Create PurpleUi that merges PurpleCoreUiOps and PurpleUiInfo

This created a lot more refactoring that I imagined, but it's mostly just moving stuff around.

I skipped the unit tests for now because we already have a `test_ui.[ch]` in the tests directory which we can/should move to a separate library or something, so it's available outside of the `libpurple/tests/` directory.

Testing Done:
Ran the unit tests, launched pidgin3, and launched finch3 with out issue.

Bugs closed: PIDGIN-17697

Reviewed at https://reviews.imfreedom.org/r/1925/

4 files changed, 102 insertions, 66 deletions

diff --git a/finch/gntui.c b/finch/finchui.c
index f0f15a1563..f4af9330fd 100644
--- a/finch/gntui.c
+++ b/finch/finchui.c
@@ -1,5 +1,6 @@
 /*
- * finch
+ * Finch - Universal Text Chat Client
+ * Copyright (C) Pidgin Developers <devel@pidgin.im>
  *
  * Finch is the legal property of its developers, whose names are too numerous
  * to list here.  Please refer to the COPYRIGHT file distributed with this
@@ -16,17 +17,16 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <config.h>
+#include <glib.h>
+#include <glib/gi18n.h>
 
-#include <glib/gi18n-lib.h>
+#define G_SETTINGS_ENABLE_BACKEND
+#include <gio/gsettingsbackend.h>
 
-#include <purple.h>
-
-#include "gntui.h"
+#include "finchui.h"
 
 #include "finchnotifications.h"
 #include "gntaccount.h"
@@ -34,15 +34,25 @@
 #include "gntconn.h"
 #include "gntconv.h"
 #include "gntdebug.h"
-#include "gntxfer.h"
 #include "gntmedia.h"
 #include "gntnotify.h"
 #include "gntplugin.h"
 #include "gntprefs.h"
+#include "gntprefs.h"
 #include "gntrequest.h"
 #include "gntroomlist.h"
 #include "gntstatus.h"
+#include "gntxfer.h"
+
+struct _FinchUi {
+	PurpleUi parent;
+};
 
+G_DEFINE_TYPE(FinchUi, finch_ui, PURPLE_TYPE_UI)
+
+/******************************************************************************
+ * Helpers
+ *****************************************************************************/
 static gboolean
 finch_history_init(GError **error) {
 	PurpleHistoryManager *manager = NULL;
@@ -74,9 +84,16 @@ finch_history_init(GError **error) {
 	return purple_history_manager_set_active(manager, id, error);
 }
 
-void
-finch_ui_init(void)
-{
+/******************************************************************************
+ * PurpleUi Implementation
+ *****************************************************************************/
+static void
+finch_ui_prefs_init(G_GNUC_UNUSED PurpleUi *ui) {
+	finch_prefs_init();
+}
+
+static void
+finch_ui_start(G_GNUC_UNUSED PurpleUi *ui) {
 	GError *error = NULL;
 
 	finch_debug_init();
@@ -144,9 +161,8 @@ finch_ui_init(void)
 #ifdef STANDALONE
 }
 
-void
-finch_ui_uninit(void)
-{
+static void
+finch_ui_stop(G_GNUC_UNUSED PurpleUi *ui) {
 	purple_accounts_set_ui_ops(NULL);
 	finch_accounts_uninit();
 
@@ -182,3 +198,49 @@ finch_ui_uninit(void)
 #endif /* _WIN32 */
 #endif /* STANDALONE */
 }
+
+static gpointer
+finch_ui_get_settings_backend(G_GNUC_UNUSED PurpleUi *ui) {
+	GSettingsBackend *backend = NULL;
+	char *config = NULL;
+
+	config = g_build_filename(purple_config_dir(), "finch3.ini", NULL);
+	backend = g_keyfile_settings_backend_new(config, "/", NULL);
+
+	g_free(config);
+
+	return backend;
+}
+
+/******************************************************************************
+ * GObject Implementation
+ *****************************************************************************/
+static void
+finch_ui_init(G_GNUC_UNUSED FinchUi *ui) {
+}
+
+static void
+finch_ui_class_init(FinchUiClass *klass) {
+	PurpleUiClass *ui_class = PURPLE_UI_CLASS(klass);
+
+	ui_class->prefs_init = finch_ui_prefs_init;
+	ui_class->start = finch_ui_start;
+	ui_class->stop = finch_ui_stop;
+	ui_class->get_settings_backend = finch_ui_get_settings_backend;
+}
+
+/******************************************************************************
+ * Public API
+ *****************************************************************************/
+PurpleUi *
+finch_ui_new(void) {
+	return g_object_new(
+		FINCH_TYPE_UI,
+		"id", "finch3",
+		"name", _("Finch"),
+		"version", VERSION,
+		"website", "https://pidgin.im",
+		"support-website", "https://pidgin.im/contact/",
+		"client-type", "console",
+		NULL);
+}
diff --git a/finch/gntui.h b/finch/finchui.h
index 36597cae56..4913707067 100644
--- a/finch/gntui.h
+++ b/finch/finchui.h
@@ -1,5 +1,6 @@
 /*
- * finch
+ * Finch - Universal Text Chat Client
+ * Copyright (C) Pidgin Developers <devel@pidgin.im>
  *
  * Finch is the legal property of its developers, whose names are too numerous
  * to list here.  Please refer to the COPYRIGHT file distributed with this
@@ -16,8 +17,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
  */
 
 #if !defined(FINCH_GLOBAL_HEADER_INSIDE) && !defined(FINCH_COMPILATION)
@@ -27,10 +27,25 @@
 #ifndef FINCH_UI_H
 #define FINCH_UI_H
 
-#include "gnt.h"
+#include <purple.h>
 
-void finch_ui_init(void);
-void finch_ui_uninit(void);
+G_BEGIN_DECLS
+
+#define FINCH_TYPE_UI (finch_ui_get_type())
+G_DECLARE_FINAL_TYPE(FinchUi, finch_ui, FINCH, UI, PurpleUi)
+
+/**
+ * finch_ui_new:
+ *
+ * Creates the [class@Purple.Ui] for finch.
+ *
+ * Note: This isn't really useful outside of Finch itself.
+ *
+ * Since: 3.0.0
+ */
+PurpleUi *finch_ui_new(void);
+
+G_END_DECLS
 
 #endif /* FINCH_UI_H */
 
diff --git a/finch/libfinch.c b/finch/libfinch.c
index 191a9eb9e4..d978d34289 100644
--- a/finch/libfinch.c
+++ b/finch/libfinch.c
@@ -26,54 +26,19 @@
 #include <glib/gi18n-lib.h>
 #include <glib/gstdio.h>
 
-#define G_SETTINGS_ENABLE_BACKEND
-#include <gio/gsettingsbackend.h>
-
 #include <locale.h>
 
 #include <purple.h>
 
+#include "finchui.h"
 #include "gntdebug.h"
 #include "gntidle.h"
 #include "gntprefs.h"
-#include "gntui.h"
 #include "libfinch.h"
 
 #include "config.h"
 #include "package_revision.h"
 
-static void
-finch_quit(void)
-{
-	finch_ui_uninit();
-}
-
-static gpointer
-finch_get_settings_backend(void) {
-	GSettingsBackend *backend = NULL;
-	char *config = NULL;
-
-	config = g_build_filename(purple_config_dir(), "finch3.ini", NULL);
-	backend = g_keyfile_settings_backend_new(config, "/", NULL);
-
-	g_free(config);
-
-	return backend;
-}
-
-static PurpleCoreUiOps core_ops = {
-	.ui_prefs_init = finch_prefs_init,
-	.ui_init = finch_ui_init,
-	.quit = finch_quit,
-	.get_settings_backend = finch_get_settings_backend,
-};
-
-static PurpleCoreUiOps *
-gnt_core_get_ui_ops(void)
-{
-	return &core_ops;
-}
-
 static gboolean
 start_with_debugwin(gpointer null)
 {
@@ -106,7 +71,6 @@ finch_plugins_init(void) {
 static int
 init_libpurple(int argc, char **argv)
 {
-	PurpleUiInfo *ui_info = NULL;
 	gboolean opt_nologin = FALSE;
 	gboolean opt_version = FALSE;
 	gboolean opt_debug = FALSE;
@@ -196,14 +160,9 @@ init_libpurple(int argc, char **argv)
 		g_timeout_add(0, start_with_debugwin, NULL);
 	}
 
-	purple_core_set_ui_ops(gnt_core_get_ui_ops());
 	purple_idle_set_ui(finch_idle_new());
 
-	ui_info = purple_ui_info_new("finch3", _("Finch"), VERSION,
-	                             "https://pidgin.im",
-	                             "https://developer.pidgin.im", "console");
-
-	if (!purple_core_init(ui_info))
+	if (!purple_core_init(finch_ui_new()))
 	{
 		fprintf(stderr,
 				"Initialization of the Purple core failed. Dumping core.\n"
diff --git a/finch/meson.build b/finch/meson.build
index e6b7bcca12..56d5af6ab6 100644
--- a/finch/meson.build
+++ b/finch/meson.build
@@ -79,6 +79,7 @@ enable_consoleui = true
 
 libfinch_SOURCES = [
 	'finchnotifications.c',
+	'finchui.c',
 	'gntaccount.c',
 	'gntblist.c',
 	'gntconn.c',
@@ -93,7 +94,6 @@ libfinch_SOURCES = [
 	'gntrequest.c',
 	'gntroomlist.c',
 	'gntstatus.c',
-	'gntui.c',
 	'gntxfer.c',
 	package_revision,
 	'libfinch.c'
@@ -101,6 +101,7 @@ libfinch_SOURCES = [
 
 libfinch_headers = [
 	'finchnotifications.h',
+	'finchui.h',
 	'gntaccount.h',
 	'gntblist.h',
 	'gntconn.h',
@@ -115,7 +116,6 @@ libfinch_headers = [
 	'gntrequest.h',
 	'gntroomlist.h',
 	'gntstatus.h',
-	'gntui.h',
 	'gntxfer.h',
 	'libfinch.h'
 ]