[hci] Provide a general concept of a text widget set

Create a generic abstraction of a text widget, refactor the existing
editable text box widget to use this abstraction, add an
implementation of a non-editable text label widget, and generalise the
login user interface to use this generic widget abstraction.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

9 files changed, 509 insertions, 140 deletions

diff --git a/src/hci/mucurses/widgets/editbox.c b/src/hci/mucurses/widgets/editbox.c
index fddd274..79e7cdd 100644
--- a/src/hci/mucurses/widgets/editbox.c
+++ b/src/hci/mucurses/widgets/editbox.c
@@ -25,6 +25,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <string.h>
 #include <assert.h>
+#include <ipxe/ansicol.h>
 #include <ipxe/editbox.h>
 
 /** @file
@@ -36,38 +37,15 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define EDITBOX_MIN_CHARS 3
 
 /**
- * Initialise text box widget
- *
- * @v box		Editable text box widget
- * @v buf		Dynamically allocated string buffer
- * @v win		Containing window
- * @v row		Row
- * @v col		Starting column
- * @v width		Width
- * @v flags		Flags
- */
-void init_editbox ( struct edit_box *box, char **buf,
-		    WINDOW *win, unsigned int row, unsigned int col,
-		    unsigned int width, unsigned int flags ) {
-	memset ( box, 0, sizeof ( *box ) );
-	init_editstring ( &box->string, buf );
-	box->string.cursor = ( *buf ? strlen ( *buf ) : 0 );
-	box->win = ( win ? win : stdscr );
-	box->row = row;
-	box->col = col;
-	box->width = width;
-	box->flags = flags;
-}
-
-/**
  * Draw text box widget
  *
- * @v box		Editable text box widget
- *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
  */
-void draw_editbox ( struct edit_box *box ) {
+static void draw_editbox ( struct widgets *widgets, struct widget *widget ) {
+	struct edit_box *box = container_of ( widget, struct edit_box, widget );
 	const char *content = *(box->string.buf);
-	size_t width = box->width;
+	size_t width = widget->width;
 	char buf[ width + 1 ];
 	signed int cursor_offset, underflow, overflow, first;
 	size_t len;
@@ -93,15 +71,36 @@ void draw_editbox ( struct edit_box *box ) {
 	len = ( content ? ( strlen ( content ) - first ) : 0 );
 	if ( len > width )
 		len = width;
-	if ( box->flags & EDITBOX_STARS ) {
+	if ( widget->flags & WIDGET_SECRET ) {
 		memset ( buf, '*', len );
 	} else {
 		memcpy ( buf, ( content + first ), len );
 	}
 
 	/* Print box content and move cursor */
-	if ( ! box->win )
-		box->win = stdscr;
-	mvwprintw ( box->win, box->row, box->col, "%s", buf );
-	wmove ( box->win, box->row, ( box->col + cursor_offset ) );
+	color_set ( CPAIR_EDIT, NULL );
+	mvwprintw ( widgets->win, widget->row, widget->col, "%s", buf );
+	wmove ( widgets->win, widget->row, ( widget->col + cursor_offset ) );
+	color_set ( CPAIR_NORMAL, NULL );
 }
+
+/**
+ * Edit text box widget
+ *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
+ * @v key		Key pressed by user
+ * @ret key		Key returned to application, or zero
+ */
+static int edit_editbox ( struct widgets *widgets __unused,
+			  struct widget *widget, int key ) {
+	struct edit_box *box = container_of ( widget, struct edit_box, widget );
+
+	return edit_string ( &box->string, key );
+}
+
+/** Text box widget operations */
+struct widget_operations editbox_operations = {
+	.draw = draw_editbox,
+	.edit = edit_editbox,
+};
diff --git a/src/hci/mucurses/widgets/label.c b/src/hci/mucurses/widgets/label.c
new file mode 100644
index 0000000..29645a6
--- /dev/null
+++ b/src/hci/mucurses/widgets/label.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 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
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <string.h>
+#include <assert.h>
+#include <ipxe/label.h>
+
+/** @file
+ *
+ * Text label widget
+ *
+ */
+
+/**
+ * Draw text label widget
+ *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
+ */
+static void draw_label ( struct widgets *widgets, struct widget *widget ) {
+	struct label *label = container_of ( widget, struct label, widget );
+	unsigned int width = widget->width;
+	unsigned int col = widget->col;
+	const char *text = label->text;
+
+	/* Centre label if width is non-zero */
+	if ( width )
+		col += ( ( width - strlen ( text ) ) / 2 );
+
+	/* Print label content */
+	attron ( A_BOLD );
+	mvwprintw ( widgets->win, widget->row, col, "%s", text );
+	attroff ( A_BOLD );
+}
+
+/**
+ * Edit text label widget
+ *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
+ * @v key		Key pressed by user
+ * @ret key		Key returned to application, or zero
+ */
+static int edit_label ( struct widgets *widgets __unused,
+			struct widget *widget __unused, int key ) {
+
+	/* Cannot be edited */
+	return key;
+}
+
+/** Text label widget operations */
+struct widget_operations label_operations = {
+	.draw = draw_label,
+	.edit = edit_label,
+};
diff --git a/src/hci/tui/login_ui.c b/src/hci/tui/login_ui.c
index bd24991..b76afb9 100644
--- a/src/hci/tui/login_ui.c
+++ b/src/hci/tui/login_ui.c
@@ -35,6 +35,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <curses.h>
 #include <ipxe/console.h>
 #include <ipxe/settings.h>
+#include <ipxe/label.h>
 #include <ipxe/editbox.h>
 #include <ipxe/keys.h>
 #include <ipxe/ansicol.h>
@@ -45,90 +46,55 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define USERNAME_ROW		( ( LINES / 2U ) - 2U )
 #define PASSWORD_LABEL_ROW	( ( LINES / 2U ) + 2U )
 #define PASSWORD_ROW		( ( LINES / 2U ) + 4U )
-#define LABEL_COL		( ( COLS / 2U ) - 4U )
-#define EDITBOX_COL		( ( COLS / 2U ) - 10U )
-#define EDITBOX_WIDTH		20U
+#define WIDGET_COL		( ( COLS / 2U ) - 10U )
+#define WIDGET_WIDTH		20U
 
 int login_ui ( void ) {
 	char *username;
 	char *password;
-	struct edit_box username_box;
-	struct edit_box password_box;
-	struct edit_box *current_box = &username_box;
-	int key;
-	int rc = -EINPROGRESS;
+	struct {
+		struct widgets widgets;
+		struct label username_label;
+		struct label password_label;
+		struct edit_box username_box;
+		struct edit_box password_box;
+	} widgets;
+	int rc;
 
 	/* Fetch current setting values */
 	fetchf_setting_copy ( NULL, &username_setting, NULL, NULL, &username );
 	fetchf_setting_copy ( NULL, &password_setting, NULL, NULL, &password );
 
-	/* Initialise UI */
-	initscr();
-	start_color();
-	init_editbox ( &username_box, &username, NULL, USERNAME_ROW,
-		       EDITBOX_COL, EDITBOX_WIDTH, 0 );
-	init_editbox ( &password_box, &password, NULL, PASSWORD_ROW,
-		       EDITBOX_COL, EDITBOX_WIDTH, EDITBOX_STARS );
+	/* Construct user interface */
+	memset ( &widgets, 0, sizeof ( widgets ) );
+	init_widgets ( &widgets.widgets, NULL );
+	init_label ( &widgets.username_label, USERNAME_LABEL_ROW, WIDGET_COL,
+		     WIDGET_WIDTH, "Username" );
+	init_label ( &widgets.password_label, PASSWORD_LABEL_ROW, WIDGET_COL,
+		     WIDGET_WIDTH, "Password" );
+	init_editbox ( &widgets.username_box, USERNAME_ROW, WIDGET_COL,
+		       WIDGET_WIDTH, 0, &username );
+	init_editbox ( &widgets.password_box, PASSWORD_ROW, WIDGET_COL,
+		       WIDGET_WIDTH, WIDGET_SECRET, &password );
+	add_widget ( &widgets.widgets, &widgets.username_label.widget );
+	add_widget ( &widgets.widgets, &widgets.password_label.widget );
+	add_widget ( &widgets.widgets, &widgets.username_box.widget );
+	add_widget ( &widgets.widgets, &widgets.password_box.widget );
 
-	/* Draw initial UI */
-	color_set ( CPAIR_NORMAL, NULL );
-	erase();
-	attron ( A_BOLD );
-	mvprintw ( USERNAME_LABEL_ROW, LABEL_COL, "Username:" );
-	mvprintw ( PASSWORD_LABEL_ROW, LABEL_COL, "Password:" );
-	attroff ( A_BOLD );
-	color_set ( CPAIR_EDIT, NULL );
-	draw_editbox ( &username_box );
-	draw_editbox ( &password_box );
-
-	/* Main loop */
-	while ( rc == -EINPROGRESS ) {
-
-		draw_editbox ( current_box );
-
-		key = getkey ( 0 );
-		switch ( key ) {
-		case KEY_DOWN:
-			current_box = &password_box;
-			break;
-		case KEY_UP:
-			current_box = &username_box;
-			break;
-		case TAB:
-			current_box = ( ( current_box == &username_box ) ?
-					&password_box : &username_box );
-			break;
-		case KEY_ENTER:
-			if ( current_box == &username_box ) {
-				current_box = &password_box;
-			} else {
-				rc = 0;
-			}
-			break;
-		case CTRL_C:
-		case ESC:
-			rc = -ECANCELED;
-			break;
-		default:
-			edit_editbox ( current_box, key );
-			break;
-		}
-	}
-
-	/* Terminate UI */
-	color_set ( CPAIR_NORMAL, NULL );
-	erase();
-	endwin();
+	/* Present user interface */
+	if ( ( rc = widget_ui ( &widgets.widgets ) ) != 0 )
+		goto err_ui;
 
 	/* Store settings on successful completion */
-	if ( rc == 0 )
-		rc = storef_setting ( NULL, &username_setting, username );
-	if ( rc == 0 )
-		rc = storef_setting ( NULL, &password_setting, password );
+	if ( ( rc = storef_setting ( NULL, &username_setting, username ) ) !=0)
+		goto err_store_username;
+	if ( ( rc = storef_setting ( NULL, &password_setting, password ) ) !=0)
+		goto err_store_password;
 
-	/* Free setting values */
+ err_store_username:
+ err_store_password:
+ err_ui:
 	free ( username );
 	free ( password );
-
 	return rc;
 }
diff --git a/src/hci/tui/settings_ui.c b/src/hci/tui/settings_ui.c
index 95cbd77..53bf24d 100644
--- a/src/hci/tui/settings_ui.c
+++ b/src/hci/tui/settings_ui.c
@@ -108,6 +108,8 @@ struct settings_ui {
 	struct jump_scroller scroll;
 	/** Current row */
 	struct settings_ui_row row;
+	/** Widget set used for editing setting */
+	struct widgets widgets;
 };
 
 /**
@@ -164,10 +166,11 @@ static unsigned int select_setting_row ( struct settings_ui *ui,
 	}
 
 	/* Initialise edit box */
-	init_editbox ( &ui->row.editbox, &ui->row.buf, NULL, ui->row.row,
+	memset ( &ui->row.editbox, 0, sizeof ( ui->row.editbox ) );
+	init_editbox ( &ui->row.editbox, ui->row.row,
 		       ( SETTINGS_LIST_COL +
 			 offsetof ( typeof ( *text ), u.setting.value ) ),
-		       sizeof ( text->u.setting.value ), 0 );
+		       sizeof ( text->u.setting.value ), 0, &ui->row.buf );
 
 	return count;
 }
@@ -250,7 +253,7 @@ static void draw_setting_row ( struct settings_ui *ui ) {
 static int edit_setting ( struct settings_ui *ui, int key ) {
 	assert ( ui->row.setting.name != NULL );
 	ui->row.editing = 1;
-	return edit_editbox ( &ui->row.editbox, key );
+	return edit_widget ( &ui->widgets, &ui->row.editbox.widget, key );
 }
 
 /**
@@ -454,6 +457,7 @@ static int main_loop ( struct settings *settings ) {
 	/* Print initial screen content */
 	color_set ( CPAIR_NORMAL, NULL );
 	memset ( &ui, 0, sizeof ( ui ) );
+	init_widgets ( &ui.widgets, NULL );
 	select_settings ( &ui, settings );
 
 	while ( 1 ) {
@@ -477,9 +481,7 @@ static int main_loop ( struct settings *settings ) {
 			assert ( ui.row.setting.name != NULL );
 
 			/* Redraw edit box */
-			color_set ( CPAIR_EDIT, NULL );
-			draw_editbox ( &ui.row.editbox );
-			color_set ( CPAIR_NORMAL, NULL );
+			draw_widget ( &ui.widgets, &ui.row.editbox.widget );
 
 			/* Process keypress */
 			key = edit_setting ( &ui, getkey ( 0 ) );
diff --git a/src/hci/tui/widget_ui.c b/src/hci/tui/widget_ui.c
new file mode 100644
index 0000000..5079eef
--- /dev/null
+++ b/src/hci/tui/widget_ui.c
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 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
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * Text widget UI
+ *
+ */
+
+#include <errno.h>
+#include <curses.h>
+#include <ipxe/ansicol.h>
+#include <ipxe/widget.h>
+
+/**
+ * Find editable widget in widget set
+ *
+ * @v widgets		Text widget set
+ * @v index		Editable widget index
+ * @ret widget		Editable widget, or NULL
+ */
+static struct widget * find_widget ( struct widgets *widgets,
+				     unsigned int index ) {
+	struct widget *widget;
+
+	list_for_each_entry ( widget, &widgets->list, list ) {
+		if ( ! ( widget->flags & WIDGET_EDITABLE ) )
+			continue;
+		if ( index-- == 0 )
+			return widget;
+	}
+	return NULL;
+}
+
+/**
+ * Text widget user interface main loop
+ *
+ * @v widgets		Text widget set
+ * @ret rc		Return status code
+ */
+static int widget_ui_loop ( struct widgets *widgets ) {
+	struct widget *widget;
+	unsigned int current;
+	unsigned int count;
+	int key;
+
+	/* Draw all widgets */
+	list_for_each_entry ( widget, &widgets->list, list )
+		draw_widget ( widgets, widget );
+
+	/* Count editable widgets */
+	count = 0;
+	while ( find_widget ( widgets, count ) != NULL )
+		count++;
+
+	/* Main loop */
+	current = 0;
+	while ( 1 ) {
+
+		/* Identify current widget */
+		widget = find_widget ( widgets, current );
+		if ( ! widget )
+			return -ENOENT;
+
+		/* Redraw current widget */
+		draw_widget ( widgets, widget );
+
+		/* Process keypress */
+		key = edit_widget ( widgets, widget, getkey ( 0 ) );
+		switch ( key ) {
+		case KEY_UP:
+			if ( current > 0 )
+				current--;
+			break;
+		case KEY_DOWN:
+			if ( ++current == count )
+				current--;
+			break;
+		case TAB:
+			if ( ++current == count )
+				current = 0;
+			break;
+		case KEY_ENTER:
+			current++;
+			if ( current >= count )
+				return 0;
+			break;
+		case CTRL_C:
+		case ESC:
+			return -ECANCELED;
+		default:
+			/* Do nothing for unrecognised keys or edit errors */
+			break;
+		}
+	}
+}
+
+/**
+ * Present text widget user interface
+ *
+ * @v widgets		Text widget set
+ * @ret rc		Return status code
+ */
+int widget_ui ( struct widgets *widgets ) {
+	int rc;
+
+	/* Initialise UI */
+	initscr();
+	start_color();
+	color_set ( CPAIR_NORMAL, NULL );
+	erase();
+
+	/* Run main loop */
+	rc = widget_ui_loop ( widgets );
+
+	/* Terminate UI */
+	color_set ( CPAIR_NORMAL, NULL );
+	endwin();
+
+	return rc;
+}
diff --git a/src/include/ipxe/editbox.h b/src/include/ipxe/editbox.h
index c14bbdc..1f62485 100644
--- a/src/include/ipxe/editbox.h
+++ b/src/include/ipxe/editbox.h
@@ -11,51 +11,39 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <curses.h>
 #include <ipxe/editstring.h>
+#include <ipxe/widget.h>
 
 /** An editable text box widget */
 struct edit_box {
+	/** Text widget */
+	struct widget widget;
 	/** Editable string */
 	struct edit_string string;
-	/** Containing window */
-	WINDOW *win;
-	/** Row */
-	unsigned int row;
-	/** Starting column */
-	unsigned int col;
-	/** Width */
-	unsigned int width;
 	/** First displayed character */
 	unsigned int first;
-	/** Flags */
-	unsigned int flags;
 };
 
-/** Editable text box widget flags */
-enum edit_box_flags {
-	/** Show stars instead of contents (for password widgets) */
-	EDITBOX_STARS = 0x0001,
-};
-
-extern void init_editbox ( struct edit_box *box, char **buf,
-			   WINDOW *win, unsigned int row, unsigned int col,
-			   unsigned int width, unsigned int flags )
-			   __attribute__ (( nonnull (1, 2) ));
-extern void draw_editbox ( struct edit_box *box ) __nonnull;
-static inline int edit_editbox ( struct edit_box *box, int key ) __nonnull;
+extern struct widget_operations editbox_operations;
 
 /**
- * Edit text box widget
+ * Initialise text box widget
  *
  * @v box		Editable text box widget
- * @v key		Key pressed by user
- * @ret key		Key returned to application, or zero
- *
- * You must call draw_editbox() to update the display after calling
- * edit_editbox().
- *
+ * @v row		Row
+ * @v col		Starting column
+ * @v width		Width
+ * @v flags		Flags
+ * @v buf		Dynamically allocated string buffer
  */
-static inline int edit_editbox ( struct edit_box *box, int key ) {
-	return edit_string ( &box->string, key );
+static inline __attribute__ (( always_inline )) void
+init_editbox ( struct edit_box *box, unsigned int row, unsigned int col,
+	       unsigned int width, unsigned int flags, char **buf ) {
+
+	init_widget ( &box->widget, &editbox_operations, row, col,
+		      width, ( flags | WIDGET_EDITABLE ) );
+	init_editstring ( &box->string, buf );
+	if ( *buf )
+		box->string.cursor = strlen ( *buf );
 }
 
 #endif /* _IPXE_EDITBOX_H */
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 96981dd..a9ce656 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -417,6 +417,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_x25519		      ( ERRFILE_OTHER | 0x005f0000 )
 #define ERRFILE_des		      ( ERRFILE_OTHER | 0x00600000 )
 #define ERRFILE_editstring	      ( ERRFILE_OTHER | 0x00610000 )
+#define ERRFILE_widget_ui	      ( ERRFILE_OTHER | 0x00620000 )
 
 /** @} */
 
diff --git a/src/include/ipxe/label.h b/src/include/ipxe/label.h
new file mode 100644
index 0000000..48e36cb
--- /dev/null
+++ b/src/include/ipxe/label.h
@@ -0,0 +1,42 @@
+#ifndef _IPXE_LABEL_H
+#define _IPXE_LABEL_H
+
+/** @file
+ *
+ * Text label widget
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <curses.h>
+#include <ipxe/widget.h>
+
+/** A text label widget */
+struct label {
+	/** Text widget */
+	struct widget widget;
+	/** Label text */
+	const char *text;
+};
+
+extern struct widget_operations label_operations;
+
+/**
+ * Initialise text label widget
+ *
+ * @v label		Text label widget
+ * @v row		Row
+ * @v col		Starting column
+ * @v width		Width
+ * @v text		Label text
+ */
+static inline __attribute__ (( always_inline )) void
+init_label ( struct label *label, unsigned int row, unsigned int col,
+	     unsigned int width, const char *text ) {
+
+	init_widget ( &label->widget, &label_operations, row, col, width, 0 );
+	label->text = text;
+}
+
+#endif /* _IPXE_LABEL_H */
diff --git a/src/include/ipxe/widget.h b/src/include/ipxe/widget.h
new file mode 100644
index 0000000..fe93b9f
--- /dev/null
+++ b/src/include/ipxe/widget.h
@@ -0,0 +1,151 @@
+#ifndef _IPXE_WIDGET_H
+#define _IPXE_WIDGET_H
+
+/** @file
+ *
+ * Text widgets
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <curses.h>
+#include <ipxe/list.h>
+
+/** A text widget set */
+struct widgets {
+	/** List of widgets (in tab order) */
+	struct list_head list;
+	/** Containing window */
+	WINDOW *win;
+};
+
+/** A text widget */
+struct widget {
+	/** List of widgets (in tab order) */
+	struct list_head list;
+	/** Widget operations */
+	struct widget_operations *op;
+
+	/** Row */
+	unsigned int row;
+	/** Starting column */
+	unsigned int col;
+	/** Width */
+	unsigned int width;
+	/** Flags */
+	unsigned int flags;
+};
+
+/** Text widget flags */
+enum widget_flags {
+	/** Widget may have input focus */
+	WIDGET_EDITABLE = 0x0001,
+	/** Widget contains a secret */
+	WIDGET_SECRET = 0x0002,
+};
+
+/** Text widget operations */
+struct widget_operations {
+	/**
+	 * Draw widget
+	 *
+	 * @v widgets		Text widget set
+	 * @v widget		Text widget
+	 */
+	void ( * draw ) ( struct widgets *widgets, struct widget *widget );
+	/**
+	 * Edit widget
+	 *
+	 * @v widgets		Text widget set
+	 * @v widget		Text widget
+	 * @v key		Key pressed by user
+	 * @ret key		Key returned to application, or zero
+	 *
+	 * This will not update the display: you must call the draw()
+	 * method to ensure that any changes to an editable widget are
+	 * displayed to the user.
+	 */
+	int ( * edit ) ( struct widgets *widgets, struct widget *widget,
+			 int key );
+};
+
+/**
+ * Initialise text widget set
+ *
+ * @v widgets		Text widget set
+ * @v win		Containing window
+ */
+static inline __attribute__ (( always_inline )) void
+init_widgets ( struct widgets *widgets, WINDOW *win ) {
+
+	INIT_LIST_HEAD ( &widgets->list );
+	widgets->win = ( win ? win : stdscr );
+}
+
+/**
+ * Initialise text widget
+ *
+ * @v widget		Text widget
+ * @v op		Text widget operations
+ * @v row		Row
+ * @v col		Starting column
+ * @v width		Width
+ */
+static inline __attribute__ (( always_inline )) void
+init_widget ( struct widget *widget, struct widget_operations *op,
+	      unsigned int row, unsigned int col, unsigned int width,
+	      unsigned int flags ) {
+
+	widget->op = op;
+	widget->row = row;
+	widget->col = col;
+	widget->width = width;
+	widget->flags = flags;
+}
+
+/**
+ * Append text widget
+ *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
+ */
+static inline __attribute__ (( always_inline )) void
+add_widget ( struct widgets *widgets, struct widget *widget ) {
+
+	list_add_tail ( &widget->list, &widgets->list );
+}
+
+/**
+ * Draw text widget
+ *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
+ */
+static inline __attribute__ (( always_inline )) void
+draw_widget ( struct widgets *widgets, struct widget *widget ) {
+
+	widget->op->draw ( widgets, widget );
+}
+
+/**
+ * Edit text widget
+ *
+ * @v widgets		Text widget set
+ * @v widget		Text widget
+ * @v key		Key pressed by user
+ * @ret key		Key returned to application, or zero
+ *
+ * This will not update the display: you must call draw_widget() to
+ * ensure that any changes to an editable widget are displayed to the
+ * user.
+ */
+static inline __attribute__ (( always_inline )) int
+edit_widget ( struct widgets *widgets, struct widget *widget, int key ) {
+
+	return widget->op->edit ( widgets, widget, key );
+}
+
+extern int widget_ui ( struct widgets *widgets );
+
+#endif /* _IPXE_WIDGET_H */