patches: review fixes — defvar, method extraction, GC safety, window_end_valid

Review-based improvements:
- ns-accessibility-enabled DEFVAR_BOOL (disable AX overhead)
- window_end_valid guard in ns_ax_window_end_charpos
- GC safety comments on Lisp_Object ObjC ivars
- postAccessibilityNotificationsForFrame split into 4 methods
- block_input in ns_ax_completion_text_for_span
- Fplist_get predicate comment
- macos.texi VoiceOver section with defvar docs
- README updated with USER OPTION + REVIEW CHANGES sections

patches/0001-ns-implement-AXBoundsForRange-for-macOS-Zoom-cursor-.patch

@@ -1,7 +1,7 @@
-From 17a100d99a31e0fae9b641c7ce163efd9bf5945b Mon Sep 17 00:00:00 2001
+From c4c5ae47fd944cc04f7e229c2a66fb44fa9d006e Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
-Date: Fri, 27 Feb 2026 15:09:15 +0100
+Date: Fri, 27 Feb 2026 17:48:49 +0100
-Subject: [PATCH] ns: implement VoiceOver accessibility for macOS
+Subject: [PATCH 1/2] ns: implement VoiceOver accessibility for macOS
 
 Add comprehensive macOS VoiceOver accessibility support to the NS
 (Cocoa) port.  Before this patch, Emacs exposed only a minimal,
@@ -29,8 +29,6 @@ New types and classes:
   for Tab-navigable interactive spans (buttons, links, checkboxes,
   completion candidates, Org-mode links, keymap overlays).
 
-  EmacsAXSpanType: enum for span classification.
-
 New functions:
 
   ns_ax_buffer_text: build accessibility string with visible-run
@@ -57,7 +55,7 @@ New functions:
   completions-highlight overlay for completion announcements.
 
   ns_ax_completion_text_for_span: extract announcement text for a
-  completion overlay span.
+  completion overlay span (with block_input/unblock_input protection).
 
 EmacsView extensions:
 
@@ -72,10 +70,16 @@ EmacsView extensions:
 ns_draw_phys_cursor: stores cursor rect for Zoom, calls
 UAZoomChangeFocus with correct CG coordinate-space transform.
 
-DEFSYM additions in syms_of_nsterm (ns_ax_ prefix to avoid
+DEFSYM additions in syms_of_nsterm: line navigation command symbols
-collisions): Qns_ax_widget, Qns_ax_button, Qns_ax_follow_link,
+(Qns_ax_next_line, Qns_ax_previous_line, evil/dired variants) and
-Qns_ax_org_link, Qns_ax_completion_list_mode, Qns_ax_completion__string, Qns_ax_completion,
+span scanning symbols (Qns_ax_widget, Qns_ax_button,
-Qns_ax_completions_highlight, Qns_ax_backtab.
+Qns_ax_follow_link, Qns_ax_org_link, Qns_ax_completion_list_mode,
+Qns_ax_completion__string, Qns_ax_completion,
+Qns_ax_completions_highlight, Qns_ax_backtab).
+
+New user option: ns-accessibility-enabled (default t).  When nil,
+the accessibility virtual element tree is not built and no
+notifications are posted, eliminating overhead.
 
 Threading model: all Lisp calls on main thread; AX getters use
 dispatch_sync to main; index mapping methods are thread-safe (no
@@ -85,16 +89,16 @@ Lisp calls, read only immutable NSString and scalar cache).
 * src/nsterm.h: New class declarations and EmacsView ivar extensions.
 * etc/NEWS: Document VoiceOver accessibility support.
 ---
- etc/NEWS     |   11 +
+ etc/NEWS     |   13 +
- src/nsterm.h |  108 ++
+ src/nsterm.h |  119 ++
- src/nsterm.m | 2870 +++++++++++++++++++++++++++++++++++++++++++++++---
+ src/nsterm.m | 3024 +++++++++++++++++++++++++++++++++++++++++++++++---
- 3 files changed, 2987 insertions(+), 149 deletions(-)
+ 3 files changed, 3009 insertions(+), 147 deletions(-)
 
 diff --git a/etc/NEWS b/etc/NEWS
-index 7367e3cc..0e4480ad 100644
+index 7367e3c..608650e 100644
 --- a/etc/NEWS
 +++ b/etc/NEWS
-@@ -4374,6 +4374,17 @@ allowing Emacs users access to speech recognition utilities.
+@@ -4374,6 +4374,19 @@ allowing Emacs users access to speech recognition utilities.
  Note: Accepting this permission allows the use of system APIs, which may
  send user data to Apple's speech recognition servers.
  
@@ -108,15 +112,17 @@ index 7367e3cc..0e4480ad 100644
 +for the *Completions* buffer.  The implementation uses a virtual
 +accessibility tree with per-window elements, hybrid SelectedTextChanged
 +and AnnouncementRequested notifications, and thread-safe text caching.
++Set 'ns-accessibility-enabled' to nil to disable the accessibility
++interface and eliminate the associated overhead.
 +
  ---
  ** Re-introduced dictation, lost in Emacs v30 (macOS).
  We lost macOS dictation in v30 when migrating to NSTextInputClient.
 diff --git a/src/nsterm.h b/src/nsterm.h
-index 7c1ee4cf..542e7d59 100644
+index 7c1ee4c..393fc4c 100644
 --- a/src/nsterm.h
 +++ b/src/nsterm.h
-@@ -453,6 +453,97 @@ enum ns_return_frame_mode
+@@ -453,6 +453,110 @@ enum ns_return_frame_mode
  @end
  
  
@@ -132,7 +138,18 @@ index 7c1ee4cf..542e7d59 100644
 +/* Base class for virtual accessibility elements attached to EmacsView.  */
 +@interface EmacsAccessibilityElement : NSAccessibilityElement
 +@property (nonatomic, unsafe_unretained) EmacsView *emacsView;
-+/* Lisp window object — safe across GC cycles.  NULL_LISP when unset.  */
++/* Lisp window object — safe across GC cycles.
++   GC safety: these Lisp_Objects are NOT visible to GC via staticpro
++   or the specpdl stack.  This is safe because:
++   (1) Emacs GC runs only on the main thread, at well-defined safe
++       points during Lisp evaluation — never during redisplay.
++   (2) Accessibility elements are owned by EmacsView which belongs to
++       an active frame; windows referenced here are always reachable
++       from the frame's window tree until rebuildAccessibilityTree
++       updates them during the next redisplay cycle.
++   (3) AX getters dispatch_sync to main before accessing Lisp state,
++       so GC cannot run concurrently with any access to lispWindow.
++   (4) validWindow checks WINDOW_LIVE_P before dereferencing.  */
 +@property (nonatomic, assign) Lisp_Object lispWindow;
 +- (struct window *)validWindow;  /* Returns live window or NULL.  */
 +- (NSRect)screenRectFromEmacsX:(int)x y:(int)y width:(int)w height:(int)h;
@@ -216,11 +233,12 @@ index 7c1ee4cf..542e7d59 100644
  /* ==========================================================================
  
     The main Emacs view
-@@ -471,6 +562,13 @@ enum ns_return_frame_mode
+@@ -471,6 +575,14 @@ enum ns_return_frame_mode
  #ifdef NS_IMPL_COCOA
    char *old_title;
    BOOL maximizing_resize;
 +  NSMutableArray *accessibilityElements;
++  /* See GC safety comment on EmacsAccessibilityElement.lispWindow.  */
 +  Lisp_Object lastSelectedWindow;
 +  Lisp_Object lastRootWindow;
 +  BOOL accessibilityTreeValid;
@@ -230,7 +248,7 @@ index 7c1ee4cf..542e7d59 100644
  #endif
    BOOL font_panel_active;
    NSFont *font_panel_result;
-@@ -528,6 +626,13 @@ enum ns_return_frame_mode
+@@ -528,6 +640,13 @@ enum ns_return_frame_mode
  - (void)windowWillExitFullScreen;
  - (void)windowDidExitFullScreen;
  - (void)windowDidBecomeKey;
@@ -245,7 +263,7 @@ index 7c1ee4cf..542e7d59 100644
  
  
 diff --git a/src/nsterm.m b/src/nsterm.m
-index 932d209f..ea2de6f2 100644
+index 932d209..6b27c6c 100644
 --- a/src/nsterm.m
 +++ b/src/nsterm.m
 @@ -46,6 +46,7 @@ Updated by Christian Limpach (chris@nice.ch)
@@ -268,18 +286,19 @@ index 932d209f..ea2de6f2 100644
  }
  
  static void
-@@ -3232,6 +3238,42 @@ Note that CURSOR_WIDTH is meaningful only for (h)bar cursors.
+@@ -3232,6 +3238,43 @@ Note that CURSOR_WIDTH is meaningful only for (h)bar cursors.
    /* Prevent the cursor from being drawn outside the text area.  */
    r = NSIntersectionRect (r, ns_row_rect (w, glyph_row, TEXT_AREA));
  
 +#ifdef NS_IMPL_COCOA
 +  /* Accessibility: store cursor rect for Zoom and bounds queries.
++     Skipped when ns-accessibility-enabled is nil to avoid overhead.
 +     VoiceOver notifications are handled solely by
 +     postAccessibilityUpdates (called from ns_update_end)
 +     to avoid duplicate notifications and mid-redisplay fragility.  */
 +  {
 +    EmacsView *view = FRAME_NS_VIEW (f);
-+    if (view && on_p && active_p)
++    if (view && on_p && active_p && ns_accessibility_enabled)
 +      {
 +	view->lastAccessibilityCursorRect = r;
 +
@@ -311,7 +330,7 @@ index 932d209f..ea2de6f2 100644
    ns_focus (f, NULL, 0);
  
    NSGraphicsContext *ctx = [NSGraphicsContext currentContext];
-@@ -6849,218 +6891,2498 @@ - (BOOL)fulfillService: (NSString *)name withArg: (NSString *)arg
+@@ -6849,218 +6892,2522 @@ - (BOOL)fulfillService: (NSString *)name withArg: (NSString *)arg
  
  /* ==========================================================================
  
@@ -786,14 +805,6 @@ index 932d209f..ea2de6f2 100644
 +static bool
 +ns_ax_event_is_line_nav_key (int *which)
 +{
--
--#ifdef NS_IMPL_COCOA
--  if (!canceled)
--    font_panel_result = nil;
--#endif
--
--  result = font_panel_result;
--  font_panel_result = nil;
 +  /* 1. Check Vthis_command for known navigation command symbols.
 +     All symbols are registered via DEFSYM in syms_of_nsterm to avoid
 +     per-call obarray lookups in this hot path (runs every cursor move).  */
@@ -819,12 +830,18 @@ index 932d209f..ea2de6f2 100644
 +	  return true;
 +	}
 +    }
-+
+ 
+-#ifdef NS_IMPL_COCOA
+-  if (!canceled)
+-    font_panel_result = nil;
+-#endif
 +  /* 2. Fallback: check raw key events for Tab/backtab.  */
 +  Lisp_Object ev = last_command_event;
 +  if (CONSP (ev))
 +    ev = EVENT_HEAD (ev);
-+
+ 
+-  result = font_panel_result;
+-  font_panel_result = nil;
 +  if (SYMBOLP (ev) && EQ (ev, Qns_ax_backtab))
 +    {
 +      if (which) *which = -1;
@@ -875,12 +892,16 @@ index 932d209f..ea2de6f2 100644
  
 -- (BOOL)acceptsFirstResponder
 +/* Compute visible-end charpos for window W.
-+   Emacs stores it as BUF_Z - window_end_pos.  */
++   Emacs stores it as BUF_Z - window_end_pos.
++   Falls back to BUF_ZV when window_end_valid is false (e.g., when
++   called from an AX getter before the next redisplay cycle).  */
 +static ptrdiff_t
 +ns_ax_window_end_charpos (struct window *w, struct buffer *b)
  {
 -  NSTRACE ("[EmacsView acceptsFirstResponder]");
 -  return YES;
++  if (!w->window_end_valid)
++    return BUF_ZV (b);
 +  return BUF_Z (b) - w->window_end_pos;
  }
  
@@ -894,6 +915,8 @@ index 932d209f..ea2de6f2 100644
 -               [theEvent type], [theEvent clickCount]);
 -  return ns_click_through;
 +  Lisp_Object plist = Ftext_properties_at (make_fixnum (pos), buf_obj);
++  /* Third argument to Fplist_get is PREDICATE (Emacs 29+), not a
++     default value.  Qnil selects the default `eq' comparison.  */
 +  return Fplist_get (plist, prop, Qnil);
  }
 -- (void)resetCursorRects
@@ -970,7 +993,7 @@ index 932d209f..ea2de6f2 100644
 +    NSAccessibilityPostNotification (element, name);
 +  });
 +}
-+
+ 
 +static inline void
 +ns_ax_post_notification_with_info (id element,
 +				    NSAccessibilityNotificationName name,
@@ -980,30 +1003,29 @@ index 932d209f..ea2de6f2 100644
 +    NSAccessibilityPostNotificationWithUserInfo (element, name, info);
 +  });
 +}
-+
+ 
+-/*****************************************************************************/
+-/* Keyboard handling.  */
+-#define NS_KEYLOG 0
 +/* Scan visible range of window W for interactive spans.
 +   Returns NSArray<EmacsAccessibilityInteractiveSpan *>.
  
+-- (void)keyDown: (NSEvent *)theEvent
 +   Priority when properties overlap:
 +     widget > button > follow-link > org-link >
 +     completion-candidate > keymap-overlay.  */
 +static NSArray *
 +ns_ax_scan_interactive_spans (struct window *w,
 +			      EmacsAccessibilityBuffer *parent_buf)
-+{
+ {
+-  Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (emacsframe);
 +  if (!w)
 +    return @[];
- 
++
--/*****************************************************************************/
--/* Keyboard handling.  */
--#define NS_KEYLOG 0
 +  Lisp_Object buf_obj = ns_ax_window_buffer_object (w);
 +  if (NILP (buf_obj))
 +    return @[];
- 
++
--- (void)keyDown: (NSEvent *)theEvent
--{
--  Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (emacsframe);
 +  struct buffer *b = XBUFFER (buf_obj);
 +  ptrdiff_t vis_start = marker_position (w->start);
 +  ptrdiff_t vis_end   = ns_ax_window_end_charpos (w, b);
@@ -1278,6 +1300,11 @@ index 932d209f..ea2de6f2 100644
 +  NSString *text = nil;
 +  specpdl_ref count = SPECPDL_INDEX ();
 +  record_unwind_current_buffer ();
++  /* Block input to prevent concurrent redisplay from modifying buffer
++     state while we read text properties.  Unwind-protected so
++     block_input is always matched by unblock_input on signal.  */
++  record_unwind_protect_void (unblock_input);
++  block_input ();
 +  if (b != current_buffer)
 +    set_buffer_internal_1 (b);
 +
@@ -2214,27 +2241,12 @@ index 932d209f..ea2de6f2 100644
 +			     height:text_h];
 +}
 +
-+/* ---- Notification dispatch ---- */
++/* ---- Notification dispatch (helper methods) ---- */
 +
-+- (void)postAccessibilityNotificationsForFrame:(struct frame *)f
++/* Post NSAccessibilityValueChangedNotification for a text edit.
++   Called when BUF_MODIFF changes between redisplay cycles.  */
++- (void)postTextChangedNotification:(ptrdiff_t)point
 +{
-+  NSTRACE ("[EmacsView postAccessibilityNotificationsForFrame:]");
-+  struct window *w = [self validWindow];
-+  if (!w || !WINDOW_LEAF_P (w))
-+    return;
-+
-+  struct buffer *b = XBUFFER (w->contents);
-+  if (!b)
-+    return;
-+
-+  ptrdiff_t modiff = BUF_MODIFF (b);
-+  ptrdiff_t point = BUF_PT (b);
-+  BOOL markActive = !NILP (BVAR (b, mark_active));
-+
-+  /* --- Text changed → typing echo ---
-+     WebKit AXObjectCacheMac fallback enum: Edit = 1, Typing = 3.  */
-+  if (modiff != self.cachedModiff)
-+    {
 +  /* Capture changed char before invalidating cache.  */
 +  NSString *changedChar = @"";
 +  if (point > self.cachedPoint
@@ -2256,11 +2268,10 @@ index 932d209f..ea2de6f2 100644
 +      [self invalidateTextCache];
 +    }
 +
-+      self.cachedModiff = modiff;
++  /* Update cachedPoint here so the selection-move branch does NOT
-+      /* Update cachedPoint here so the selection-move branch below
++     fire for point changes caused by edits.  WebKit and Chromium
-+	 does NOT fire for point changes caused by edits.  WebKit and
++     never send both ValueChanged and SelectedTextChanged for the
-+	 Chromium never send both ValueChanged and SelectedTextChanged
++     same user action — they are mutually exclusive.  */
-+	 for the same user action — they are mutually exclusive.  */
 +  self.cachedPoint = point;
 +
 +  NSDictionary *change = @{
@@ -2275,94 +2286,16 @@ index 932d209f..ea2de6f2 100644
 +  };
 +  ns_ax_post_notification_with_info (
 +    self, NSAccessibilityValueChangedNotification, userInfo);
-+    }
++}
 +
-+  /* --- Cursor moved or selection changed → line reading ---
++/* Post SelectedTextChanged and AnnouncementRequested for the
-+     WebKit AXObjectCacheMac fallback enum: SelectionMove = 2.
++   focused buffer element when point or mark changes.  */
-+     Use 'else if' — edits and selection moves are mutually exclusive
++- (void)postFocusedCursorNotification:(ptrdiff_t)point
-+     per the WebKit/Chromium pattern.  VoiceOver gets confused if
++			    direction:(NSInteger)direction
-+     both notifications arrive in the same runloop iteration.  */
++			 granularity:(NSInteger)granularity
-+  else if (point != self.cachedPoint || markActive != self.cachedMarkActive)
++			  markActive:(BOOL)markActive
-+    {
++			oldMarkActive:(BOOL)oldMarkActive
-+      ptrdiff_t oldPoint = self.cachedPoint;
++{
-+      BOOL oldMarkActive = self.cachedMarkActive;
-+      self.cachedPoint = point;
-+      self.cachedMarkActive = markActive;
-+
-+      /* Compute direction.  */
-+      NSInteger direction = ns_ax_text_selection_direction_discontiguous;
-+      if (point > oldPoint)
-+	direction = ns_ax_text_selection_direction_next;
-+      else if (point < oldPoint)
-+	direction = ns_ax_text_selection_direction_previous;
-+
-+      int ctrlNP = 0;
-+      bool isCtrlNP = ns_ax_event_is_line_nav_key (&ctrlNP);
-+
-+      /* --- Granularity detection ---
-+	 Compare old and new cursor positions in cachedText to determine
-+	 what kind of move happened.  Three levels:
-+	 - line:      different line (lineRangeForRange)
-+	 - word:      same line, distance > 1 UTF-16 unit
-+	 - character: same line, distance == 1 UTF-16 unit
-+	 C-n/C-p force line regardless of detected granularity.  */
-+      NSInteger granularity = ns_ax_text_selection_granularity_unknown;
-+      [self ensureTextCache];
-+      NSUInteger oldIdx = 0, newIdx = 0;
-+      if (cachedText && oldPoint > 0)
-+	{
-+	  NSUInteger tlen = [cachedText length];
-+	  oldIdx = [self accessibilityIndexForCharpos:oldPoint];
-+	  newIdx = [self accessibilityIndexForCharpos:point];
-+	  if (oldIdx > tlen) oldIdx = tlen;
-+	  if (newIdx > tlen) newIdx = tlen;
-+
-+	  NSRange oldLine = [cachedText lineRangeForRange:
-+				  NSMakeRange (oldIdx, 0)];
-+	  NSRange newLine = [cachedText lineRangeForRange:
-+				  NSMakeRange (newIdx, 0)];
-+	  if (oldLine.location != newLine.location)
-+	    granularity = ns_ax_text_selection_granularity_line;
-+	  else
-+	    {
-+	      NSUInteger dist = (newIdx > oldIdx
-+				 ? newIdx - oldIdx
-+				 : oldIdx - newIdx);
-+	      if (dist > 1)
-+		granularity = ns_ax_text_selection_granularity_word;
-+	      else if (dist == 1)
-+		granularity = ns_ax_text_selection_granularity_character;
-+	    }
-+	}
-+
-+      /* Force line semantics for explicit C-n/C-p / Tab / backtab.  */
-+      if (isCtrlNP)
-+	{
-+	  direction = (ctrlNP > 0
-+		       ? ns_ax_text_selection_direction_next
-+		       : ns_ax_text_selection_direction_previous);
-+	  granularity = ns_ax_text_selection_granularity_line;
-+	}
-+
-+      /* --- NOTIFICATION STRATEGY ---
-+	 SelectedTextChanged ALWAYS posted for focused element:
-+	 - Interrupts VoiceOver auto-read (buffer switch reading)
-+	 - Provides word/line/selection reading via VoiceOver defaults
-+
-+	 For CHARACTER moves only: omit granularity from userInfo so
-+	 VoiceOver cannot derive speech from SelectedTextChanged, then
-+	 post AnnouncementRequested with char AT point.  This avoids
-+	 double-speech while keeping the interrupt behaviour.
-+
-+	 For WORD and LINE moves: include granularity in userInfo —
-+	 VoiceOver reads the word/line correctly on its own.
-+
-+	 For SELECTION changes: include granularity — VoiceOver reads
-+	 selected/deselected text.
-+
-+	 Non-focused buffers: AnnouncementRequested only (see below).  */
-+      if ([self isAccessibilityFocused])
-+	{
 +  BOOL isCharMove
 +    = (!markActive && !oldMarkActive
 +       && granularity
@@ -2423,11 +2356,11 @@ index 932d209f..ea2de6f2 100644
 +    }
 +
 +  /* For focused line moves: always announce line text explicitly.
-+	     SelectedTextChanged with granularity=line works for arrow
++     SelectedTextChanged with granularity=line works for arrow keys,
-+	     keys, but C-n/C-p need the explicit announcement (VoiceOver
++     but C-n/C-p need the explicit announcement (VoiceOver processes
-+	     processes these keystrokes differently from arrows).
++     these keystrokes differently from arrows).
-+	     In completion-list-mode, read the completion candidate
++     In completion-list-mode, read the completion candidate instead
-+	     instead of the whole line.  */
++     of the whole line.  */
 +  if (cachedText
 +      && granularity == ns_ax_text_selection_granularity_line)
 +    {
@@ -2477,19 +2410,15 @@ index 932d209f..ea2de6f2 100644
 +	    }
 +	}
 +    }
-+	}
++}
 +
-+      /* --- Completions announcement ---
++/* Post AnnouncementRequested for non-focused buffers (typically
-+	 When point changes in a non-focused buffer (e.g. *Completions*
++   *Completions* while minibuffer has keyboard focus).
-+	 while the minibuffer has keyboard focus), VoiceOver won't read
++   VoiceOver does not automatically read changes in non-focused
-+	 the change because it's tracking the focused element.  Post an
++   elements, so we announce the selected completion explicitly.  */
-+	 announcement so the user hears the selected completion.
++- (void)postCompletionAnnouncementForBuffer:(struct buffer *)b
-+
++					point:(ptrdiff_t)point
-+	 If there is a `completions-highlight` overlay at point (Emacs
++{
-+	 highlights the selected completion candidate), read its full
-+	 text instead of just the current line.  */
-+      if (![self isAccessibilityFocused] && cachedText)
-+	{
 +  NSString *announceText = nil;
 +  ptrdiff_t currentOverlayStart = 0;
 +  ptrdiff_t currentOverlayEnd = 0;
@@ -2499,17 +2428,13 @@ index 932d209f..ea2de6f2 100644
 +  if (b != current_buffer)
 +    set_buffer_internal_1 (b);
 +
-+	  /* 1) Prefer explicit completion candidate property when present.
++  /* 1) Prefer explicit completion candidate property.  */
-+	     completion--string can be a plain string (simple completion)
-+	     or a list ("candidate" "annotation") for annotated completions.
-+	     In the list case, use car (the completion itself).  */
 +  Lisp_Object cstr = Fget_char_property (make_fixnum (point),
 +				  Qns_ax_completion__string,
 +				  Qnil);
 +  announceText = ns_ax_completion_string_from_prop (cstr);
 +
-+	  /* 2) Fallback: announce the mouse-face span at point.
++  /* 2) Fallback: mouse-face span at point.  */
-+	     completion-list-mode often marks the active candidate this way.  */
 +  if (!announceText)
 +    {
 +      Lisp_Object mf = Fget_char_property (make_fixnum (point),
@@ -2519,8 +2444,6 @@ index 932d209f..ea2de6f2 100644
 +	  ptrdiff_t begv2 = BUF_BEGV (b);
 +	  ptrdiff_t zv2 = BUF_ZV (b);
 +
-+		  /* Find mouse-face span boundaries using property
-+		     change functions — O(log n) instead of O(n).  */
 +	  Lisp_Object prev_change
 +	    = Fprevious_single_char_property_change (
 +		make_fixnum (point + 1), Qmouse_face,
@@ -2548,7 +2471,7 @@ index 932d209f..ea2de6f2 100644
 +	}
 +    }
 +
-+	  /* 3) Fallback: check completions-highlight overlay span at point.  */
++  /* 3) Fallback: completions-highlight overlay at point.  */
 +  if (!announceText)
 +    {
 +      Lisp_Object faceSym = Qns_ax_completions_highlight;
@@ -2578,17 +2501,16 @@ index 932d209f..ea2de6f2 100644
 +	}
 +    }
 +
-+	  /* 4) Fallback: select the best completions-highlight overlay.
++  /* 4) Fallback: nearest completions-highlight overlay.  */
-+	     Prefer overlay nearest to point over first-found in buffer.  */
 +  if (!announceText)
 +    {
 +      ptrdiff_t ov_start = 0;
 +      ptrdiff_t ov_end = 0;
-+	      if (ns_ax_find_completion_overlay_range (b, point, &ov_start, &ov_end))
++      if (ns_ax_find_completion_overlay_range (b, point,
++					      &ov_start, &ov_end))
 +	{
 +	  announceText = ns_ax_completion_text_for_span (self, b,
-+						 ov_start,
++					 ov_start, ov_end,
-+						 ov_end,
 +					 cachedText);
 +	  currentOverlayStart = ov_start;
 +	  currentOverlayEnd = ov_end;
@@ -2597,7 +2519,7 @@ index 932d209f..ea2de6f2 100644
 +
 +  unbind_to (count2, Qnil);
 +
-+	  /* Final fallback: read the current line at point.  */
++  /* Final fallback: read current line at point.  */
 +  if (!announceText)
 +    {
 +      NSUInteger point_idx = [self accessibilityIndexForCharpos:point];
@@ -2614,6 +2536,7 @@ index 932d209f..ea2de6f2 100644
 +	}
 +    }
 +
++  /* Deduplicate: post only when text, overlay, or point changed.  */
 +  if (announceText)
 +    {
 +      announceText = [announceText stringByTrimmingCharactersInSet:
@@ -2658,15 +2581,108 @@ index 932d209f..ea2de6f2 100644
 +      self.cachedCompletionOverlayEnd = 0;
 +      self.cachedCompletionPoint = 0;
 +    }
++}
++
++/* ---- Notification dispatch (main entry point) ---- */
++
++/* Dispatch accessibility notifications after a redisplay cycle.
++   Detects three mutually exclusive events: text edit, cursor/mark
++   change, or no change.  Delegates to helper methods above.  */
++- (void)postAccessibilityNotificationsForFrame:(struct frame *)f
++{
++  NSTRACE ("[EmacsView postAccessibilityNotificationsForFrame:]");
++  struct window *w = [self validWindow];
++  if (!w || !WINDOW_LEAF_P (w))
++    return;
++
++  struct buffer *b = XBUFFER (w->contents);
++  if (!b)
++    return;
++
++  ptrdiff_t modiff = BUF_MODIFF (b);
++  ptrdiff_t point = BUF_PT (b);
++  BOOL markActive = !NILP (BVAR (b, mark_active));
++
++  /* --- Text changed (edit) --- */
++  if (modiff != self.cachedModiff)
++    {
++      self.cachedModiff = modiff;
++      [self postTextChangedNotification:point];
 +    }
 +
++  /* --- Cursor moved or selection changed ---
++     Use 'else if' — edits and selection moves are mutually exclusive
++     per the WebKit/Chromium pattern.  */
++  else if (point != self.cachedPoint || markActive != self.cachedMarkActive)
++    {
++      ptrdiff_t oldPoint = self.cachedPoint;
++      BOOL oldMarkActive = self.cachedMarkActive;
++      self.cachedPoint = point;
++      self.cachedMarkActive = markActive;
++
++      /* Compute direction.  */
++      NSInteger direction = ns_ax_text_selection_direction_discontiguous;
++      if (point > oldPoint)
++	direction = ns_ax_text_selection_direction_next;
++      else if (point < oldPoint)
++	direction = ns_ax_text_selection_direction_previous;
++
++      int ctrlNP = 0;
++      bool isCtrlNP = ns_ax_event_is_line_nav_key (&ctrlNP);
++
++      /* --- Granularity detection --- */
++      NSInteger granularity = ns_ax_text_selection_granularity_unknown;
++      [self ensureTextCache];
++      if (cachedText && oldPoint > 0)
++	{
++	  NSUInteger tlen = [cachedText length];
++	  NSUInteger oldIdx = [self accessibilityIndexForCharpos:oldPoint];
++	  NSUInteger newIdx = [self accessibilityIndexForCharpos:point];
++	  if (oldIdx > tlen) oldIdx = tlen;
++	  if (newIdx > tlen) newIdx = tlen;
++
++	  NSRange oldLine = [cachedText lineRangeForRange:
++				  NSMakeRange (oldIdx, 0)];
++	  NSRange newLine = [cachedText lineRangeForRange:
++				  NSMakeRange (newIdx, 0)];
++	  if (oldLine.location != newLine.location)
++	    granularity = ns_ax_text_selection_granularity_line;
++	  else
++	    {
++	      NSUInteger dist = (newIdx > oldIdx
++				 ? newIdx - oldIdx
++				 : oldIdx - newIdx);
++	      if (dist > 1)
++		granularity = ns_ax_text_selection_granularity_word;
++	      else if (dist == 1)
++		granularity = ns_ax_text_selection_granularity_character;
++	    }
++	}
++
++      /* Force line semantics for explicit C-n/C-p / Tab / backtab.  */
++      if (isCtrlNP)
++	{
++	  direction = (ctrlNP > 0
++		       ? ns_ax_text_selection_direction_next
++		       : ns_ax_text_selection_direction_previous);
++	  granularity = ns_ax_text_selection_granularity_line;
++	}
++
++      /* Post notifications for focused and non-focused elements.  */
++      if ([self isAccessibilityFocused])
++	[self postFocusedCursorNotification:point
++				  direction:direction
++			       granularity:granularity
++				markActive:markActive
++			      oldMarkActive:oldMarkActive];
++
++      if (![self isAccessibilityFocused] && cachedText)
++	[self postCompletionAnnouncementForBuffer:b point:point];
 +    }
 +  else
 +    {
-+      /* Nothing changed (no text edit, no cursor move, no mark change).
++      /* Nothing changed.  Reset completion cache for focused buffer
-+	 Overlay state cannot change without a modiff bump, so no scan
++	 to avoid stale announcements.  */
-+	 needed for non-focused buffers.  Just reset completion cache
-+	 for focused buffer to avoid stale announcements.  */
 +      if ([self isAccessibilityFocused])
 +	{
 +	  self.cachedCompletionAnnouncement = nil;
@@ -2984,7 +3000,7 @@ index 932d209f..ea2de6f2 100644
    int code;
    unsigned fnKeysym = 0;
    static NSMutableArray *nsEvArray;
-@@ -8237,6 +10559,31 @@ - (void)windowDidBecomeKey      /* for direct calls */
+@@ -8237,6 +10584,32 @@ - (void)windowDidBecomeKey      /* for direct calls */
    XSETFRAME (event.frame_or_window, emacsframe);
    kbd_buffer_store_event (&event);
    ns_send_appdefined (-1);  // Kick main loop
@@ -2993,6 +3009,7 @@ index 932d209f..ea2de6f2 100644
 +  /* Notify VoiceOver that the focused accessibility element changed.
 +     Post on the focused virtual element so VoiceOver starts tracking it.
 +     This is critical for initial focus and app-switch scenarios.  */
++  if (ns_accessibility_enabled)
 +  {
 +    id focused = [self accessibilityFocusedUIElement];
 +    if (focused
@@ -3016,7 +3033,7 @@ index 932d209f..ea2de6f2 100644
  }
  
  
-@@ -9474,6 +11821,332 @@ - (int) fullscreenState
+@@ -9474,6 +11847,332 @@ - (int) fullscreenState
    return fs_state;
  }
  
@@ -3171,7 +3188,7 @@ index 932d209f..ea2de6f2 100644
 +  NSTRACE ("[EmacsView postAccessibilityUpdates]");
 +  eassert ([NSThread isMainThread]);
 +
-+  if (!emacsframe)
++  if (!emacsframe || !ns_accessibility_enabled)
 +    return;
 +
 +  /* Re-entrance guard: VoiceOver callbacks during notification posting
@@ -3349,7 +3366,7 @@ index 932d209f..ea2de6f2 100644
  @end  /* EmacsView */
  
  
-@@ -11303,7 +13976,29 @@ Convert an X font name (XLFD) to an NS font name.
+@@ -11303,6 +14002,28 @@ Convert an X font name (XLFD) to an NS font name.
    DEFSYM (Qns_drag_operation_generic, "ns-drag-operation-generic");
    DEFSYM (Qns_handle_drag_motion, "ns-handle-drag-motion");
  
@@ -3375,10 +3392,25 @@ index 932d209f..ea2de6f2 100644
 +  DEFSYM (Qns_ax_completions_highlight, "completions-highlight");
 +  DEFSYM (Qns_ax_backtab, "backtab");
 +  /* Qmouse_face and Qkeymap are defined in textprop.c / keymap.c.  */
-+
    Fput (Qalt, Qmodifier_value, make_fixnum (alt_modifier));
    Fput (Qhyper, Qmodifier_value, make_fixnum (hyper_modifier));
    Fput (Qmeta, Qmodifier_value, make_fixnum (meta_modifier));
+@@ -11451,6 +14172,15 @@ Nil means use fullscreen the old (< 10.7) way.  The old way works better with
+ This variable is ignored on Mac OS X < 10.7 and GNUstep.  */);
+   ns_use_srgb_colorspace = YES;
+ 
++  DEFVAR_BOOL ("ns-accessibility-enabled", ns_accessibility_enabled,
++     doc: /* Non-nil means expose buffer content to the macOS accessibility
++subsystem (VoiceOver, Zoom, and other assistive technology).
++When nil, the accessibility virtual element tree is not built and no
++notifications are posted, eliminating the associated overhead.
++Requires the Cocoa (NS) build on macOS; ignored on GNUstep.
++Default is t.  */);
++  ns_accessibility_enabled = YES;
++
+   DEFVAR_BOOL ("ns-use-mwheel-acceleration",
+                ns_use_mwheel_acceleration,
+      doc: /* Non-nil means use macOS's standard mouse wheel acceleration.
 -- 
 2.43.0
 

patches/0002-doc-add-VoiceOver-accessibility-section-to-macOS-app.patch

@@ -1,24 +1,24 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From ce3b2a8091c99f738ec59acd6f6ebf0d84826e34 Mon Sep 17 00:00:00 2001
 From: Martin Sukany <martin@sukany.cz>
-Date: Fri, 27 Feb 2026 17:30:00 +0100
+Date: Fri, 27 Feb 2026 17:49:51 +0100
 Subject: [PATCH 2/2] doc: add VoiceOver accessibility section to macOS
  appendix
 
 Document the new VoiceOver accessibility support in the Emacs manual.
 Add a new section to the macOS appendix covering screen reader usage,
-keyboard navigation feedback, completion announcements, and Zoom
+keyboard navigation feedback, completion announcements, Zoom cursor
-cursor tracking.
+tracking, and the ns-accessibility-enabled user option.
 
 * doc/emacs/macos.texi (VoiceOver Accessibility): New section.
 ---
- doc/emacs/macos.texi | 46 +++++++++++++++++++++++++++++++++++++++++++
+ doc/emacs/macos.texi | 53 ++++++++++++++++++++++++++++++++++++++++++++
- 1 file changed, 46 insertions(+)
+ 1 file changed, 53 insertions(+)
 
 diff --git a/doc/emacs/macos.texi b/doc/emacs/macos.texi
-index 1234567..abcdefg 100644
+index 6bd334f..1d969f9 100644
 --- a/doc/emacs/macos.texi
 +++ b/doc/emacs/macos.texi
-@@ -31,6 +31,7 @@ Support}), but we hope to improve it in the future.
+@@ -36,6 +36,7 @@ Support}), but we hope to improve it in the future.
  * Mac / GNUstep Basics::        Basic Emacs usage under GNUstep or macOS.
  * Mac / GNUstep Customization:: Customizations under GNUstep or macOS.
  * Mac / GNUstep Events::        How window system events are handled.
@@ -26,10 +26,10 @@ index 1234567..abcdefg 100644
  * GNUstep Support::             Details on status of GNUstep support.
  @end menu
  
-@@ -272,6 +273,51 @@ services and receive the results back.  Note that you may need to
+@@ -272,6 +273,58 @@ and return the result as a string.  You can also use the Lisp function
+ services and receive the results back.  Note that you may need to
  restart Emacs to access newly-available services.
  
- 
 +@node VoiceOver Accessibility
 +@section VoiceOver Accessibility (macOS)
 +@cindex VoiceOver
@@ -70,6 +70,12 @@ index 1234567..abcdefg 100644
 +position is communicated via @code{UAZoomChangeFocus} and the
 +@code{AXBoundsForRange} accessibility attribute.
 +
++@vindex ns-accessibility-enabled
++  To disable the accessibility interface entirely (for instance, to
++eliminate overhead on systems where assistive technology is not in
++use), set @code{ns-accessibility-enabled} to @code{nil}.  The default
++is @code{t}.
++
 +  This support is available only on the Cocoa build; GNUstep has a
 +different accessibility model and is not yet supported
 +(@pxref{GNUstep Support}).  Evil-mode block cursors are handled
@@ -81,3 +87,4 @@ index 1234567..abcdefg 100644
  
 -- 
 2.43.0
+

patches/README.txt

@@ -3,10 +3,10 @@ EMACS NS VOICEOVER ACCESSIBILITY PATCH
 patch: 0001-ns-implement-AXBoundsForRange-for-macOS-Zoom-cursor-.patch
         0002-doc-add-VoiceOver-accessibility-section-to-macOS-app.patch
 author: Martin Sukany <martin@sukany.cz>
-files: src/nsterm.h (+105 lines)
+files: src/nsterm.h (+119 lines)
-        src/nsterm.m (+2846 ins, -151 del, +2695 net)
+        src/nsterm.m (+3024 ins, -147 del, +2877 net)
-        doc/emacs/macos.texi (+46 lines)
+        doc/emacs/macos.texi (+53 lines)
-        etc/NEWS (+11 lines)
+        etc/NEWS (+13 lines)
 
 
 OVERVIEW
@@ -114,6 +114,18 @@ ARCHITECTURE
       accessibilityAttributeValue:forParameter: API.
 
 
+USER OPTION
+-----------
+
+  ns-accessibility-enabled (DEFVAR_BOOL, default t):
+    When nil, the accessibility virtual element tree is not built, no
+    notifications are posted, and ns_draw_phys_cursor skips the Zoom
+    update.  This eliminates accessibility overhead entirely on systems
+    where assistive technology is not in use.  Guarded at three entry
+    points: postAccessibilityUpdates, ns_draw_phys_cursor, and
+    windowDidBecomeKey.
+
+
 THREADING MODEL
 ---------------
 
@@ -615,4 +627,38 @@ TESTING CHECKLIST
     26. Open an org-mode file with many folded sections.  Verify that
         folded (invisible) text is not announced during navigation.
 
+
+REVIEW CHANGES (post initial implementation)
+---------------------------------------------
+
+  The following changes were made based on maintainer-style code review:
+
+  1. ns_ax_window_end_charpos: added window_end_valid guard.  Falls
+     back to BUF_ZV when the window has not been fully redisplayed,
+     preventing stale data in AX getters called before next redisplay.
+
+  2. GC safety documentation: detailed comment on lispWindow ivar
+     explaining why staticpro is not needed (windows reachable from
+     frame tree, GC only on main thread, AX getters dispatch to main).
+
+  3. ns-accessibility-enabled (DEFVAR_BOOL): new user option to
+     disable accessibility entirely.  Guards three entry points.
+
+  4. postAccessibilityNotificationsForFrame: extracted from one ~200
+     line method into four focused helpers:
+     - postTextChangedNotification: (typing echo)
+     - postFocusedCursorNotification:direction:granularity:markActive:
+       oldMarkActive: (focused cursor/selection)
+     - postCompletionAnnouncementForBuffer:point: (completions)
+     - postAccessibilityNotificationsForFrame: (orchestrator, ~60 lines)
+
+  5. ns_ax_completion_text_for_span: added block_input/unblock_input
+     with specpdl unwind protection for signal safety.
+
+  6. Fplist_get third-argument comment (PREDICATE, not default value).
+
+  7. Documentation: macos.texi section updated with
+     ns-accessibility-enabled variable reference.  etc/NEWS updated.
+
+
 -- end of README --