// Open opens a given snap file with the right backend
func Open(path string) (Container, error) {
// see if it's a snapdir first
if osutil.FileExists(filepath.Join(path, "meta", "snap.yaml")) {
return snapdir.New(path), nil
}
// open the file and check magic
f, err := os.Open(path)
if err != nil {
return nil, fmt.Errorf("cannot open snap: %v", err)
}
defer f.Close()
header := make([]byte, 20)
if _, err := f.ReadAt(header, 0); err != nil {
return nil, fmt.Errorf("cannot read snap: %v", err)
}
for _, h := range formatHandlers {
if bytes.HasPrefix(header, h.magic) {
return h.open(path)
}
}
return nil, fmt.Errorf("cannot open snap: unknown header: %q", header)
}
func (s *SnapdirTestSuite) TestReadFile(c *C) {
d := c.MkDir()
needle := []byte(`stuff`)
err := ioutil.WriteFile(filepath.Join(d, "foo"), needle, 0644)
c.Assert(err, IsNil)
snap := snapdir.New(d)
content, err := snap.ReadFile("foo")
c.Assert(err, IsNil)
c.Assert(content, DeepEquals, needle)
}
func (s *SnapdirTestSuite) TestInstall(c *C) {
tryBaseDir := c.MkDir()
snap := snapdir.New(tryBaseDir)
varLibSnapd := c.MkDir()
targetPath := filepath.Join(varLibSnapd, "foo_1.0.snap")
err := snap.Install(targetPath, "unused-mount-dir")
c.Assert(err, IsNil)
symlinkTarget, err := filepath.EvalSymlinks(targetPath)
c.Assert(err, IsNil)
c.Assert(symlinkTarget, Equals, tryBaseDir)
}
func (s *SnapdirTestSuite) TestListDir(c *C) {
d := c.MkDir()
err := os.MkdirAll(filepath.Join(d, "test"), 0755)
c.Assert(err, IsNil)
err = ioutil.WriteFile(filepath.Join(d, "test", "test1"), nil, 0644)
c.Assert(err, IsNil)
err = ioutil.WriteFile(filepath.Join(d, "test", "test2"), nil, 0644)
c.Assert(err, IsNil)
snap := snapdir.New(d)
fileNames, err := snap.ListDir("test")
c.Assert(err, IsNil)
c.Assert(fileNames, HasLen, 2)
c.Check(fileNames[0], Equals, "test1")
c.Check(fileNames[1], Equals, "test2")
}