patch 9.1.0055: formatting long lines is slow

Problem:  formatting long lines is slow
          (kawaii-Code)
Solution: optimize gq (internal_format) for long
          lines (kawaii-Code)

Implemented two workarounds that significantly reduce
the amount of pointless calls. Ideally the algorithm
would be rewritten not to be n^2, but it's too complicated
with too many corner cases.

closes: #13914

Signed-off-by: kawaii-Code <nia.personal.0@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
This commit is contained in:
kawaii-Code
2024-01-25 21:40:05 +01:00
committed by Christian Brabandt
parent 703f9bc943
commit 78019df645
2 changed files with 26 additions and 6 deletions

View File

@ -90,11 +90,18 @@ internal_format(
colnr_T end_col;
int wcc; // counter for whitespace chars
int did_do_comment = FALSE;
int first_pass;
virtcol = get_nolist_virtcol()
+ char2cells(c != NUL ? c : gchar_cursor());
if (virtcol <= (colnr_T)textwidth)
break;
// Cursor is currently at the end of line. No need to format
// if line length is less than textwidth (8 * textwidth for
// utf safety)
if (curwin->w_cursor.col < 8 * textwidth)
{
virtcol = get_nolist_virtcol()
+ char2cells(c != NUL ? c : gchar_cursor());
if (virtcol <= (colnr_T)textwidth)
break;
}
if (no_leader)
do_comments = FALSE;
@ -144,9 +151,17 @@ internal_format(
coladvance((colnr_T)textwidth);
wantcol = curwin->w_cursor.col;
curwin->w_cursor.col = startcol;
// If startcol is large (a long line), formatting takes too much
// time. The algorithm is O(n^2), it walks from the end of the
// line to textwidth border every time for each line break.
//
// Ceil to 8 * textwidth to optimize.
curwin->w_cursor.col = startcol < 8 * textwidth ? startcol :
8 * textwidth;
foundcol = 0;
skip_pos = 0;
first_pass = TRUE;
// Find position to break at.
// Stop at first entered white when 'formatoptions' has 'v'
@ -155,8 +170,11 @@ internal_format(
|| curwin->w_cursor.lnum != Insstart.lnum
|| curwin->w_cursor.col >= Insstart.col)
{
if (curwin->w_cursor.col == startcol && c != NUL)
if (first_pass && c != NUL)
{
cc = c;
first_pass = FALSE;
}
else
cc = gchar_cursor();
if (WHITECHAR(cc))