patches: fix O(position) lag — O(1) fast path in charposForAccessibilityIndex:

charposForAccessibilityIndex: walked composed character sequences
from the start of a visible run to the target AX index.  For a run
covering an entire ASCII buffer, this is O(cursor_position): moving
to line 10,000 requires ~500,000 iterations per call.

The method is called on every SelectedTextChanged notification
response (accessibilityBoundsForRange: from the AX server for cursor
tracking), making cursor movement O(position) in large files.

Fix: when ax_length == length for a run (all characters are single
AX index units — true for all ASCII/Latin text), the charpos offset
is simply ax_idx - run.ax_start.  O(1) instead of O(position).

Multi-byte runs (emoji, CJK, non-BMP) fall back to the sequence walk,
bounded by run length (visible window size), not total buffer size.
This commit is contained in:
2026-03-01 09:03:01 +01:00
parent 31ad038360
commit fb68dd50ea
9 changed files with 73 additions and 66 deletions

View File

@@ -1,7 +1,7 @@
From 0e5f90b02aa9d9b9ba1fdba7d88ae54e17417fe9 Mon Sep 17 00:00:00 2001
From 8dd1a4cd6d3f58a3c6f9454ba1690a442c2048fe Mon Sep 17 00:00:00 2001
From: Martin Sukany <martin@sukany.cz>
Date: Sat, 28 Feb 2026 14:46:25 +0100
Subject: [PATCH 8/9] ns: announce overlay completion candidates for VoiceOver
Subject: [PATCH 7/8] ns: announce overlay completion candidates for VoiceOver
Completion frameworks such as Vertico, Ivy, and Icomplete render
candidates via overlay before-string/after-string properties rather
@@ -61,7 +61,7 @@ index 6e830de..2102fb9 100644
@property (nonatomic, assign) BOOL cachedMarkActive;
@property (nonatomic, copy) NSString *cachedCompletionAnnouncement;
diff --git a/src/nsterm.m b/src/nsterm.m
index f8b7a8d..3e005e0 100644
index 0a70f3e..c74eaf1 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -7254,11 +7254,154 @@ Accessibility virtual elements (macOS / Cocoa only)
@@ -329,7 +329,7 @@ index f8b7a8d..3e005e0 100644
@synchronized (self)
{
if (visibleRunCount == 0)
@@ -8172,7 +8307,7 @@ - (ptrdiff_t)charposForAccessibilityIndex:(NSUInteger)ax_idx
@@ -8180,7 +8315,7 @@ the slow path (composed character sequence walk), which is
return cp;
}
}
@@ -338,7 +338,7 @@ index f8b7a8d..3e005e0 100644
if (lo > 0)
{
ns_ax_visible_run *last = &visibleRuns[visibleRunCount - 1];
@@ -8194,7 +8329,7 @@ - (ptrdiff_t)charposForAccessibilityIndex:(NSUInteger)ax_idx
@@ -8202,7 +8337,7 @@ the slow path (composed character sequence walk), which is
deadlocking the AX server thread. This is prevented by:
1. validWindow checks WINDOW_LIVE_P and BUFFERP before every
@@ -347,7 +347,7 @@ index f8b7a8d..3e005e0 100644
2. All dispatch_sync blocks run on the main thread where no
concurrent Lisp code can modify state between checks.
3. block_input prevents timer events and process output from
@@ -8548,6 +8683,50 @@ - (NSInteger)accessibilityInsertionPointLineNumber
@@ -8556,6 +8691,50 @@ - (NSInteger)accessibilityInsertionPointLineNumber
return [self lineForAXIndex:point_idx];
}
@@ -398,7 +398,7 @@ index f8b7a8d..3e005e0 100644
- (NSRange)accessibilityRangeForLine:(NSInteger)line
{
if (![NSThread isMainThread])
@@ -8770,7 +8949,7 @@ - (NSRect)accessibilityFrame
@@ -8778,7 +8957,7 @@ - (NSRect)accessibilityFrame
/* ===================================================================
@@ -407,7 +407,7 @@ index f8b7a8d..3e005e0 100644
These methods notify VoiceOver of text and selection changes.
Called from the redisplay cycle (postAccessibilityUpdates).
@@ -8785,7 +8964,7 @@ - (void)postTextChangedNotification:(ptrdiff_t)point
@@ -8793,7 +8972,7 @@ - (void)postTextChangedNotification:(ptrdiff_t)point
if (point > self.cachedPoint
&& point - self.cachedPoint == 1)
{
@@ -416,7 +416,7 @@ index f8b7a8d..3e005e0 100644
[self invalidateTextCache];
[self ensureTextCache];
if (cachedText)
@@ -8804,7 +8983,7 @@ - (void)postTextChangedNotification:(ptrdiff_t)point
@@ -8812,7 +8991,7 @@ - (void)postTextChangedNotification:(ptrdiff_t)point
/* Update cachedPoint here so the selection-move branch does NOT
fire for point changes caused by edits. WebKit and Chromium
never send both ValueChanged and SelectedTextChanged for the
@@ -425,7 +425,7 @@ index f8b7a8d..3e005e0 100644
self.cachedPoint = point;
NSDictionary *change = @{
@@ -9137,16 +9316,83 @@ - (void)postAccessibilityNotificationsForFrame:(struct frame *)f
@@ -9145,16 +9324,83 @@ - (void)postAccessibilityNotificationsForFrame:(struct frame *)f
BOOL markActive = !NILP (BVAR (b, mark_active));
/* --- Text changed (edit) --- */
@@ -513,7 +513,7 @@ index f8b7a8d..3e005e0 100644
{
ptrdiff_t oldPoint = self.cachedPoint;
BOOL oldMarkActive = self.cachedMarkActive;
@@ -9314,7 +9560,7 @@ - (NSRect)accessibilityFrame
@@ -9322,7 +9568,7 @@ - (NSRect)accessibilityFrame
/* ===================================================================
@@ -522,7 +522,7 @@ index f8b7a8d..3e005e0 100644
=================================================================== */
/* Scan visible range of window W for interactive spans.
@@ -9522,7 +9768,7 @@ - (void) setAccessibilityFocused: (BOOL) focused
@@ -9530,7 +9776,7 @@ - (void) setAccessibilityFocused: (BOOL) focused
dispatch_async (dispatch_get_main_queue (), ^{
/* lwin is a Lisp_Object captured by value. This is GC-safe
because Lisp_Objects are tagged integers/pointers that
@@ -531,7 +531,7 @@ index f8b7a8d..3e005e0 100644
Emacs. The WINDOW_LIVE_P check below guards against the
window being deleted between capture and execution. */
if (!WINDOWP (lwin) || NILP (Fwindow_live_p (lwin)))
@@ -9548,7 +9794,7 @@ - (void) setAccessibilityFocused: (BOOL) focused
@@ -9556,7 +9802,7 @@ - (void) setAccessibilityFocused: (BOOL) focused
@end
@@ -540,7 +540,7 @@ index f8b7a8d..3e005e0 100644
Methods are kept here (same .m file) so they access the ivars
declared in the @interface ivar block. */
@implementation EmacsAccessibilityBuffer (InteractiveSpans)
@@ -12270,7 +12516,7 @@ - (int) fullscreenState
@@ -12278,7 +12524,7 @@ - (int) fullscreenState
if (WINDOW_LEAF_P (w))
{
@@ -549,7 +549,7 @@ index f8b7a8d..3e005e0 100644
EmacsAccessibilityBuffer *elem
= [existing objectForKey:[NSValue valueWithPointer:w]];
if (!elem)
@@ -12304,7 +12550,7 @@ - (int) fullscreenState
@@ -12312,7 +12558,7 @@ - (int) fullscreenState
}
else
{
@@ -558,7 +558,7 @@ index f8b7a8d..3e005e0 100644
Lisp_Object child = w->contents;
while (!NILP (child))
{
@@ -12416,7 +12662,7 @@ - (void)postAccessibilityUpdates
@@ -12424,7 +12670,7 @@ - (void)postAccessibilityUpdates
accessibilityUpdating = YES;
/* Detect window tree change (split, delete, new buffer). Compare
@@ -567,7 +567,7 @@ index f8b7a8d..3e005e0 100644
Lisp_Object curRoot = FRAME_ROOT_WINDOW (emacsframe);
if (!EQ (curRoot, lastRootWindow))
{
@@ -12425,12 +12671,12 @@ - (void)postAccessibilityUpdates
@@ -12433,12 +12679,12 @@ - (void)postAccessibilityUpdates
}
/* If tree is stale, rebuild FIRST so we don't iterate freed