Various features I need for bootc-delta

cmd/tar-diff/main.go

@@ -27,7 +27,10 @@ func (p *prefixList) Set(value string) error {
 var version = flag.Bool("version", false, "Show version")
 var compressionLevel = flag.Int("compression-level", 3, "zstd compression level")
 var maxBsdiffSize = flag.Int("max-bsdiff-size", 192, "Max file size in megabytes to consider using bsdiff, or 0 for no limit")
+var tmpDir = flag.String("tmp-dir", defaultTmpDir, "Directory for temporary files")
+var applyWhiteouts = flag.Bool("apply-whiteouts", false, "Apply docker/OCI whiteout files when analyzing old tar layers")
 var sourcePrefixes prefixList
+var ignoreSourcePrefixes prefixList
 
 func closeAndWarn(file *os.File) {
 	if err := file.Close(); err != nil {
@@ -37,6 +40,7 @@ func closeAndWarn(file *os.File) {
 
 func realMain() int {
 	flag.Var(&sourcePrefixes, "source-prefix", "Only use source files with this path prefix for delta (can be specified multiple times)")
+	flag.Var(&ignoreSourcePrefixes, "ignore-source-prefix", "Ignore source files with this path prefix for delta (can be specified multiple times)")
 
 	flag.Usage = func() {
 		_, _ = fmt.Fprintf(flag.CommandLine.Output(), "Usage: %s [OPTION] old1.tar.gz [old2.tar.gz ...] new.tar.gz result.tardiff\n", path.Base(os.Args[0]))
@@ -93,6 +97,13 @@ func realMain() int {
 	if len(sourcePrefixes) > 0 {
 		options.SetSourcePrefixes(sourcePrefixes)
 	}
+	if len(ignoreSourcePrefixes) > 0 {
+		options.SetIgnoreSourcePrefixes(ignoreSourcePrefixes)
+	}
+	options.SetTmpDir(*tmpDir)
+	if *applyWhiteouts {
+		options.SetApplyWhiteouts(true)
+	}
 
 	err = tardiff.Diff(oldFiles, newFile, deltaFile, options)
 	if err != nil {

cmd/tar-diff/tmpdir_unix.go

@@ -0,0 +1,5 @@
+//go:build !windows
+
+package main
+
+const defaultTmpDir = "/var/tmp"

cmd/tar-diff/tmpdir_windows.go

@@ -0,0 +1,7 @@
+//go:build windows
+
+package main
+
+import "os"
+
+var defaultTmpDir = os.TempDir()