From 475e31ca38054b5abb51fc4eae7c654fe573b72d Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Fri, 19 Aug 2016 15:59:46 +1200
Subject: Translate apf(1) to POSIX sh

We lose the ability to include newlines in options, but probably a
pretty good tradeoff, especially since it makes the *rc files
hand-editable in theory.

Also add skipping comments and blank lines.

Update ISSUES.markdown. There are two more Bash scripts left; one of
them, han(1), does actually require Bash, though.
---
 bin/apf | 62 ++++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 42 insertions(+), 20 deletions(-)

(limited to 'bin')

diff --git a/bin/apf b/bin/apf
index 733d67fc..0a0cbeea 100755
--- a/bin/apf
+++ b/bin/apf
@@ -1,30 +1,52 @@
-#!/usr/bin/env bash
-# Prepend arguments from a file to a command call
+#!/bin/sh
+# Prepend arguments from a file to the given arguments for a command
 self=apf
 
-# Give up completely if no BASH_VERSINFO (<2.0)
-[ -n "$BASH_VERSINFO" ] || exit
-
-# Require at least two arguments, give usage otherwise
-if (($# < 2)) ; then
+# Require at least two arguments
+if [ "$#" -lt 2 ] ; then
     printf >&2 '%s: Need an arguments file and a command\n' "$self"
     exit 2
 fi
 
 # First argument is the file containing the null-delimited arguments
-argfile=$1
-shift
+argf=$1 cmd=$2
+shift 2
 
-# Read all the null-delimited arguments from the file
-declare -a args
-while IFS= read -rd '' arg ; do
-    args[${#args[@]}]=$arg
-done < "$argfile"
+# If the file exists, we'll read it. If it doesn't, this is not an error (think
+# personal config files like ~/.vimrc)
+if [ -f "$argf" ] ; then
 
-# Next argument is the command to run
-cmd=$1
-shift
+    # Create a temporary directory with name in $td, and handle POSIX-ish traps to
+    # remove it when the script exits.
+    td=
+    cleanup() {
+        [ -n "$td" ] && rm -fr -- "$td"
+        if [ "$1" != EXIT ] ; then
+            trap - "$1"
+            kill "-$1" "$$"
+        fi
+    }
+    for sig in EXIT HUP INT TERM ; do
+        # shellcheck disable=SC2064
+        trap "cleanup $sig" "$sig"
+    done
+    td=$(mktd "$self") || exit
+    
+    # Write the arguments in reverse to a temporary file
+    revf=$td/revf
+    sed '1!G;$!{h;d}' "$argf" > "$revf" || exit
+    
+    # Stack up all the arguments from the file. Skip blank lines and comments.
+    # An empty file is also fine.
+    while IFS= read -r arg ; do
+        case $arg in
+            '#'*) continue ;;
+            *[![:space:]]*) ;;
+            *) continue ;;
+        esac
+        set -- "$arg" "$@"
+    done < "$revf"
+fi
 
-# Run the command with the retrieved arguments first, then the rest of the
-# command line as passed to the function
-command "$cmd" "${args[@]}" "$@"
+# Run the command with the changed arguments
+exec "$cmd" "$@"
-- 
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