execute: retain what the user typed before a tool was invoked

When the user types something at the Execute prompt and then invokes
one of the six tools or special functions (that don't take any input),
stash the typed string and restore it upon the next invocation of the
Execute menu.  This way the typed string is not lost when the tool or
special function was invoked by accident -- which it likely was, as
those tools and functions don't take any input from the prompt.

This addresses https://savannah.gnu.org/bugs/?66637.
Suggested-by: Evgeny Pestov <fsdhfhhf@gmail.com>

src/files.c

@@ -1197,6 +1197,12 @@ void insert_a_file_or(bool execute)
 	/* Reset the flag that is set by the Spell Checker and Linter and such. */
 	ran_a_tool = FALSE;
 
+#ifndef NANO_TINY
+	/* If something was typed at the Execute prompt without being run, restore it. */
+	if (execute && *foretext)
+		given = mallocstrcpy(given, foretext);
+#endif
+
 	while (TRUE) {
 #ifndef NANO_TINY
 		if (execute) {

src/global.c

@@ -52,8 +52,13 @@ bool more_than_one = FALSE;
 		/* Whether more than one buffer is or has been open. */
 bool report_size = TRUE;
 		/* Whether to show the number of lines when the minibar is used. */
+
 bool ran_a_tool = FALSE;
 		/* Whether a tool has been run at the Execute-Command prompt. */
+#ifndef NANO_TINY
+char *foretext = NULL;
+		/* What was typed at the Execute prompt before invoking a tool. */
+#endif
 
 bool inhelp = FALSE;
 		/* Whether we are in the help viewer. */

src/nano.c

@@ -2384,6 +2384,9 @@ int main(int argc, char **argv)
 			whitelen[1] = 1;
 		}
 	}
+
+	/* Initialize a special stash for something typed at the Execute prompt. */
+	foretext = copy_of("");
 #endif /* !NANO_TINY */
 
 	/* Initialize the search string. */

src/prompt.c

@@ -538,6 +538,11 @@ functionptrtype acquire_an_answer(int *actual, bool *listed,
 		else if (function && !handle_editing(function)) {
 			/* When it's a permissible shortcut, run it and done. */
 			if (!ISSET(VIEW_MODE) || !changes_something(function)) {
+#ifndef NANO_TINY
+				/* When invoking a tool at the Execute prompt, stash an "answer". */
+				if (currmenu == MEXECUTE)
+					foretext = mallocstrcpy(foretext, answer);
+#endif
 				function();
 				break;
 			} else
@@ -549,6 +554,11 @@ functionptrtype acquire_an_answer(int *actual, bool *listed,
 #endif
 	}
 
+#ifndef NANO_TINY
+	/* When an external command was run, clear a possibly stashed answer. */
+	if (currmenu == MEXECUTE && function == do_enter)
+		*foretext = '\0';
+#endif
 #ifdef ENABLE_HISTORIES
 	/* If the history pointer was moved, point it at the bottom again. */
 	if (stored_string != NULL) {

src/prototypes.h

@@ -37,7 +37,9 @@ extern bool bracketed_paste;
 extern bool we_are_running;
 extern bool more_than_one;
 extern bool report_size;
+
 extern bool ran_a_tool;
+extern char *foretext;
 
 extern bool inhelp;
 extern char *title;