system: update doc commands and remove mutex

The mutex is not really doing anything, none of these methods make sense when called concurrently anyway. The copylocks analysis is still satisfied by the noCopy struct.

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

system/link.go

@@ -5,32 +5,29 @@ import (
 	"os"
 )
 
-// Link registers an Op that links dst to src.
+// Link appends [HardlinkOp] to [I] the [Process] criteria.
 func (sys *I) Link(oldname, newname string) *I { return sys.LinkFileType(Process, oldname, newname) }
 
-// LinkFileType registers a file linking Op labelled with type et.
+// LinkFileType appends [HardlinkOp] to [I].
 func (sys *I) LinkFileType(et Enablement, oldname, newname string) *I {
-	sys.lock.Lock()
-	defer sys.lock.Unlock()
-
-	sys.ops = append(sys.ops, &Hardlink{et, newname, oldname})
-
+	sys.ops = append(sys.ops, &HardlinkOp{et, newname, oldname})
 	return sys
 }
 
-type Hardlink struct {
+// HardlinkOp maintains a hardlink until its [Enablement] is no longer satisfied.
+type HardlinkOp struct {
 	et       Enablement
 	dst, src string
 }
 
-func (l *Hardlink) Type() Enablement { return l.et }
+func (l *HardlinkOp) Type() Enablement { return l.et }
 
-func (l *Hardlink) 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 *Hardlink) revert(_ *I, ec *Criteria) error {
+func (l *HardlinkOp) revert(_ *I, ec *Criteria) error {
 	if ec.hasType(l) {
 		msg.Verbosef("removing hard link %q", l.dst)
 		return newOpError("hardlink", os.Remove(l.dst), true)
@@ -40,6 +37,10 @@ func (l *Hardlink) revert(_ *I, ec *Criteria) error {
 	}
 }
 
-func (l *Hardlink) Is(o Op) bool   { l0, ok := o.(*Hardlink); return ok && l0 != nil && *l == *l0 }
-func (l *Hardlink) Path() string   { return l.src }
-func (l *Hardlink) String() string { return fmt.Sprintf("%q from %q", l.dst, l.src) }
+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) }