Add bash_completion to contrib

Contributed by "Alexis S. L. Carvalho" <[e-mail]>

Attached is a file that implements bash completion for hg.  Just
reading it from your .bashrc should be enough to use it - I think: I'm
using the /etc/bash_completion from debian and I'm not sure whether it
sets some important option.

It gets the list of commands, aliases and options from the output of hg
help and then adds some specific stuff - e.g. completing update with
tags; pull and push with path aliases and directories, etc.

contrib/bash_completion

@@ -0,0 +1,129 b''
+_hg_commands()
+{
+    local commands="$(hg -v help | sed -e '1,/^list of commands:/d' \
+                                       -e '/^global options:/Q' \
+				       -e '/^ [^ ]/!d; s/[,:]//g;')"
+    
+    # hide debug commands from users, but complete them if 
+    # specifically asked for
+    if [[ "$cur" == de* ]]; then
+	commands="$commands debugcheckstate debugstate debugindex"
+	commands="$commands debugindexdot debugwalk"
+    fi
+    COMPREPLY=( ${COMPREPLY[@]:-} $(compgen -W "$commands" -- "$cur") )
+}
+
+_hg_paths()
+{
+    local paths="$(hg paths | sed -e 's/ = .*$//')"
+    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -W "$paths" -- "$cur" ))
+}
+
+_hg_tags()
+{
+    local tags="$(hg tags | sed -e 's/[0-9]*:[a-f0-9]\{40\}$//; s/ *$//')"
+    COMPREPLY=( ${COMPREPLY[@]:-} $(compgen -W "$tags" -- "$cur") )
+}
+
+# this is "kind of" ugly...
+_hg_count_non_option()
+{
+    local i count=0
+    local filters="$1"
+
+    for (( i=1; $i<=$COMP_CWORD; i++ )); do
+	if [[ "${COMP_WORDS[i]}" != -* ]]; then
+	    for f in $filters; do
+		if [[ ${COMP_WORDS[i-1]} == $f ]]; then
+		    continue 2
+		fi
+	    done
+	    count=$(($count + 1))
+	fi
+    done
+
+    echo $(($count - 1))
+}
+
+_hg()
+{
+    local cur prev cmd opts i
+
+    COMPREPLY=()
+    cur="$2"
+    prev="$3"
+
+    # searching for the command 
+    # (first non-option argument that doesn't follow -R/--repository)
+    for (( i=1; $i<=$COMP_CWORD; i++ )); do
+	if [[ ${COMP_WORDS[i]} != -* ]] \
+	   && [ "${COMP_WORDS[i-1]}" != -R ] \
+	   && [ "${COMP_WORDS[i-1]}" != --repository ]; then
+	    cmd="${COMP_WORDS[i]}"
+	    break
+	fi
+    done
+
+    if [[ "$cur" == -* ]]; then
+	opts="$(hg -v help | sed -e '1,/^global options/d; /^ -/!d')"
+
+	if [ -n "$cmd" ]; then
+	    opts="$opts $(hg help "$cmd" | sed -e '/^ -/!d; s/ [^-][^ ]*//')"
+	fi
+
+	COMPREPLY=( ${COMPREPLY[@]:-} $(compgen -W "$opts" -- "$cur") )
+	return
+    fi
+
+    if [ "$prev" = -R ] || [ "$prev" = --repository ]; then
+        COMPREPLY=(${COMPREPLY[@]:-} $( compgen -d -- "$cur" ))
+	return
+    fi
+
+    if [ -z "$cmd" ] || [ $COMP_CWORD -eq $i ]; then
+	_hg_commands
+	return
+    fi
+
+    if [ "$cmd" != status ] && [ "$prev" = -r ] || [ "$prev" = --rev ]; then
+	_hg_tags
+	return
+    fi
+
+    case "$cmd" in
+	help)
+	    _hg_commands
+	;;
+	export|manifest|update|checkout|up|co)
+	    _hg_tags
+	;;
+	pull|push)
+	    _hg_paths
+	    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -d -- "$cur" ))
+	;;
+	paths)
+	    _hg_paths
+	;;
+	clone)
+	    local count=$(_hg_count_non_option)
+	    if [ $count = 1 ]; then
+		_hg_paths
+	    fi
+	    COMPREPLY=(${COMPREPLY[@]:-} $( compgen -d -- "$cur" ))
+	;;
+	cat)
+	    local count=$(_hg_count_non_option -o --output)
+	    if [ $count = 2 ]; then
+		_hg_tags
+	    else
+		COMPREPLY=(${COMPREPLY[@]:-} $( compgen -f -- "$cur" ))
+	    fi
+	;;
+	*) 
+            COMPREPLY=(${COMPREPLY[@]:-} $( compgen -f -- "$cur" ))
+	;;
+    esac
+
+}
+
+complete -o filenames -F _hg hg