From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 12 Nov 2011 11:56:57 +0000 (+0200)
Subject: Verify glyph row's hash values.
X-Git-Tag: emacs-pretest-24.0.92~203
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=7a7270ddb6e2a0b5f8c7404277a46272d80a8100;p=emacs.git

Verify glyph row's hash values.

 src/dispnew.c (verify_row_hash) [XASSERTS]: New function.
 (adjust_glyph_matrix, row_equal_p): Use it in xassert to verify
 that the hash value of glyph rows is correct.
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 71c2ff3131e..286896be6e3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -2,6 +2,9 @@
 
 	* dispnew.c (scrolling_window): Fix incorrect indices in accessing
 	current_matrix and desired_matrix.  (Bug#9990)
+	(verify_row_hash) [XASSERTS]: New function.
+	(adjust_glyph_matrix, row_equal_p): Use it in xassert to verify
+	that the hash value of glyph rows is correct.
 
 2011-11-12  Martin Rudalics  <rudalics@gmx.at>
 
diff --git a/src/dispnew.c b/src/dispnew.c
index dafb8127eb3..7b594c5b4e8 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -429,6 +429,25 @@ margin_glyphs_to_reserve (struct window *w, int total_glyphs, Lisp_Object margin
   return n;
 }
 
+#if XASSERTS
+/* Return non-zero if ROW's hash value is correct, zero if not.  */
+int
+verify_row_hash (struct glyph_row *row)
+{
+  int area, k;
+  unsigned row_hash = 0;
+
+  for (area = LEFT_MARGIN_AREA; area < LAST_AREA; ++area)
+    for (k = 0; k < row->used[area]; ++k)
+      row_hash = ((((row_hash << 4) + (row_hash >> 24)) & 0x0fffffff)
+		  + row->glyphs[area][k].u.val
+		  + row->glyphs[area][k].face_id
+		  + row->glyphs[area][k].padding_p
+		  + (row->glyphs[area][k].type << 2));
+
+  return row_hash == row->hash;
+}
+#endif
 
 /* Adjust glyph matrix MATRIX on window W or on a frame to changed
    window sizes.
@@ -600,6 +619,7 @@ adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y
 		  row->glyphs[LAST_AREA]
 		    = row->glyphs[LEFT_MARGIN_AREA] + dim.width;
 		}
+	      xassert (!row->enabled_p || verify_row_hash (row));
 	      ++row;
 	    }
 	}
@@ -1271,6 +1291,9 @@ line_draw_cost (struct glyph_matrix *matrix, int vpos)
 static inline int
 row_equal_p (struct glyph_row *a, struct glyph_row *b, int mouse_face_p)
 {
+  xassert (verify_row_hash (a));
+  xassert (verify_row_hash (b));
+
   if (a == b)
     return 1;
   else if (a->hash != b->hash)