cpiocat

cpiocat/cpiocat.go

@@ -0,0 +1,181 @@
+package cpiocat
+
+import (
+	"io"
+	"os"
+
+	"github.com/cavaliergopher/cpio"
+)
+
+// Append: legacy append call.
+func Append(out io.Writer, in io.Reader, filesToAppend []string) (err error) {
+	cat := New(out)
+
+	cat.AppendArch(in)
+
+	for _, file := range filesToAppend {
+		cat.AppendFile(file, file)
+	}
+
+	return cat.Close()
+}
+
+type Cat struct {
+	out  io.Writer
+	cout *cpio.Writer
+	err  error
+}
+
+func New(out io.Writer) *Cat {
+	cout := cpio.NewWriter(out)
+	return &Cat{out: out, cout: cout}
+}
+
+func (c *Cat) Err() error {
+	return c.err
+}
+
+func (c *Cat) Close() error {
+	err := c.cout.Close()
+
+	if c.err != nil {
+		return c.err
+	}
+
+	return err
+}
+
+func (c *Cat) AppendArchFile(srcPath string) (r *Cat) {
+	r = c
+	if c.err != nil {
+		return
+	}
+
+	f, err := os.Open(srcPath)
+	if err != nil {
+		c.err = err
+		return
+	}
+
+	defer f.Close()
+
+	return c.AppendArch(f)
+}
+
+func (c *Cat) AppendArch(in io.Reader) (r *Cat) {
+	r = c
+	if c.err != nil {
+		return
+	}
+
+	cin := cpio.NewReader(in)
+
+	for {
+		hdr, err := cin.Next()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			c.err = err
+			return
+		}
+
+		mode := hdr.FileInfo().Mode()
+
+		if mode&os.ModeSymlink != 0 {
+			// symlink target must be written after
+			hdr.Size = int64(len(hdr.Linkname))
+		}
+
+		err = c.cout.WriteHeader(hdr)
+		if err != nil {
+			c.err = err
+			return
+		}
+
+		if mode.IsRegular() {
+			_, err = io.Copy(c.cout, cin)
+
+		} else if mode&os.ModeSymlink != 0 {
+			_, err = c.cout.Write([]byte(hdr.Linkname))
+		}
+
+		if err != nil {
+			c.err = err
+			return
+		}
+	}
+
+	return
+}
+
+func (c *Cat) AppendFile(srcPath, archPath string) (r *Cat) {
+	r = c
+	if c.err != nil {
+		return
+	}
+
+	var err error
+	defer func() { c.err = err }()
+
+	stat, err := os.Lstat(srcPath)
+	if err != nil {
+		return
+	}
+
+	link := ""
+	if stat.Mode()&os.ModeSymlink != 0 {
+		link, err = os.Readlink(srcPath)
+		if err != nil {
+			return
+		}
+	}
+
+	hdr, err := cpio.FileInfoHeader(stat, link)
+	if err != nil {
+		return
+	}
+
+	hdr.Name = archPath
+
+	c.cout.WriteHeader(hdr)
+
+	if stat.Mode().IsRegular() {
+		var f *os.File
+		f, err = os.Open(srcPath)
+		if err != nil {
+			return
+		}
+		defer f.Close()
+
+		_, err = io.Copy(c.cout, f)
+
+	} else if stat.Mode()&os.ModeSymlink != 0 {
+		_, err = c.cout.Write([]byte(link))
+	}
+
+	return
+}
+
+func (c *Cat) AppendBytes(content []byte, archPath string, mode cpio.FileMode) (r *Cat) {
+	r = c
+	if c.err != nil {
+		return
+	}
+
+	var err error
+	defer func() { c.err = err }()
+
+	err = c.cout.WriteHeader(&cpio.Header{
+		Name: archPath,
+		Mode: mode,
+		Size: int64(len(content)),
+	})
+	if err != nil {
+		return
+	}
+
+	_, err = c.cout.Write(content)
+
+	return
+}