refactor: Decompose index func

internal/suffix/config.go

@@ -0,0 +1,12 @@
+package suffix
+
+const (
+	CompressionFormatGZipSuffix      = ".gz"
+	CompressionFormatLZ4Suffix       = ".lz4"
+	CompressionFormatZStandardSuffix = ".zst"
+	CompressionFormatBrotliSuffix    = ".br"
+	CompressionFormatBzip2Suffix     = ".bz2"
+
+	EncryptionFormatAgeSuffix = ".age"
+	EncryptionFormatPGPSuffix = ".pgp"
+)

internal/suffix/remove.go

@@ -0,0 +1,41 @@
+package suffix
+
+import (
+	"strings"
+
+	"github.com/pojntfx/stfs/pkg/config"
+)
+
+func RemoveSuffix(name string, compressionFormat string, encryptionFormat string) (string, error) {
+	switch encryptionFormat {
+	case config.EncryptionFormatAgeKey:
+		name = strings.TrimSuffix(name, EncryptionFormatAgeSuffix)
+	case config.EncryptionFormatPGPKey:
+		name = strings.TrimSuffix(name, EncryptionFormatPGPSuffix)
+	case config.NoneKey:
+	default:
+		return "", config.ErrUnsupportedEncryptionFormat
+	}
+
+	switch compressionFormat {
+	case config.CompressionFormatGZipKey:
+		fallthrough
+	case config.CompressionFormatParallelGZipKey:
+		name = strings.TrimSuffix(name, CompressionFormatGZipSuffix)
+	case config.CompressionFormatLZ4Key:
+		name = strings.TrimSuffix(name, CompressionFormatLZ4Suffix)
+	case config.CompressionFormatZStandardKey:
+		name = strings.TrimSuffix(name, CompressionFormatZStandardSuffix)
+	case config.CompressionFormatBrotliKey:
+		name = strings.TrimSuffix(name, CompressionFormatBrotliSuffix)
+	case config.CompressionFormatBzip2Key:
+		fallthrough
+	case config.CompressionFormatBzip2ParallelKey:
+		name = strings.TrimSuffix(name, CompressionFormatBzip2Suffix)
+	case config.NoneKey:
+	default:
+		return "", config.ErrUnsupportedCompressionFormat
+	}
+
+	return name, nil
+}

internal/tape/read.go

@@ -0,0 +1,27 @@
+package tape
+
+import "os"
+
+func OpenTapeReadOnly(tape string) (f *os.File, isRegular bool, err error) {
+	fileDescription, err := os.Stat(tape)
+	if err != nil {
+		return nil, false, err
+	}
+
+	isRegular = fileDescription.Mode().IsRegular()
+	if isRegular {
+		f, err = os.Open(tape)
+		if err != nil {
+			return f, isRegular, err
+		}
+
+		return f, isRegular, nil
+	}
+
+	f, err = os.OpenFile(tape, os.O_RDONLY, os.ModeCharDevice)
+	if err != nil {
+		return f, isRegular, err
+	}
+
+	return f, isRegular, nil
+}