ipc: Add support for reference space usage

src/xrt/ipc/client/ipc_client_space_overseer.c

@@ -7,6 +7,7 @@
  * @ingroup ipc_client
  */
 
+#include "xrt/xrt_defines.h"
 #include "xrt/xrt_space.h"
 
 #include "ipc_client_generated.h"
@@ -26,6 +27,8 @@ struct ipc_client_space_overseer
 	struct xrt_space_overseer base;
 
 	struct ipc_connection *ipc_c;
+
+	struct xrt_reference ref_space_use[XRT_SPACE_REFERENCE_TYPE_COUNT];
 };
 
 
@@ -171,6 +174,42 @@ locate_device(struct xrt_space_overseer *xso,
 	IPC_CHK_ALWAYS_RET(icspo->ipc_c, xret, "ipc_call_space_locate_device");
 }
 
+static xrt_result_t
+ref_space_inc(struct xrt_space_overseer *xso, enum xrt_reference_space_type type)
+{
+	struct ipc_client_space_overseer *icspo = ipc_client_space_overseer(xso);
+	xrt_result_t xret;
+
+	// No more checking then this.
+	assert(type < XRT_SPACE_REFERENCE_TYPE_COUNT);
+
+	// If it wasn't zero nothing to do.
+	if (!xrt_reference_inc_and_was_zero(&icspo->ref_space_use[type])) {
+		return XRT_SUCCESS;
+	}
+
+	xret = ipc_call_space_mark_ref_space_in_use(icspo->ipc_c, type);
+	IPC_CHK_ALWAYS_RET(icspo->ipc_c, xret, "ipc_call_space_mark_ref_space_in_use");
+}
+
+static xrt_result_t
+ref_space_dec(struct xrt_space_overseer *xso, enum xrt_reference_space_type type)
+{
+	struct ipc_client_space_overseer *icspo = ipc_client_space_overseer(xso);
+	xrt_result_t xret;
+
+	// No more checking then this.
+	assert(type < XRT_SPACE_REFERENCE_TYPE_COUNT);
+
+	// If it is not zero we are done.
+	if (!xrt_reference_dec_and_is_zero(&icspo->ref_space_use[type])) {
+		return XRT_SUCCESS;
+	}
+
+	xret = ipc_call_space_unmark_ref_space_in_use(icspo->ipc_c, type);
+	IPC_CHK_ALWAYS_RET(icspo->ipc_c, xret, "ipc_call_space_unmark_ref_space_in_use");
+}
+
 static void
 destroy(struct xrt_space_overseer *xso)
 {
@@ -219,6 +258,8 @@ ipc_client_space_overseer_create(struct ipc_connection *ipc_c)
 	icspo->base.create_pose_space = create_pose_space;
 	icspo->base.locate_space = locate_space;
 	icspo->base.locate_device = locate_device;
+	icspo->base.ref_space_inc = ref_space_inc;
+	icspo->base.ref_space_dec = ref_space_dec;
 	icspo->base.destroy = destroy;
 	icspo->ipc_c = ipc_c;
 

src/xrt/ipc/server/ipc_server.h

@@ -117,6 +117,9 @@ struct ipc_client_state
 	//! Ptrs to the spaces.
 	struct xtr_space *xspcs[IPC_MAX_CLIENT_SPACES];
 
+	//! Which of the references spaces is the client using.
+	bool ref_space_used[XRT_SPACE_REFERENCE_TYPE_COUNT];
+
 	//! Socket fd used for client comms
 	struct ipc_message_channel imc;
 

src/xrt/ipc/server/ipc_server_handler.c

@@ -82,6 +82,17 @@ set_swapchain_info(volatile struct ipc_client_state *ics,
 	ics->swapchain_data[index].image_count = xsc->image_count;
 }
 
+static xrt_result_t
+validate_reference_space_type(volatile struct ipc_client_state *ics, enum xrt_reference_space_type type)
+{
+	if ((uint32_t)type >= XRT_SPACE_REFERENCE_TYPE_COUNT) {
+		IPC_ERROR(ics->server, "Invalid reference space type %u", type);
+		return XRT_ERROR_IPC_FAILURE;
+	}
+
+	return XRT_SUCCESS;
+}
+
 static xrt_result_t
 validate_space_id(volatile struct ipc_client_state *ics, int64_t space_id, struct xrt_space **out_xspc)
 {
@@ -477,6 +488,63 @@ ipc_handle_space_destroy(volatile struct ipc_client_state *ics, uint32_t space_i
 	return XRT_SUCCESS;
 }
 
+xrt_result_t
+ipc_handle_space_mark_ref_space_in_use(volatile struct ipc_client_state *ics, enum xrt_reference_space_type type)
+{
+	struct xrt_space_overseer *xso = ics->server->xso;
+	xrt_result_t xret;
+
+	xret = validate_reference_space_type(ics, type);
+	if (xret != XRT_SUCCESS) {
+		return XRT_ERROR_IPC_FAILURE;
+	}
+
+	// Is this space already used?
+	if (ics->ref_space_used[type]) {
+		IPC_ERROR(ics->server, "Space '%u' already used!", type);
+		return XRT_ERROR_IPC_FAILURE;
+	}
+
+	xret = xrt_space_overseer_ref_space_inc(xso, type);
+	if (xret != XRT_SUCCESS) {
+		IPC_ERROR(ics->server, "xrt_space_overseer_ref_space_inc failed");
+		return xret;
+	}
+
+	// Can now mark it as used.
+	ics->ref_space_used[type] = true;
+
+	return XRT_SUCCESS;
+}
+
+xrt_result_t
+ipc_handle_space_unmark_ref_space_in_use(volatile struct ipc_client_state *ics, enum xrt_reference_space_type type)
+{
+	struct xrt_space_overseer *xso = ics->server->xso;
+	xrt_result_t xret;
+
+	xret = validate_reference_space_type(ics, type);
+	if (xret != XRT_SUCCESS) {
+		return XRT_ERROR_IPC_FAILURE;
+	}
+
+	if (!ics->ref_space_used[type]) {
+		IPC_ERROR(ics->server, "Space '%u' not used!", type);
+		return XRT_ERROR_IPC_FAILURE;
+	}
+
+	xret = xrt_space_overseer_ref_space_dec(xso, type);
+	if (xret != XRT_SUCCESS) {
+		IPC_ERROR(ics->server, "xrt_space_overseer_ref_space_dec failed");
+		return xret;
+	}
+
+	// Now we can mark it as not used.
+	ics->ref_space_used[type] = false;
+
+	return XRT_SUCCESS;
+}
+
 xrt_result_t
 ipc_handle_compositor_get_info(volatile struct ipc_client_state *ics, struct xrt_compositor_info *out_info)
 {

src/xrt/ipc/server/ipc_server_per_client_thread.c

@@ -67,6 +67,17 @@ common_shutdown(volatile struct ipc_client_state *ics)
 		xrt_space_reference((struct xrt_space **)&ics->xspcs[i], NULL);
 	}
 
+	// Mark an still in use reference spaces as no longer used.
+	for (uint32_t i = 0; i < ARRAY_SIZE(ics->ref_space_used); i++) {
+		bool used = ics->ref_space_used[i];
+		if (!used) {
+			continue;
+		}
+
+		xrt_space_overseer_ref_space_dec(ics->server->xso, i);
+		ics->ref_space_used[i] = false;
+	}
+
 	// Should we stop the server when a client disconnects?
 	if (ics->server->exit_on_disconnect) {
 		ics->server->running = false;

src/xrt/ipc/shared/ipc_protocol.h

@@ -19,6 +19,7 @@
 #include "xrt/xrt_instance.h"
 #include "xrt/xrt_compositor.h"
 #include "xrt/xrt_device.h"
+#include "xrt/xrt_space.h"
 #include "xrt/xrt_tracking.h"
 #include "xrt/xrt_config_build.h"
 

src/xrt/ipc/shared/proto.json

@@ -136,6 +136,18 @@
 		]
 	},
 
+	"space_mark_ref_space_in_use": {
+		"in": [
+			{"name": "type", "type": "enum xrt_reference_space_type"}
+		]
+	},
+
+	"space_unmark_ref_space_in_use": {
+		"in": [
+			{"name": "type", "type": "enum xrt_reference_space_type"}
+		]
+	},
+
 	"compositor_get_info": {
 		"out": [
 			{"name": "info", "type": "struct xrt_compositor_info"}