1 files changed, 140 insertions, 0 deletions
diff --git a/api/option/option.go b/api/option/option.go
new file mode 100644
index 0000000..b5d2531
--- /dev/null
+++ b/api/option/option.go
@@ -0,0 +1,140 @@
+// Package option provides interface-based, resource-agnostic configuration
+// options shared by the file, dir, and link resource packages.
+package option
+
+import (
+	"log"
+	"os"
+)
+
+// Option configures a resource. It is applied to the concrete resource value
+// (e.g. *file.File) during construction.
+type Option func(any)
+
+// Capability interfaces. A resource implements only the setters it supports.
+type (
+	Owner      interface{ SetOwner(string) }
+	Grouped    interface{ SetGroup(string) }
+	Moded      interface{ SetMode(os.FileMode) }
+	Sourced    interface{ SetSource(string) }
+	Contented  interface{ SetContent(string) }
+	FileModed  interface{ SetFileMode(os.FileMode) }
+	Prunable   interface{ SetPrune() }
+	Absentable interface{ SetAbsent() }
+	Linkable   interface {
+		SetSymlink(target string)
+		SetHardlink(target string)
+	}
+)
+
+// WithOwner sets the owning user of the resource.
+func WithOwner(owner string) Option {
+	return func(t any) {
+		r, ok := t.(Owner)
+		if !ok {
+			log.Fatalf("%T does not support WithOwner", t)
+		}
+		r.SetOwner(owner)
+	}
+}
+
+// WithGroup sets the owning group of the resource.
+func WithGroup(group string) Option {
+	return func(t any) {
+		r, ok := t.(Grouped)
+		if !ok {
+			log.Fatalf("%T does not support WithGroup", t)
+		}
+		r.SetGroup(group)
+	}
+}
+
+// WithMode sets the resource's own file mode.
+func WithMode(mode os.FileMode) Option {
+	return func(t any) {
+		r, ok := t.(Moded)
+		if !ok {
+			log.Fatalf("%T does not support WithMode", t)
+		}
+		r.SetMode(mode)
+	}
+}
+
+// WithSource sets the source path the resource is populated from.
+func WithSource(source string) Option {
+	return func(t any) {
+		r, ok := t.(Sourced)
+		if !ok {
+			log.Fatalf("%T does not support WithSource", t)
+		}
+		r.SetSource(source)
+	}
+}
+
+// WithContent sets literal content for the resource.
+func WithContent(content string) Option {
+	return func(t any) {
+		r, ok := t.(Contented)
+		if !ok {
+			log.Fatalf("%T does not support WithContent", t)
+		}
+		r.SetContent(content)
+	}
+}
+
+// WithFileMode sets the mode applied to regular files copied from a source
+// tree (distinct from the resource's own mode).
+func WithFileMode(mode os.FileMode) Option {
+	return func(t any) {
+		r, ok := t.(FileModed)
+		if !ok {
+			log.Fatalf("%T does not support WithFileMode", t)
+		}
+		r.SetFileMode(mode)
+	}
+}
+
+// WithPrune enables reconciliation of extra destination entries during a
+// source copy, and recursive removal during IsAbsent().
+func WithPrune() Option {
+	return func(t any) {
+		r, ok := t.(Prunable)
+		if !ok {
+			log.Fatalf("%T does not support WithPrune", t)
+		}
+		r.SetPrune()
+	}
+}
+
+// IsAbsent marks the resource for removal.
+func IsAbsent() Option {
+	return func(t any) {
+		r, ok := t.(Absentable)
+		if !ok {
+			log.Fatalf("%T does not support IsAbsent", t)
+		}
+		r.SetAbsent()
+	}
+}
+
+// WithSymlink makes the resource a symbolic link pointing at target.
+func WithSymlink(target string) Option {
+	return func(t any) {
+		r, ok := t.(Linkable)
+		if !ok {
+			log.Fatalf("%T does not support WithSymlink", t)
+		}
+		r.SetSymlink(target)
+	}
+}
+
+// WithHardlink makes the resource a hard link pointing at target.
+func WithHardlink(target string) Option {
+	return func(t any) {
+		r, ok := t.(Linkable)
+		if !ok {
+			log.Fatalf("%T does not support WithHardlink", t)
+		}
+		r.SetHardlink(target)
+	}
+}