hst/fs: implement link fstype

Symlinks do not require special treatment, and doing this allows placing links in order.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 58 insertions, 0 deletions

diff --git a/hst/fslink.go b/hst/fslink.go
new file mode 100644
index 00000000..8bba9b49
--- /dev/null
+++ b/hst/fslink.go
@@ -0,0 +1,58 @@
+package hst
+
+import (
+	"encoding/gob"
+	"path"
+
+	"hakurei.app/container"
+)
+
+func init() { gob.Register(new(FSLink)) }
+
+// FilesystemLink is the type string of a symbolic link.
+const FilesystemLink = "link"
+
+// FSLink represents a symlink in the container filesystem.
+type FSLink struct {
+	// link path in container
+	Target *container.Absolute `json:"dst"`
+	// linkname the symlink points to
+	Linkname string `json:"linkname"`
+	// whether to dereference linkname before creating the link
+	Dereference bool `json:"dereference,omitempty"`
+}
+
+func (l *FSLink) Valid() bool {
+	if l == nil || l.Target == nil || l.Linkname == "" {
+		return false
+	}
+	return !l.Dereference || path.IsAbs(l.Linkname)
+}
+
+func (l *FSLink) Path() *container.Absolute {
+	if !l.Valid() {
+		return nil
+	}
+	return l.Target
+}
+
+func (l *FSLink) Host() []*container.Absolute { return nil }
+
+func (l *FSLink) Apply(z *ApplyState) {
+	if !l.Valid() {
+		return
+	}
+	z.Link(l.Target, l.Linkname, l.Dereference)
+}
+
+func (l *FSLink) String() string {
+	if !l.Valid() {
+		return "<invalid>"
+	}
+
+	dereference := ""
+	if l.Dereference {
+		dereference = "*"
+	}
+	return "&" + l.Target.String() + ":" + dereference + l.Linkname
+}