internal/pipewire: implement message header

Test cases are from interactions between pw-container and PipeWire. Results are validated against corresponding body.

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

internal/pipewire/header_test.go

@@ -0,0 +1,89 @@
+package pipewire_test
+
+import (
+	"reflect"
+	"testing"
+
+	"hakurei.app/internal/pipewire"
+)
+
+func TestHeader(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name string
+		data []byte
+		want pipewire.Header
+	}{
+		{"PW_SECURITY_CONTEXT_METHOD_CREATE", []byte{
+			// Id
+			3, 0, 0, 0,
+			// size
+			0xd8, 0, 0,
+			// opcode
+			1,
+			// seq
+			5, 0, 0, 0,
+			// n_fds
+			2, 0, 0, 0,
+		}, pipewire.Header{ID: 3, Opcode: pipewire.PW_SECURITY_CONTEXT_METHOD_CREATE,
+			Size: 0xd8, Sequence: 5, FileCount: 2}},
+
+		{"PW_SECURITY_CONTEXT_METHOD_NUM", []byte{
+			// Id
+			0, 0, 0, 0,
+			// size
+			0x28, 0, 0,
+			// opcode
+			2,
+			// seq
+			6, 0, 0, 0,
+			// n_fds
+			0, 0, 0, 0,
+		}, pipewire.Header{ID: 0, Opcode: pipewire.PW_SECURITY_CONTEXT_METHOD_NUM,
+			Size: 0x28, Sequence: 6, FileCount: 0}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			t.Run("decode", func(t *testing.T) {
+				t.Parallel()
+
+				var got pipewire.Header
+				if err := got.UnmarshalBinary(tc.data); err != nil {
+					t.Fatalf("UnmarshalBinary: error = %v", err)
+				}
+				if got != tc.want {
+					t.Fatalf("UnmarshalBinary: %#v, want %#v", got, tc.want)
+				}
+			})
+
+			t.Run("encode", func(t *testing.T) {
+				t.Parallel()
+
+				if got, err := tc.want.MarshalBinary(); err != nil {
+					t.Fatalf("MarshalBinary: error = %v", err)
+				} else if string(got) != string(tc.data) {
+					t.Fatalf("MarshalBinary: %#v, want %#v", got, tc.data)
+				}
+			})
+		})
+	}
+
+	t.Run("size range", func(t *testing.T) {
+		t.Parallel()
+
+		if _, err := (&pipewire.Header{Size: 0xff000000}).MarshalBinary(); !reflect.DeepEqual(err, pipewire.ErrSizeRange) {
+			t.Errorf("UnmarshalBinary: error = %v", err)
+		}
+	})
+
+	t.Run("header size", func(t *testing.T) {
+		t.Parallel()
+
+		if err := (*pipewire.Header)(nil).UnmarshalBinary(nil); !reflect.DeepEqual(err, pipewire.ErrBadHeader) {
+			t.Errorf("UnmarshalBinary: error = %v", err)
+		}
+	})
+}