12 files changed, 65 insertions, 73 deletions

diff --git a/event-basic.c b/event-basic.c
index cb2d2c1..d59ef8a 100644
--- a/event-basic.c
+++ b/event-basic.c
@@ -6,7 +6,7 @@
 bool vis_event_emit(Vis *vis, enum VisEvents id, ...) {
 	if (!vis->initialized) {
 		vis->initialized = true;
-		ui_init(vis->ui, vis);
+		ui_init(&vis->ui, vis);
 	}
 
 	va_list ap;
diff --git a/main.c b/main.c
index d19b6f4..85330cb 100644
--- a/main.c
+++ b/main.c
@@ -1229,7 +1229,7 @@ static const char *macro_replay(Vis *vis, const char *keys, const Arg *arg) {
 }
 
 static const char *suspend(Vis *vis, const char *keys, const Arg *arg) {
-	ui_terminal_suspend(vis->ui);
+	ui_terminal_suspend(&vis->ui);
 	return keys;
 }
 
@@ -2214,7 +2214,7 @@ static void signal_handler(int signum, siginfo_t *siginfo, void *context) {
 }
 
 int main(int argc, char *argv[]) {
-	vis = vis_new(ui_terminal_new());
+	vis = vis_new();
 	if (!vis)
 		return EXIT_FAILURE;
 
diff --git a/ui-terminal-curses.c b/ui-terminal-curses.c
index 2b4a6fd..c3ae064 100644
--- a/ui-terminal-curses.c
+++ b/ui-terminal-curses.c
@@ -276,8 +276,8 @@ static bool ui_term_backend_init(Ui *tui, char *term) {
 	return true;
 }
 
-static Ui *ui_term_backend_new(void) {
-	return calloc(1, sizeof(Ui));
+static bool ui_backend_init(Ui *ui) {
+	return true;
 }
 
 void ui_terminal_resume(Ui *term) { }
diff --git a/ui-terminal-vt100.c b/ui-terminal-vt100.c
index dffc235..a1c92f3 100644
--- a/ui-terminal-vt100.c
+++ b/ui-terminal-vt100.c
@@ -59,11 +59,6 @@
 #define CELL_ATTR_ITALIC    (1 << 4)
 #define CELL_ATTR_DIM       (1 << 5)
 
-typedef struct {
-	Ui uiterm;
-	Buffer buf;
-} UiVt100;
-
 static inline bool cell_color_equal(CellColor c1, CellColor c2) {
 	if (c1.index != (uint8_t)-1 || c2.index != (uint8_t)-1)
 		return c1.index == c2.index;
@@ -97,7 +92,7 @@ static void cursor_visible(bool visible) {
 }
 
 static void ui_term_backend_blit(Ui *tui) {
-	Buffer *buf = &((UiVt100*)tui)->buf;
+	Buffer *buf = tui->ctx;
 	buffer_clear(buf);
 	CellAttr attr = CELL_ATTR_NORMAL;
 	CellColor fg = CELL_COLOR_DEFAULT, bg = CELL_COLOR_DEFAULT;
@@ -199,18 +194,20 @@ static bool ui_term_backend_init(Ui *tui, char *term) {
 	return true;
 }
 
-static Ui *ui_term_backend_new(void) {
-	UiVt100 *vtui = calloc(1, sizeof *vtui);
-	if (!vtui)
-		return NULL;
-	buffer_init(&vtui->buf);
-	return (Ui*)vtui;
+static bool ui_backend_init(Ui *ui) {
+	Buffer *buf = calloc(1, sizeof(Buffer));
+	if (!buf)
+		return false;
+	buffer_init(buf);
+	ui->ctx = buf;
+	return true;
 }
 
 static void ui_term_backend_free(Ui *tui) {
-	UiVt100 *vtui = (UiVt100*)tui;
+	Buffer *buf = tui->ctx;
 	ui_term_backend_suspend(tui);
-	buffer_release(&vtui->buf);
+	buffer_release(buf);
+	free(buf);
 }
 
 static bool is_default_color(CellColor c) {
diff --git a/ui-terminal.c b/ui-terminal.c
index 048ba7f..d19724a 100644
--- a/ui-terminal.c
+++ b/ui-terminal.c
@@ -615,20 +615,19 @@ err:
 	return false;
 }
 
-Ui *ui_terminal_new(void) {
+bool ui_terminal_init(Ui *tui) {
 	size_t styles_size = UI_STYLE_MAX * sizeof(CellStyle);
 	CellStyle *styles = calloc(1, styles_size);
 	if (!styles)
-		return NULL;
-	Ui *tui = ui_term_backend_new();
-	if (!tui) {
+		return false;
+	if (!ui_backend_init(tui)) {
 		free(styles);
-		return NULL;
+		return false;
 	}
 	tui->styles_size = styles_size;
 	tui->styles = styles;
 	tui->doupdate = true;
-	return tui;
+	return true;
 }
 
 void ui_terminal_free(Ui *tui) {
@@ -641,5 +640,4 @@ void ui_terminal_free(Ui *tui) {
 		termkey_destroy(tui->termkey);
 	free(tui->cells);
 	free(tui->styles);
-	free(tui);
 }
diff --git a/ui.h b/ui.h
index 806b9ce..c03a709 100644
--- a/ui.h
+++ b/ui.h
@@ -107,6 +107,7 @@ typedef struct Ui {
 	size_t cells_size;        /* #bytes allocated for 2D grid (grows only) */
 	Cell *cells;              /* 2D grid of cells, at least as large as current terminal size */
 	bool doupdate;            /* Whether to update the screen after refreshing contents */
+	void *ctx;                /* Any additional data needed by the backend */
 } Ui;
 
 #include "view.h"
@@ -115,7 +116,7 @@ typedef struct Ui {
 
 #define UI_OPTIONS_GET(ui) ((ui) ? (ui)->options : 0)
 
-Ui *ui_terminal_new(void);
+bool ui_terminal_init(Ui*);
 int  ui_terminal_colors(void);
 void ui_terminal_free(Ui*);
 void ui_terminal_restore(Ui*);
diff --git a/vis-cmds.c b/vis-cmds.c
index 1515bc8..ae9ba49 100644
--- a/vis-cmds.c
+++ b/vis-cmds.c
@@ -246,8 +246,7 @@ static bool cmd_set(Vis *vis, Win *win, Command *cmd, const char *argv[], Select
 		break;
 	case OPTION_ESCDELAY:
 	{
-		TermKey *termkey = vis->ui->termkey;
-		termkey_set_waittime(termkey, arg.i);
+		termkey_set_waittime(vis->ui.termkey, arg.i);
 		break;
 	}
 	case OPTION_EXPANDTAB:
@@ -354,7 +353,7 @@ static bool cmd_set(Vis *vis, Win *win, Command *cmd, const char *argv[], Select
 			vis_info_show(vis, "Invalid layout `%s', expected 'h' or 'v'", arg.s);
 			return false;
 		}
-		ui_arrange(vis->ui, layout);
+		ui_arrange(&vis->ui, layout);
 		break;
 	}
 	case OPTION_IGNORECASE:
@@ -542,7 +541,7 @@ static bool cmd_split(Vis *vis, Win *win, Command *cmd, const char *argv[], Sele
 	if (!win)
 		return false;
 	enum UiOption options = UI_OPTIONS_GET(win->view->ui);
-	ui_arrange(vis->ui, UI_LAYOUT_HORIZONTAL);
+	ui_arrange(&vis->ui, UI_LAYOUT_HORIZONTAL);
 	if (!argv[1])
 		return vis_window_split(win);
 	bool ret = openfiles(vis, &argv[1]);
@@ -555,7 +554,7 @@ static bool cmd_vsplit(Vis *vis, Win *win, Command *cmd, const char *argv[], Sel
 	if (!win)
 		return false;
 	enum UiOption options = UI_OPTIONS_GET(win->view->ui);
-	ui_arrange(vis->ui, UI_LAYOUT_VERTICAL);
+	ui_arrange(&vis->ui, UI_LAYOUT_VERTICAL);
 	if (!argv[1])
 		return vis_window_split(win);
 	bool ret = openfiles(vis, &argv[1]);
@@ -565,12 +564,12 @@ static bool cmd_vsplit(Vis *vis, Win *win, Command *cmd, const char *argv[], Sel
 }
 
 static bool cmd_new(Vis *vis, Win *win, Command *cmd, const char *argv[], Selection *sel, Filerange *range) {
-	ui_arrange(vis->ui, UI_LAYOUT_HORIZONTAL);
+	ui_arrange(&vis->ui, UI_LAYOUT_HORIZONTAL);
 	return vis_window_new(vis, NULL);
 }
 
 static bool cmd_vnew(Vis *vis, Win *win, Command *cmd, const char *argv[], Selection *sel, Filerange *range) {
-	ui_arrange(vis->ui, UI_LAYOUT_VERTICAL);
+	ui_arrange(&vis->ui, UI_LAYOUT_VERTICAL);
 	return vis_window_new(vis, NULL);
 }
 
@@ -775,7 +774,7 @@ static void print_symbolic_keys(Vis *vis, Text *txt) {
 		TERMKEY_SYM_KPEQUALS,
 	};
 
-	TermKey *termkey = vis->ui->termkey;
+	TermKey *termkey = vis->ui.termkey;
 	text_appendf(txt, "  ␣ (a literal \" \" space symbol must be used to refer to <Space>)\n");
 	for (size_t i = 0; i < LENGTH(keys); i++) {
 		text_appendf(txt, "  <%s>\n", termkey_get_keyname(termkey, keys[i]));
diff --git a/vis-core.h b/vis-core.h
index 9746fc9..7d729f7 100644
--- a/vis-core.h
+++ b/vis-core.h
@@ -168,7 +168,6 @@ struct Win {
 };
 
 struct Vis {
-	Ui *ui;                              /* user interface responsible for visual appearance */
 	File *files;                         /* all files currently managed by this editor instance */
 	File *command_file;                  /* special internal file used to store :-command prompt */
 	File *search_file;                   /* special internal file used to store /,? search prompt */
@@ -176,6 +175,7 @@ struct Vis {
 	Win *windows;                        /* all windows currently managed by this editor instance */
 	Win *win;                            /* currently active/focused window */
 	Win *message_window;                 /* special window to display multi line messages */
+	Ui ui;                               /* user interface responsible for visual appearance */
 	Register registers[VIS_REG_INVALID]; /* registers used for text manipulations yank/put etc. and macros */
 	Macro *recording, *last_recording;   /* currently (if non NULL) and least recently recorded macro */
 	const Macro *replaying;              /* macro currently being replayed */
diff --git a/vis-lua.c b/vis-lua.c
index 3b5f784..6bd8a08 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -1399,7 +1399,7 @@ static int vis_index(lua_State *L) {
 		}
 
 		if (strcmp(key, "registers") == 0) {
-			obj_ref_new(L, vis->ui, VIS_LUA_TYPE_REGISTERS);
+			obj_ref_new(L, &vis->ui, VIS_LUA_TYPE_REGISTERS);
 			return 1;
 		}
 
@@ -1415,7 +1415,7 @@ static int vis_index(lua_State *L) {
 		}
 
 		if (strcmp(key, "ui") == 0) {
-			obj_ref_new(L, vis->ui, VIS_LUA_TYPE_UI);
+			obj_ref_new(L, &vis->ui, VIS_LUA_TYPE_UI);
 			return 1;
 		}
 	}
@@ -1429,8 +1429,7 @@ static int vis_options_assign(Vis *vis, lua_State *L, const char *key, int next)
 	} else if (strcmp(key, "changecolors") == 0) {
 		vis->change_colors = lua_toboolean(L, next);
 	} else if (strcmp(key, "escdelay") == 0) {
-		TermKey *tk = vis->ui->termkey;
-		termkey_set_waittime(tk, luaL_checkint(L, next));
+		termkey_set_waittime(vis->ui.termkey, luaL_checkint(L, next));
 	} else if (strcmp(key, "ignorecase") == 0 || strcmp(key, "ic") == 0) {
 		vis->ignorecase = lua_toboolean(L, next);
 	} else if (strcmp(key, "loadmethod") == 0) {
@@ -1570,8 +1569,7 @@ static int vis_options_index(lua_State *L) {
 			lua_pushboolean(L, vis->change_colors);
 			return 1;
 		} else if (strcmp(key, "escdelay") == 0) {
-			TermKey *tk = vis->ui->termkey;
-			lua_pushunsigned(L, termkey_get_waittime(tk));
+			lua_pushunsigned(L, termkey_get_waittime(vis->ui.termkey));
 			return 1;
 		} else if (strcmp(key, "ignorecase") == 0 || strcmp(key, "ic") == 0) {
 			lua_pushboolean(L, vis->ignorecase);
@@ -3612,7 +3610,7 @@ static void vis_lua_ui_draw(Vis *vis) {
 bool vis_event_emit(Vis *vis, enum VisEvents id, ...) {
 	if (!vis->initialized) {
 		vis->initialized = true;
-		ui_init(vis->ui, vis);
+		ui_init(&vis->ui, vis);
 		vis_lua_init(vis);
 	}
 
diff --git a/vis-prompt.c b/vis-prompt.c
index 474a32c..dd67161 100644
--- a/vis-prompt.c
+++ b/vis-prompt.c
@@ -182,7 +182,7 @@ void vis_prompt_show(Vis *vis, const char *title) {
 void vis_info_show(Vis *vis, const char *msg, ...) {
 	va_list ap;
 	va_start(ap, msg);
-	ui_info_show(vis->ui, msg, ap);
+	ui_info_show(&vis->ui, msg, ap);
 	va_end(ap);
 }
 
diff --git a/vis.c b/vis.c
index be4a66a..9bac2a8 100644
--- a/vis.c
+++ b/vis.c
@@ -202,8 +202,7 @@ static void window_free(Win *win) {
 		if (other->parent == win)
 			other->parent = NULL;
 	}
-	if (vis->ui)
-		ui_window_free(win->ui);
+	ui_window_free(win->ui);
 	view_free(win->view);
 	for (size_t i = 0; i < LENGTH(win->modes); i++)
 		map_free(win->modes[i].bindings);
@@ -382,7 +381,7 @@ Win *window_new_file(Vis *vis, File *file, enum UiOption options) {
 	win->file = file;
 	win->view = view_new(file->text);
 	win->expandtab = false;
-	win->ui = ui_window_new(vis->ui, win, options);
+	win->ui = ui_window_new(&vis->ui, win, options);
 	if (!win->view || !win->ui) {
 		window_free(win);
 		return NULL;
@@ -434,7 +433,7 @@ bool vis_window_change_file(Win *win, const char* filename) {
 }
 
 bool vis_window_split(Win *original) {
-	original->vis->ui->doupdate = false;
+	original->vis->ui.doupdate = false;
 	Win *win = window_new_file(original->vis, original->file, UI_OPTION_STATUSBAR);
 	if (!win)
 		return false;
@@ -447,7 +446,7 @@ bool vis_window_split(Win *original) {
 	win->file = original->file;
 	view_options_set(win->view, UI_OPTIONS_GET(original->view->ui));
 	view_cursors_to(win->view->selection, view_cursor_get(original->view));
-	win->vis->ui->doupdate = true;
+	win->vis->ui.doupdate = true;
 	return true;
 }
 
@@ -482,21 +481,21 @@ void vis_draw(Vis *vis) {
 }
 
 void vis_redraw(Vis *vis) {
-	ui_redraw(vis->ui);
-	ui_draw(vis->ui);
+	ui_redraw(&vis->ui);
+	ui_draw(&vis->ui);
 }
 
 bool vis_window_new(Vis *vis, const char *filename) {
 	File *file = file_new(vis, filename, false);
 	if (!file)
 		return false;
-	vis->ui->doupdate = false;
+	vis->ui.doupdate = false;
 	Win *win = window_new_file(vis, file, UI_OPTION_STATUSBAR|UI_OPTION_SYMBOL_EOF);
 	if (!win) {
 		file_free(vis, file);
 		return false;
 	}
-	vis->ui->doupdate = true;
+	vis->ui.doupdate = true;
 
 	return true;
 }
@@ -567,14 +566,15 @@ void vis_window_close(Win *win) {
 	vis_draw(vis);
 }
 
-Vis *vis_new(Ui *ui) {
-	if (!ui)
-		return NULL;
+Vis *vis_new(void) {
 	Vis *vis = calloc(1, sizeof(Vis));
 	if (!vis)
 		return NULL;
 	vis->exit_status = -1;
-	vis->ui = ui;
+	if (!ui_terminal_init(&vis->ui)) {
+		free(vis);
+		return NULL;
+	}
 	vis->change_colors = true;
 	for (size_t i = 0; i < LENGTH(vis->registers); i++)
 		register_init(&vis->registers[i]);
@@ -629,7 +629,7 @@ void vis_free(Vis *vis) {
 	file_free(vis, vis->error_file);
 	for (int i = 0; i < LENGTH(vis->registers); i++)
 		register_release(&vis->registers[i]);
-	ui_terminal_free(vis->ui);
+	ui_terminal_free(&vis->ui);
 	if (vis->usercmds) {
 		const char *name;
 		while (map_first(vis->usercmds, &name) && vis_cmd_unregister(vis, name));
@@ -960,7 +960,7 @@ void vis_cancel(Vis *vis) {
 void vis_die(Vis *vis, const char *msg, ...) {
 	va_list ap;
 	va_start(ap, msg);
-	ui_die(vis->ui, msg, ap);
+	ui_die(&vis->ui, msg, ap);
 	va_end(ap);
 }
 
@@ -968,7 +968,7 @@ const char *vis_keys_next(Vis *vis, const char *keys) {
 	if (!keys || !*keys)
 		return NULL;
 	TermKeyKey key;
-	TermKey *termkey = vis->ui->termkey;
+	TermKey *termkey = vis->ui.termkey;
 	const char *next = NULL;
 	/* first try to parse a special key of the form <Key> */
 	if (*keys == '<' && keys[1] && (next = termkey_strpkey(termkey, keys+1, &key, TERMKEY_FORMAT_VIM)) && *next == '>')
@@ -996,7 +996,7 @@ long vis_keys_codepoint(Vis *vis, const char *keys) {
 	long codepoint = -1;
 	const char *next;
 	TermKeyKey key;
-	TermKey *termkey = vis->ui->termkey;
+	TermKey *termkey = vis->ui.termkey;
 
 	if (!keys[0])
 		return -1;
@@ -1189,9 +1189,9 @@ static void vis_keys_push(Vis *vis, const char *input, size_t pos, bool record)
 
 static const char *getkey(Vis *vis) {
 	TermKeyKey key = { 0 };
-	if (!ui_getkey(vis->ui, &key))
+	if (!ui_getkey(&vis->ui, &key))
 		return NULL;
-	ui_info_hide(vis->ui);
+	ui_info_hide(&vis->ui);
 	bool use_keymap = vis->mode->id != VIS_MODE_INSERT &&
 	                  vis->mode->id != VIS_MODE_REPLACE &&
 	                  !vis->keymap_disabled;
@@ -1205,7 +1205,7 @@ static const char *getkey(Vis *vis) {
 		}
 	}
 
-	TermKey *termkey = vis->ui->termkey;
+	TermKey *termkey = vis->ui.termkey;
 	if (key.type == TERMKEY_TYPE_UNKNOWN_CSI) {
 		long args[18];
 		size_t nargs;
@@ -1299,16 +1299,16 @@ int vis_run(Vis *vis) {
 		}
 
 		if (vis->resume) {
-			ui_terminal_resume(vis->ui);
+			ui_terminal_resume(&vis->ui);
 			vis->resume = false;
 		}
 
 		if (vis->need_resize) {
-			ui_resize(vis->ui);
+			ui_resize(&vis->ui);
 			vis->need_resize = false;
 		}
 
-		ui_draw(vis->ui);
+		ui_draw(&vis->ui);
 		idle.tv_sec = vis->mode->idle_timeout;
 		int r = pselect(vis_process_before_tick(&fds) + 1, &fds, NULL, NULL,
 		                timeout, &emptyset);
@@ -1328,8 +1328,7 @@ int vis_run(Vis *vis) {
 			continue;
 		}
 
-		TermKey *termkey = vis->ui->termkey;
-		termkey_advisereadable(termkey);
+		termkey_advisereadable(vis->ui.termkey);
 		const char *key;
 
 		while ((key = getkey(vis)))
@@ -1624,7 +1623,7 @@ int vis_pipe(Vis *vis, File *file, Filerange *range, const char *argv[],
 		return -1;
 	}
 
-	ui_terminal_save(vis->ui, fullscreen);
+	ui_terminal_save(&vis->ui, fullscreen);
 	pid_t pid = fork();
 
 	if (pid == -1) {
@@ -1818,7 +1817,7 @@ err:
 	sigaction(SIGTERM, &sigterm_old, NULL);
 
 	vis->interrupted = false;
-	ui_terminal_restore(vis->ui);
+	ui_terminal_restore(&vis->ui);
 
 	if (WIFEXITED(status))
 		return WEXITSTATUS(status);
diff --git a/vis.h b/vis.h
index 032b00b..eb8ec92 100644
--- a/vis.h
+++ b/vis.h
@@ -90,8 +90,8 @@ typedef struct {
  * @defgroup vis_lifecycle
  * @{
  */
-/** Create a new editor instance using the given user interface. */
-Vis *vis_new(Ui*);
+/** Create a new editor instance. */
+Vis *vis_new(void);
 /** Free all resources associated with this editor instance, terminates UI. */
 void vis_free(Vis*);
 /**