From 7b523884249f904f45b1e9a7eae8152c2ac1248d Mon Sep 17 00:00:00 2001
From: nyorain <nyorain@gmail.com>
Date: Mon, 24 Sep 2018 23:17:08 +0200
Subject: Rework session handling

Sessions can now be retrieved from a backend in a more general manner.
Multi-backend gets back its `session` field that contains the session
if one was created, removing the interfacing from multi backend with the
drm backend directly. This adds the possibility to use sessions even
without the drm backend.

It additionally fixes the bug that 2 session objects got created when
WLR_BACKENDS were set to "libinput,drm".

To allow vt switching without drm backend (and drm fd) on logind, start
listening to PropertiesChanged signals from dbus and parse the session
"Active" property when no master fd was created (this does not change
current drm backend behaviour in any way).
---
 backend/backend.c | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

(limited to 'backend/backend.c')

diff --git a/backend/backend.c b/backend/backend.c
index 78b90007..2d6464b7 100644
--- a/backend/backend.c
+++ b/backend/backend.c
@@ -15,6 +15,7 @@
 #include <wlr/backend/wayland.h>
 #include <wlr/config.h>
 #include <wlr/util/log.h>
+#include "backend/multi.h"
 
 /* WLR_HAS_X11_BACKEND needs to be after wlr/config.h */
 #ifdef WLR_HAS_X11_BACKEND
@@ -56,6 +57,13 @@ struct wlr_renderer *wlr_backend_get_renderer(struct wlr_backend *backend) {
 	return NULL;
 }
 
+struct wlr_session *wlr_backend_get_session(struct wlr_backend *backend) {
+	if (backend->impl->get_session) {
+		return backend->impl->get_session(backend);
+	}
+	return NULL;
+}
+
 static size_t parse_outputs_env(const char *name) {
 	const char *outputs_str = getenv(name);
 	if (outputs_str == NULL) {
@@ -158,10 +166,12 @@ static struct wlr_backend *attempt_backend_by_name(struct wl_display *display,
 		return attempt_headless_backend(display, create_renderer_func);
 	} else if (strcmp(name, "drm") == 0 || strcmp(name, "libinput") == 0) {
 		// DRM and libinput need a session
-		*session = wlr_session_create(display);
 		if (!*session) {
-			wlr_log(WLR_ERROR, "failed to start a session");
-			return NULL;
+			*session = wlr_session_create(display);
+			if (!*session) {
+				wlr_log(WLR_ERROR, "failed to start a session");
+				return NULL;
+			}
 		}
 
 		if (strcmp(name, "libinput") == 0) {
@@ -178,13 +188,12 @@ static struct wlr_backend *attempt_backend_by_name(struct wl_display *display,
 struct wlr_backend *wlr_backend_autocreate(struct wl_display *display,
 		wlr_renderer_create_func_t create_renderer_func) {
 	struct wlr_backend *backend = wlr_multi_backend_create(display);
+	struct wlr_multi_backend *multi = (struct wlr_multi_backend *)backend;
 	if (!backend) {
 		wlr_log(WLR_ERROR, "could not allocate multibackend");
 		return NULL;
 	}
 
-	struct wlr_session *session = NULL;
-
 	char *names = getenv("WLR_BACKENDS");
 	if (names) {
 		names = strdup(names);
@@ -197,12 +206,12 @@ struct wlr_backend *wlr_backend_autocreate(struct wl_display *display,
 		char *saveptr;
 		char *name = strtok_r(names, ",", &saveptr);
 		while (name != NULL) {
-			struct wlr_backend *subbackend =
-				attempt_backend_by_name(display, backend, &session, name, create_renderer_func);
+			struct wlr_backend *subbackend = attempt_backend_by_name(display,
+				backend, &multi->session, name, create_renderer_func);
 			if (subbackend == NULL) {
 				wlr_log(WLR_ERROR, "failed to start backend '%s'", name);
 				wlr_backend_destroy(backend);
-				wlr_session_destroy(session);
+				wlr_session_destroy(multi->session);
 				free(names);
 				return NULL;
 			}
@@ -210,7 +219,7 @@ struct wlr_backend *wlr_backend_autocreate(struct wl_display *display,
 			if (!wlr_multi_backend_add(backend, subbackend)) {
 				wlr_log(WLR_ERROR, "failed to add backend '%s'", name);
 				wlr_backend_destroy(backend);
-				wlr_session_destroy(session);
+				wlr_session_destroy(multi->session);
 				free(names);
 				return NULL;
 			}
@@ -245,29 +254,30 @@ struct wlr_backend *wlr_backend_autocreate(struct wl_display *display,
 #endif
 
 	// Attempt DRM+libinput
-	session = wlr_session_create(display);
-	if (!session) {
+	multi->session = wlr_session_create(display);
+	if (!multi->session) {
 		wlr_log(WLR_ERROR, "Failed to start a DRM session");
 		wlr_backend_destroy(backend);
 		return NULL;
 	}
 
-	struct wlr_backend *libinput = wlr_libinput_backend_create(display, session);
+	struct wlr_backend *libinput = wlr_libinput_backend_create(display,
+		multi->session);
 	if (!libinput) {
 		wlr_log(WLR_ERROR, "Failed to start libinput backend");
 		wlr_backend_destroy(backend);
-		wlr_session_destroy(session);
+		wlr_session_destroy(multi->session);
 		return NULL;
 	}
 	wlr_multi_backend_add(backend, libinput);
 
-	struct wlr_backend *primary_drm =
-		attempt_drm_backend(display, backend, session, create_renderer_func);
+	struct wlr_backend *primary_drm = attempt_drm_backend(display, backend,
+		multi->session, create_renderer_func);
 	if (!primary_drm) {
 		wlr_log(WLR_ERROR, "Failed to open any DRM device");
 		wlr_backend_destroy(libinput);
 		wlr_backend_destroy(backend);
-		wlr_session_destroy(session);
+		wlr_session_destroy(multi->session);
 		return NULL;
 	}
 
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