utils/fs: add OpenFile method to filesystem interface. (#104)

* utils/fs: add OpenFile method to filesystem interface.

* added OpenFile to fs.Filesystem interface.
* added OpenFile implementation to 'os' filesystem.
* bring back BaseFile.

* utils/fs/os: do not use wildcard import.

* utils/fs/os: implement Open and Create using OpenFile.

3 files changed, 163 insertions, 52 deletions

diff --git a/utils/fs/fs.go b/utils/fs/fs.go
index 463425c..7e6c01f 100644
--- a/utils/fs/fs.go
+++ b/utils/fs/fs.go
@@ -14,10 +14,9 @@ var (
 )
 
 type Filesystem interface {
-	//Create opens a file in write-only mode.
 	Create(filename string) (File, error)
-	//Open opens a file in read-only mode.
 	Open(filename string) (File, error)
+	OpenFile(filename string, flag int, perm os.FileMode) (File, error)
 	Stat(filename string) (FileInfo, error)
 	ReadDir(path string) ([]FileInfo, error)
 	TempFile(dir, prefix string) (File, error)
@@ -38,3 +37,16 @@ type File interface {
 }
 
 type FileInfo os.FileInfo
+
+type BaseFile struct {
+	BaseFilename string
+	Closed       bool
+}
+
+func (f *BaseFile) Filename() string {
+	return f.BaseFilename
+}
+
+func (f *BaseFile) IsClosed() bool {
+	return f.Closed
+}
diff --git a/utils/fs/os/os.go b/utils/fs/os/os.go
index 800bd41..02395d6 100644
--- a/utils/fs/os/os.go
+++ b/utils/fs/os/os.go
@@ -6,7 +6,7 @@ import (
 	"path"
 	"path/filepath"
 
-	. "gopkg.in/src-d/go-git.v4/utils/fs"
+	"gopkg.in/src-d/go-git.v4/utils/fs"
 )
 
 // OS a filesystem base on the os filesystem
@@ -21,15 +21,24 @@ func NewOS(baseDir string) *OS {
 	}
 }
 
-// Create creates a new GlusterFSFile
-func (fs *OS) Create(filename string) (File, error) {
+// Create creates a file and opens it with standard permissions
+// and modes O_RDWR, O_CREATE and O_TRUNC.
+func (fs *OS) Create(filename string) (fs.File, error) {
+	return fs.OpenFile(filename, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
+}
+
+// OpenFile is equivalent to standard os.OpenFile.
+// If flag os.O_CREATE is set, all parent directories will be created.
+func (fs *OS) OpenFile(filename string, flag int, perm os.FileMode) (fs.File, error) {
 	fullpath := path.Join(fs.base, filename)
 
-	if err := fs.createDir(fullpath); err != nil {
-		return nil, err
+	if flag|os.O_CREATE != 0 {
+		if err := fs.createDir(fullpath); err != nil {
+			return nil, err
+		}
 	}
 
-	f, err := os.Create(fullpath)
+	f, err := os.OpenFile(fullpath, flag, perm)
 	if err != nil {
 		return nil, err
 	}
@@ -55,15 +64,15 @@ func (fs *OS) createDir(fullpath string) error {
 
 // ReadDir returns the filesystem info for all the archives under the specified
 // path.
-func (fs *OS) ReadDir(path string) ([]FileInfo, error) {
-	fullpath := fs.Join(fs.base, path)
+func (ofs *OS) ReadDir(path string) ([]fs.FileInfo, error) {
+	fullpath := ofs.Join(ofs.base, path)
 
 	l, err := ioutil.ReadDir(fullpath)
 	if err != nil {
 		return nil, err
 	}
 
-	var s = make([]FileInfo, len(l))
+	var s = make([]fs.FileInfo, len(l))
 	for i, f := range l {
 		s[i] = f
 	}
@@ -82,20 +91,13 @@ func (fs *OS) Rename(from, to string) error {
 	return os.Rename(from, to)
 }
 
-// Open opens the named file for reading. If successful, methods on the returned
-// file can be used for reading only.
-func (fs *OS) Open(filename string) (File, error) {
-	fullpath := fs.Join(fs.base, filename)
-	f, err := os.Open(fullpath)
-	if err != nil {
-		return nil, err
-	}
-
-	return newOSFile(filename, f), nil
+// Open opens a file in read-only mode.
+func (fs *OS) Open(filename string) (fs.File, error) {
+	return fs.OpenFile(filename, os.O_RDONLY, 0)
 }
 
 // Stat returns the FileInfo structure describing file.
-func (fs *OS) Stat(filename string) (FileInfo, error) {
+func (fs *OS) Stat(filename string) (fs.FileInfo, error) {
 	fullpath := fs.Join(fs.base, filename)
 	return os.Stat(fullpath)
 }
@@ -105,7 +107,7 @@ func (fs *OS) Remove(filename string) error {
 	return os.Remove(fullpath)
 }
 
-func (fs *OS) TempFile(dir, prefix string) (File, error) {
+func (fs *OS) TempFile(dir, prefix string) (fs.File, error) {
 	fullpath := fs.Join(fs.base, dir)
 	if err := fs.createDir(fullpath + string(os.PathSeparator)); err != nil {
 		return nil, err
@@ -136,7 +138,7 @@ func (fs *OS) Join(elem ...string) string {
 
 // Dir returns a new Filesystem from the same type of fs using as baseDir the
 // given path
-func (fs *OS) Dir(path string) Filesystem {
+func (fs *OS) Dir(path string) fs.Filesystem {
 	return NewOS(fs.Join(fs.base, path))
 }
 
@@ -147,15 +149,13 @@ func (fs *OS) Base() string {
 
 // osFile represents a file in the os filesystem
 type osFile struct {
-	filename string
-	closed   bool
-	file     *os.File
+	fs.BaseFile
+	file *os.File
 }
 
-func newOSFile(filename string, file *os.File) File {
+func newOSFile(filename string, file *os.File) fs.File {
 	return &osFile{
-		filename: filename,
-		closed:   false,
+		BaseFile: fs.BaseFile{BaseFilename: filename},
 		file:     file,
 	}
 }
@@ -173,7 +173,7 @@ func (f *osFile) Write(p []byte) (int, error) {
 }
 
 func (f *osFile) Close() error {
-	f.closed = true
+	f.BaseFile.Closed = true
 
 	return f.file.Close()
 }
@@ -181,13 +181,3 @@ func (f *osFile) Close() error {
 func (f *osFile) ReadAt(p []byte, off int64) (n int, err error) {
 	return f.file.ReadAt(p, off)
 }
-
-//Filename returns the filename from the File
-func (f *osFile) Filename() string {
-	return f.filename
-}
-
-//IsClosed returns if te file is closed
-func (f *osFile) IsClosed() bool {
-	return f.closed
-}
diff --git a/utils/fs/test/fs_suite.go b/utils/fs/test/fs_suite.go
index a809309..4c0fd09 100644
--- a/utils/fs/test/fs_suite.go
+++ b/utils/fs/test/fs_suite.go
@@ -3,6 +3,7 @@ package test
 import (
 	"fmt"
 	"io/ioutil"
+	"os"
 	"strings"
 	"testing"
 
@@ -35,13 +36,13 @@ func (s *FilesystemSuite) TestCreateDepthAbsolute(c *C) {
 }
 
 func (s *FilesystemSuite) TestCreateOverwrite(c *C) {
-	for i := 0; i < 2; i++ {
+	for i := 0; i < 3; i++ {
 		f, err := s.Fs.Create("foo")
 		c.Assert(err, IsNil)
 
-		l, err := f.Write([]byte("foo"))
+		l, err := f.Write([]byte(fmt.Sprintf("foo%d", i)))
 		c.Assert(err, IsNil)
-		c.Assert(l, Equals, 3)
+		c.Assert(l, Equals, 4)
 
 		err = f.Close()
 		c.Assert(err, IsNil)
@@ -52,7 +53,7 @@ func (s *FilesystemSuite) TestCreateOverwrite(c *C) {
 
 	wrote, err := ioutil.ReadAll(f)
 	c.Assert(err, IsNil)
-	c.Assert(wrote, DeepEquals, []byte("foo"))
+	c.Assert(string(wrote), DeepEquals, "foo2")
 }
 
 func (s *FilesystemSuite) TestCreateClose(c *C) {
@@ -60,17 +61,127 @@ func (s *FilesystemSuite) TestCreateClose(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(f.IsClosed(), Equals, false)
 
-	f.Write([]byte("foo"))
+	_, err = f.Write([]byte("foo"))
+	c.Assert(err, IsNil)
+	c.Assert(f.Close(), IsNil)
+
+	f, err = s.Fs.Open(f.Filename())
+	c.Assert(err, IsNil)
+
+	wrote, err := ioutil.ReadAll(f)
+	c.Assert(err, IsNil)
+	c.Assert(string(wrote), DeepEquals, "foo")
 	c.Assert(f.Close(), IsNil)
+}
+
+func (s *FilesystemSuite) TestOpenFileNoTruncate(c *C) {
+	defaultMode := os.FileMode(0666)
+
+	// Create when it does not exist
+	f, err := s.Fs.OpenFile("foo1", os.O_CREATE|os.O_WRONLY, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testWriteClose(c, f, "foo1")
+
+	f, err = s.Fs.OpenFile("foo1", os.O_RDONLY, defaultMode)
+	c.Assert(err, IsNil)
+	s.testReadClose(c, f, "foo1")
+
+	// Create when it does exist
+	f, err = s.Fs.OpenFile("foo1", os.O_CREATE|os.O_WRONLY, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testWriteClose(c, f, "bar")
+
+	f, err = s.Fs.OpenFile("foo1", os.O_RDONLY, defaultMode)
+	c.Assert(err, IsNil)
+	s.testReadClose(c, f, "bar1")
+}
+
+func (s *FilesystemSuite) TestOpenFileAppend(c *C) {
+	defaultMode := os.FileMode(0666)
+
+	f, err := s.Fs.OpenFile("foo1", os.O_CREATE|os.O_WRONLY|os.O_APPEND, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testWriteClose(c, f, "foo1")
+
+	f, err = s.Fs.OpenFile("foo1", os.O_WRONLY|os.O_APPEND, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testWriteClose(c, f, "bar1")
+
+	f, err = s.Fs.OpenFile("foo1", os.O_RDONLY, defaultMode)
+	c.Assert(err, IsNil)
+	s.testReadClose(c, f, "foo1bar1")
+}
+
+func (s *FilesystemSuite) TestOpenFileReadWrite(c *C) {
+	defaultMode := os.FileMode(0666)
 
-	file, err := s.Fs.Open(f.Filename())
+	f, err := s.Fs.OpenFile("foo1", os.O_CREATE|os.O_TRUNC|os.O_RDWR, defaultMode)
 	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
 
-	wrote, err := ioutil.ReadAll(file)
+	written, err := f.Write([]byte("foobar"))
+	c.Assert(written, Equals, 6)
 	c.Assert(err, IsNil)
-	c.Assert(wrote, DeepEquals, []byte("foo"))
 
-	c.Assert(f.IsClosed(), Equals, true)
+	_, err = f.Seek(0, os.SEEK_SET)
+	c.Assert(err, IsNil)
+
+	written, err = f.Write([]byte("qux"))
+	c.Assert(written, Equals, 3)
+	c.Assert(err, IsNil)
+
+	_, err = f.Seek(0, os.SEEK_SET)
+	c.Assert(err, IsNil)
+
+	s.testReadClose(c, f, "quxbar")
+}
+
+func (s *FilesystemSuite) TestOpenFile(c *C) {
+	defaultMode := os.FileMode(0666)
+
+	f, err := s.Fs.OpenFile("foo1", os.O_CREATE|os.O_WRONLY|os.O_TRUNC, defaultMode)
+	c.Assert(err, IsNil)
+	s.testWriteClose(c, f, "foo1")
+
+	// Truncate if it exists
+	f, err = s.Fs.OpenFile("foo1", os.O_CREATE|os.O_WRONLY|os.O_TRUNC, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testWriteClose(c, f, "foo1overwritten")
+
+	// Read-only if it exists
+	f, err = s.Fs.OpenFile("foo1", os.O_RDONLY, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testReadClose(c, f, "foo1overwritten")
+
+	// Create when it does exist
+	f, err = s.Fs.OpenFile("foo1", os.O_CREATE|os.O_WRONLY|os.O_TRUNC, defaultMode)
+	c.Assert(err, IsNil)
+	c.Assert(f.Filename(), Equals, "foo1")
+	s.testWriteClose(c, f, "bar")
+
+	f, err = s.Fs.OpenFile("foo1", os.O_RDONLY, defaultMode)
+	c.Assert(err, IsNil)
+	s.testReadClose(c, f, "bar")
+}
+
+func (s *FilesystemSuite) testWriteClose(c *C, f File, content string) {
+	written, err := f.Write([]byte(content))
+	c.Assert(written, Equals, len(content))
+	c.Assert(err, IsNil)
+	c.Assert(f.Close(), IsNil)
+}
+
+func (s *FilesystemSuite) testReadClose(c *C, f File, content string) {
+	read, err := ioutil.ReadAll(f)
+	c.Assert(err, IsNil)
+	c.Assert(string(read), Equals, content)
+	c.Assert(f.Close(), IsNil)
 }
 
 func (s *FilesystemSuite) TestReadDirAndDir(c *C) {
@@ -148,14 +259,12 @@ func (s *FilesystemSuite) TestTempFile(c *C) {
 func (s *FilesystemSuite) TestTempFileWithPath(c *C) {
 	f, err := s.Fs.TempFile("foo", "bar")
 	c.Assert(err, IsNil)
-	fmt.Printf("f: %s\n", f.Filename())
 	c.Assert(strings.HasPrefix(f.Filename(), s.Fs.Join("foo", "bar")), Equals, true)
 }
 
 func (s *FilesystemSuite) TestTempFileFullWithPath(c *C) {
 	f, err := s.Fs.TempFile("/foo", "bar")
 	c.Assert(err, IsNil)
-	fmt.Printf("f: %s\n", f.Filename())
 	c.Assert(strings.HasPrefix(f.Filename(), s.Fs.Join("foo", "bar")), Equals, true)
 }