Support daemon mode on MS-Windows (bug#19688)

 src/emacs.c <w32_daemon_event> [WINDOWSNT]: New global var.
 (main) [WINDOWSNT]: Initialize it to NULL.  Create the event to
 signal clients we are ready for connections.
 (Fdaemon_initialized): Use DAEMON_RUNNING.
 [WINDOWSNT]: MS-Windows specific code to signal clients we are
 ready for connections.
 src/lisp.h (DAEMON_RUNNING): New macro, encapsulates Posix and
 MS-Windows conditions for running in daemon mode.
 src/minibuf.c (read_minibuf): Use DAEMON_RUNNING.
 src/keyboard.c (kbd_buffer_get_event): Use DAEMON_RUNNING.
 src/dispnew.c (init_display) [WINDOWSNT]: Initialize frames/terminal
 even in daemon mode.

 nt/inc/ms-w32.h (W32_DAEMON_EVENT): New macro.

 lib-src/emacsclient.c (decode_options) [WINDOWSNT]: Don't reject empty
 arguments for --alternate-editor.
 (print_help_and_exit) [WINDOWSNT]: Don't refrain from advertising
 empty arguments for --alternate-editor.
 (start_daemon_and_retry_set_socket) [WINDOWSNT]: MS-Windows
 specific code to start Emacs in daemon mode and wait for it to be
 ready for client connections.

 lisp/server.el (server-process-filter): Force GUI frames on
 MS-Windows in daemon mode, even if a TTY frame was requested.
 lisp/frameset.el (frameset-keep-original-display-p): Don't assume
 windows-nt cannot be in daemon mode.
 lisp/frame.el (window-system-for-display): Don't assume windows-nt
 cannot be in daemon mode.

6 files changed, 65 insertions, 10 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index bf4043666c6..61bb321649f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,23 @@
+2015-02-27  Mark Laws  <mdl@60hz.org>
+
+        Support daemon mode on MS-Windows (bug#19688)
+        * emacs.c <w32_daemon_event> [WINDOWSNT]: New global var.
+        (main) [WINDOWSNT]: Initialize it to NULL.  Create the event to
+        signal clients we are ready for connections.
+        (Fdaemon_initialized): Use DAEMON_RUNNING.
+        [WINDOWSNT]: MS-Windows specific code to signal clients we are
+        ready for connections.
+
+        * lisp.h (DAEMON_RUNNING): New macro, encapsulates Posix and
+        MS-Windows conditions for running in daemon mode.
+
+        * minibuf.c (read_minibuf): Use DAEMON_RUNNING.
+
+        * keyboard.c (kbd_buffer_get_event): Use DAEMON_RUNNING.
+
+        * dispnew.c (init_display) [WINDOWSNT]: Initialize frames/terminal
+        even in daemon mode.
+
 2015-02-26  Jan Djärv  <jan.h.d@swipnet.se>
 
         * xmenu.c (create_and_show_popup_menu): Call XTranslateCoordinates,
diff --git a/src/dispnew.c b/src/dispnew.c
index a1782913154..6bc24697cb7 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -5949,9 +5949,12 @@ init_display (void)
     }
 #endif /* SIGWINCH */
 
-  /* If running as a daemon, no need to initialize any frames/terminal. */
+  /* If running as a daemon, no need to initialize any frames/terminal,
+     except on Windows, where we at least want to initialize it.  */
+#ifndef WINDOWSNT
   if (IS_DAEMON)
       return;
+#endif
 
   /* If the user wants to use a window system, we shouldn't bother
      initializing the terminal.  This is especially important when the
diff --git a/src/emacs.c b/src/emacs.c
index cb0c8417794..ca5633da2dd 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -195,9 +195,13 @@ bool no_site_lisp;
 /* Name for the server started by the daemon.*/
 static char *daemon_name;
 
+#ifndef WINDOWSNT
 /* Pipe used to send exit notification to the daemon parent at
    startup.  */
 int daemon_pipe[2];
+#else
+HANDLE w32_daemon_event;
+#endif
 
 /* Save argv and argc.  */
 char **initial_argv;
@@ -982,8 +986,12 @@ main (int argc, char **argv)
       exit (0);
     }
 
+#ifndef WINDOWSNT
   /* Make sure IS_DAEMON starts up as false.  */
   daemon_pipe[1] = 0;
+#else
+  w32_daemon_event = NULL;
+#endif
 
   if (argmatch (argv, argc, "-daemon", "--daemon", 5, NULL, &skip_args)
       || argmatch (argv, argc, "-daemon", "--daemon", 5, &dname_arg, &skip_args))
@@ -1107,16 +1115,25 @@ Using an Emacs configured with --with-x-toolkit=lucid does not have this problem
       }
 #endif /* DAEMON_MUST_EXEC */
 
-      if (dname_arg)
-        daemon_name = xstrdup (dname_arg);
       /* Close unused reading end of the pipe.  */
       emacs_close (daemon_pipe[0]);
 
       setsid ();
-#else /* DOS_NT */
+#elif defined(WINDOWSNT)
+      /* Indicate that we want daemon mode.  */
+      w32_daemon_event = CreateEvent (NULL, TRUE, FALSE, W32_DAEMON_EVENT);
+      if (w32_daemon_event == NULL)
+        {
+          fprintf (stderr, "Couldn't create MS-Windows event for daemon: %s\n",
+                   w32_strerror (0));
+          exit (1);
+        }
+#else /* MSDOS */
       fprintf (stderr, "This platform does not support the -daemon flag.\n");
       exit (1);
-#endif /* DOS_NT */
+#endif /* MSDOS */
+      if (dname_arg)
+        daemon_name = xstrdup (dname_arg);
     }
 
 #if defined HAVE_PTHREAD && !defined SYSTEM_MALLOC \
@@ -2313,17 +2330,18 @@ This finishes the daemonization process by doing the other half of detaching
 from the parent process and its tty file descriptors.  */)
   (void)
 {
-  int nfd;
   bool err = 0;
 
   if (!IS_DAEMON)
     error ("This function can only be called if emacs is run as a daemon");
 
-  if (daemon_pipe[1] < 0)
+  if (!DAEMON_RUNNING)
     error ("The daemon has already been initialized");
 
   if (NILP (Vafter_init_time))
     error ("This function can only be called after loading the init files");
+#ifndef WINDOWSNT
+  int nfd;
 
   /* Get rid of stdin, stdout and stderr.  */
   nfd = emacs_open ("/dev/null", O_RDWR, 0);
@@ -2344,6 +2362,13 @@ from the parent process and its tty file descriptors.  */)
   err |= emacs_close (daemon_pipe[1]) != 0;
   /* Set it to an invalid value so we know we've already run this function.  */
   daemon_pipe[1] = -1;
+#else  /* WINDOWSNT */
+  /* Signal the waiting emacsclient process.  */
+  err |= SetEvent (w32_daemon_event) == 0;
+  err |= CloseHandle (w32_daemon_event) == 0;
+  /* Set it to an invalid value so we know we've already run this function.  */
+  w32_daemon_event = INVALID_HANDLE_VALUE;
+#endif
 
   if (err)
     error ("I/O error during daemon initialization");
diff --git a/src/keyboard.c b/src/keyboard.c
index c2174539ea7..e1c5691324d 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -3853,7 +3853,7 @@ kbd_buffer_get_event (KBOARD **kbp,
   if (noninteractive
       /* In case we are running as a daemon, only do this before
          detaching from the terminal.  */
-      || (IS_DAEMON && daemon_pipe[1] >= 0))
+      || (IS_DAEMON && DAEMON_RUNNING))
     {
       int c = getchar ();
       XSETINT (obj, c);
diff --git a/src/lisp.h b/src/lisp.h
index 9764b096ef0..fb436776121 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4222,9 +4222,16 @@ extern bool noninteractive;
 extern bool no_site_lisp;
 
 /* Pipe used to send exit notification to the daemon parent at
-   startup.  */
+   startup.  On Windows, we use a kernel event instead.  */
+#ifndef WINDOWSNT
 extern int daemon_pipe[2];
 #define IS_DAEMON (daemon_pipe[1] != 0)
+#define DAEMON_RUNNING (daemon_pipe[1] >= 0)
+#else  /* WINDOWSNT */
+extern void *w32_daemon_event;
+#define IS_DAEMON (w32_daemon_event != NULL)
+#define DAEMON_RUNNING (w32_daemon_event != INVALID_HANDLE_VALUE)
+#endif
 
 /* True if handling a fatal error already.  */
 extern bool fatal_error_in_progress;
diff --git a/src/minibuf.c b/src/minibuf.c
index 2dc5c544457..e7c288b251b 100644
--- a/src/minibuf.c
+++ b/src/minibuf.c
@@ -459,7 +459,7 @@ read_minibuf (Lisp_Object map, Lisp_Object initial, Lisp_Object prompt,
   if ((noninteractive
        /* In case we are running as a daemon, only do this before
           detaching from the terminal.  */
-       || (IS_DAEMON && (daemon_pipe[1] >= 0)))
+       || (IS_DAEMON && DAEMON_RUNNING))
       && NILP (Vexecuting_kbd_macro))
     {
       val = read_minibuf_noninteractive (map, initial, prompt,