Adding pathlib.File

file.go

@@ -0,0 +1,9 @@
+package pathlib
+
+import "github.com/spf13/afero"
+
+// File represents a file in the filesystem. It inherits the afero.File interface
+// but might also include additional functionality.
+type File struct {
+	afero.File
+}

path.go

@@ -90,14 +90,21 @@ func (p *Path) MkdirAll(perm os.FileMode) error {
 	return p.Fs().MkdirAll(p.Path(), perm)
 }
 
-// Open opens a file, returning it or an error, if any happens.
-func (p *Path) Open() (afero.File, error) {
-	return p.Fs().Open(p.Path())
+// Open opens a file for read-only, returning it or an error, if any happens.
+func (p *Path) Open() (*File, error) {
+	handle, err := p.Fs().Open(p.Path())
+	return &File{
+		File: handle,
+	}, err
 }
 
 // OpenFile opens a file using the given flags and the given mode.
-func (p *Path) OpenFile(flag int, perm os.FileMode) (afero.File, error) {
-	return p.Fs().OpenFile(p.Path(), flag, perm)
+// See the list of flags at: https://golang.org/pkg/os/#pkg-constants
+func (p *Path) OpenFile(flag int, perm os.FileMode) (*File, error) {
+	handle, err := p.Fs().OpenFile(p.Path(), flag, perm)
+	return &File{
+		File: handle,
+	}, err
 }
 
 // Remove removes a file, returning an error, if any
@@ -342,9 +349,16 @@ func (p *Path) IsFile() (bool, error) {
 }
 
 // IsSymlink returns true if the given path is a symlink.
+// Fails if the filesystem doesn't implement afero.Lstater.
 func (p *Path) IsSymlink() (bool, error) {
-	fileInfo, err := p.Fs().Stat(p.Path())
-	if err != nil {
+	lStater, ok := p.Fs().(afero.Lstater)
+	if !ok {
+		return false, p.doesNotImplementErr("afero.Lstater")
+	}
+	fileInfo, lstatCalled, err := lStater.LstatIfPossible(p.Path())
+	if err != nil || !lstatCalled {
+		// If lstat wasn't called then the filesystem doesn't implement it.
+		// Thus, it isn't a symlink
 		return false, err
 	}
 

path_test.go

@@ -1,7 +1,9 @@
 package pathlib
 
 import (
+	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -21,6 +23,9 @@ type PathSuite struct {
 }
 
 func (p *PathSuite) SetupTest() {
+	// We actually can't use the MemMapFs because some of the tests
+	// are testing symlink behavior. We might want to split these
+	// tests out to use MemMapFs when possible.
 	tmpdir, err := ioutil.TempDir("", "")
 	require.NoError(p.T(), err)
 	p.tmpdir = NewPath(tmpdir)
@@ -150,6 +155,81 @@ func (p *PathSuite) TestGetLatestEmpty() {
 	assert.Nil(p.T(), latest)
 }
 
+func (p *PathSuite) TestOpen() {
+	msg := "cubs > cardinals"
+	file := p.tmpdir.Join("file.txt")
+	require.NoError(p.T(), file.WriteFile([]byte(msg), 0o644))
+	fileHandle, err := file.Open()
+	require.NoError(p.T(), err)
+
+	readBytes := make([]byte, len(msg)+5)
+	n, err := fileHandle.Read(readBytes)
+	p.Equal(len(msg), n)
+	p.Equal(msg, string(readBytes[0:n]))
+}
+
+func (p *PathSuite) TestOpenFile() {
+	file := p.tmpdir.Join("file.txt")
+	fileHandle, err := file.OpenFile(os.O_RDWR|os.O_CREATE, 0o644)
+	require.NoError(p.T(), err)
+
+	msg := "do you play croquet?"
+	n, err := fileHandle.WriteString(msg)
+	p.Equal(len(msg), n)
+	p.NoError(err)
+
+	bytes := make([]byte, len(msg)+5)
+	n, err = fileHandle.ReadAt(bytes, 0)
+	p.Equal(len(msg), n)
+	p.True(errors.Is(err, io.EOF))
+	p.Equal(msg, string(bytes[0:n]))
+}
+
+func (p *PathSuite) TestDirExists() {
+	dir1 := p.tmpdir.Join("subdir")
+	exists, err := dir1.DirExists()
+	require.NoError(p.T(), err)
+	p.False(exists)
+
+	require.NoError(p.T(), dir1.Mkdir(0o755))
+	exists, err = dir1.DirExists()
+	require.NoError(p.T(), err)
+	p.True(exists)
+}
+
+func (p *PathSuite) TestIsFile() {
+	file1 := p.tmpdir.Join("file.txt")
+
+	require.NoError(p.T(), file1.WriteFile([]byte(""), 0o644))
+	exists, err := file1.IsFile()
+	require.NoError(p.T(), err)
+	p.True(exists)
+}
+
+func (p *PathSuite) TestIsEmpty() {
+	file1 := p.tmpdir.Join("file.txt")
+
+	require.NoError(p.T(), file1.WriteFile([]byte(""), 0o644))
+	isEmpty, err := file1.IsEmpty()
+	require.NoError(p.T(), err)
+	p.True(isEmpty)
+}
+
+func (p *PathSuite) TestIsSymlink() {
+	file1 := p.tmpdir.Join("file.txt")
+	require.NoError(p.T(), file1.WriteFile([]byte(""), 0o644))
+
+	symlink := p.tmpdir.Join("symlink")
+	p.NoError(symlink.Symlink(file1))
+	isSymlink, err := symlink.IsSymlink()
+	require.NoError(p.T(), err)
+	p.True(isSymlink)
+
+	stat, _ := symlink.Stat()
+	p.T().Logf("%v", stat.Mode())
+	p.T().Logf(symlink.Path())
+}
+
 func TestPathSuite(t *testing.T) {
 	suite.Run(t, new(PathSuite))
 }