internal/system: relocate from system

These packages are highly specific to hakurei and are difficult to use safely from other pieces of code.

Their exported symbols are made available until v0.4.0 where they will be removed for #24.

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

internal/system/mkdir.go

@@ -0,0 +1,76 @@
+package system
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"hakurei.app/container/check"
+	"hakurei.app/hst"
+)
+
+// Ensure ensures the existence of a directory.
+func (sys *I) Ensure(name *check.Absolute, perm os.FileMode) *I {
+	sys.ops = append(sys.ops, &mkdirOp{User, name.String(), perm, false})
+	return sys
+}
+
+// Ephemeral ensures the existence of a directory until its [Enablement] is no longer satisfied.
+func (sys *I) Ephemeral(et hst.Enablement, name *check.Absolute, perm os.FileMode) *I {
+	sys.ops = append(sys.ops, &mkdirOp{et, name.String(), perm, true})
+	return sys
+}
+
+// mkdirOp implements [I.Ensure] and [I.Ephemeral].
+type mkdirOp struct {
+	et        hst.Enablement
+	path      string
+	perm      os.FileMode
+	ephemeral bool
+}
+
+func (m *mkdirOp) Type() hst.Enablement { return m.et }
+
+func (m *mkdirOp) apply(sys *I) error {
+	sys.msg.Verbose("ensuring directory", m)
+
+	if err := sys.mkdir(m.path, m.perm); err != nil {
+		if !errors.Is(err, os.ErrExist) {
+			return newOpError("mkdir", err, false)
+		}
+		// directory exists, ensure mode
+		return newOpError("mkdir", sys.chmod(m.path, m.perm), false)
+	} else {
+		return nil
+	}
+}
+
+func (m *mkdirOp) revert(sys *I, ec *Criteria) error {
+	if !m.ephemeral {
+		// skip non-ephemeral dir and do not log anything
+		return nil
+	}
+
+	if ec.hasType(m.Type()) {
+		sys.msg.Verbose("destroying ephemeral directory", m)
+		return newOpError("mkdir", sys.remove(m.path), true)
+	} else {
+		sys.msg.Verbose("skipping ephemeral directory", m)
+		return nil
+	}
+}
+
+func (m *mkdirOp) Is(o Op) bool {
+	target, ok := o.(*mkdirOp)
+	return ok && m != nil && target != nil && *m == *target
+}
+
+func (m *mkdirOp) Path() string { return m.path }
+
+func (m *mkdirOp) String() string {
+	t := "ensure"
+	if m.ephemeral {
+		t = TypeString(m.Type())
+	}
+	return fmt.Sprintf("mode: %s type: %s path: %q", m.perm.String(), t, m.path)
+}