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>

1 files changed, 142 insertions, 0 deletions

diff --git a/git-browse-help.sh b/git-browse-help.sh
new file mode 100755
index 0000000..76eff01
--- /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