Add an interface for file compress (#155)

* Add an interface for file compress

* make sure GZip implements the interface Compress

Author: LinuxSuRen

pkg/compress/gzip.go

@@ -0,0 +1,97 @@
+package compress
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// GZip implements a compress which based gzip
+type GZip struct {
+	additionBinaries []string
+}
+
+// NewGZip creates an instance of GZip
+// additionBinaries could be empty or nil
+func NewGZip(additionBinaries []string) *GZip {
+	return &GZip{additionBinaries: additionBinaries}
+}
+
+// make sure GZip implements the interface Compress
+var _ Compress = &GZip{}
+
+// ExtractFiles extracts files from a target compress file
+func (c *GZip) ExtractFiles(sourceFile, targetName string) (err error) {
+	if targetName == "" {
+		err = errors.New("target filename is empty")
+		return
+	}
+
+	var f *os.File
+	var gzf *gzip.Reader
+	if f, err = os.Open(sourceFile); err != nil {
+		return
+	}
+	defer func() {
+		_ = f.Close()
+	}()
+
+	if gzf, err = gzip.NewReader(f); err != nil {
+		return
+	}
+
+	tarReader := tar.NewReader(gzf)
+	var header *tar.Header
+	var found bool
+	for {
+		if header, err = tarReader.Next(); err == io.EOF {
+			err = nil
+			break
+		} else if err != nil {
+			break
+		}
+		name := header.Name
+
+		switch header.Typeflag {
+		case tar.TypeReg:
+			if err = extraFile(name, targetName, sourceFile, header, tarReader); err == nil {
+				found = true
+			} else {
+				break
+			}
+
+			for i := range c.additionBinaries {
+				addition := c.additionBinaries[i]
+				if err = extraFile(addition, addition, sourceFile, header, tarReader); err != nil {
+					return
+				}
+			}
+		}
+	}
+
+	if err == nil && !found {
+		err = fmt.Errorf("cannot found item '%s' from '%s'", targetName, sourceFile)
+	}
+	return
+}
+
+func extraFile(name, targetName, tarFile string, header *tar.Header, tarReader *tar.Reader) (err error) {
+	if name != targetName && !strings.HasSuffix(name, "/"+targetName) {
+		return
+	}
+	var targetFile *os.File
+	if targetFile, err = os.OpenFile(fmt.Sprintf("%s/%s", filepath.Dir(tarFile), targetName),
+		os.O_CREATE|os.O_RDWR, os.FileMode(header.Mode)); err != nil {
+		return
+	}
+	if _, err = io.Copy(targetFile, tarReader); err != nil {
+		return
+	}
+	_ = targetFile.Close()
+	return
+}

pkg/compress/interface.go

@@ -0,0 +1,6 @@
+package compress
+
+// Compress is a common compress interface
+type Compress interface {
+	ExtractFiles(sourceFile, targetName string) error
+}

pkg/compress/xz.go

@@ -0,0 +1,3 @@
+package compress
+
+// TODO implement extract files, for instance, you can use https://github.com/ulikunitz/xz

pkg/installer/process.go

@@ -1,18 +1,15 @@
 package installer
 
 import (
-	"archive/tar"
-	"compress/gzip"
-	"errors"
 	"fmt"
 	"github.com/linuxsuren/http-downloader/pkg/common"
+	"github.com/linuxsuren/http-downloader/pkg/compress"
 	"github.com/linuxsuren/http-downloader/pkg/exec"
 	"io"
 	"os"
 	"path"
 	"path/filepath"
 	"runtime"
-	"strings"
 )
 
 // Install installs a package
@@ -116,71 +113,8 @@ func (o *Installer) OverWriteBinary(sourceFile, targetPath string) (err error) {
 }
 
 func (o *Installer) extractFiles(tarFile, targetName string) (err error) {
-	if targetName == "" {
-		err = errors.New("target filename is empty")
-		return
-	}
-
-	var f *os.File
-	var gzf *gzip.Reader
-	if f, err = os.Open(tarFile); err != nil {
-		return
-	}
-	defer func() {
-		_ = f.Close()
-	}()
-
-	if gzf, err = gzip.NewReader(f); err != nil {
-		return
-	}
-
-	tarReader := tar.NewReader(gzf)
-	var header *tar.Header
-	var found bool
-	for {
-		if header, err = tarReader.Next(); err == io.EOF {
-			err = nil
-			break
-		} else if err != nil {
-			break
-		}
-		name := header.Name
-
-		switch header.Typeflag {
-		case tar.TypeReg:
-			if err = extraFile(name, targetName, tarFile, header, tarReader); err == nil {
-				found = true
-			} else {
-				break
-			}
-
-			for i := range o.AdditionBinaries {
-				addition := o.AdditionBinaries[i]
-				if err = extraFile(addition, addition, tarFile, header, tarReader); err != nil {
-					return
-				}
-			}
-		}
-	}
-
-	if err == nil && !found {
-		err = fmt.Errorf("cannot found item '%s' from '%s'", targetName, tarFile)
-	}
-	return
-}
-
-func extraFile(name, targetName, tarFile string, header *tar.Header, tarReader *tar.Reader) (err error) {
-	if name != targetName && !strings.HasSuffix(name, "/"+targetName) {
-		return
-	}
-	var targetFile *os.File
-	if targetFile, err = os.OpenFile(fmt.Sprintf("%s/%s", filepath.Dir(tarFile), targetName),
-		os.O_CREATE|os.O_RDWR, os.FileMode(header.Mode)); err != nil {
-		return
-	}
-	if _, err = io.Copy(targetFile, tarReader); err != nil {
-		return
-	}
-	_ = targetFile.Close()
+	// TODO choose a correct compress instance
+	compressor := compress.NewGZip(o.AdditionBinaries)
+	err = compressor.ExtractFiles(tarFile, targetName)
 	return
 }