git-help: add -w|--web option to display html man page in a browser.

Now when using "git help -w cmd", we will try to show the HTML man
page "git-cmd.html" in your prefered web browser.

To do that "help.c" code will call a new shell script
"git-browse-help".

This currently works only if the HTML versions of the man page
have been installed in $(htmldir) (typically "/usr/share/doc/git-doc"),
so new target to do that is added to "Documentation/Makefile".

The browser to use can be configured using the "web.browser"
config variable.

We try to open a new tab in an existing web browser, if possible.

The code in "git-browse-help" is heavily stolen from "git-mergetool"
by Theodore Y. Ts'o. Thanks.

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

4 files changed, 171 insertions, 17 deletions

diff --git a/Documentation/Makefile b/Documentation/Makefile
index de11ee0192..f0df0b0d28 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -29,6 +29,7 @@ DOC_MAN7=$(patsubst %.txt,%.7,$(MAN7_TXT))
 
 prefix?=$(HOME)
 bindir?=$(prefix)/bin
+htmldir?=$(prefix)/share/doc/git-doc
 mandir?=$(prefix)/share/man
 man1dir=$(mandir)/man1
 man5dir=$(mandir)/man5
@@ -95,6 +96,9 @@ install-info: info
 	  echo "No directory found in $(DESTDIR)$(infodir)" >&2 ; \
 	fi
 
+install-html: html
+	sh ./install-webdoc.sh $(DESTDIR)$(htmldir)
+
 ../GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
 	$(MAKE) -C ../ GIT-VERSION-FILE
 
diff --git a/Makefile b/Makefile
index 4b418bf76e..932b0d4346 100644
--- a/Makefile
+++ b/Makefile
@@ -157,6 +157,7 @@ bindir = $(prefix)/bin
 gitexecdir = $(bindir)
 sharedir = $(prefix)/share
 template_dir = $(sharedir)/git-core/templates
+htmldir=$(sharedir)/doc/git-doc
 ifeq ($(prefix),/usr)
 sysconfdir = /etc
 else
@@ -183,7 +184,7 @@ GITWEB_FAVICON = git-favicon.png
 GITWEB_SITE_HEADER =
 GITWEB_SITE_FOOTER =
 
-export prefix bindir gitexecdir sharedir template_dir sysconfdir
+export prefix bindir gitexecdir sharedir template_dir htmldir sysconfdir
 
 CC = gcc
 AR = ar
@@ -223,7 +224,8 @@ SCRIPT_SH = \
 	git-merge-resolve.sh \
 	git-lost-found.sh git-quiltimport.sh git-submodule.sh \
 	git-filter-branch.sh \
-	git-stash.sh
+	git-stash.sh \
+	git-browse-help.sh
 
 SCRIPT_PERL = \
 	git-add--interactive.perl \
@@ -745,6 +747,7 @@ DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
 bindir_SQ = $(subst ','\'',$(bindir))
 gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
 template_dir_SQ = $(subst ','\'',$(template_dir))
+htmldir_SQ = $(subst ','\'',$(htmldir))
 prefix_SQ = $(subst ','\'',$(prefix))
 
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
@@ -808,6 +811,7 @@ $(patsubst %.sh,%,$(SCRIPT_SH)) : % : %.sh
 	    -e 's|@@PERL@@|$(PERL_PATH_SQ)|g' \
 	    -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
 	    -e 's/@@NO_CURL@@/$(NO_CURL)/g' \
+	    -e 's|@@HTMLDIR@@|$(htmldir_SQ)|g' \
 	    $@.sh >$@+ && \
 	chmod +x $@+ && \
 	mv $@+ $@
diff --git a/git-browse-help.sh b/git-browse-help.sh
new file mode 100755
index 0000000000..76eff01bab
--- /dev/null
+++ b/git-browse-help.sh
@@ -0,0 +1,142 @@
+#!/bin/sh
+#
+# This program launch a web browser on the html page
+# describing a git command.
+#
+# Copyright (c) 2007 Christian Couder
+# Copyright (c) 2006 Theodore Y. Ts'o
+#
+# This file is heavily stolen from git-mergetool.sh, by
+# Theodore Y. Ts'o (thanks) that is:
+#
+# Copyright (c) 2006 Theodore Y. Ts'o
+#
+# This file is licensed under the GPL v2, or a later version
+# at the discretion of Junio C Hamano or any other official
+# git maintainer.
+#
+
+USAGE='[--browser=browser|--tool=browser] [cmd to display] ...'
+SUBDIRECTORY_OK=Yes
+OPTIONS_SPEC=
+. git-sh-setup
+
+# Install data.
+html_dir="@@HTMLDIR@@"
+
+test -f "$html_dir/git.html" || die "No documentation directory found."
+
+valid_tool() {
+	case "$1" in
+		firefox | iceweasel | konqueror | w3m | links | lynx | dillo)
+			;; # happy
+		*)
+			return 1
+			;;
+	esac
+}
+
+init_browser_path() {
+	browser_path=`git config browser.$1.path`
+	test -z "$browser_path" && browser_path=$1
+}
+
+while test $# != 0
+do
+    case "$1" in
+	-b|--browser*|-t|--tool*)
+	    case "$#,$1" in
+		*,*=*)
+		    browser=`expr "z$1" : 'z-[^=]*=\(.*\)'`
+		    ;;
+		1,*)
+		    usage ;;
+		*)
+		    browser="$2"
+		    shift ;;
+	    esac
+	    ;;
+	--)
+	    break
+	    ;;
+	-*)
+	    usage
+	    ;;
+	*)
+	    break
+	    ;;
+    esac
+    shift
+done
+
+if test -z "$browser"; then
+    browser=`git config web.browser`
+    if test -n "$browser" && ! valid_tool "$browser"; then
+	    echo >&2 "git config option web.browser set to unknown browser: $browser"
+	    echo >&2 "Resetting to default..."
+	    unset browser
+    fi
+fi
+
+if test -z "$browser" ; then
+    if test -n "$DISPLAY"; then
+	browser_candidates="firefox iceweasel konqueror w3m links lynx dillo"
+	if test "$KDE_FULL_SESSION" = "true"; then
+	    browser_candidates="konqueror $browser_candidates"
+	fi
+    else
+	browser_candidates="w3m links lynx"
+    fi
+    echo "browser candidates: $browser_candidates"
+    for i in $browser_candidates; do
+	init_browser_path $i
+	if type "$browser_path" > /dev/null 2>&1; then
+	    browser=$i
+	    break
+	fi
+    done
+    test -z "$browser" && die "No known browser available."
+else
+    valid_tool "$browser" || die "Unknown browser '$browser'."
+
+    init_browser_path "$browser"
+
+    if ! type "$browser_path" > /dev/null 2>&1; then
+	die "The browser $browser is not available as '$browser_path'."
+    fi
+fi
+
+pages=$(for p in "$@"; do echo "$html_dir/$p.html" ; done)
+test -z "$pages" && pages="$html_dir/git.html"
+
+case "$browser" in
+    firefox|iceweasel)
+	# Check version because firefox < 2.0 does not support "-new-tab".
+	vers=$(expr "$($browser_path -version)" : '.* \([0-9][0-9]*\)\..*')
+	NEWTAB='-new-tab'
+	test "$vers" -lt 2 && NEWTAB=''
+	nohup "$browser_path" $NEWTAB $pages &
+	;;
+    konqueror)
+	case "$(basename "$browser_path")" in
+	    konqueror)
+		# It's simpler to use kfmclient to open a new tab in konqueror.
+		browser_path="$(echo "$browser_path" | sed -e 's/konqueror$/kfmclient/')"
+		type "$browser_path" > /dev/null 2>&1 || die "No '$browser_path' found."
+		eval "$browser_path" newTab $pages
+		;;
+	    kfmclient)
+		eval "$browser_path" newTab $pages
+		;;
+	    *)
+	        nohup "$browser_path" $pages &
+		;;
+	esac
+	;;
+    w3m|links|lynx)
+	eval "$browser_path" $pages
+	;;
+    dillo)
+	nohup "$browser_path" $pages &
+	;;
+esac
diff --git a/help.c b/help.c
index 0f1cb7172b..ec0d0155ac 100644
--- a/help.c
+++ b/help.c
@@ -241,7 +241,9 @@ void list_common_cmds_help(void)
 
 static const char *cmd_to_page(const char *git_cmd)
 {
-	if (!prefixcmp(git_cmd, "git"))
+	if (!git_cmd)
+		return "git";
+	else if (!prefixcmp(git_cmd, "git"))
 		return git_cmd;
 	else {
 		int page_len = strlen(git_cmd) + 4;
@@ -265,6 +267,12 @@ static void show_info_page(const char *git_cmd)
 	execlp("info", "info", page, NULL);
 }
 
+static void show_html_page(const char *git_cmd)
+{
+	const char *page = cmd_to_page(git_cmd);
+	execl_git_cmd("browse-help", page, NULL);
+}
+
 void help_unknown_cmd(const char *cmd)
 {
 	fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
@@ -277,31 +285,27 @@ int cmd_version(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static void check_help_cmd(const char *help_cmd)
+int cmd_help(int argc, const char **argv, const char *prefix)
 {
-	if (!help_cmd) {
+	const char *help_cmd = argv[1];
+
+	if (argc < 2) {
 		printf("usage: %s\n\n", git_usage_string);
 		list_common_cmds_help();
 		exit(0);
 	}
 
-	else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
+	if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
 		printf("usage: %s\n\n", git_usage_string);
 		list_commands();
-		exit(0);
 	}
-}
-
-int cmd_help(int argc, const char **argv, const char *prefix)
-{
-	const char *help_cmd = argc > 1 ? argv[1] : NULL;
-	check_help_cmd(help_cmd);
 
-	if (!strcmp(help_cmd, "--info") || !strcmp(help_cmd, "-i")) {
-		help_cmd = argc > 2 ? argv[2] : NULL;
-		check_help_cmd(help_cmd);
+	else if (!strcmp(help_cmd, "--web") || !strcmp(help_cmd, "-w")) {
+		show_html_page(argc > 2 ? argv[2] : NULL);
+	}
 
-		show_info_page(help_cmd);
+	else if (!strcmp(help_cmd, "--info") || !strcmp(help_cmd, "-i")) {
+		show_info_page(argc > 2 ? argv[2] : NULL);
 	}
 
 	else