[PATCHv2 1/5] gitweb: Add optional "time to generate page" info in footer

[Jakub Narebski <jnareb@gmail.com>]

Add "This page took XXX seconds and Y git commands to generate"
to page footer, if global feature 'timed' is enabled (disabled
by default).  Requires Time::HiRes installed for high precision
'wallclock' time.

Note that Time::HiRes is being required unconditionally of 'timed'
feature, because setting $t0 variable should be fairly early to have
running time of the whole script.  If Time::HiRes module was required
only if 'timed' feature is enabled, the earliest place where starting
time ($t0) could be calculated would be after reading gitweb config,
making "time to generate page" info inaccurate.

This code is based on example code by Petr 'Pasky' Baudis.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
This version adds custom formatting for "time to generate page"
information in the page footer, instead of reusing 'page_footer'
style.  It is now clearly separated from the gitweb footer proper.

While at it the ids were changed from "generate_info" etc. to
"generating_info" etc.

There is still a question whether Time::HiRes should be require'd
unconditionally, but otherwise this patch is out of RFC stage.


Sidenote: I have noticed that gitweb's CSS rules are unnecessary
strict, making rendering slower because of extra non needed checks
(the rule is that selectors should be as simple as possible).

 gitweb/gitweb.css  |    7 +++++++
 gitweb/gitweb.perl |   29 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/gitweb/gitweb.css b/gitweb/gitweb.css
index b59fcaf..00e2e4c 100644
--- a/gitweb/gitweb.css
+++ b/gitweb/gitweb.css
@@ -75,6 +75,13 @@ div.page_footer_text {
 	font-style: italic;
 }
 
+div#generating_info {
+	margin: 4px;
+	font-size: smaller;
+	text-align: center;
+	color: #505050;
+}
+
 div.page_body {
 	padding: 8px;
 	font-family: monospace;
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index ff2d42a..08d410d 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -18,6 +18,12 @@ use File::Find qw();
 use File::Basename qw(basename);
 binmode STDOUT, ':utf8';
 
+our $t0;
+if (eval { require Time::HiRes; 1; }) {
+	$t0 = [Time::HiRes::gettimeofday()];
+}
+our $number_of_git_cmds = 0;
+
 BEGIN {
 	CGI->compile() if $ENV{'MOD_PERL'};
 }
@@ -404,6 +410,13 @@ our %feature = (
 		'sub' => \&feature_avatar,
 		'override' => 0,
 		'default' => ['']},
+
+	# Enable displaying how much time and how many git commands
+	# it took to generate and display page.  Disabled by default.
+	# Project specific override is not supported.
+	'timed' => {
+		'override' => 0,
+		'default' => [0]},
 );
 
 sub gitweb_get_feature {
@@ -518,6 +531,7 @@ if (-e $GITWEB_CONFIG) {
 
 # version of the core git binary
 our $git_version = qx("$GIT" --version) =~ m/git version (.*)$/ ? $1 : "unknown";
+$number_of_git_cmds++;
 
 $projects_list ||= $projectroot;
 
@@ -1969,6 +1983,7 @@ sub get_feed_info {
 
 # returns path to the core git executable and the --git-dir parameter as list
 sub git_cmd {
+	$number_of_git_cmds++;
 	return $GIT, '--git-dir='.$git_dir;
 }
 
@@ -3218,6 +3233,20 @@ sub git_footer_html {
 	}
 	print "</div>\n"; # class="page_footer"
 
+	if (defined $t0 && gitweb_check_feature('timed')) {
+		print "<div id=\"generating_info\">\n";
+		print 'This page took '.
+		      '<span id="generating_time" class="time_span">'.
+		      Time::HiRes::tv_interval($t0, [Time::HiRes::gettimeofday()]).
+		      ' seconds </span>'.
+		      ' and '.
+		      '<span id="generating_cmd">'.
+		      $number_of_git_cmds.
+		      '</span> git commands '.
+		      " to generate.\n";
+		print "</div>\n"; # class="page_footer"
+	}
+
 	if (-f $site_footer) {
 		insert_file($site_footer);
 	}
-- 
1.6.3.3