1 files changed, 103 insertions, 0 deletions
diff --git a/examples/fs_implementation/main.go b/examples/fs_implementation/main.go
new file mode 100644
index 0000000..0371f7f
--- /dev/null
+++ b/examples/fs_implementation/main.go
@@ -0,0 +1,103 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/src-d/go-git.v3"
+	gogitFS "gopkg.in/src-d/go-git.v3/utils/fs"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		usage()
+		os.Exit(1)
+	}
+
+	fs := newFS(os.Args[1])
+
+	repo, err := git.NewRepositoryFromFS(fs, ".git")
+	if err != nil {
+		fmt.Fprint(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	iter, err := repo.Commits()
+	if err != nil {
+		fmt.Fprint(os.Stderr, err)
+		os.Exit(1)
+	}
+	defer iter.Close()
+
+	for {
+		commit, err := iter.Next()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+
+			fmt.Fprint(os.Stderr, err)
+			os.Exit(1)
+		}
+
+		fmt.Println(commit)
+	}
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "%s <path to .git dir>", os.Args[0])
+}
+
+// A simple proxy filesystem example: It mimics local filesystems, using
+// 'base' as its root and a funny path separator ("--").
+//
+// Example: when constructed with 'newFS("tmp")', a path like 'foo--bar'
+// will represent the local path "/tmp/foo/bar".
+type fs struct {
+	base string
+}
+
+const separator = "--"
+
+func newFS(path string) *fs {
+	return &fs{
+		base: path,
+	}
+}
+
+func (fs *fs) Stat(path string) (info os.FileInfo, err error) {
+	f, err := os.Open(fs.ToReal(path))
+	if err != nil {
+		return nil, err
+	}
+
+	defer func() {
+		errClose := f.Close()
+		if err == nil {
+			err = errClose
+		}
+	}()
+
+	return f.Stat()
+}
+
+func (fs *fs) ToReal(path string) string {
+	parts := strings.Split(path, separator)
+	return filepath.Join(fs.base, filepath.Join(parts...))
+}
+
+func (fs *fs) Open(path string) (gogitFS.ReadSeekCloser, error) {
+	return os.Open(fs.ToReal(path))
+}
+
+func (fs *fs) ReadDir(path string) ([]os.FileInfo, error) {
+	return ioutil.ReadDir(fs.ToReal(path))
+}
+
+func (fs *fs) Join(elem ...string) string {
+	return strings.Join(elem, separator)
+}