hg2git.sh: Try to get last hg repo url from state file

As one usually mirrors a git repo based on the same hg repo, it's
annoying having to specify the hg repo url all the time. Since we
intentionally stored the url in the state file already, use in the
shell wrapper and default to it.

Signed-off-by: Rocco Rutte <pdmef@gmx.net>

hg2git.sh

@@ -1,7 +1,5 @@
 #!/bin/sh
 
-USAGE='[-m max] [--quiet] repo'
-LONG_USAGE='Import hg repository <repo> up to either tip or <max>'
 ROOT="`dirname $0`"
 REPO=""
 MAX="-1"
@@ -11,6 +9,11 @@ SFX_HEADS="heads"
 SFX_STATE="state"
 QUIET=""
 
+USAGE="[-m <max>] [--quiet] [<repo>]"
+LONG_USAGE="Import hg repository <repo> up to either tip or <max>
+If <repo> is omitted, use last hg repository as obtained from state file,
+GIT_DIR/$PFX-$SFX_STATE by default."
+
 . git-sh-setup
 cd_to_toplevel
 
@@ -34,12 +37,20 @@ do
   shift
 done
 
-if [ "$#" != 1 ] ; then
-  usage
-  exit 1
+# for convenience: get default repo from state file
+if [ "$#" != 1 -a -f "$GIT_DIR/$PFX-$SFX_STATE" ] ; then
+  REPO="`egrep '^:repo ' "$GIT_DIR/$PFX-$SFX_STATE" | cut -d ' ' -f 2`"
+  echo "Using last hg repository \"$REPO\""
 fi
 
-REPO="$1"
+if [ x"$REPO" = x ] ; then
+  if [ "$#" != 1 ] ; then
+    usage
+    exit 1
+  else
+    REPO="$1"
+  fi
+fi
 
 # make sure we have a marks cache
 if [ ! -f "$GIT_DIR/$PFX-$SFX_MARKS" ] ; then