On Fri, Sep 23, 2016, at 03:15 PM, Jakub Narębski wrote:

W dniu 23.09.2016 o 11:08, Ian Kelling napisał:

quoted

The "highlight" binary can, in some cases, determine the language type
by the means of file contents, for example the shebang in the first line
for some scripting languages.  Make use of this autodetection for files
which syntax is not known by gitweb.  In that case, pass the blob
contents to "highlight --force"; the parameter is needed to make it
always generate HTML output (which includes HTML-escaping).

Right.

quoted

Although we now run highlight on files which do not end up highlighted,
performance is virtually unaffected because when we call highlight, we
also call sanitize() instead of esc_html(), which is significantly
slower.

This paragraph is a bit unclear, for example it is not obvious what
"..., which is significantly slower" refers to: sanitize() or esc_html().

I think it would be better to write:

  Although we now run highlight on files which do not end up highlighted,
  performance is virtually unaffected because when we call highlight, it
  is used for escaping HTML.  In the case that highlight is used, gitweb
  calls sanitize() instead of esc_html(), and the latter is significantly
  slower (it does more, being roughly a superset of sanitize()).

Agree. Done in v4.

quoted

       After curling blob view of unhighlighted large and small text
files of perl code and license text 100 times each on a local
Apache/2.4.23 (Debian) instance, it's logs indicate +-1% difference in
request time for all file types.

Also, "curling" is not the word I would like to see. I would say:

  Simple benchmark comparing performance of 'blob' view of files without
  syntax highlighting in gitweb before and after this change indicates
  ±1% difference in request time for all file types.  Benchmark was
  performed on local instance on Debian, using Apache/2.4.23 web server
  and CGI/PSGI/FCGI/mod_perl.

      ^^^^^^^^^^^^^^^^^^^^^^--- select one

Or something like that; I'm not sure how detailed this should be.
But it is nice to have such benchmark in the commit message.

Sounds  good. Used it in v4.

Anyway I think that adding yet another configuration toggle for selecting
whether to use "highlight" syntax autodetection or not would be just an
unnecessary complication.

Note that the performance loss might be quite higher on MS Windows, with
its higher cost of fork.  But then they probably do not configure
server-side highligher anyway.

quoted

Document the feature and improve syntax highlight documentation, add
test to ensure gitweb doesn't crash when language detection is used.

Good.

quoted

Signed-off-by: Ian Kelling <redacted>
---
 Documentation/gitweb.conf.txt          | 21 ++++++++++++++-------
 gitweb/gitweb.perl                     | 10 +++++-----
 t/t9500-gitweb-standalone-no-errors.sh |  8 ++++++++
 3 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/Documentation/gitweb.conf.txt b/Documentation/gitweb.conf.txt
index a79e350..e632089 100644
--- a/Documentation/gitweb.conf.txt
+++ b/Documentation/gitweb.conf.txt

@@ -246,13 +246,20 @@ $highlight_bin::

We should probably say what does it mean to be "highlight"[1] compatible,
but it is outside of scope for this patch, and I think also out of scope
of this series.

quoted

 	Note that 'highlight' feature must be set for gitweb to actually
 	use syntax highlighting.
 +
-*NOTE*: if you want to add support for new file type (supported by
-"highlight" but not used by gitweb), you need to modify `%highlight_ext`
-or `%highlight_basename`, depending on whether you detect type of file
-based on extension (for example "sh") or on its basename (for example
-"Makefile").  The keys of these hashes are extension and basename,
-respectively, and value for given key is name of syntax to be passed via
-`--syntax <syntax>` to highlighter.
+*NOTE*: for a file to be highlighted, its syntax type must be detected
+and that syntax must be supported by "highlight".  The default syntax
+detection is minimal, and there are many supported syntax types with no
+detection by default.  There are three options for adding syntax
+detection.  The first and second priority are `%highlight_basename` and
+`%highlight_ext`, which detect based on basename (the full filename, for
+example "Makefile") and extension (for example "sh").  The keys of these
+hashes are the basename and extension, respectively, and the value for a
+given key is the name of the syntax to be passed via `--syntax <syntax>`
+to "highlight".  The last priority is the "highlight" configuration of
+`Shebang` regular expressions to detect the language based on the first
+line in the file, (for example, matching the line "#!/bin/bash").  See
+the highlight documentation and the default config at
+/etc/highlight/filetypes.conf for more details.

All right. I guess /etc/highlight/filetypes.conf is the standard
location?

I think so. I checked packages from homebrew, fedora, suse, debian to
confirm.

quoted

 +
 For example if repositories you are hosting use "phtml" extension for
 PHP files, and you want to have correct syntax-highlighting for those

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 6cb4280..44094f4 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl

@@ -3931,15 +3931,16 @@ sub guess_file_syntax {
 # or return original FD if no highlighting
 sub run_highlighter {
 	my ($fd, $highlight, $syntax) = @_;
-	return $fd unless ($highlight && defined $syntax);
+	return $fd unless ($highlight);

 	close $fd;
+	my $syntax_arg = (defined $syntax) ? "--syntax $syntax" : "--force";
 	open $fd, quote_command(git_cmd(), "cat-file", "blob", $hash)." | ".
 	          quote_command($^X, '-CO', '-MEncode=decode,FB_DEFAULT', '-pse',
 	            '$_ = decode($fe, $_, FB_DEFAULT) if !utf8::decode($_);',
 	            '--', "-fe=$fallback_encoding")." | ".
 	          quote_command($highlight_bin).
-	          " --replace-tabs=8 --fragment --syntax $syntax |"
+	          " --replace-tabs=8 --fragment $syntax_arg |"
 		or die_error(500, "Couldn't open file or run syntax highlighter");
 	return $fd;
 }

All right, nice and understandable.

quoted

@@ -7063,8 +7064,7 @@ sub git_blob {

 	my $highlight = gitweb_check_feature('highlight');
 	my $syntax = guess_file_syntax($highlight, $file_name);
-	$fd = run_highlighter($fd, $highlight, $syntax)
-		if $syntax;
+	$fd = run_highlighter($fd, $highlight, $syntax);

 	git_header_html(undef, $expires);
 	my $formats_nav = '';

Good, run unconditionally.

quoted

@@ -7117,7 +7117,7 @@ sub git_blob {
 			$line = untabify($line);
 			printf qq!<div class="pre"><a id="l%i" href="%s#l%i" class="linenr">%4i</a> %s</div>\n!,
 			       $nr, esc_attr(href(-replay => 1)), $nr, $nr,
-			       $syntax ? sanitize($line) : esc_html($line, -nbsp=>1);
+			       $highlight ? sanitize($line) : esc_html($line, -nbsp=>1);
 		}

Good, use highlighter if possible, not only if syntax is known
and highlighter is turned on.

Nice and easy to understand after earlier change.

quoted

 	}
 	close $fd

diff --git a/t/t9500-gitweb-standalone-no-errors.sh b/t/t9500-gitweb-standalone-no-errors.sh
index e94b2f1..6d06ed9 100755
--- a/t/t9500-gitweb-standalone-no-errors.sh
+++ b/t/t9500-gitweb-standalone-no-errors.sh

@@ -709,6 +709,14 @@ test_expect_success HIGHLIGHT \
 	 git commit -m "Add test.sh" &&
 	 gitweb_run "p=.git;a=blob;f=test.sh"'

+test_expect_success HIGHLIGHT \
+	'syntax highlighting (highlighter language autodetection)' \
+	'git config gitweb.highlight yes &&
+	 echo "#!/usr/bin/perl" > test &&
+	 git add test &&
+	 git commit -m "Add test" &&
+	 gitweb_run "p=.git;a=blob;f=test"'

Nice.

quoted

+
 # ----------------------------------------------------------------------
 # forks of projects

Thanks for great  suggestions.