input: recognize the start and stop sequences of a bracketed paste

Also, tell the terminal to switch on bracketed-paste mode, and toggle
a boolean when the start and stop sequences of such a paste are seen.
This boolean can later be used to suppress auto-indent and such.

Signed-off-by: Brand Huntsman <alpha@qzx.com>

src/global.c

@@ -38,6 +38,8 @@ bool meta_key;
 		/* Whether the current keystroke is a Meta key. */
 bool shift_held;
 		/* Whether Shift was being held together with a movement key. */
+bool bracketed_paste = FALSE;
+		/* Whether text is being pasted into nano from outside. */
 bool focusing = TRUE;
 		/* Whether an update of the edit window should center the cursor. */
 
@@ -336,6 +338,11 @@ void do_cancel(void)
 {
 }
 
+/* Ignore the start and stop sequences of a bracketed paste. */
+void do_nothing(void)
+{
+}
+
 /* Add a function to the linked list of functions. */
 void add_to_funcs(void (*func)(void), int menus, const char *desc,
 					const char *help, bool blank_after, bool viewok)
@@ -447,6 +454,16 @@ const keystruct *get_shortcut(int *kbinput)
 						(*kbinput >= 0xA0 && *kbinput <= 0xFF)))
 		return NULL;
 
+	if (bracketed_paste && *kbinput != BRACKETED_PASTE_MARKER) {
+		/* Beep and ignore all non-printable characters in prompts. */
+		if (currmenu != MMAIN)
+			return NULL;
+
+		/* Beep and ignore most non-printable characters in buffer. */
+		if (*kbinput != 0x09 && *kbinput != 0xD)
+			return NULL;
+	}
+
 	for (keystruct *s = sclist; s != NULL; s = s->next) {
 		if ((s->menus & currmenu) && *kbinput == s->keycode &&
 										meta_key == s->meta)
@@ -1397,6 +1414,9 @@ void shortcut_init(void)
 #ifdef ENABLE_SPELLER
 	add_to_sclist(MMAIN, "F12", 0, do_spell, 0);
 #endif
+
+	/* Catch and ignore bracketed paste marker keys. */
+	add_to_sclist(MMOST|MHELP|MBROWSER|MYESNO, "", BRACKETED_PASTE_MARKER, do_nothing, 0);
 }
 
 #ifndef NANO_TINY

src/nano.c

@@ -304,6 +304,13 @@ void say_there_is_no_help(void)
 }
 #endif
 
+/* Tell the terminal to disable bracketed pastes. */
+void disable_bracketed_paste(void)
+{
+	printf("\e[?2004l");
+	fflush(stdout);
+}
+
 /* Exit normally: restore the terminal state and save history files. */
 void finish(void)
 {
@@ -323,6 +330,8 @@ void finish(void)
 	curs_set(1);
 	endwin();
 
+	disable_bracketed_paste();
+
 	/* Restore the old terminal settings. */
 	tcsetattr(0, TCSANOW, &original_state);
 
@@ -354,6 +363,8 @@ void die(const char *msg, ...)
 	curs_set(1);
 	endwin();
 
+	disable_bracketed_paste();
+
 	/* Restore the old terminal settings. */
 	tcsetattr(0, TCSANOW, &original_state);
 
@@ -919,6 +930,8 @@ bool scoop_stdin(void)
 	endwin();
 	tcsetattr(0, TCSANOW, &original_state);
 
+	disable_bracketed_paste();
+
 	/* When input comes from a terminal, show a helpful message. */
 	if (isatty(STANDARD_INPUT))
 		fprintf(stderr, _("Reading data from keyboard; "
@@ -1035,6 +1048,8 @@ RETSIGTYPE do_suspend(int signal)
 	curs_set(1);
 	endwin();
 
+	disable_bracketed_paste();
+
 	printf("\n\n");
 
 	/* Display our helpful message. */
@@ -1300,6 +1315,10 @@ void terminal_init(void)
 	} else
 		tcsetattr(0, TCSANOW, &desired_state);
 #endif
+
+	/* Tell the terminal to enable bracketed pastes. */
+	printf("\e[?2004h");
+	fflush(stdout);
 }
 
 /* Ask ncurses for a keycode, or assign a default one. */

src/nano.h

@@ -610,6 +610,9 @@ enum
 /* A special keycode for when <Tab> is pressed while the mark is on. */
 #define INDENT_KEY 0x4F1
 
+/* A special keycode to signal the beginning and end of a bracketed paste. */
+#define BRACKETED_PASTE_MARKER 0x4FB
+
 #ifdef USE_SLANG
 #ifdef ENABLE_UTF8
 #define KEY_BAD 0xFF  /* Clipped error code. */

src/prompt.c

@@ -485,6 +485,8 @@ functionptrtype acquire_an_answer(int *actual, bool allow_tabs,
 
 		if (func == do_cancel || func == do_enter)
 			break;
+		if (func == do_nothing)
+			finished = FALSE;
 
 #ifdef ENABLE_TABCOMP
 		if (func != do_tab)

src/proto.h

@@ -30,6 +30,7 @@ extern bool on_a_vt;
 
 extern bool meta_key;
 extern bool shift_held;
+extern bool bracketed_paste;
 
 extern bool focusing;
 
@@ -697,3 +698,4 @@ void flip_newbuffer(void);
 #endif
 void discard_buffer(void);
 void do_cancel(void);
+void do_nothing(void);

src/winio.c

@@ -1105,6 +1105,18 @@ int convert_sequence(const int *seq, size_t length, int *consumed)
 							/* Discard broken sequences that Slang produces. */
 							*consumed = 4;
 #endif
+						else if (length > 4 && seq[2] == '0' && seq[4] == '~') {
+							/* Esc [ 2 0 0 ~ == start of a bracketed paste,
+							 * Esc [ 2 0 1 ~ == end of a bracketed paste. */
+							*consumed = 5;
+							if (seq[3] == '0') {
+								bracketed_paste = TRUE;
+								return BRACKETED_PASTE_MARKER;
+							} else if (seq[3] == '1') {
+								bracketed_paste = FALSE;
+								return BRACKETED_PASTE_MARKER;
+							}
+						}
 						break;
 					case '3': /* Esc [ 3 ~ == Delete on VT220/VT320/
 							   * Linux console/xterm/Terminal. */