system: unexport Op implementations

None of these are valid with their zero value, and the implementations assume they are created by the builder methods. They are by all means an implementation detail and exporting them makes no sense.

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

system/link.go

@@ -5,29 +5,29 @@ import (
 	"os"
 )
 
-// Link appends [HardlinkOp] to [I] the [Process] criteria.
+// Link calls LinkFileType with the [Process] criteria.
 func (sys *I) Link(oldname, newname string) *I { return sys.LinkFileType(Process, oldname, newname) }
 
-// LinkFileType appends [HardlinkOp] to [I].
+// LinkFileType maintains a hardlink until its [Enablement] is no longer satisfied.
 func (sys *I) LinkFileType(et Enablement, oldname, newname string) *I {
-	sys.ops = append(sys.ops, &HardlinkOp{et, newname, oldname})
+	sys.ops = append(sys.ops, &hardlinkOp{et, newname, oldname})
 	return sys
 }
 
-// HardlinkOp maintains a hardlink until its [Enablement] is no longer satisfied.
-type HardlinkOp struct {
+// hardlinkOp implements [I.LinkFileType].
+type hardlinkOp struct {
 	et       Enablement
 	dst, src string
 }
 
-func (l *HardlinkOp) Type() Enablement { return l.et }
+func (l *hardlinkOp) Type() Enablement { return l.et }
 
-func (l *HardlinkOp) apply(*I) error {
+func (l *hardlinkOp) apply(*I) error {
 	msg.Verbose("linking", l)
 	return newOpError("hardlink", os.Link(l.src, l.dst), false)
 }
 
-func (l *HardlinkOp) revert(_ *I, ec *Criteria) error {
+func (l *hardlinkOp) revert(_ *I, ec *Criteria) error {
 	if ec.hasType(l.Type()) {
 		msg.Verbosef("removing hard link %q", l.dst)
 		return newOpError("hardlink", os.Remove(l.dst), true)
@@ -37,10 +37,10 @@ func (l *HardlinkOp) revert(_ *I, ec *Criteria) error {
 	}
 }
 
-func (l *HardlinkOp) Is(o Op) bool {
-	target, ok := o.(*HardlinkOp)
+func (l *hardlinkOp) Is(o Op) bool {
+	target, ok := o.(*hardlinkOp)
 	return ok && l != nil && target != nil && *l == *target
 }
 
-func (l *HardlinkOp) Path() string   { return l.src }
-func (l *HardlinkOp) String() string { return fmt.Sprintf("%q from %q", l.dst, l.src) }
+func (l *hardlinkOp) Path() string   { return l.src }
+func (l *hardlinkOp) String() string { return fmt.Sprintf("%q from %q", l.dst, l.src) }