From 3eb08a071c469a2237ee8f41a212d0734b79f113 Mon Sep 17 00:00:00 2001
From: Lars Brinkhoff <lars@nocrew.org>
Date: Tue, 15 Sep 2020 10:14:56 +0200
Subject: [PATCH] Add script to diff two DUMP tapes.

The script takes two file names on the command line: an old tape, and
a new tape.  Any updated files are written to a new tape diffs.tap.
The intent is that diffs.tap can be extradted with a DUMP command like
LOAD CRDIR LINKS to update an ITS system.

The script tries to avoid including binary files that only differ in
the symbol table or creation time.  Some false positives are expected.
---
 build/dump-diff.sh | 86 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 build/dump-diff.sh

diff --git a/build/dump-diff.sh b/build/dump-diff.sh
new file mode 100644
index 00000000..de1c99ff
--- /dev/null
+++ b/build/dump-diff.sh
@@ -0,0 +1,86 @@
+#!/bin/sh
+
+cleanup() {
+    cd "$home"
+    rm -rf "$tmp"
+}
+
+absolute() {
+    case "$1" in
+        /*) echo "$1";;
+        *) echo "$PWD/$1";;
+    esac
+}
+
+tape1="`absolute $1`"
+tape2="`absolute $2`"
+home="$PWD"
+tmp="$PWD/tmp.$$"
+
+trap cleanup EXIT INT TERM QUIT
+
+mkdir "$tmp"
+cd "$tmp"
+
+mkdir tape1
+cd tape1
+itstar xf "$tape1"
+rm -- */_file_.\(dir\) */m_f_d_.\(file\)
+cd "$tmp"
+mkdir tape2
+cd tape2
+itstar xf "$tape2"
+rm -- */_file_.\(dir\) */m_f_d_.\(file\)
+cd "$tmp"
+rm "$home/diffs"
+
+output() {
+    echo "$1: $2"
+    echo "$2" >> "$home/diffs"
+}
+
+diff_file() {
+    file="$1"
+    if test -L "$file"; then
+        if test -L "../tape1/$file"; then
+            l1=`readlink "../tape1/$file"`
+            l2=`readlink "$file"`
+            if test "$l1" \!= "$l2"; then
+                output "UPDATED LINK" "$file"
+            fi
+        else
+            output "NEW LINK" "$file"
+        fi
+    elif test -f "../tape1/$file"; then
+        if cmp -- "$file" "../tape1/$file" > /dev/null; then
+            :
+        else
+            dis10 "$file" 2> /dev/null | grep -v -e 'Creation time:' -e 'Symbol ' -e '^[0-7][0-7][0-7]   [0-7]' > "$tmp/TMP1"
+            dis10 "../tape1/$file" 2> /dev/null | grep -v -e 'Creation time:' -e 'Symbol ' -e '^[0-7][0-7][0-7]   [0-7]' > "$tmp/TMP2"
+            if cmp -- "$tmp/TMP1" "$tmp/TMP2" > /dev/null; then
+                :
+            else
+                output "UPDATED FILE" "$file"
+            fi
+        fi
+    else
+        output "NEW FILE" "$file"
+    fi
+}
+
+cd tape2
+for dir in *; do
+    if test -d "../tape1/$dir"; then
+        for file in $dir/*; do
+            test -r "$file" && diff_file "$file"
+        done
+    else
+        output "NEW DIRECTORY" "$dir"
+    fi
+done
+
+cd "$tmp/tape2"
+head -1 "$home/diffs" | xargs itstar cvf "$home/diffs.tap"
+tail +2 "$home/diffs" | xargs itstar rvf "$home/diffs.tap"
+cd "$home"
+rm "$home/diffs"