hst/enablement: move bits from system

This is part of the hst API, should not be in the implementation package.

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

hst/enablement.go

@@ -2,15 +2,56 @@ package hst
 
 import (
 	"encoding/json"
+	"fmt"
+	"strings"
 	"syscall"
-
-	"hakurei.app/system"
 )
 
-// NewEnablements returns the address of [system.Enablement] as [Enablements].
-func NewEnablements(e system.Enablement) *Enablements { return (*Enablements)(&e) }
+// Enablement represents an optional host service to export to the target user.
+type Enablement byte
 
-// enablementsJSON is the [json] representation of the [system.Enablement] bit field.
+const (
+	EWayland Enablement = 1 << iota
+	EX11
+	EDBus
+	EPulse
+
+	EM
+)
+
+func (e Enablement) String() string {
+	switch e {
+	case 0:
+		return "(no enablements)"
+	case EWayland:
+		return "wayland"
+	case EX11:
+		return "x11"
+	case EDBus:
+		return "dbus"
+	case EPulse:
+		return "pulseaudio"
+	default:
+		buf := new(strings.Builder)
+		buf.Grow(32)
+
+		for i := Enablement(1); i < EM; i <<= 1 {
+			if e&i != 0 {
+				buf.WriteString(", " + i.String())
+			}
+		}
+
+		if buf.Len() == 0 {
+			return fmt.Sprintf("e%x", byte(e))
+		}
+		return strings.TrimPrefix(buf.String(), ", ")
+	}
+}
+
+// NewEnablements returns the address of [Enablement] as [Enablements].
+func NewEnablements(e Enablement) *Enablements { return (*Enablements)(&e) }
+
+// enablementsJSON is the [json] representation of the [Enablement] bit field.
 type enablementsJSON struct {
 	Wayland bool `json:"wayland,omitempty"`
 	X11     bool `json:"x11,omitempty"`
@@ -18,15 +59,15 @@ type enablementsJSON struct {
 	Pulse   bool `json:"pulse,omitempty"`
 }
 
-// Enablements is the [json] adapter for [system.Enablement].
-type Enablements system.Enablement
+// Enablements is the [json] adapter for [Enablement].
+type Enablements Enablement
 
-// Unwrap returns the underlying [system.Enablement].
-func (e *Enablements) Unwrap() system.Enablement {
+// Unwrap returns the underlying [Enablement].
+func (e *Enablements) Unwrap() Enablement {
 	if e == nil {
 		return 0
 	}
-	return system.Enablement(*e)
+	return Enablement(*e)
 }
 
 func (e *Enablements) MarshalJSON() ([]byte, error) {
@@ -34,10 +75,10 @@ func (e *Enablements) MarshalJSON() ([]byte, error) {
 		return nil, syscall.EINVAL
 	}
 	return json.Marshal(&enablementsJSON{
-		Wayland: system.Enablement(*e)&system.EWayland != 0,
-		X11:     system.Enablement(*e)&system.EX11 != 0,
-		DBus:    system.Enablement(*e)&system.EDBus != 0,
-		Pulse:   system.Enablement(*e)&system.EPulse != 0,
+		Wayland: Enablement(*e)&EWayland != 0,
+		X11:     Enablement(*e)&EX11 != 0,
+		DBus:    Enablement(*e)&EDBus != 0,
+		Pulse:   Enablement(*e)&EPulse != 0,
 	})
 }
 
@@ -51,18 +92,18 @@ func (e *Enablements) UnmarshalJSON(data []byte) error {
 		return err
 	}
 
-	var ve system.Enablement
+	var ve Enablement
 	if v.Wayland {
-		ve |= system.EWayland
+		ve |= EWayland
 	}
 	if v.X11 {
-		ve |= system.EX11
+		ve |= EX11
 	}
 	if v.DBus {
-		ve |= system.EDBus
+		ve |= EDBus
 	}
 	if v.Pulse {
-		ve |= system.EPulse
+		ve |= EPulse
 	}
 	*e = Enablements(ve)
 	return nil

hst/enablement_test.go

@@ -7,9 +7,44 @@ import (
 	"testing"
 
 	"hakurei.app/hst"
-	"hakurei.app/system"
 )
 
+func TestEnablementString(t *testing.T) {
+	testCases := []struct {
+		flags hst.Enablement
+		want  string
+	}{
+		{0, "(no enablements)"},
+		{hst.EWayland, "wayland"},
+		{hst.EX11, "x11"},
+		{hst.EDBus, "dbus"},
+		{hst.EPulse, "pulseaudio"},
+		{hst.EWayland | hst.EX11, "wayland, x11"},
+		{hst.EWayland | hst.EDBus, "wayland, dbus"},
+		{hst.EWayland | hst.EPulse, "wayland, pulseaudio"},
+		{hst.EX11 | hst.EDBus, "x11, dbus"},
+		{hst.EX11 | hst.EPulse, "x11, pulseaudio"},
+		{hst.EDBus | hst.EPulse, "dbus, pulseaudio"},
+		{hst.EWayland | hst.EX11 | hst.EDBus, "wayland, x11, dbus"},
+		{hst.EWayland | hst.EX11 | hst.EPulse, "wayland, x11, pulseaudio"},
+		{hst.EWayland | hst.EDBus | hst.EPulse, "wayland, dbus, pulseaudio"},
+		{hst.EX11 | hst.EDBus | hst.EPulse, "x11, dbus, pulseaudio"},
+		{hst.EWayland | hst.EX11 | hst.EDBus | hst.EPulse, "wayland, x11, dbus, pulseaudio"},
+
+		{1 << 5, "e20"},
+		{1 << 6, "e40"},
+		{1 << 7, "e80"},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.want, func(t *testing.T) {
+			if got := tc.flags.String(); got != tc.want {
+				t.Errorf("String: %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
 func TestEnablements(t *testing.T) {
 	testCases := []struct {
 		name  string
@@ -19,11 +54,11 @@ func TestEnablements(t *testing.T) {
 	}{
 		{"nil", nil, "null", `{"value":null,"magic":3236757504}`},
 		{"zero", hst.NewEnablements(0), `{}`, `{"value":{},"magic":3236757504}`},
-		{"wayland", hst.NewEnablements(system.EWayland), `{"wayland":true}`, `{"value":{"wayland":true},"magic":3236757504}`},
-		{"x11", hst.NewEnablements(system.EX11), `{"x11":true}`, `{"value":{"x11":true},"magic":3236757504}`},
-		{"dbus", hst.NewEnablements(system.EDBus), `{"dbus":true}`, `{"value":{"dbus":true},"magic":3236757504}`},
-		{"pulse", hst.NewEnablements(system.EPulse), `{"pulse":true}`, `{"value":{"pulse":true},"magic":3236757504}`},
-		{"all", hst.NewEnablements(system.EWayland | system.EX11 | system.EDBus | system.EPulse), `{"wayland":true,"x11":true,"dbus":true,"pulse":true}`, `{"value":{"wayland":true,"x11":true,"dbus":true,"pulse":true},"magic":3236757504}`},
+		{"wayland", hst.NewEnablements(hst.EWayland), `{"wayland":true}`, `{"value":{"wayland":true},"magic":3236757504}`},
+		{"x11", hst.NewEnablements(hst.EX11), `{"x11":true}`, `{"value":{"x11":true},"magic":3236757504}`},
+		{"dbus", hst.NewEnablements(hst.EDBus), `{"dbus":true}`, `{"value":{"dbus":true},"magic":3236757504}`},
+		{"pulse", hst.NewEnablements(hst.EPulse), `{"pulse":true}`, `{"value":{"pulse":true},"magic":3236757504}`},
+		{"all", hst.NewEnablements(hst.EWayland | hst.EX11 | hst.EDBus | hst.EPulse), `{"wayland":true,"x11":true,"dbus":true,"pulse":true}`, `{"value":{"wayland":true,"x11":true,"dbus":true,"pulse":true},"magic":3236757504}`},
 	}
 
 	for _, tc := range testCases {
@@ -88,7 +123,7 @@ func TestEnablements(t *testing.T) {
 		})
 
 		t.Run("val", func(t *testing.T) {
-			if got := hst.NewEnablements(system.EWayland | system.EPulse).Unwrap(); got != system.EWayland|system.EPulse {
+			if got := hst.NewEnablements(hst.EWayland | hst.EPulse).Unwrap(); got != hst.EWayland|hst.EPulse {
 				t.Errorf("Unwrap: %v", got)
 			}
 		})

hst/hst.go

@@ -8,7 +8,6 @@ import (
 
 	"hakurei.app/container"
 	"hakurei.app/container/seccomp"
-	"hakurei.app/system"
 	"hakurei.app/system/dbus"
 )
 
@@ -71,7 +70,7 @@ func Template() *Config {
 			"--ozone-platform=wayland",
 		},
 
-		Enablements: NewEnablements(system.EWayland | system.EDBus | system.EPulse),
+		Enablements: NewEnablements(EWayland | EDBus | EPulse),
 
 		SessionBus: &dbus.Config{
 			See: nil,