Re: [PATCHv2 6/7] web--browse: use (x-)www-browser if available

Debian and derivatives have an alternatives-based default browser
configuration that uses the /usr/bin/gnome-www-browser,
/usr/bin/x-www-browser and /usr/bin/www-browser symlinks.

When no browser is selected by the user and the Debian alternatives are
available, try to see if they are one of our recognized selection and
in the affermative case use it. Otherwise, warn the user about them
being unsupported and move on with the previous detection logic.

Signed-off-by: Giuseppe Bilotta <redacted>
---
 Documentation/git-web--browse.txt |    4 ++
 git-web--browse.sh                |   59 +++++++++++++++++++++++++++++++++++--
 2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-web--browse.txt b/Documentation/git-web--browse.txt
index c0416e5..de034a5 100644
--- a/Documentation/git-web--browse.txt
+++ b/Documentation/git-web--browse.txt

@@ -36,6 +36,10 @@ The following browsers (or commands) are currently supported:

 Custom commands may also be specified.

+If no default browser is specified, and /usr/bin/x-www-browser
+(under X) or /usr/bin/www-browser is present, they are used to determine
+the browser to use.

+
 OPTIONS
 -------
 -b <browser>::

diff --git a/git-web--browse.sh b/git-web--browse.sh
index d0e99f5..48ea168 100755
--- a/git-web--browse.sh
+++ b/git-web--browse.sh

@@ -49,6 +49,38 @@ init_browser_path() {

       test -z "$browser_path" && browser_path="$1"
 }

+# check if a given executable is a browser we like
+valid_exe() {
+       testexe="$1"
+       basename=$(basename $(readlink -f "$testexe"))
+       if valid_tool "$basename" ; then
+               browser="$basename"
+               browser_path="$testexe"
+               return 0
+       fi
+
+       # if the linked executable doesn't match a browser name,
+       # look at the version string
+       verstring="$("$testexe" --version 2> /dev/null)"
+       browser="$(echo "$verstring" | head -n 1 | cut -f1 -d' ' | tr A-Z a-z)"
+       case "$browser" in
+               mozilla)
+                       browser="$(echo "$verstring" | head -n 1 | cut -f2 -d' ' | tr A-Z a-z)"
+                       ;;
+               google)
+                       browser="google-chrome"
+                       ;;
+       esac
+       if valid_tool "$browser" ; then
+               browser_path="$i"
+               return 0
+       fi
+
+       echo >&2 "$basename ($browser) is not a supported browser, skipping"

+       browser=""
+       return 1
+}
+
 while test $# != 0
 do
       case "$1" in

@@ -106,6 +138,26 @@ then

       fi
 fi

+# Debian and derivatives use gnome-www-browser, x-www-browser or www-browser to
+# set the default browser for the system. If the user did not specify a tool and
+# we detect that one of the *www-browser links to a supported one, we pick it.
+# Otherwise, we warn the user about them being unsupported and proceed to look
+# for a supported browser.
+if test -z "$browser" ; then
+       wwwbrowser="/usr/bin/www-browser"
+       if test -n "$DISPLAY"; then
+               wwwbrowser="/usr/bin/x-www-browser $wwwbrowser"
+               if test -n "$GNOME_DESKTOP_SESSION_ID"; then
+                       wwwbrowser="/usr/bin/gnome-www-browser $wwwbrowser"
+               fi
+       fi
+       for i in $wwwbrowser; do
+               if test -x $i && valid_exe $i ; then
+                       break
+               fi
+       done
+fi
+
 if test -z "$browser" ; then
       if test -n "$DISPLAY"; then
               browser_candidates="firefox iceweasel google-chrome chrome chromium chromium-browser konqueror opera seamonkey iceape w3m elinks links lynx dillo"

@@ -133,7 +185,7 @@ if test -z "$browser" ; then

               fi
       done
       test -z "$browser" && die "No known browser available."
-else
+else if test -z "$browser_path"; then