feat: Enable indexing record and block numbers by iterating over all files in drive/archive

cmd/stfs-get-header/main.go

@@ -1,70 +0,0 @@
-package main
-
-import (
-	"archive/tar"
-	"bytes"
-	"flag"
-	"fmt"
-	"io"
-	"os"
-)
-
-const (
-	blockSize  = 20
-	headerSize = 512
-)
-
-type HeaderInBlock struct {
-	OffsetInBlock int
-	Header        string
-}
-
-func main() {
-	file := flag.String("file", "/dev/nst0", "File (tape drive or tar file) to open")
-
-	flag.Parse()
-
-	fileDescription, err := os.Stat(*file)
-	if err != nil {
-		panic(err)
-	}
-
-	var f *os.File
-	if fileDescription.Mode().IsRegular() {
-		f, err = os.Open(*file)
-		if err != nil {
-			panic(err)
-		}
-	} else {
-		f, err = os.OpenFile(*file, os.O_RDONLY, os.ModeCharDevice)
-		if err != nil {
-			panic(err)
-		}
-	}
-	defer f.Close()
-
-	// Read exactly one block
-	bf := make([]byte, blockSize*headerSize)
-	if _, err := io.ReadFull(f, bf); err != nil {
-		panic(err)
-	}
-
-	// Get the headers from the block
-	headers := []HeaderInBlock{}
-	for i := 0; i < blockSize; i++ {
-		tr := tar.NewReader(bytes.NewReader(bf[headerSize*i : headerSize*(i+1)]))
-		hdr, err := tr.Next()
-		if err != nil {
-			continue
-		}
-
-		headers = append(headers, HeaderInBlock{
-			OffsetInBlock: i,
-			Header:        fmt.Sprintf("%v", hdr),
-		})
-	}
-
-	if len(headers) > 0 {
-		fmt.Println(headers)
-	}
-}

cmd/stfs-tvf/main.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"archive/tar"
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+const (
+	blockSize = 512
+)
+
+type HeaderInBlock struct {
+	Record int
+	Block  int
+	Header string
+}
+
+func main() {
+	file := flag.String("file", "/dev/nst0", "File (tape drive or tar file) to open")
+	recordSize := flag.Int("recordSize", 20, "Amount of 512-bit blocks per record")
+	checkpoint := flag.Int("checkpoint", 0, "Log current record after checkpoint kilobytes have been read")
+
+	flag.Parse()
+
+	fileDescription, err := os.Stat(*file)
+	if err != nil {
+		panic(err)
+	}
+
+	var f *os.File
+	if fileDescription.Mode().IsRegular() {
+		f, err = os.Open(*file)
+		if err != nil {
+			panic(err)
+		}
+	} else {
+		f, err = os.OpenFile(*file, os.O_RDONLY, os.ModeCharDevice)
+		if err != nil {
+			panic(err)
+		}
+	}
+	defer f.Close()
+
+	record := 0
+	for {
+		// Lock the current record if requested
+		if *checkpoint > 0 && record%*checkpoint == 0 {
+			log.Println("Checkpoint:", record)
+		}
+
+		// Read exactly one record
+		bf := make([]byte, *recordSize*blockSize)
+		if _, err := io.ReadFull(f, bf); err != nil {
+			panic(err)
+		}
+
+		// Get the headers from the record
+		headers := []HeaderInBlock{}
+		for i := 0; i < *recordSize; i++ {
+			tr := tar.NewReader(bytes.NewReader(bf[blockSize*i : blockSize*(i+1)]))
+			hdr, err := tr.Next()
+			if err != nil {
+				continue
+			}
+
+			if hdr.Format == tar.FormatUnknown {
+				// EOF
+				break
+			}
+
+			headers = append(headers, HeaderInBlock{
+				Record: record,
+				Block:  i,
+				Header: fmt.Sprintf("%v", hdr),
+			})
+		}
+
+		if len(headers) > 0 {
+			fmt.Println(headers)
+		}
+
+		record++
+	}
+}