feat: add --without-ncurses option for daemon-only builds

Add a dummy curses stub header that provides all ncurses types, macros,
and no-op function stubs. When configured with --without-ncurses, the
build uses this stub instead of linking to the real ncurses library.

This allows rtorrent to be built for daemon-only usage (e.g. with
ruTorrent or Flood) without requiring ncurses to be installed.

Closes #1613

configure.ac

@@ -41,10 +41,20 @@ AC_ARG_ENABLE(execinfo,
   ])
 
 AX_PTHREAD([], AC_MSG_ERROR([requires pthread]))
-AX_WITH_CURSES
 
-if test "x$ax_cv_ncursesw" != xyes && test "x$ax_cv_ncurses" != xyes; then
+AC_ARG_WITH([ncurses],
-  AC_MSG_ERROR([requires either NcursesW or Ncurses library])
+  [AS_HELP_STRING([--without-ncurses], [build without ncurses (daemon-only mode)])],
+  [with_ncurses=$withval],
+  [with_ncurses=yes])
+
+if test "x$with_ncurses" != xno; then
+  AX_WITH_CURSES
+
+  if test "x$ax_cv_ncursesw" != xyes && test "x$ax_cv_ncurses" != xyes; then
+    AC_MSG_ERROR([requires either NcursesW or Ncurses library])
+  fi
+else
+  AC_DEFINE([HAVE_NO_NCURSES], [1], [Define to 1 if building without ncurses])
 fi
 
 PKG_CHECK_MODULES([CPPUNIT], [cppunit],, [no_cppunit="yes"])
@@ -70,9 +80,20 @@ AC_DEFINE(USER_AGENT, [std::string(PACKAGE "/" VERSION)], Http user agent)
 
 dnl Only update global build variables immediately before generating the output,
 dnl to avoid affecting the global build environment for other autoconf checks.
-LIBS="$PTHREAD_LIBS $CURSES_LIB $CURSES_LIBS $ZLIB_LIBS $DEPENDENCIES_LIBS $LIBS"
+if test "x$with_ncurses" != xno; then
-CFLAGS="$CFLAGS $PTHREAD_CFLAGS $CURSES_CFLAGS $ZLIB_CFLAGS $DEPENDENCIES_CFLAGS"
+  LIBS="$PTHREAD_LIBS $CURSES_LIB $CURSES_LIBS $ZLIB_LIBS $DEPENDENCIES_LIBS $LIBS"
-CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS $CURSES_CFLAGS $ZLIB_CFLAGS $DEPENDENCIES_CFLAGS"
+else
+  LIBS="$PTHREAD_LIBS $ZLIB_LIBS $DEPENDENCIES_LIBS $LIBS"
+fi
+if test "x$with_ncurses" != xno; then
+  CFLAGS="$CFLAGS $PTHREAD_CFLAGS $CURSES_CFLAGS $ZLIB_CFLAGS $DEPENDENCIES_CFLAGS"
+  CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS $CURSES_CFLAGS $ZLIB_CFLAGS $DEPENDENCIES_CFLAGS"
+else
+  CFLAGS="$CFLAGS $PTHREAD_CFLAGS $ZLIB_CFLAGS $DEPENDENCIES_CFLAGS"
+  CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS $ZLIB_CFLAGS $DEPENDENCIES_CFLAGS"
+fi
+
+AM_CONDITIONAL([NO_NCURSES], [test "x$with_ncurses" = xno])
 
 TORRENT_CHECK_CACHELINE
 TORRENT_CHECK_POPCOUNT

src/Makefile.am

@@ -205,4 +205,8 @@ libsub_root_a_SOURCES = \
 	signal_handler.h
 
 
+if NO_NCURSES
+libsub_root_a_SOURCES += display/curses_stub.cc display/curses_stub.h
+endif
+
 AM_CPPFLAGS = -I$(srcdir) -I$(top_srcdir) -DPACKAGE_DATADIR=\"$(pkgdatadir)\"

src/display/attributes.h

@@ -4,7 +4,9 @@
 #include <string>
 #include <vector>
 
-#if defined(HAVE_NCURSESW_CURSES_H)
+#if defined(HAVE_NO_NCURSES)
+#include "curses_stub.h"
+#elif defined(HAVE_NCURSESW_CURSES_H)
 #include <ncursesw/curses.h>
 #elif defined(HAVE_NCURSESW_H)
 #include <ncursesw.h>

src/display/color_map.h

@@ -4,7 +4,11 @@
 #include <array>
 #include <map>
 
+#if defined(HAVE_NO_NCURSES)
+#include "curses_stub.h"
+#else
 #include <curses.h>
+#endif
 
 namespace display {
 

src/display/curses_stub.cc

@@ -0,0 +1,6 @@
+// Dummy ncurses stub: provides the stdscr symbol expected by the codebase.
+
+#include "curses_stub.h"
+
+// Define stdscr as a null pointer; all ncurses calls are no-ops in this stub.
+WINDOW* stdscr = nullptr;

src/display/curses_stub.h

@@ -0,0 +1,107 @@
+// Dummy ncurses stub header for building rtorrent without ncurses.
+// Provides types, macros, and no-op function stubs so the codebase
+// compiles without a real curses library. All display functions become
+// no-ops; use with system.daemon.set = true.
+
+#ifndef RTORRENT_DISPLAY_CURSES_STUB_H
+#define RTORRENT_DISPLAY_CURSES_STUB_H
+
+#include <cstdarg>
+#include <cstdio>
+#include <cstddef>
+
+// Opaque window type
+typedef void* WINDOW;
+
+// Character type used by curses
+typedef unsigned int chtype;
+typedef unsigned int attr_t;
+
+// The standard screen
+extern WINDOW* stdscr;
+
+// Boolean constants and return codes
+#ifndef TRUE
+#define TRUE 1
+#endif
+#ifndef FALSE
+#define FALSE 0
+#endif
+#ifndef ERR
+#define ERR (-1)
+#endif
+
+// Attribute constants
+#define A_NORMAL   0
+#define A_STANDOUT (1U << 8)
+#define A_UNDERLINE (1U << 9)
+#define A_REVERSE  (1U << 10)
+#define A_BLINK    (1U << 11)
+#define A_DIM      (1U << 12)
+#define A_BOLD     (1U << 13)
+
+// Color support
+#define COLORS 0
+#define COLOR_BLACK   0
+#define COLOR_RED     1
+#define COLOR_GREEN   2
+#define COLOR_YELLOW  3
+#define COLOR_BLUE    4
+#define COLOR_MAGENTA 5
+#define COLOR_CYAN    6
+#define COLOR_WHITE   7
+
+#define COLOR_PAIR(n) 0
+
+// Key constants
+#define KEY_DOWN        0x102
+#define KEY_UP          0x103
+#define KEY_LEFT        0x104
+#define KEY_RIGHT       0x105
+#define KEY_HOME        0x106
+#define KEY_BACKSPACE   0x107
+#define KEY_DC          0x14a
+#define KEY_ENTER       0x157
+#define KEY_NPAGE       0x152
+#define KEY_PPAGE       0x153
+#define KEY_END         0x168
+#define KEY_MOUSE       0x199
+#define KEY_RESIZE      0x19a
+
+// Stubbed functions
+inline WINDOW* initscr() { return nullptr; }
+inline int     endwin() { return 0; }
+inline WINDOW* newwin(int, int, int, int) { return nullptr; }
+inline int     delwin(WINDOW*) { return 0; }
+inline int     wresize(WINDOW*, int, int) { return 0; }
+inline int     mvwin(WINDOW*, int, int) { return 0; }
+inline int     wnoutrefresh(WINDOW*) { return 0; }
+inline int     redrawwin(WINDOW*) { return 0; }
+inline int     werase(WINDOW*) { return 0; }
+inline int     wmove(WINDOW*, int, int) { return 0; }
+inline int     vw_printw(WINDOW*, char*, va_list) { return 0; }
+inline int     waddch(WINDOW*, const chtype) { return 0; }
+inline int     mvwaddch(WINDOW*, int, int, const chtype) { return 0; }
+inline int     mvwchgat(WINDOW*, int, int, int, attr_t, short, const void*) { return 0; }
+inline int     wattrset(WINDOW*, int) { return 0; }
+inline int     wattr_get(WINDOW*, attr_t*, short*, void*) { return 0; }
+inline int     wattr_set(WINDOW*, attr_t, short, void*) { return 0; }
+inline int     doupdate() { return 0; }
+inline int     start_color() { return 0; }
+inline int     use_default_colors() { return 0; }
+inline int     raw() { return 0; }
+inline int     noraw() { return 0; }
+inline int     noecho() { return 0; }
+inline int     nodelay(WINDOW*, bool) { return 0; }
+inline int     keypad(WINDOW*, bool) { return 0; }
+inline int     curs_set(int) { return 0; }
+inline int     init_pair(short, short, short) { return 0; }
+inline int     pair_content(short, short*, short*) { return 0; }
+inline int     resizeterm(int, int) { return 0; }
+inline int     getch() { return ERR; }
+
+// getyx / getmaxyx are macros in real ncurses; stub them as no-ops
+#define getyx(w, y, x)     do { (y) = 0; (x) = 0; } while (0)
+#define getmaxyx(w, y, x)  do { (y) = 24; (x) = 80; } while (0)
+
+#endif // RTORRENT_DISPLAY_CURSES_STUB_H