Adding upstream version 1.2.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>

selfupdate/uncompress.go

@@ -0,0 +1,136 @@
+package selfupdate
+
+import (
+	"archive/tar"
+	"archive/zip"
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"github.com/ulikunitz/xz"
+	"io"
+	"io/ioutil"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+func matchExecutableName(cmd, target string) bool {
+	if cmd == target {
+		return true
+	}
+
+	o, a := runtime.GOOS, runtime.GOARCH
+
+	// When the contained executable name is full name (e.g. foo_darwin_amd64),
+	// it is also regarded as a target executable file. (#19)
+	for _, d := range []rune{'_', '-'} {
+		c := fmt.Sprintf("%s%c%s%c%s", cmd, d, o, d, a)
+		if o == "windows" {
+			c += ".exe"
+		}
+		if c == target {
+			return true
+		}
+	}
+
+	return false
+}
+
+func unarchiveTar(src io.Reader, url, cmd string) (io.Reader, error) {
+	t := tar.NewReader(src)
+	for {
+		h, err := t.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, fmt.Errorf("Failed to unarchive .tar file: %s", err)
+		}
+		_, name := filepath.Split(h.Name)
+		if matchExecutableName(cmd, name) {
+			log.Println("Executable file", h.Name, "was found in tar archive")
+			return t, nil
+		}
+	}
+
+	return nil, fmt.Errorf("File '%s' for the command is not found in %s", cmd, url)
+}
+
+// UncompressCommand uncompresses the given source. Archive and compression format is
+// automatically detected from 'url' parameter, which represents the URL of asset.
+// This returns a reader for the uncompressed command given by 'cmd'. '.zip',
+// '.tar.gz', '.tar.xz', '.tgz', '.gz' and '.xz' are supported.
+func UncompressCommand(src io.Reader, url, cmd string) (io.Reader, error) {
+	if strings.HasSuffix(url, ".zip") {
+		log.Println("Uncompressing zip file", url)
+
+		// Zip format requires its file size for uncompressing.
+		// So we need to read the HTTP response into a buffer at first.
+		buf, err := ioutil.ReadAll(src)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to create buffer for zip file: %s", err)
+		}
+
+		r := bytes.NewReader(buf)
+		z, err := zip.NewReader(r, r.Size())
+		if err != nil {
+			return nil, fmt.Errorf("Failed to uncompress zip file: %s", err)
+		}
+
+		for _, file := range z.File {
+			_, name := filepath.Split(file.Name)
+			if !file.FileInfo().IsDir() && matchExecutableName(cmd, name) {
+				log.Println("Executable file", file.Name, "was found in zip archive")
+				return file.Open()
+			}
+		}
+
+		return nil, fmt.Errorf("File '%s' for the command is not found in %s", cmd, url)
+	} else if strings.HasSuffix(url, ".tar.gz") || strings.HasSuffix(url, ".tgz") {
+		log.Println("Uncompressing tar.gz file", url)
+
+		gz, err := gzip.NewReader(src)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to uncompress .tar.gz file: %s", err)
+		}
+
+		return unarchiveTar(gz, url, cmd)
+	} else if strings.HasSuffix(url, ".gzip") || strings.HasSuffix(url, ".gz") {
+		log.Println("Uncompressing gzip file", url)
+
+		r, err := gzip.NewReader(src)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to uncompress gzip file downloaded from %s: %s", url, err)
+		}
+
+		name := r.Header.Name
+		if !matchExecutableName(cmd, name) {
+			return nil, fmt.Errorf("File name '%s' does not match to command '%s' found in %s", name, cmd, url)
+		}
+
+		log.Println("Executable file", name, "was found in gzip file")
+		return r, nil
+	} else if strings.HasSuffix(url, ".tar.xz") {
+		log.Println("Uncompressing tar.xz file", url)
+
+		xzip, err := xz.NewReader(src)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to uncompress .tar.xz file: %s", err)
+		}
+
+		return unarchiveTar(xzip, url, cmd)
+	} else if strings.HasSuffix(url, ".xz") {
+		log.Println("Uncompressing xzip file", url)
+
+		xzip, err := xz.NewReader(src)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to uncompress xzip file downloaded from %s: %s", url, err)
+		}
+
+		log.Println("Uncompressed file from xzip is assumed to be an executable", cmd)
+		return xzip, nil
+	}
+
+	log.Println("Uncompression is not needed", url)
+	return src, nil
+}