vim-patch:9.1.0055: formatting long lines is slow (#27199)

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: vim/vim#13914

78019df645

Co-authored-by: kawaii-Code <nia.personal.0@gmail.com>
This commit is contained in:
zeertzjq 2024-01-26 06:26:02 +08:00 committed by GitHub
parent 1e0996b572
commit 89a9745a1a
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GPG Key ID: B5690EEEBB952194
1 changed files with 18 additions and 5 deletions

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@ -106,9 +106,14 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
colnr_T col;
bool did_do_comment = false;
colnr_T 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) {
colnr_T virtcol = get_nolist_virtcol() + char2cells(c != NUL ? c : gchar_cursor());
if (virtcol <= (colnr_T)textwidth) {
break;
}
}
if (no_leader) {
@ -156,9 +161,16 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
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;
int skip_pos = 0;
bool first_pass = true;
// Find position to break at.
// Stop at first entered white when 'formatoptions' has 'v'
@ -166,8 +178,9 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
|| (flags & INSCHAR_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();
}