lots of fixes

[distro-setup] / path_add-function

diff --git a/path_add-function b/path_add-function
index 6f06ed9b2c95dba2766fda574750ca04b3737759..540306ca03f0d8aed9af772b7840696f38973fce 100644 (file)
--- a/path_add-function
+++ b/path_add-function
@@ -1,36 +1,79 @@
 #!/bin/bash
-# no bashisms so it can be used in debian profile run by dash
-# --start adds to start of path, which will give it highest priority
-# --ifexists will add to path only if the directory exists
+# Copyright (C) 2016 Ian Kelling
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# avoiding bashisms so it can be used in edge cases where I don't have bash,
+# however, I'm not super confident that I've avoided them all
+#
 path_add() {
-    local found x y z
-    local ifexists start
+    local help="usage: path_add [options] PATH
+--help:     print this
+--end:      adds to end of path, which will give it lowest priority
+--ifexists: add to path only if directory exists"
+    local found x y z ifexists end loop newpath
     ifexists=false
-    start=false
-    while [ "$1" = --* ]; do
-        if [ "$1" = --start ]; then
-            start=true
-        elif [ "$1" = --ifexists ]; then
-            ifexists=true
-        fi
-        shift
+    end=false
+    loop=true
+    # portable substring matching is ugly http://mywiki.wooledge.org/BashFAQ/041
+    while $loop; do
+        case $1 in
+            --*)
+                if [ "$1" = --end ]; then
+                    end=true
+                elif [ "$1" = --ifexists ]; then
+                    ifexists=true
+                elif [ "$1" = --help ]; then
+                    echo "$help"
+                    return
+                fi
+                shift
+                ;;
+            *)
+                loop=false
+                ;;
+        esac
     done
-    for x in "$@"; do
-        found=false
-        IFS=:
-        for y in $PATH; do
-            [ "$x" = "$y" ] && found=true
+    IFS=:
+    # build up the path without the components we want to add
+    for y in $PATH; do
+        for x in "$@"; do
+            if [ "$x" = "$y" ]; then
+                found=true
+            else
+                found=false
+            fi
         done
-        unset IFS
         if ! $found; then
-            if ! $ifexists || [ -d $x ]; then
-                if [ ! "$PATH" ]; then
-                    PATH="$x"
-                elif $start; then
-                    PATH="$x:$PATH"
-                else
-                    PATH="$PATH:$x"
-                fi
+            if [ ! "$newpath" ]; then
+                newpath="$y"
+            else
+                newpath="$newpath:$y"
+            fi
+        fi
+    done
+
+    unset IFS
+    PATH="$newpath"
+    for x in "$@"; do
+        if ! $ifexists || [ -d "$x" ]; then
+            if [ ! "$PATH" ]; then
+                PATH="$x"
+            elif $end; then
+                PATH="$PATH:$x"
+            else
+                PATH="$x:$PATH"
             fi
         fi
     done