xquartz: add non-dispatch fallbacks for 10.5

Based on https://github.com/XQuartz/xorg-server/blob/server-1.20-legacy

hw/xquartz/NSUserDefaults+XQuartzDefaults.m

@@ -6,8 +6,14 @@
 //  Copyright (c) 2021 Apple Inc. All rights reserved.
 //
 
-#import "NSUserDefaults+XQuartzDefaults.h"
-#import <dispatch/dispatch.h>
+#include "NSUserDefaults+XQuartzDefaults.h"
+#include "osxcompat.h"
+
+#ifdef HAS_LIBDISPATCH
+#include <dispatch/dispatch.h>
+#else
+#include <pthread.h>
+#endif
 
 NSString * const XQuartzPrefKeyAppsMenu = @"apps_menu";
 NSString * const XQuartzPrefKeyFakeButtons = @"enable_fake_buttons";
@@ -128,32 +134,50 @@ xquartzDefaultsOnce(void *arg)
     [*defaults registerDefaults:systemDefaultsDict];
 }
 
+#ifdef HAS_LIBDISPATCH
+    typedef dispatch_once_t compat_once_t;
+    #define COMPAT_ONCE_INIT 0
+    #define compat_once_f dispatch_once_f
+#else
+    typedef pthread_once_t compat_once_t;
+    #define COMPAT_ONCE_INIT PTHREAD_ONCE_INIT
+    static inline void compat_once_f(compat_once_t *once, void *context, void (*func)(void *)) {
+        // pthread_once only takes a void(*)(void), so wrap context in a static
+        static void *compat_context;
+        static void (*compat_func)(void *);
+        compat_context = context;
+        compat_func = func;
+        void wrapper(void) { compat_func(compat_context); }
+        pthread_once(once, wrapper);
+    }
+#endif
+
 @implementation NSUserDefaults (XQuartzDefaults)
 
 + (NSUserDefaults *)globalDefaults
 {
-    static dispatch_once_t once;
+    static compat_once_t once = COMPAT_ONCE_INIT;
     static NSUserDefaults *defaults;
 
-    dispatch_once_f(&once, &defaults, globalDefaultsOnce);
+    compat_once_f(&once, &defaults, globalDefaultsOnce);
     return defaults;
 }
 
 + (NSUserDefaults *)dockDefaults
 {
-    static dispatch_once_t once;
+    static compat_once_t once = COMPAT_ONCE_INIT;
     static NSUserDefaults *defaults;
 
-    dispatch_once_f(&once, &defaults, dockDefaultsOnce);
+    compat_once_f(&once, &defaults, dockDefaultsOnce);
     return defaults;
 }
 
 + (NSUserDefaults *)xquartzDefaults
 {
-    static dispatch_once_t once;
+    static compat_once_t once = COMPAT_ONCE_INIT;
     static NSUserDefaults *defaults;
 
-    dispatch_once_f(&once, &defaults, xquartzDefaultsOnce);
+    compat_once_f(&once, &defaults, xquartzDefaultsOnce);
     return defaults;
 }
 

hw/xquartz/X11Application.m

@@ -61,9 +61,14 @@ xpbproxy_run(void);
 #define XSERVER_VERSION "?"
 #endif
 
+#ifdef HAS_LIBDISPATCH
 #include <dispatch/dispatch.h>
 
 static dispatch_queue_t eventTranslationQueue;
+#else
+// aquaMenuBarHeight is just a proxy for initialization
+#define eventTranslationQueue aquaMenuBarHeight
+#endif
 
 #ifndef __has_feature
 #define __has_feature(x) 0
@@ -483,8 +488,12 @@ sendX11NSEvent_fptr(void *e_ptr)
     }
 
     if (for_x) {
+#ifdef HAS_LIBDISPATCH
         NSEvent *event_copy = [e retain];
         dispatch_async_f(eventTranslationQueue, event_copy, sendX11NSEvent_fptr);
+#else
+        [self sendX11NSEvent:e];
+#endif
     }
 }
 
@@ -842,13 +851,20 @@ X11ApplicationMain(int argc, char **argv, char **envp)
 
         /* Calculate the height of the menubar so we can avoid it. */
         aquaMenuBarHeight = [[NSApp mainMenu] menuBarHeight];
+#if ! __LP64__
+        if (!aquaMenuBarHeight) {
+            aquaMenuBarHeight = [NSMenuView menuBarHeight];
+        }
+#endif
         if (!aquaMenuBarHeight) {
             NSScreen* primaryScreen = [[NSScreen screens] objectAtIndex:0];
             aquaMenuBarHeight = NSHeight(primaryScreen.frame) - NSMaxY(primaryScreen.visibleFrame);
         }
 
+#ifdef HAS_LIBDISPATCH
         eventTranslationQueue = dispatch_queue_create(BUNDLE_ID_PREFIX ".X11.NSEventsToX11EventsQueue", NULL);
         assert(eventTranslationQueue != NULL);
+#endif
 
         /* Set the key layout seed before we start the server */
         last_key_layout = TISCopyCurrentKeyboardLayoutInputSource();

hw/xquartz/mach-startup/bundle-main.c

@@ -57,7 +57,9 @@
 #include "mach_startupServer.h"
 #include "osxcompat.h"
 
+#ifdef HAS_LIBDISPATCH
 #include <dispatch/dispatch.h>
+#endif
 
 #include <asl.h>
 
@@ -116,6 +118,23 @@ static char *pref_app_to_run;
 static char *pref_login_shell;
 static char *pref_startx_script;
 
+#ifndef HAS_LIBDISPATCH
+/*** Pthread Magics ***/
+static pthread_t
+create_thread(void *(*func)(void *), void *arg)
+{
+    pthread_attr_t attr;
+    pthread_t tid;
+
+    pthread_attr_init(&attr);
+    pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+    pthread_create(&tid, &attr, func, arg);
+    pthread_attr_destroy(&attr);
+
+    return tid;
+}
+#endif
 
 /*** Mach-O IPC Stuffs ***/
 
@@ -223,9 +242,16 @@ typedef struct {
 /* This thread accepts an incoming connection and hands off the file
  * descriptor for the new connection to accept_fd_handoff()
  */
+#ifdef HAS_LIBDISPATCH
 static void
 socket_handoff(socket_handoff_t *handoff_data)
 {
+#else
+static void *
+socket_handoff_thread(void *arg)
+{
+    socket_handoff_t *handoff_data = (socket_handoff_t *)arg;
+#endif
 
     int launchd_fd = -1;
     int connected_fd;
@@ -260,6 +286,9 @@ socket_handoff(socket_handoff_t *handoff_data)
         launchd_fd);
     DarwinListenOnOpenFD(launchd_fd);
 
+#ifndef HAS_LIBDISPATCH
+    return NULL;
+#endif
 }
 
 static int
@@ -347,9 +376,13 @@ do_request_fd_handoff_socket(mach_port_t port, string_t filename)
 
     strlcpy(filename, handoff_data->filename, STRING_T_SIZE);
 
+#ifdef HAS_LIBDISPATCH
     dispatch_async_f(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
                      handoff_data,
                      socketHandoff_fptr);
+#else
+    create_thread(socket_handoff_thread, handoff_data);
+#endif
 
 #ifdef DEBUG
     ErrorF(

hw/xquartz/meson.build

@@ -69,7 +69,7 @@ libxquartz_defs = [
 ]
 
 if cc.has_function('dispatch_async')
-    libxquartz_defs += '-DHAVE_LIBDISPATCH'
+    libxquartz_defs += '-DHAS_LIBDISPATCH'
 endif
 
 libXquartz = static_library('Xquartz',

hw/xquartz/quartzKeyboard.c

@@ -60,6 +60,7 @@
 #include "exevents.h"
 #include "X11/keysym.h"
 #include "keysym2ucs.h"
+#include "osxcompat.h"
 
 extern void
 CopyKeyClass(DeviceIntPtr device, DeviceIntPtr master);
@@ -771,11 +772,15 @@ QuartzReadSystemKeymap(darwinKeyboardInfo *info)
     KeySym *k;
 
     /* This is an ugly ant-pattern, but it is more expedient to address the problem right now. */
+#ifdef HAS_LIBDISPATCH
     if (pthread_main_np()) {
         getKeyboardData(&ctx);
     } else {
         dispatch_sync_f(dispatch_get_main_queue(), &ctx, getKeyboardData);
     }
+#else
+    getKeyboardData(&ctx);
+#endif
 
     if (ctx.chr_data == NULL) {
         ErrorF("Couldn't get uchr or kchr resource\n");

hw/xquartz/xpr/xprEvent.c

@@ -52,10 +52,13 @@
 #include "quartzKeyboard.h"
 #include "rootlessWindow.h"
 #include "xprEvent.h"
+#include "osxcompat.h"
+
+#ifdef HAS_LIBDISPATCH
+#include <dispatch/dispatch.h>
+#endif
 
 #if XPLUGIN_VERSION >= 6
-#include <dispatch/dispatch.h>
-
 static void bringAllToFront(void *unused) {
   (void)unused; /* to silence the compiler warning */
   xp_window_bring_all_to_front();
@@ -76,7 +79,7 @@ bool QuartzModeEventHandler(int screenNum, XQuartzEvent *e, DeviceIntPtr dev) {
 
   case kXquartzBringAllToFront:
     DEBUG_LOG("kXquartzBringAllToFront\n");
-#if XPLUGIN_VERSION >= 6
+#if defined(HAS_LIBDISPATCH) && (XPLUGIN_VERSION >= 6)
     dispatch_async_f(
         dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), NULL,
         bringAllToFront);

hw/xquartz/xpr/xprFrame.c

@@ -44,8 +44,13 @@
 #include <X11/Xatom.h>
 #include "windowstr.h"
 #include "quartz.h"
+#include "osxcompat.h"
 
+#ifdef HAS_LIBDISPATCH
 #include <dispatch/dispatch.h>
+#else
+#include <pthread.h>
+#endif
 
 #define DEFINE_ATOM_HELPER(func, atom_name)                      \
     static Atom func(void) {                                       \
@@ -63,7 +68,11 @@ typedef struct _WindowHashInsertCtx {
 static x_hash_table * window_hash;
 
 /* Need to guard window_hash since xprIsX11Window can be called from any thread. */
+#ifdef HAS_LIBDISPATCH
 static dispatch_queue_t window_hash_serial_q;
+#else
+static pthread_rwlock_t window_hash_rwlock;
+#endif
 
 /* Prototypes for static functions */
 static Bool
@@ -206,6 +215,7 @@ xprCreateFrame(RootlessWindowPtr pFrame, ScreenPtr pScreen,
         return FALSE;
     }
 
+#ifdef HAS_LIBDISPATCH
     WindowHashInsertCtx *ctx = malloc(sizeof(WindowHashInsertCtx));
     if (!ctx) return FALSE;
 
@@ -213,6 +223,12 @@ xprCreateFrame(RootlessWindowPtr pFrame, ScreenPtr pScreen,
     ctx->frame = pFrame;
 
     dispatch_async_f(window_hash_serial_q, ctx, windowHashInsert);
+#else
+    pthread_rwlock_wrlock(&window_hash_rwlock);
+    x_hash_table_insert(window_hash, pFrame->wid, pFrame);
+    pthread_rwlock_unlock(&window_hash_rwlock);
+#endif
+
     xprSetNativeProperty(pFrame);
 
     return TRUE;
@@ -248,11 +264,18 @@ static void windowLookup(void *arg) {
 static void
 xprDestroyFrame(RootlessFrameID wid)
 {
+#ifdef HAS_LIBDISPATCH
     WindowHashRemoveCtx *ctx = malloc(sizeof(WindowHashRemoveCtx));
     if (!ctx) FatalError("Could not allocate memory for the hash removal context.");
 
     ctx->wid = wid;
+
     dispatch_async_f(window_hash_serial_q, ctx, windowHashRemove);
+#else
+    pthread_rwlock_wrlock(&window_hash_rwlock);
+    x_hash_table_remove(window_hash, wid);
+    pthread_rwlock_unlock(&window_hash_rwlock);
+#endif
 
     xp_error err = xp_destroy_window(x_cvt_vptr_to_uint(wid));
     if (err != Success)
@@ -324,7 +347,13 @@ xprRestackFrame(RootlessFrameID wid, RootlessFrameID nextWid)
         wc.sibling = x_cvt_vptr_to_uint(nextWid);
     }
 
+#ifdef HAS_LIBDISPATCH
     dispatch_sync_f(window_hash_serial_q, &ctx, windowLookup);
+#else
+    pthread_rwlock_rdlock(&window_hash_rwlock);
+    winRec = x_hash_table_lookup(window_hash, wid, NULL);
+    pthread_rwlock_unlock(&window_hash_rwlock);
+#endif
 
     if (winRec) {
         if (XQuartzIsRootless)
@@ -515,9 +544,13 @@ xprInit(ScreenPtr pScreen)
     rootless_CopyWindow_threshold = xp_scroll_area_threshold;
 
     assert((window_hash = x_hash_table_new(NULL, NULL, NULL, NULL)));
+#ifdef HAS_LIBDISPATCH
     assert((window_hash_serial_q =
                 dispatch_queue_create(BUNDLE_ID_PREFIX ".X11.xpr_window_hash",
                                       NULL)));
+#else
+    assert(0 == pthread_rwlock_init(&window_hash_rwlock, NULL));
+#endif
 
     return TRUE;
 }
@@ -535,12 +568,19 @@ WindowPtr
 xprGetXWindow(xp_window_id wid)
 {
     RootlessWindowRec *winRec;
+#ifdef HAS_LIBDISPATCH
     WindowGetCtx ctx = {
         .wid = x_cvt_uint_to_vptr(wid),
         .winrec = &winRec
     };
 
     dispatch_sync_f(window_hash_serial_q, &ctx, windowGet);
+#else
+    RootlessWindowRec *winRec;
+    pthread_rwlock_rdlock(&window_hash_rwlock);
+    winRec = x_hash_table_lookup(window_hash, x_cvt_uint_to_vptr(wid), NULL);
+    pthread_rwlock_unlock(&window_hash_rwlock);
+#endif
 
     return winRec != NULL ? winRec->win : NULL;
 }