implement bundle storage

Author: Andrey Zverev

bundle.go

@@ -0,0 +1,114 @@
+package bundle
+
+// type IBundle interface {
+// 	CreateBundle(bundleName string) error
+// 	OpenBundle(bundleName string) error
+// 	CloseBundle() error
+// 	AddContent(fileName string, b []byte) error
+// 	GetContent(fileName string) ([]byte, error)
+// }
+
+import (
+	"archive/tar"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+)
+
+type BundleTAR struct {
+	bundleFile *os.File
+	tarWriter  *tar.Writer
+	tarReader  *tar.Reader
+	isOpen     bool
+}
+
+func (b *BundleTAR) CreateBundle(bundleName string) error {
+	if b.bundleFile != nil {
+		return fmt.Errorf("cat not create bundle already created")
+	}
+
+	file, err := os.Create(bundleName)
+	if err != nil {
+		return fmt.Errorf("failed to create bundle: %s", err)
+	}
+	b.bundleFile = file
+	b.tarWriter = tar.NewWriter(file)
+	b.isOpen = true
+	return nil
+}
+
+func (b *BundleTAR) OpenBundle(bundleName string) error {
+	file, err := os.Open(bundleName)
+	if err != nil {
+		return fmt.Errorf("failed to open bundle: %s", err)
+	}
+	b.bundleFile = file
+	b.tarReader = tar.NewReader(file)
+	b.isOpen = true
+	return nil
+
+}
+
+func (b *BundleTAR) CloseBundle() error {
+	if b.isOpen == true {
+		if b.tarWriter != nil {
+			if err := b.tarWriter.Close(); err != nil {
+				return fmt.Errorf("failed to close bundle: %s", err)
+			}
+		}
+		if b.bundleFile != nil {
+			if err := b.bundleFile.Close(); err != nil {
+				return fmt.Errorf("failed to close bundle: %s", err)
+			}
+		}
+	}
+	b.isOpen = false
+	return nil
+}
+
+func (b *BundleTAR) AddContent(fileName string, data []byte) error {
+	if b.isOpen == false || b.tarWriter == nil {
+		return fmt.Errorf("bundle is uknown to proccess")
+	}
+	header := &tar.Header{
+		Name: fileName,
+		Mode: 0600,
+		Size: int64(len(data)),
+	}
+	if err := b.tarWriter.WriteHeader(header); err != nil {
+		return fmt.Errorf("failed to write header to bundle: %s", err)
+	}
+	_, err := b.tarWriter.Write(data)
+	if err != nil {
+		return fmt.Errorf("failed to write content for %s to bundle: %s", fileName, err)
+	}
+	return nil
+}
+
+func (b *BundleTAR) GetContent(fileName string) ([]byte, error) {
+	var content bytes.Buffer
+
+	if b.isOpen == false || b.tarReader == nil {
+		return nil, fmt.Errorf("bundle is uknown to proccess")
+	}
+	for {
+		header, err := b.tarReader.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, fmt.Errorf("failed to read bundle header: %s", err)
+		}
+
+		if header.Name == fileName {
+			_, err := io.Copy(&content, b.tarReader)
+			if err != nil {
+				return nil, fmt.Errorf("failed to read content for %s from bundle: %s", fileName, err)
+			}
+			return content.Bytes(), nil
+		}
+	}
+
+	return nil, fmt.Errorf("unable to find file %s in bundle", fileName)
+}

bundle_test.go

@@ -0,0 +1,139 @@
+package bundle_test
+
+import (
+	"bytes"
+	"os"
+	"testing"
+
+	bundle "github.com/andrejzverev/mm_bundle"
+)
+
+func TestCreateBundle(t *testing.T) {
+	b := &bundle.BundleTAR{}
+	err := b.CreateBundle("test_bundle.bundle")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer func() {
+		err := b.CloseBundle()
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+		err = os.Remove("test_bundle.bundle")
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+	}()
+}
+
+func TestAddGetContent(t *testing.T) {
+	b := &bundle.BundleTAR{}
+
+	err := b.CreateBundle("test_bundle.bundle")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	defer func() {
+		err := b.CloseBundle()
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+		err = os.Remove("test_bundle.bundle")
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+	}()
+
+	content := []byte("TEST DATA")
+	err = b.AddContent("testfile.txt", content)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	err = b.OpenBundle("test_bundle.bundle")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	extractedContent, err := b.GetContent("testfile.txt")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if !bytes.Equal(extractedContent, content) {
+		t.Errorf("expected: %s, got: %s",
+			content, extractedContent)
+	}
+
+}
+
+func TestGetContentFileNotFound(t *testing.T) {
+	b := &bundle.BundleTAR{}
+
+	err := b.CreateBundle("test_bundle.bundle")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	defer func() {
+		err := b.CloseBundle()
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+		err = os.Remove("test_bundle.bundle")
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+	}()
+	content := []byte("TEST DATA")
+	err = b.AddContent("file1.txt", content)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	err = b.OpenBundle("test_bundle.bundle")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	_, err = b.GetContent("nonexistentfile.txt")
+	if err == nil {
+		t.Fatalf("must get error because no suchfile")
+	}
+}
+
+func TestGetContentWithoutOpen(t *testing.T) {
+	b := &bundle.BundleTAR{}
+	_, err := b.GetContent("file1.txt")
+	if err == nil {
+		t.Fatalf("must get error because trying to read without open first")
+	}
+}
+
+func TestCreateBundleTwice(t *testing.T) {
+	b := &bundle.BundleTAR{}
+
+	err := b.CreateBundle("test_bundle.bundle")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	defer func() {
+		err := b.CloseBundle()
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+		err = os.Remove("test_bundle.bundle")
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+		os.Remove("test_bundle2.bundle")
+
+	}()
+
+	err = b.CreateBundle("test_bundle2.bundle")
+	if err == nil {
+		t.Fatalf("err: %s", err)
+	}
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/andrejzverev/mm_bundle
+
+go 1.23.4