ui-commit: add support for 'commit-filter' option

This new option specifies a filter which is executed on the commit
message, i.e. the commit message is written to the filters STDIN and
the filters STDOUT is included verbatim as the commit message.

This can be used to implement commit linking by creating a simple
shell script in e.g. /usr/bin/cgit-commit-filter.sh like this:

#/bin/sh
sed -re 's|\b([0-9a-fA-F]{6,40})\b|<a href="./?id=\1">\1</a>|g'

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgit.c

@@ -90,6 +90,8 @@ void config_cb(const char *name, const char *value)
 		ctx.cfg.cache_static_ttl = atoi(value);
 	else if (!strcmp(name, "cache-dynamic-ttl"))
 		ctx.cfg.cache_dynamic_ttl = atoi(value);
+	else if (!strcmp(name, "commit-filter"))
+		ctx.cfg.commit_filter = new_filter(value, 0);
 	else if (!strcmp(name, "embedded"))
 		ctx.cfg.embedded = atoi(value);
 	else if (!strcmp(name, "max-message-length"))

cgit.h

@@ -183,6 +183,7 @@ struct cgit_config {
 	int summary_branches;
 	int summary_log;
 	int summary_tags;
+	struct cgit_filter *commit_filter;
 	struct cgit_filter *source_filter;
 };
 

cgitrc.5.txt

@@ -55,6 +55,12 @@ clone-prefix::
 	setting is only used if `repo.clone-url` is unspecified. Default value:
 	none.
 
+commit-filter::
+	Specifies a command which will be invoked to format commit messages.
+	The command will get the message on its STDIN, and the STDOUT from the
+	command will be included verbatim as the commit message, i.e. this can
+	be used to implement bugtracker integration. Default value: none.
+
 css::
 	Url which specifies the css document to include in all cgit pages.
 	Default value: "/cgit.css".

ui-commit.c

@@ -89,11 +89,19 @@ void cgit_print_commit(char *hex)
 	}
 	html("</table>\n");
 	html("<div class='commit-subject'>");
+	if (ctx.cfg.commit_filter)
+		cgit_open_filter(ctx.cfg.commit_filter);
 	html_txt(info->subject);
+	if (ctx.cfg.commit_filter)
+		cgit_close_filter(ctx.cfg.commit_filter);
 	show_commit_decorations(commit);
 	html("</div>");
 	html("<div class='commit-msg'>");
+	if (ctx.cfg.commit_filter)
+		cgit_open_filter(ctx.cfg.commit_filter);
 	html_txt(info->msg);
+	if (ctx.cfg.commit_filter)
+		cgit_close_filter(ctx.cfg.commit_filter);
 	html("</div>");
 	if (parents < 3) {
 		if (parents)