internal/pipewire: implement client generation footer

This corresponds with the core generation footer and seem to be the only other possible footer type.

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

internal/pipewire/core.go

@@ -81,6 +81,16 @@ type FooterCoreGeneration struct {
 	RegistryGeneration Long `json:"registry_generation"`
 }
 
+// The FooterClientGeneration indicates to the server what is the last
+// registry generation number the client has processed.
+//
+// The client shall include this footer in the next message it sends,
+// after it has processed an incoming message whose footer includes a
+// registry generation update.
+type FooterClientGeneration struct {
+	ClientGeneration Long `json:"client_generation"`
+}
+
 // A CoreInfo event is emitted by the server upon connection
 // with the more information about the server.
 type CoreInfo struct {

internal/pipewire/core_test.go

@@ -10,15 +10,32 @@ func TestFooterCoreGeneration(t *testing.T) {
 	t.Parallel()
 
 	encodingTestCases[pipewire.Footer[pipewire.FooterCoreGeneration], *pipewire.Footer[pipewire.FooterCoreGeneration]]{
-		{"sample", samplePWContainer[1][0][2], pipewire.Footer[pipewire.FooterCoreGeneration]{
+		/* recvmsg 0 */
+
+		{"sample0", samplePWContainer[1][0][2], pipewire.Footer[pipewire.FooterCoreGeneration]{
 			Opcode:  pipewire.FOOTER_CORE_OPCODE_GENERATION,
 			Payload: pipewire.FooterCoreGeneration{RegistryGeneration: 0x22},
 		}, nil},
 
-		{"sample*", samplePWContainer[1][5][2], pipewire.Footer[pipewire.FooterCoreGeneration]{
+		{"sample1", samplePWContainer[1][5][2], pipewire.Footer[pipewire.FooterCoreGeneration]{
 			Opcode:  pipewire.FOOTER_CORE_OPCODE_GENERATION,
 			Payload: pipewire.FooterCoreGeneration{RegistryGeneration: 0x23},
 		}, nil},
+
+		{"sample2", samplePWContainer[1][42][2], pipewire.Footer[pipewire.FooterCoreGeneration]{
+			Opcode:  pipewire.FOOTER_CORE_OPCODE_GENERATION,
+			Payload: pipewire.FooterCoreGeneration{RegistryGeneration: 0x24},
+		}, nil},
+	}.run(t)
+
+	encodingTestCases[pipewire.Footer[pipewire.FooterClientGeneration], *pipewire.Footer[pipewire.FooterClientGeneration]]{
+		/* sendmsg 1 */
+
+		{"sample0", samplePWContainer[3][0][2], pipewire.Footer[pipewire.FooterClientGeneration]{
+			Opcode: pipewire.FOOTER_CORE_OPCODE_GENERATION,
+			// why does this not match FooterCoreGeneration sample2?
+			Payload: pipewire.FooterClientGeneration{ClientGeneration: 0x23},
+		}, nil},
 	}.run(t)
 }