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Revert "Re-enable Unicode ZWJ handling code that had been disabled pending an ICU update (#4035)" (#4036)

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This reverts commit afd2e6b81883c110eb2d585b51ecfc871e8d8f1e.

Fuchsia is still using an older version of ICU that does not support this.

Also temporarily disable a unit test that failed without the reverted patch.
This commit is contained in:
Jason Simmons 2017-08-29 12:53:25 -07:00 committed by GitHub
parent afd2e6b818
commit f9e00a7c72
2 changed files with 19 additions and 17 deletions
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32
third_party/txt/src/minikin/GraphemeBreak.cpp vendored
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@ -112,7 +112,8 @@ bool GraphemeBreak::isGraphemeBreak(const float* advances,
return false;
}
// Rule GB9, x (Extend | ZWJ); Rule GB9a, x SpacingMark; Rule GB9b, Prepend x
if (p2 == U_GCB_EXTEND || p2 == U_GCB_ZWJ || p2 == U_GCB_SPACING_MARK ||
// TODO(abarth): Add U_GCB_ZWJ once we update ICU.
if (p2 == U_GCB_EXTEND || /* p2 == U_GCB_ZWJ || */ p2 == U_GCB_SPACING_MARK ||
p1 == U_GCB_PREPEND) {
return false;
}
@ -156,26 +157,25 @@ bool GraphemeBreak::isGraphemeBreak(const float* advances,
}
}
// TODO(abarth): Enablet his code once we update ICU.
// Tailored version of Rule GB11, ZWJ × (Glue_After_Zwj | EBG)
// We try to make emoji sequences with ZWJ a single grapheme cluster, but only
// if they actually merge to one cluster. So we are more relaxed than the UAX
// #29 rules in accepting any emoji character after the ZWJ, but are tighter
// in that we only treat it as one cluster if a ligature is actually formed
// and we also require the character before the ZWJ to also be an emoji.
if (p1 == U_GCB_ZWJ && isEmoji(c2) && offset_back > start) {
// look at character before ZWJ to see that both can participate in an
// emoji zwj sequence
uint32_t c0 = 0;
size_t offset_backback = offset_back;
U16_PREV(buf, start, offset_backback, c0);
if (c0 == 0xFE0F && offset_backback > start) {
// skip over emoji variation selector
U16_PREV(buf, start, offset_backback, c0);
}
if (isEmoji(c0)) {
return false;
}
}
// and we also require the character before the ZWJ to also be an emoji. if
// (p1 == U_GCB_ZWJ && isEmoji(c2) && offset_back > start) {
// // look at character before ZWJ to see that both can participate in an
// emoji zwj sequence uint32_t c0 = 0; size_t offset_backback =
// offset_back; U16_PREV(buf, start, offset_backback, c0); if (c0 ==
// 0xFE0F && offset_backback > start) {
// // skip over emoji variation selector
// U16_PREV(buf, start, offset_backback, c0);
// }
// if (isEmoji(c0)) {
// return false;
// }
// }
// Tailored version of Rule GB12 and Rule GB13 that look at even-odd cases.
// sot (RI RI)* RI x RI

4
third_party/txt/tests/GraphemeBreakTests.cpp vendored
View File

@ -143,7 +143,9 @@ TEST(GraphemeBreak, rules) {
// Rule GB9, x (Extend | ZWJ)
EXPECT_FALSE(IsBreak("'a' | U+0301")); // combining accent
EXPECT_FALSE(IsBreak("'a' | U+200D")); // ZWJ
// TODO(jsimmons): re-enable this test when ICU has been updated in all
// Flutter platforms.
//EXPECT_FALSE(IsBreak("'a' | U+200D")); // ZWJ
// Rule GB9a, x SpacingMark
EXPECT_FALSE(IsBreak("U+0915 | U+093E")); // KA, AA (spacing mark)
// Rule GB9b, Prepend x