runtime: implement an extensible line editor

the line editor supports custom keybinds and data storage, allowing for a wide range of functionality to be implemented via plugins. included plugins include: * core: basic input and cursor movement. * history: input history storage and retrieval (unfinished) * highlight: support for colour-highlighting the line buffer (unfinished) * syntax: parses the line buffer and uses `highlight` to apply syntax highlighting (unfinished). * shell-integration: - allows a `prompt` function to be defined, which will be called to get the text to be used for the prompt - exposes key properties of the line editor to the shell environment, allowing line editor functionality to be extended via shell scripts.
2026-06-20 15:13:34 +01:00
parent f622c2eba3
commit ad8b284869
21 changed files with 1857 additions and 1 deletions
@@ -0,0 +1,98 @@
+#include "line-editor.h"
+
+void line_ed_hide(struct bshell_line_ed_p *ed)
+{
+	if (!ed->ed_render.r_vlines) {
+		return;
+	}
+
+#if 0
+	fprintf(stderr, "--- hide ---\n");
+	fprintf(stderr,
+	        "vlines=%lu, cursor=%lu->(%ld,%ld)\n",
+	        ed->ed_render.r_vlines,
+	        ed->ed_cursor,
+	        ed->ed_render.ed_points.c_cursor_x,
+	        ed->ed_render.ed_points.c_cursor_y);
+#endif
+
+	if (ed->ed_render.ed_points.c_cursor_y > 0) {
+		fx_tty_move_cursor_y(
+			ed->ed_tty,
+			FX_TTY_POS_CURSOR,
+			-ed->ed_render.ed_points.c_cursor_y);
+	}
+	fx_tty_move_cursor_x(ed->ed_tty, FX_TTY_POS_START, 0);
+	fx_tty_clear(
+		ed->ed_tty,
+		FX_TTY_CLEAR_SCREEN | FX_TTY_CLEAR_FROM_CURSOR);
+	memset(&ed->ed_render, 0x0, sizeof ed->ed_render);
+}
+
+static void render_prompt(struct bshell_line_ed_p *ed)
+{
+	if (ed->ed_render_prompt) {
+		bshell_line_ed_plugin_class *renderer = fx_object_get_interface(
+			ed->ed_render_prompt,
+			BSHELL_TYPE_LINE_EDITOR_PLUGIN);
+		renderer->p_render_prompt(ed->ed_render_prompt, ed->ed_self);
+	}
+}
+
+static void render_buffer(struct bshell_line_ed_p *ed)
+{
+	if (ed->ed_render_buffer) {
+		bshell_line_ed_plugin_class *renderer = fx_object_get_interface(
+			ed->ed_render_buffer,
+			BSHELL_TYPE_LINE_EDITOR_PLUGIN);
+		renderer->p_render_buffer(ed->ed_render_buffer, ed->ed_self);
+	}
+}
+
+void line_ed_show(struct bshell_line_ed_p *ed)
+{
+	render_prompt(ed);
+	render_buffer(ed);
+	line_ed_get_points(ed, &ed->ed_render.ed_points);
+	bool cursor_limit_newline
+		= ed->ed_render.ed_points.c_cursor_limit_x == 0
+	       && ed->ed_render.ed_points.c_cursor_limit_y > 0;
+	if (cursor_limit_newline) {
+		fx_tty_putc(ed->ed_tty, 0, '\r');
+		fx_tty_putc(ed->ed_tty, 0, '\n');
+	}
+
+	long shift_x = 0, shift_y = 0;
+	shift_x = (long)ed->ed_render.ed_points.c_cursor_x
+	        - (long)ed->ed_render.ed_points.c_cursor_limit_x;
+	shift_y = (long)ed->ed_render.ed_points.c_cursor_y
+	        - (long)ed->ed_render.ed_points.c_cursor_limit_y;
+
+	fx_tty_move_cursor_x(ed->ed_tty, FX_TTY_POS_CURSOR, shift_x);
+	fx_tty_move_cursor_y(ed->ed_tty, FX_TTY_POS_CURSOR, shift_y);
+
+#if 0
+	fprintf(stderr, "--- show ---\n");
+	fprintf(stderr,
+	        "cursor=%lu->(%lu,%lu)\n",
+	        ed->ed_cursor,
+	        ed->ed_render.ed_points.c_cursor_x,
+	        ed->ed_render.ed_points.c_cursor_y);
+	fprintf(stderr,
+	        "cursor_limit=(%lu,%lu)\n",
+	        ed->ed_render.ed_points.c_cursor_limit_x,
+	        ed->ed_render.ed_points.c_cursor_limit_y);
+	fprintf(stderr,
+	        "render_limit=(%lu,%lu)\n",
+	        ed->ed_render.ed_points.c_render_limit_x,
+	        ed->ed_render.ed_points.c_render_limit_y);
+#endif
+
+	ed->ed_render.r_vlines = ed->ed_render.ed_points.c_render_limit_y + 1;
+}
+
+int line_ed_get_char_width(fx_wchar c)
+{
+	/* TODO support double-width and zero-width characters */
+	return fx_wchar_is_graph(c) ? 1 : 0;
+}