git-help: add "help.format" config variable.

This config variable makes it possible to choose the default format
used to display help. This format will be used only if no option
like -a|--all|-i|--info|-m|--man|-w|--web is passed to "git-help".

The following values are possible for this variable:

	- "man"  --> "man" program is used
	- "info" --> "info" program is used
	- "web"  --> "git-browse-help" is used

By default we still show help using "man".

This patch also adds -m|--man command line option to use "man"
to allow overriding the "help.format" configuration variable.

Note that this patch also revert some recent changes in
"git-browse-help" because they prevented to look for config
variables in the global configuration file.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 62 insertions, 2 deletions

diff --git a/help.c b/help.c
index c96b1670f3..551b5b93b3 100644
--- a/help.c
+++ b/help.c
@@ -8,6 +8,44 @@
 #include "exec_cmd.h"
 #include "common-cmds.h"
 
+static const char *help_default_format;
+
+static enum help_format {
+	man_format,
+	info_format,
+	web_format,
+} help_format = man_format;
+
+static void parse_help_format(const char *format)
+{
+	if (!format) {
+		help_format = man_format;
+		return;
+	}
+	if (!strcmp(format, "man")) {
+		help_format = man_format;
+		return;
+	}
+	if (!strcmp(format, "info")) {
+		help_format = info_format;
+		return;
+	}
+	if (!strcmp(format, "web") || !strcmp(format, "html")) {
+		help_format = web_format;
+		return;
+	}
+	die("unrecognized help format '%s'", format);
+}
+
+static int git_help_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "help.format")) {
+		help_default_format = xstrdup(value);
+		return 0;
+	}
+	return git_default_config(var, value);
+}
+
 /* most GUI terminals set COLUMNS (although some don't export it) */
 static int term_columns(void)
 {
@@ -331,8 +369,30 @@ int cmd_help(int argc, const char **argv, const char *prefix)
 		show_info_page(argc > 2 ? argv[2] : NULL);
 	}
 
-	else
-		show_man_page(help_cmd);
+	else if (!strcmp(help_cmd, "--man") || !strcmp(help_cmd, "-m")) {
+		show_man_page(argc > 2 ? argv[2] : NULL);
+	}
+
+	else {
+		int nongit;
+
+		setup_git_directory_gently(&nongit);
+		git_config(git_help_config);
+		if (help_default_format)
+			parse_help_format(help_default_format);
+
+		switch (help_format) {
+		case man_format:
+			show_man_page(help_cmd);
+			break;
+		case info_format:
+			show_info_page(help_cmd);
+			break;
+		case web_format:
+			show_html_page(help_cmd);
+			break;
+		}
+	}
 
 	return 0;
 }