From ceadf84262ed4c048b17ae167f5ea9ed96d4d875 Mon Sep 17 00:00:00 2001
From: Steven Baltakatei Sandoval <baltakatei@gmail.com>
Date: Thu, 2 Jul 2020 17:53:03 +0000
Subject: [PATCH 1/1] feat(unitproc):Add checkTar. Makes sure a tar exists

Added checkTar() Bash function template. It checks to see if file arg1 is a
valid tar archive. If file exists but `tar` doesn't recognize it as
valid, then rename it with a nonce and create an empty tar in its place.
---
 unitproc/bktemp-checkTar | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 unitproc/bktemp-checkTar

diff --git a/unitproc/bktemp-checkTar b/unitproc/bktemp-checkTar
new file mode 100644
index 0000000..2485f3a
--- /dev/null
+++ b/unitproc/bktemp-checkTar
@@ -0,0 +1,35 @@
+#!/bin/bash
+
+# Desc: Checks that a valid tar archive exists, creates one otherwise
+
+# Yell, Die, Try Three-Fingered Claw technique
+# Ref/Attrib: https://stackoverflow.com/a/25515370
+yell() { echo "$0: $*" >&2; }
+die() { yell "$*"; exit 111; }
+try() { "$@" || die "cannot $*"; }
+
+checkTar() {
+    # Desc: Checks that a valid tar archive exists, creates one otherwise
+    # Usage: checkTar [ path ]
+    # Input: arg1: path of tar archive
+    # Output: exit code 0: tar exists and is valid
+    # Depends: try, tar, date
+    local PATH_TAR="$1"
+
+    # Check if file is a valid tar archive
+    if tar --list --file="$PATH_TAR" 1>/dev/null 2>&1; then
+	## T1: return success
+	return 0;
+    else
+	## F1: Check if file exists
+	if [[ -f "$PATH_TAR" ]]; then
+	    ### T: Rename file
+	    try mv "$PATH_TAR" "$PATH_TAR""--broken--""$(date +%Y%m%dT%H%M%S)";
+	else
+	    ### F: -
+	    :
+	fi
+	## F2: Create tar archive
+	try tar --create --file="$PATH_TAR" --files-from=/dev/null;
+    fi
+} # checks if arg1 is tar; creates one otherwise
-- 
2.30.2