[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
master 616da8fa8e: Merge branch 'feature/fix-the-long-lines-display-bug'
|
From: |
Gregory Heytings |
|
Subject: |
master 616da8fa8e: Merge branch 'feature/fix-the-long-lines-display-bug' |
|
Date: |
Thu, 21 Jul 2022 06:39:32 -0400 (EDT) |
branch: master
commit 616da8fa8efa9023f56fa731072d877e2150afbc
Merge: 51f8e86374 e09c056a44
Author: Gregory Heytings <gregory@heytings.org>
Commit: Gregory Heytings <gregory@heytings.org>
Merge branch 'feature/fix-the-long-lines-display-bug'
---
doc/emacs/emacs.texi | 1 -
doc/emacs/trouble.texi | 59 ----------------------
etc/NEWS | 24 +++++----
etc/PROBLEMS | 6 ---
lisp/{ => obsolete}/longlines.el | 1 +
src/buffer.c | 26 +++++++---
src/buffer.h | 11 +++--
src/composite.c | 6 +++
src/dispextern.h | 5 ++
src/insdel.c | 18 +++----
src/lisp.h | 14 ++++--
src/search.c | 2 +-
src/textprop.c | 2 +-
src/window.c | 2 +-
src/window.h | 1 +
src/xdisp.c | 103 +++++++++++++++++++++++++++++++++++----
16 files changed, 168 insertions(+), 113 deletions(-)
diff --git a/doc/emacs/emacs.texi b/doc/emacs/emacs.texi
index 5e72699bbe..b43c966f87 100644
--- a/doc/emacs/emacs.texi
+++ b/doc/emacs/emacs.texi
@@ -1190,7 +1190,6 @@ Dealing with Emacs Trouble
* Crashing:: What Emacs does when it crashes.
* After a Crash:: Recovering editing in an Emacs session that crashed.
* Emergency Escape:: What to do if Emacs stops responding.
-* Long Lines:: Mitigating slowness due to extremely long lines.
* DEL Does Not Delete:: What to do if @key{DEL} doesn't delete.
Reporting Bugs
diff --git a/doc/emacs/trouble.texi b/doc/emacs/trouble.texi
index f06b93759d..887e5c6170 100644
--- a/doc/emacs/trouble.texi
+++ b/doc/emacs/trouble.texi
@@ -158,7 +158,6 @@ Emacs.
* Crashing:: What Emacs does when it crashes.
* After a Crash:: Recovering editing in an Emacs session that crashed.
* Emergency Escape:: What to do if Emacs stops responding.
-* Long Lines:: Mitigating slowness due to extremely long lines.
* DEL Does Not Delete:: What to do if @key{DEL} doesn't delete.
@end menu
@@ -433,64 +432,6 @@ program.
emergency escape---but there are cases where it won't work, when a
system call hangs or when Emacs is stuck in a tight loop in C code.
-@node Long Lines
-@subsection Long Lines
-@cindex long lines
-
- For a variety of reasons (some of which are fundamental to the Emacs
-redisplay code and the complex range of possibilities it handles;
-others of which are due to modes and features which do not scale well
-in unusual circumstances), Emacs can perform poorly when extremely
-long lines are present (where ``extremely long'' usually means at
-least many thousands of characters).
-
-@cindex @code{so-long} mode
-@findex global-so-long-mode
-@vindex so-long-action
- A particular problem is that Emacs may ``hang'' for a long time at
-the point of visiting a file with extremely long lines. This can be
-mitigated by enabling the @file{so-long} library, which detects when a
-visited file contains abnormally long lines, and takes steps to
-disable features which are liable to cause slowness in that situation.
-To enable this library, type @kbd{M-x global-so-long-mode @key{RET}},
-or turn on the @code{global-so-long-mode} in your init file
-(@pxref{Init File}), or customize the @code{global-so-long-mode}
-option. You can tailor this mode's operation by customizing the
-variable @code{so-long-action}.
-
- The @file{so-long} library can also significantly improve
-performance when moving and editing in a buffer with long lines.
-Performance is still likely to degrade as you get deeper into the long
-lines, but the improvements from using this library can nevertheless
-be substantial.
-
-@findex so-long-commentary
- Use @kbd{M-x so-long-commentary} to view the documentation for this
-library and learn more about how to enable and configure it.
-
-@vindex max-redisplay-ticks
- If even @code{so-long-mode} doesn't help making Emacs responsive
-enough, or if you'd rather not disable the display-related features
-that @code{so-long-mode} turns off, you can instead customize the
-variable @code{max-redisplay-ticks} to a non-zero value. Then Emacs
-will abort redisplay of a window and commands, like @kbd{C-n} and
-@kbd{M-v}, which use the display code to do their job, if processing a
-window needs more low-level display operations than the value of this
-variable. The display of the offending window will then remain
-outdated, and possibly incomplete, on the screen, but Emacs should
-otherwise be responsive, and you could then switch to another buffer,
-or kill the problematic buffer, or turn on @code{so-long-mode} or
-@code{so-long-minor-mode} in that buffer. When the display of a
-window is aborted due to this reason, the buffer shown in that window
-will not have any of its windows redisplayed until the buffer is
-modified or until you type @kbd{C-l} (@pxref{Recentering}) in one of
-that buffer's windows.
-
- If you decide to customize this variable to a non-zero value, we
-recommend to use a value between 100,000 and 1,000,000, depending on
-your patience and the speed of your system. The default value is
-zero, which disables this feature.
-
@node DEL Does Not Delete
@subsection If @key{DEL} Fails to Delete
@cindex @key{DEL} vs @key{BACKSPACE}
diff --git a/etc/NEWS b/etc/NEWS
index 9f0643fdde..9de106c26f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -334,7 +334,16 @@ Use something like 'M-x shell RET ssh <host> RET' instead.
* Changes in Emacs 29.1
---
-** 'longlines-mode' is no longer obsolete.
+** Emacs is now capable of editing files with arbitrarily long lines.
+The display of long lines has been optimized, and Emacs no longer
+chokes when a buffer on display contains long lines. If you still
+experience slowdowns while editing files with long lines, this is
+either due to font locking, which you can turn off with M-x
+font-lock-mode or C-u C-x x f, or to the current major mode or one of
+the enabled minor modes, in which case you should open the the file
+with M-x find-file-literally instead of C-x C-f. The variable
+'long-line-threshold' controls whether and when these display
+optimizations are used.
+++
** New command to change the font size globally.
@@ -356,10 +365,10 @@ Get the parent directory of a file.
This variable is used by some operations (mostly syntax-propertization
and font-locking) to treat lines longer than this variable as if they
were made up of various smaller lines. This can help reduce the
-pathological slowdowns seen in buffers made of a single long line, but
-can also cause misbehavior in the presence of such long lines (tho
-most of that misbehavior should usually be limited to mis-highlighting).
-You can recover the previous behavior with:
+slowdowns seen in buffers made of a single long line, but can also
+cause misbehavior in the presence of such long lines (tho most of that
+misbehavior should usually be limited to mis-highlighting). You can
+recover the previous behavior with:
(setq syntax-wholeline-max most-positive-fixnum)
@@ -471,11 +480,6 @@ including those typed in response to passwords prompt
(this was the
previous behavior). The default is nil, which inhibits recording of
passwords.
-+++
-** New user option 'longlines-break-chars'.
-This is a string containing chars that could be used as break point in
-longlines mode.
-
+++
** New function 'command-query'.
This function makes its argument command prompt the user for
diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index 56b5362611..98ddd192b4 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -568,12 +568,6 @@ This can happen with CVS versions 1.12.8 and 1.12.9.
Upgrade to CVS
** Miscellaneous problems
-*** Editing files with very long lines is slow.
-
-For example, simply moving through a file that contains hundreds of
-thousands of characters per line is slow, and consumes a lot of CPU.
-This is a known limitation of Emacs with no solution at this time.
-
*** Display artifacts on GUI frames on X-based systems.
This is known to be caused by using double-buffering (which is enabled
diff --git a/lisp/longlines.el b/lisp/obsolete/longlines.el
similarity index 99%
rename from lisp/longlines.el
rename to lisp/obsolete/longlines.el
index 4ad2cab2b2..1e2ae698c6 100644
--- a/lisp/longlines.el
+++ b/lisp/obsolete/longlines.el
@@ -6,6 +6,7 @@
;; Alex Schroeder <alex@gnu.org>
;; Chong Yidong <cyd@stupidchicken.com>
;; Maintainer: emacs-devel@gnu.org
+;; Obsolete-since: 24.4
;; Keywords: convenience, wp
;; This file is part of GNU Emacs.
diff --git a/src/buffer.c b/src/buffer.c
index 4994a31043..a55af906e2 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -985,6 +985,7 @@ reset_buffer (register struct buffer *b)
/* It is more conservative to start out "changed" than "unchanged". */
b->clip_changed = 0;
b->prevent_redisplay_optimizations_p = 1;
+ b->long_line_optimizations_p = 0;
bset_backed_up (b, Qnil);
bset_local_minor_modes (b, Qnil);
BUF_AUTOSAVE_MODIFF (b) = 0;
@@ -1501,7 +1502,7 @@ state of the current buffer. Use with care. */)
decrease SAVE_MODIFF and auto_save_modified or increase
MODIFF. */
if (SAVE_MODIFF >= MODIFF)
- SAVE_MODIFF = modiff_incr (&MODIFF);
+ SAVE_MODIFF = modiff_incr (&MODIFF, 1);
if (EQ (flag, Qautosaved))
BUF_AUTOSAVE_MODIFF (b) = MODIFF;
}
@@ -2446,6 +2447,7 @@ results, see Info node `(elisp)Swapping Text'. */)
swapfield (bidi_paragraph_cache, struct region_cache *);
current_buffer->prevent_redisplay_optimizations_p = 1;
other_buffer->prevent_redisplay_optimizations_p = 1;
+ swapfield (long_line_optimizations_p, bool_bf);
swapfield (overlays_before, struct Lisp_Overlay *);
swapfield (overlays_after, struct Lisp_Overlay *);
swapfield (overlay_center, ptrdiff_t);
@@ -2465,12 +2467,12 @@ results, see Info node `(elisp)Swapping Text'. */)
bset_point_before_scroll (current_buffer, Qnil);
bset_point_before_scroll (other_buffer, Qnil);
- modiff_incr (¤t_buffer->text->modiff);
- modiff_incr (&other_buffer->text->modiff);
- modiff_incr (¤t_buffer->text->chars_modiff);
- modiff_incr (&other_buffer->text->chars_modiff);
- modiff_incr (¤t_buffer->text->overlay_modiff);
- modiff_incr (&other_buffer->text->overlay_modiff);
+ modiff_incr (¤t_buffer->text->modiff, 1);
+ modiff_incr (&other_buffer->text->modiff, 1);
+ modiff_incr (¤t_buffer->text->chars_modiff, 1);
+ modiff_incr (&other_buffer->text->chars_modiff, 1);
+ modiff_incr (¤t_buffer->text->overlay_modiff, 1);
+ modiff_incr (&other_buffer->text->overlay_modiff, 1);
current_buffer->text->beg_unchanged = current_buffer->text->gpt;
current_buffer->text->end_unchanged = current_buffer->text->gpt;
other_buffer->text->beg_unchanged = other_buffer->text->gpt;
@@ -4009,7 +4011,7 @@ modify_overlay (struct buffer *buf, ptrdiff_t start,
ptrdiff_t end)
bset_redisplay (buf);
- modiff_incr (&BUF_OVERLAY_MODIFF (buf));
+ modiff_incr (&BUF_OVERLAY_MODIFF (buf), 1);
}
/* Remove OVERLAY from LIST. */
@@ -6427,6 +6429,14 @@ Since `clone-indirect-buffer' calls
`make-indirect-buffer', this hook
will run for `clone-indirect-buffer' calls as well. */);
Vclone_indirect_buffer_hook = Qnil;
+ DEFVAR_LISP ("long-line-threshold", Vlong_line_threshold,
+ doc: /* Line length above which specific display optimizations
are used.
+Display optimizations for long lines will automatically be enabled in
+buffers which contain one or more lines whose length is above that
+threshold.
+When nil, these display optimizations are disabled. */);
+ XSETFASTINT (Vlong_line_threshold, 10000);
+
defsubr (&Sbuffer_live_p);
defsubr (&Sbuffer_list);
defsubr (&Sget_buffer);
diff --git a/src/buffer.h b/src/buffer.h
index 135eaf72d3..47b4bdf749 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -237,9 +237,10 @@ struct buffer_text
ptrdiff_t z_byte; /* Byte pos of end of buffer. */
ptrdiff_t gap_size; /* Size of buffer's gap. */
modiff_count modiff; /* This counts buffer-modification events
- for this buffer. It is incremented for
- each such event, and never otherwise
- changed. */
+ for this buffer. It is increased
+ logarithmically to the extent of the
+ modification for each such event,
+ and never otherwise changed. */
modiff_count chars_modiff; /* This is modified with character change
events for this buffer. It is set to
modiff for each such event, and never
@@ -681,6 +682,10 @@ struct buffer
defined, as well as by with-temp-buffer, for example. */
bool_bf inhibit_buffer_hooks : 1;
+ /* Non-zero when the buffer contains long lines and specific
+ display optimizations must be used. */
+ bool_bf long_line_optimizations_p : 1;
+
/* List of overlays that end at or before the current center,
in order of end-position. */
struct Lisp_Overlay *overlays_before;
diff --git a/src/composite.c b/src/composite.c
index 2dee42b550..b04d34337b 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -1580,6 +1580,7 @@ find_automatic_composition (ptrdiff_t pos, ptrdiff_t
limit, ptrdiff_t backlim,
Lisp_Object window;
struct window *w;
bool need_adjustment = 0;
+ ptrdiff_t narrowed_begv;
window = Fget_buffer_window (Fcurrent_buffer (), Qnil);
if (NILP (window))
@@ -1596,6 +1597,11 @@ find_automatic_composition (ptrdiff_t pos, ptrdiff_t
limit, ptrdiff_t backlim,
}
else
head = backlim;
+ /* In buffers with very long lines, this function becomes very
+ slow. Pretend that the buffer is narrowed to make it fast. */
+ narrowed_begv = get_narrowed_begv (w);
+ if (narrowed_begv && pos > narrowed_begv)
+ head = narrowed_begv;
tail = ZV;
stop = GPT;
cur.pos_byte = CHAR_TO_BYTE (cur.pos);
diff --git a/src/dispextern.h b/src/dispextern.h
index 916dba5319..1cdfdca74c 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2332,6 +2332,10 @@ struct it
with which display_string was called. */
ptrdiff_t end_charpos;
+ /* Alternate begin position of the buffer that may be used to
+ optimize display (see the SET_WITH_NARROWED_BEGV macro). */
+ ptrdiff_t narrowed_begv;
+
/* C string to iterate over. Non-null means get characters from
this string, otherwise characters are read from current_buffer
or it->string. */
@@ -3396,6 +3400,7 @@ void mark_window_display_accurate (Lisp_Object, bool);
void redisplay_preserve_echo_area (int);
void init_iterator (struct it *, struct window *, ptrdiff_t,
ptrdiff_t, struct glyph_row *, enum face_id);
+ptrdiff_t get_narrowed_begv (struct window *w);
void init_iterator_to_row_start (struct it *, struct window *,
struct glyph_row *);
void start_display (struct it *, struct window *, struct text_pos);
diff --git a/src/insdel.c b/src/insdel.c
index 9b29239853..38d5fbda00 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -909,7 +909,7 @@ insert_1_both (const char *string,
the insertion. This, together with recording the insertion,
will add up to the right stuff in the undo list. */
record_insert (PT, nchars);
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars);
CHARS_MODIFF = MODIFF;
memcpy (GPT_ADDR, string, nbytes);
@@ -1037,7 +1037,7 @@ insert_from_string_1 (Lisp_Object string, ptrdiff_t pos,
ptrdiff_t pos_byte,
#endif
record_insert (PT, nchars);
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars);
CHARS_MODIFF = MODIFF;
GAP_SIZE -= outgoing_nbytes;
@@ -1122,7 +1122,7 @@ insert_from_gap (ptrdiff_t nchars, ptrdiff_t nbytes, bool
text_at_gap_tail)
of this dance. */
invalidate_buffer_caches (current_buffer, GPT, GPT);
record_insert (GPT, nchars);
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars);
CHARS_MODIFF = MODIFF;
insert_from_gap_1 (nchars, nbytes, text_at_gap_tail);
@@ -1251,7 +1251,7 @@ insert_from_buffer_1 (struct buffer *buf,
#endif
record_insert (PT, nchars);
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars);
CHARS_MODIFF = MODIFF;
GAP_SIZE -= outgoing_nbytes;
@@ -1352,7 +1352,7 @@ adjust_after_replace (ptrdiff_t from, ptrdiff_t from_byte,
if (len == 0)
evaporate_overlays (from);
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars_del + len);
CHARS_MODIFF = MODIFF;
}
@@ -1547,7 +1547,7 @@ replace_range (ptrdiff_t from, ptrdiff_t to, Lisp_Object
new,
check_markers ();
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars_del + inschars);
CHARS_MODIFF = MODIFF;
if (adjust_match_data)
@@ -1681,7 +1681,7 @@ replace_range_2 (ptrdiff_t from, ptrdiff_t from_byte,
check_markers ();
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars_del + inschars);
CHARS_MODIFF = MODIFF;
}
@@ -1856,7 +1856,7 @@ del_range_2 (ptrdiff_t from, ptrdiff_t from_byte,
at the end of the text before the gap. */
adjust_markers_for_delete (from, from_byte, to, to_byte);
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, nchars_del);
CHARS_MODIFF = MODIFF;
/* Relocate point as if it were a marker. */
@@ -1910,7 +1910,7 @@ modify_text (ptrdiff_t start, ptrdiff_t end)
BUF_COMPUTE_UNCHANGED (current_buffer, start - 1, end);
if (MODIFF <= SAVE_MODIFF)
record_first_change ();
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, end - start);
CHARS_MODIFF = MODIFF;
bset_point_before_scroll (current_buffer, Qnil);
diff --git a/src/lisp.h b/src/lisp.h
index dc496cc165..2afe135674 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3911,10 +3911,14 @@ integer_to_uintmax (Lisp_Object num, uintmax_t *n)
typedef intmax_t modiff_count;
INLINE modiff_count
-modiff_incr (modiff_count *a)
-{
- modiff_count a0 = *a;
- bool modiff_overflow = INT_ADD_WRAPV (a0, 1, a);
+modiff_incr (modiff_count *a, ptrdiff_t len)
+{
+ modiff_count a0 = *a; int incr = len ? 1 : 0;
+ /* Increase the counter more for a large modification and less for a
+ small modification. Increase it logarithmically to avoid
+ increasing it too much. */
+ while (len >>= 1) incr++;
+ bool modiff_overflow = INT_ADD_WRAPV (a0, incr, a);
eassert (!modiff_overflow && *a >> 30 >> 30 == 0);
return a0;
}
@@ -4762,6 +4766,8 @@ extern ptrdiff_t fast_c_string_match_ignore_case
(Lisp_Object, const char *,
ptrdiff_t);
extern ptrdiff_t fast_looking_at (Lisp_Object, ptrdiff_t, ptrdiff_t,
ptrdiff_t, ptrdiff_t, Lisp_Object);
+extern ptrdiff_t find_newline1 (ptrdiff_t, ptrdiff_t, ptrdiff_t, ptrdiff_t,
+ ptrdiff_t, ptrdiff_t *, ptrdiff_t *, bool);
extern ptrdiff_t find_newline (ptrdiff_t, ptrdiff_t, ptrdiff_t, ptrdiff_t,
ptrdiff_t, ptrdiff_t *, ptrdiff_t *, bool);
extern void scan_newline (ptrdiff_t, ptrdiff_t, ptrdiff_t, ptrdiff_t,
diff --git a/src/search.c b/src/search.c
index 9d6bd074e1..b5d6a442c0 100644
--- a/src/search.c
+++ b/src/search.c
@@ -3192,7 +3192,7 @@ DEFUN ("regexp-quote", Fregexp_quote, Sregexp_quote, 1,
1, 0,
}
/* Like find_newline, but doesn't use the cache, and only searches forward. */
-static ptrdiff_t
+ptrdiff_t
find_newline1 (ptrdiff_t start, ptrdiff_t start_byte, ptrdiff_t end,
ptrdiff_t end_byte, ptrdiff_t count, ptrdiff_t *counted,
ptrdiff_t *bytepos, bool allow_quit)
diff --git a/src/textprop.c b/src/textprop.c
index 96d07b44be..c91a2b729c 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -88,7 +88,7 @@ modify_text_properties (Lisp_Object buffer, Lisp_Object
start, Lisp_Object end)
BUF_COMPUTE_UNCHANGED (buf, b - 1, e);
if (MODIFF <= SAVE_MODIFF)
record_first_change ();
- modiff_incr (&MODIFF);
+ modiff_incr (&MODIFF, 1);
bset_point_before_scroll (current_buffer, Qnil);
diff --git a/src/window.c b/src/window.c
index 10373f8a2b..8f88958558 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1028,7 +1028,7 @@ window_body_unit_from_symbol (Lisp_Object unit)
/* Return the number of lines/pixels of W's body. Don't count any mode
or header line or horizontal divider of W. Rounds down to nearest
integer when not working pixelwise. */
-static int
+int
window_body_height (struct window *w, enum window_body_unit pixelwise)
{
int height = (w->pixel_height
diff --git a/src/window.h b/src/window.h
index 298a80a536..c63b1b24d4 100644
--- a/src/window.h
+++ b/src/window.h
@@ -1193,6 +1193,7 @@ enum window_body_unit
WINDOW_BODY_IN_REMAPPED_CHARS
};
extern int window_body_width (struct window *w, enum window_body_unit);
+extern int window_body_height (struct window *w, enum window_body_unit);
enum margin_unit { MARGIN_IN_LINES, MARGIN_IN_PIXELS };
extern int window_scroll_margin (struct window *, enum margin_unit);
extern void temp_output_buffer_show (Lisp_Object);
diff --git a/src/xdisp.c b/src/xdisp.c
index b693df4adb..ebeaf2a3da 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -3425,6 +3425,9 @@ init_iterator (struct it *it, struct window *w,
}
}
+ if (current_buffer->long_line_optimizations_p)
+ it->narrowed_begv = get_narrowed_begv (w);
+
/* If a buffer position was specified, set the iterator there,
getting overlays and face properties from that position. */
if (charpos >= BUF_BEG (current_buffer))
@@ -3491,6 +3494,45 @@ init_iterator (struct it *it, struct window *w,
CHECK_IT (it);
}
+/* Compute a suitable alternate value for BEGV that may be used
+ temporarily to optimize display if the buffer in window W contains
+ long lines. */
+
+ptrdiff_t
+get_narrowed_begv (struct window *w)
+{
+ int len, fact; ptrdiff_t begv;
+ /* In a character-only terminal, only one font size is used, so we
+ can use a smaller factor. */
+ fact = EQ (Fterminal_live_p (Qnil), Qt) ? 2 : 3;
+ len = fact * (window_body_width (w, WINDOW_BODY_IN_CANONICAL_CHARS) *
+ window_body_height (w, WINDOW_BODY_IN_CANONICAL_CHARS));
+ begv = max ((window_point (w) / len - 1) * len, BEGV);
+ return begv == BEGV ? 0 : begv;
+}
+
+static void
+unwind_narrowed_begv (Lisp_Object point_min)
+{
+ SET_BUF_BEGV (current_buffer, XFIXNUM (point_min));
+}
+
+/* Set DST to EXPR. When IT indicates that BEGV should temporarily be
+ updated to optimize display, evaluate EXPR with an updated BEGV. */
+
+#define SET_WITH_NARROWED_BEGV(IT,DST,EXPR) \
+ do { \
+ if (IT->narrowed_begv) \
+ {
\
+ specpdl_ref count = SPECPDL_INDEX (); \
+ record_unwind_protect (unwind_narrowed_begv, Fpoint_min ()); \
+ SET_BUF_BEGV (current_buffer, IT->narrowed_begv); \
+ DST = EXPR; \
+ unbind_to (count, Qnil); \
+ }
\
+ else \
+ DST = EXPR; \
+ } while (0)
/* Initialize IT for the display of window W with window start POS. */
@@ -6992,7 +7034,8 @@ back_to_previous_line_start (struct it *it)
ptrdiff_t cp = IT_CHARPOS (*it), bp = IT_BYTEPOS (*it);
dec_both (&cp, &bp);
- IT_CHARPOS (*it) = find_newline_no_quit (cp, bp, -1, &IT_BYTEPOS (*it));
+ SET_WITH_NARROWED_BEGV (it, IT_CHARPOS (*it),
+ find_newline_no_quit (cp, bp, -1, &IT_BYTEPOS (*it)));
}
@@ -7210,7 +7253,8 @@ back_to_previous_visible_line_start (struct it *it)
it->continuation_lines_width = 0;
eassert (IT_CHARPOS (*it) >= BEGV);
- eassert (IT_CHARPOS (*it) == BEGV
+ eassert (it->narrowed_begv > BEGV
+ || IT_CHARPOS (*it) == BEGV
|| FETCH_BYTE (IT_BYTEPOS (*it) - 1) == '\n');
CHECK_IT (it);
}
@@ -8623,7 +8667,12 @@ get_visually_first_element (struct it *it)
{
bool string_p = STRINGP (it->string) || it->s;
ptrdiff_t eob = (string_p ? it->bidi_it.string.schars : ZV);
- ptrdiff_t bob = (string_p ? 0 : BEGV);
+ ptrdiff_t bob;
+ ptrdiff_t obegv = BEGV;
+
+ SET_WITH_NARROWED_BEGV (it, bob,
+ string_p ? 0 :
+ IT_BYTEPOS (*it) < BEGV ? obegv : BEGV);
if (STRINGP (it->string))
{
@@ -8663,9 +8712,10 @@ get_visually_first_element (struct it *it)
if (string_p)
it->bidi_it.charpos = it->bidi_it.bytepos = 0;
else
- it->bidi_it.charpos = find_newline_no_quit (IT_CHARPOS (*it),
- IT_BYTEPOS (*it), -1,
- &it->bidi_it.bytepos);
+ SET_WITH_NARROWED_BEGV (it, it->bidi_it.charpos,
+ find_newline_no_quit (IT_CHARPOS (*it),
+ IT_BYTEPOS (*it), -1,
+ &it->bidi_it.bytepos));
bidi_paragraph_init (it->paragraph_embedding, &it->bidi_it, true);
do
{
@@ -10583,7 +10633,8 @@ move_it_vertically_backward (struct it *it, int dy)
ptrdiff_t cp = IT_CHARPOS (*it), bp = IT_BYTEPOS (*it);
dec_both (&cp, &bp);
- cp = find_newline_no_quit (cp, bp, -1, NULL);
+ SET_WITH_NARROWED_BEGV (it, cp,
+ find_newline_no_quit (cp, bp, -1, NULL));
move_it_to (it, cp, -1, -1, -1, MOVE_TO_POS);
}
bidi_unshelve_cache (it3data, true);
@@ -18879,11 +18930,25 @@ set_vertical_scroll_bar (struct window *w)
&& NILP (echo_area_buffer[0])))
{
struct buffer *buf = XBUFFER (w->contents);
+ ptrdiff_t window_end_pos = w->window_end_pos;
+
+ /* If w->window_end_pos cannot be trusted, recompute it "the
+ hard way". */
+ if (!w->window_end_valid)
+ {
+ struct it it;
+ struct text_pos start_pos;
+
+ SET_TEXT_POS_FROM_MARKER (start_pos, w->start);
+ start_display (&it, w, start_pos);
+ move_it_to (&it, -1, it.last_visible_x, window_box_height (w), -1,
+ MOVE_TO_X | MOVE_TO_Y);
+ window_end_pos = BUF_Z (buf) - IT_CHARPOS (it);
+ }
+
whole = BUF_ZV (buf) - BUF_BEGV (buf);
start = marker_position (w->start) - BUF_BEGV (buf);
- /* I don't think this is guaranteed to be right. For the
- moment, we'll pretend it is. */
- end = BUF_Z (buf) - w->window_end_pos - BUF_BEGV (buf);
+ end = BUF_Z (buf) - window_end_pos - BUF_BEGV (buf);
if (end < start)
end = start;
@@ -19232,6 +19297,24 @@ redisplay_window (Lisp_Object window, bool
just_this_one_p)
}
}
+ /* Check whether the buffer to be displayed contains long lines. */
+ if (!NILP (Vlong_line_threshold)
+ && !current_buffer->long_line_optimizations_p
+ && MODIFF - UNCHANGED_MODIFIED > 8)
+ {
+ ptrdiff_t cur, next, found, max = 0, threshold;
+ threshold = XFIXNUM (Vlong_line_threshold);
+ for (cur = 1; cur < Z; cur = next)
+ {
+ next = find_newline1 (cur, CHAR_TO_BYTE (cur), 0, -1, 1,
+ &found, NULL, true);
+ if (next - cur > max) max = next - cur;
+ if (!found || max > threshold) break;
+ }
+ if (max > threshold)
+ current_buffer->long_line_optimizations_p = true;
+ }
+
/* If window-start is screwed up, choose a new one. */
if (XMARKER (w->start)->buffer != current_buffer)
goto recenter;