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>

Documentation/git-help.txt

@@ -7,7 +7,7 @@ git-help - display help information about git
 
 SYNOPSIS
 --------
-'git help' [-a|--all|-i|--info|-w|--web] [COMMAND]
+'git help' [-a|--all|-i|--info|-m|--man|-w|--web] [COMMAND]
 
 DESCRIPTION
 -----------
@@ -21,7 +21,7 @@ printed on the standard output.
 
 If a git command is named, a manual page for that command is brought
 up. The 'man' program is used by default for this purpose, but this
-can be overriden by other options.
+can be overriden by other options or configuration variables.
 
 Note that 'git --help ...' is identical as 'git help ...' because the
 former is internally converted into the latter.
@@ -36,6 +36,11 @@ OPTIONS
 	Use the 'info' program to display the manual page, instead of
 	the 'man' program that is used by default.
 
+-m|--man::
+	Use the 'man' program to display the manual page. This may be
+	used to override a value set in the 'help.format'
+	configuration variable.
+
 -w|--web::
 	Use a web browser to display the HTML manual page, instead of
 	the 'man' program that is used by default.
@@ -54,6 +59,34 @@ is available in PATH.
 Note that the script tries, as much as possible, to display the HTML
 page in a new tab on an already opened browser.
 
+CONFIGURATION VARIABLES
+-----------------------
+
+If no command line option is passed, the 'help.format' configuration
+variable will be checked. The following values are supported for this
+variable; they make 'git-help' behave as their corresponding command
+line option:
+
+* "man" corresponds to '-m|--man',
+* "info" corresponds to '-i|--info',
+* "web" or "html" correspond to '-w|--web',
+
+The 'help.browser', 'web.browser' and 'browser.<tool>.path' will also
+be checked if the 'web' format is choosen (either by command line
+option or configuration variable). See '-w|--web' in the OPTIONS
+section above.
+
+Note that these configuration variables should probably be set using
+the '--global' flag, for example like this:
+
+------------------------------------------------
+$ git config --global help.format web
+$ git config --global web.browser firefox
+------------------------------------------------
+
+as they are probably more user specific than repository specific.
+See gitlink:git-config[1] for more information about this.
+
 Author
 ------
 Written by Junio C Hamano <gitster@pobox.com> and the git-list

git-browse-help.sh

@@ -39,7 +39,7 @@ valid_tool() {
 }
 
 init_browser_path() {
-	test -z "$GIT_DIR" || browser_path=`git config browser.$1.path`
+	browser_path=`git config browser.$1.path`
 	test -z "$browser_path" && browser_path=$1
 }
 
@@ -71,7 +71,7 @@ do
     shift
 done
 
-if test -z "$browser" && test -n "$GIT_DIR"
+if test -z "$browser"
 then
     for opt in "help.browser" "web.browser"
     do

git-sh-setup.sh

@@ -124,13 +124,8 @@ get_author_ident_from_commit () {
 
 # Make sure we are in a valid repository of a vintage we understand,
 # if we require to be in a git repository.
-if test -n "$NONGIT_OK"
+if test -z "$NONGIT_OK"
 then
-	if git rev-parse --git-dir >/dev/null 2>&1
-	then
-		: ${GIT_DIR=.git}
-	fi
-else
 	if [ -z "$SUBDIRECTORY_OK" ]
 	then
 		: ${GIT_DIR=.git}

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;
 }