[Emacs-diffs] harfbuzz 1cef2d7: Fix text direction of the HarfBuzz shaping buffer

[Eli Zaretskii]

branch: harfbuzz
commit 1cef2d7cbea407eaeff5c65e9594e03fabe3bf5e
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix text direction of the HarfBuzz shaping buffer
    
    * src/indent.c (scan_for_column, compute_motion):
    * src/xdisp.c (CHAR_COMPOSED_P): Pass PDIR argument to
    composition_reseat_it.
    * src/composite.c (composition_reseat_it): Accept an
    additional argument PDIR that provides the current paragraph's
    base direction; all callers changed.  Use PDIR to fix
    calculation of the DIRECTION argument to autocmp_chars.
    (Bug#33944)
    * src/composite.h: Include dispextern.h.
    (composition_reseat_it): Update prototype.
---
 src/composite.c | 20 +++++++++++++++-----
 src/composite.h |  3 ++-
 src/indent.c    |  4 ++--
 src/xdisp.c     |  1 +
 4 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/composite.c b/src/composite.c
index 4882494..7cb9793 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -1167,7 +1167,9 @@ composition_compute_stop_pos (struct composition_it 
*cmp_it, ptrdiff_t charpos,
    characters to be composed.  FACE, if non-NULL, is a base face of
    the character.  If STRING is not nil, it is a string containing the
    character to check, and CHARPOS and BYTEPOS are indices in the
-   string.  In that case, FACE must not be NULL.
+   string.  In that case, FACE must not be NULL.  PDIR is the base
+   direction of the current paragraph, and is used to calculate the
+   direction argument to pass to the font shaper.
 
    If the character is composed, setup members of CMP_IT (id, nglyphs,
    from, to, reversed_p), and return true.  Otherwise, update
@@ -1176,7 +1178,7 @@ composition_compute_stop_pos (struct composition_it 
*cmp_it, ptrdiff_t charpos,
 bool
 composition_reseat_it (struct composition_it *cmp_it, ptrdiff_t charpos,
                       ptrdiff_t bytepos, ptrdiff_t endpos, struct window *w,
-                      struct face *face, Lisp_Object string)
+                      bidi_dir_t pdir, struct face *face, Lisp_Object string)
 {
   if (cmp_it->ch == -2)
     {
@@ -1206,7 +1208,7 @@ composition_reseat_it (struct composition_it *cmp_it, 
ptrdiff_t charpos,
   else if (w)
     {
       Lisp_Object lgstring = Qnil;
-      Lisp_Object val, elt;
+      Lisp_Object val, elt, direction = Qnil;
 
       val = CHAR_TABLE_REF (Vcomposition_function_table, cmp_it->ch);
       for (EMACS_INT i = 0; i < cmp_it->rule_idx; i++, val = XCDR (val))
@@ -1221,8 +1223,12 @@ composition_reseat_it (struct composition_it *cmp_it, 
ptrdiff_t charpos,
                continue;
              if (XFIXNAT (AREF (elt, 1)) != cmp_it->lookback)
                goto no_composition;
+             if (pdir == L2R)
+               direction = QL2R;
+             else if (pdir == R2L)
+               direction = QR2L;
              lgstring = autocmp_chars (elt, charpos, bytepos, endpos,
-                                       w, face, string, QL2R);
+                                       w, face, string, direction);
              if (composition_gstring_p (lgstring))
                break;
              lgstring = Qnil;
@@ -1246,8 +1252,12 @@ composition_reseat_it (struct composition_it *cmp_it, 
ptrdiff_t charpos,
              else
                bpos = CHAR_TO_BYTE (cpos);
            }
+         if (pdir == L2R)
+           direction = QR2L;
+         else if (pdir == R2L)
+           direction = QL2R;
          lgstring = autocmp_chars (elt, cpos, bpos, charpos + 1, w, face,
-                                   string, QR2L);
+                                   string, direction);
          if (! composition_gstring_p (lgstring)
              || cpos + LGSTRING_CHAR_LEN (lgstring) - 1 != charpos)
            /* Composition failed or didn't cover the current
diff --git a/src/composite.h b/src/composite.h
index ad39a08..44f7ab7 100644
--- a/src/composite.h
+++ b/src/composite.h
@@ -26,6 +26,7 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #define EMACS_COMPOSITE_H
 
 #include "font.h"
+#include "dispextern.h"
 
 INLINE_HEADER_BEGIN
 
@@ -321,7 +322,7 @@ extern void composition_compute_stop_pos (struct 
composition_it *,
                                           Lisp_Object);
 extern bool composition_reseat_it (struct composition_it *, ptrdiff_t,
                                   ptrdiff_t, ptrdiff_t, struct window *,
-                                  struct face *, Lisp_Object);
+                                  bidi_dir_t, struct face *, Lisp_Object);
 extern int composition_update_it (struct composition_it *,
                                   ptrdiff_t, ptrdiff_t, Lisp_Object);
 
diff --git a/src/indent.c b/src/indent.c
index 1885576..e0d35f8 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -599,7 +599,7 @@ scan_for_column (ptrdiff_t *endpos, EMACS_INT *goalcol, 
ptrdiff_t *prevcol)
       if (cmp_it.id >= 0
          || (scan == cmp_it.stop_pos
              && composition_reseat_it (&cmp_it, scan, scan_byte, end,
-                                       w, NULL, Qnil)))
+                                       w, NEUTRAL_DIR, NULL, Qnil)))
        composition_update_it (&cmp_it, scan, scan_byte, Qnil);
       if (cmp_it.id >= 0)
        {
@@ -1506,7 +1506,7 @@ compute_motion (ptrdiff_t from, ptrdiff_t frombyte, 
EMACS_INT fromvpos,
          if (cmp_it.id >= 0
              || (pos == cmp_it.stop_pos
                  && composition_reseat_it (&cmp_it, pos, pos_byte, to, win,
-                                           NULL, Qnil)))
+                                           NEUTRAL_DIR, NULL, Qnil)))
            composition_update_it (&cmp_it, pos, pos_byte, Qnil);
          if (cmp_it.id >= 0)
            {
diff --git a/src/xdisp.c b/src/xdisp.c
index 4d9990c..413d64f 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -6906,6 +6906,7 @@ static next_element_function const 
get_next_element[NUM_IT_METHODS] =
    || ((IT)->cmp_it.stop_pos == (CHARPOS)                              \
        && composition_reseat_it (&(IT)->cmp_it, CHARPOS, BYTEPOS,      \
                                 END_CHARPOS, (IT)->w,                  \
+                                (IT)->bidi_it.paragraph_dir,           \
                                 FACE_FROM_ID_OR_NULL ((IT)->f,         \
                                                       (IT)->face_id),  \
                                 (IT)->string)))