frontend: add a line editor for shell input

frontend/line-ed/input.c

@@ -0,0 +1,204 @@
+#include "buffer.h"
+#include "cursor.h"
+#include "history.h"
+#include "hook.h"
+#include "line-ed.h"
+#include "prompt.h"
+#include "refresh.h"
+
+#include <stdio.h>
+
+void put_char(struct line_ed *ed, char c)
+{
+	if (ed->l_buf_ptr > ed->l_line_end + 1) {
+		return;
+	}
+
+	struct refresh_state state = {
+		.r_prev_cursor_x = ed->l_cursor_x,
+		.r_prev_cursor_y = ed->l_cursor_y,
+	};
+
+	unsigned int prev_cursor = ed->l_buf_ptr - ed->l_buf;
+
+	char *dest = ed->l_buf_ptr;
+	unsigned int len = ed->l_line_end - ed->l_buf_ptr + 1;
+
+	if (dest < ed->l_line_end) {
+		memmove(dest + 1, dest, len);
+	}
+
+	ed->l_cursor_x++;
+	ed->l_line_end++;
+	ed->l_buf_ptr++;
+	*dest = c;
+
+	if (ed->l_buf_ptr == ed->l_line_end) {
+		*ed->l_buf_ptr = '\0';
+	}
+
+	hook_buffer_modified(ed);
+
+	put_refresh(ed, &state);
+}
+
+static void backspace_simple(struct line_ed *ed)
+{
+	if (ed->l_buf_ptr == ed->l_buf) {
+		return;
+	}
+
+	struct refresh_state state = {
+		.r_prev_cursor_x = ed->l_cursor_x,
+		.r_prev_cursor_y = ed->l_cursor_y,
+	};
+
+	unsigned int prev_cursor = ed->l_buf_ptr - ed->l_buf;
+
+	char *dest = ed->l_buf_ptr;
+	unsigned int len = ed->l_line_end - ed->l_buf_ptr + 1;
+	memmove(dest - 1, dest, len);
+
+	ed->l_cursor_x--;
+	ed->l_line_end--;
+	ed->l_buf_ptr--;
+
+	hook_buffer_modified(ed);
+
+	backspace_simple_refresh(ed, &state);
+}
+
+static void backspace_nl(struct line_ed *ed)
+{
+	unsigned int prev_line_len = line_length(ed, ed->l_cursor_y - 1);
+
+	struct refresh_state state = {
+		.r_prev_cursor_x = ed->l_cursor_x,
+		.r_prev_cursor_y = ed->l_cursor_y,
+		.r_prev_line_len = prev_line_len,
+	};
+
+	char *dest = ed->l_buf_ptr;
+	unsigned int len = ed->l_line_end - ed->l_buf_ptr + 1;
+	memmove(dest - 1, dest, len);
+
+	ed->l_cursor_x = prev_line_len - 1;
+	ed->l_cursor_y--;
+	ed->l_buf_ptr--;
+	ed->l_line_end--;
+
+	hook_buffer_modified(ed);
+
+	backspace_nl_refresh(ed, &state);
+}
+
+void backspace(struct line_ed *ed)
+{
+	if (ed->l_buf_ptr == ed->l_buf) {
+		return;
+	}
+
+	if (ed->l_cursor_x == 0 && ed->l_cursor_y <= ed->l_continuations) {
+		return;
+	}
+
+	if (ed->l_cursor_x == 0 && ed->l_cursor_y > 0) {
+		backspace_nl(ed);
+	} else {
+		backspace_simple(ed);
+	}
+}
+
+void cursor_left(struct line_ed *ed)
+{
+	if (ed->l_cursor_x != 0) {
+		fputs("\010", stdout);
+		fflush(stdout);
+		ed->l_cursor_x--;
+		ed->l_buf_ptr--;
+		return;
+	}
+
+	if (ed->l_cursor_y <= ed->l_continuations || ed->l_buf_ptr <= ed->l_buf) {
+		return;
+	}
+
+	ed->l_cursor_y--;
+	ed->l_buf_ptr--;
+	unsigned int prompt_len = 0;
+	if (ed->l_cursor_y == 0) {
+		prompt_len = prompt_length(ed, PROMPT_MAIN);
+	}
+
+	unsigned int len = line_length(ed, ed->l_cursor_y);
+	ed->l_cursor_x = len - 1;
+
+	printf("\033[A\033[%dG", len + prompt_len);
+	fflush(stdout);
+}
+
+void cursor_right(struct line_ed *ed)
+{
+	if (ed->l_buf_ptr >= ed->l_line_end) {
+		return;
+	}
+
+	if (*ed->l_buf_ptr != '\n') {
+		ed->l_cursor_x++;
+		ed->l_buf_ptr++;
+		fputs("\033[C", stdout);
+		fflush(stdout);
+		return;
+	}
+
+	if (ed->l_buf_ptr >= ed->l_line_end) {
+		return;
+	}
+
+	ed->l_cursor_y++;
+	ed->l_cursor_x = 0;
+	ed->l_buf_ptr++;
+
+	printf("\033[B\033[G");
+	fflush(stdout);
+}
+
+void arrow_up(struct line_ed *ed)
+{
+	if (ed->l_history_pos == 0) {
+		return;
+	}
+
+	if (ed->l_cursor_y > 0) {
+		printf("\033[%uA", ed->l_cursor_y);
+	}
+
+	printf("\033[%zuG\033[J", prompt_length(ed, PROMPT_MAIN) + 1);
+
+	save_buf_to_history(ed);
+	ed->l_history_pos--;
+	load_buf_from_history(ed);
+
+	print_buffer(ed);
+	fflush(stdout);
+}
+
+void arrow_down(struct line_ed *ed)
+{
+	if (ed->l_history_pos == b_array_size(ed->l_history) - 1) {
+		return;
+	}
+
+	if (ed->l_cursor_y > 0) {
+		printf("\033[%uA", ed->l_cursor_y);
+	}
+
+	printf("\033[%zuG\033[J", prompt_length(ed, PROMPT_MAIN) + 1);
+
+	save_buf_to_history(ed);
+	ed->l_history_pos++;
+	load_buf_from_history(ed);
+
+	print_buffer(ed);
+	fflush(stdout);
+}