sub { $ENV{GL_USER} = $cgi->remote_user || "gitweb"; }
+   Otherwise it is treated as boolean value: if true gitweb would process
+   config file once per request, if false it would process config file only
+   once.  Note: $my_url, $my_uri, and $base_url are overwritten with
+   their default values before every request, so if you want to change
+   them, be sure to set this variable to true or a code reference effecting
+   the desired changes.  The default is true.
 
 Projects list file format
 ~~~~~~~~~~~~~~~~~~~~~~~~~

gitweb/gitweb.perl

@@ -611,6 +611,14 @@ sub filter_snapshot_fmts {
 		!$known_snapshot_formats{$_}{'disabled'}} @fmts;
 }
 
+# If it is set to code reference, it is code that it is to be run once per
+# request, allowing updating configurations that change with each request,
+# while running other code in config file only once.
+#
+# Otherwise, if it is false then gitweb would process config file only once;
+# if it is true then gitweb config would be run for each request.
+our $per_request_config = 1;
+
 our ($GITWEB_CONFIG, $GITWEB_CONFIG_SYSTEM);
 sub evaluate_gitweb_config {
 	our $GITWEB_CONFIG = $ENV{'GITWEB_CONFIG'} || "++GITWEB_CONFIG++";
@@ -1081,12 +1089,22 @@ sub reset_timer {
 	our $number_of_git_cmds = 0;
 }
 
+our $first_request = 1;
 sub run_request {
 	reset_timer();
 
 	evaluate_uri();
+	if ($first_request) {
 		evaluate_gitweb_config();
 		evaluate_git_version();
+	}
+	if ($per_request_config) {
+		if (ref($per_request_config) eq 'CODE') {
+			$per_request_config->();
+		} elsif (!$first_request) {
+			evaluate_gitweb_config();
+		}
+	}
 	check_loadavg();
 
 	# $projectroot and $projects_list might be set in gitweb config file
@@ -1140,6 +1158,7 @@ sub evaluate_argv {
 sub run {
 	evaluate_argv();
 
+	$first_request = 1;
 	$pre_listen_hook->()
 		if $pre_listen_hook;
 
@@ -1152,6 +1171,7 @@ sub run {
 
 		$post_dispatch_hook->()
 			if $post_dispatch_hook;
+		$first_request = 0;
 
 		last REQUEST if ($is_last_request->());
 	}