Add Plan 9 support

Not all the tests pass yet but this makes go-git usable on Plan 9.
Please merge this after https://github.com/src-d/go-billy/pull/78.

Fixes #756

Signed-off-by: Fazlul Shahriar <fshahriar@gmail.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/worktree_plan9.go b/worktree_plan9.go
new file mode 100644
index 0000000..16d3915
--- /dev/null
+++ b/worktree_plan9.go
@@ -0,0 +1,31 @@
+package git
+
+import (
+	"syscall"
+	"time"
+
+	"gopkg.in/src-d/go-git.v4/plumbing/format/index"
+)
+
+func init() {
+	fillSystemInfo = func(e *index.Entry, sys interface{}) {
+		if os, ok := sys.(*syscall.Dir); ok {
+			// Plan 9 doesn't have a CreatedAt field.
+			e.CreatedAt = time.Unix(int64(os.Mtime), 0)
+
+			e.Dev = uint32(os.Dev)
+
+			// Plan 9 has no Inode.
+			// ext2srv(4) appears to store Inode in Qid.Path.
+			e.Inode = uint32(os.Qid.Path)
+
+			// Plan 9 has string UID/GID
+			e.GID = 0
+			e.UID = 0
+		}
+	}
+}
+
+func isSymlinkWindowsNonAdmin(err error) bool {
+	return true
+}