Fix emoji ZWJ and modifier sequence line breaking

third_party/WebKit/Source/platform/text/TextBreakIteratorTest.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "platform/text/TextBreakIterator.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+class TextBreakIteratorTest : public testing::Test {
+protected:
+    void SetTestString(const char* testString)
+    {
+        m_testString = String::fromUTF8(testString);
+    }
+
+    // The expected break positions must be specified UTF-16 character boundaries.
+    void MatchLineBreaks(LineBreakType lineBreakType, const Vector<int> expectedBreakPositions)
+    {
+        if (m_testString.is8Bit()) {
+            m_testString = String::make16BitFrom8BitSource(m_testString.characters8(), m_testString.length());
+        }
+        LazyLineBreakIterator lazyBreakIterator(m_testString);
+        int nextBreakable = 0;
+        for (auto breakPosition : expectedBreakPositions) {
+            int triggerPos = std::min(static_cast<unsigned>(nextBreakable + 1), m_testString.length());
+            bool isBreakable = lazyBreakIterator.isBreakable(triggerPos, nextBreakable, lineBreakType);
+            if (isBreakable) {
+                ASSERT_EQ(triggerPos, breakPosition);
+            }
+            ASSERT_EQ(breakPosition, nextBreakable);
+        }
+    }
+
+private:
+    String m_testString;
+};
+
+// Initializing Vector from an initializer list still not possible, C++ feature banned in Blink.
+#define DECLARE_BREAKSVECTOR(...)                   \
+    static const int32_t breaksArray[] = __VA_ARGS__; \
+    Vector<int> breaks;                                         \
+    breaks.append(breaksArray, sizeof(breaksArray) / sizeof(*breaksArray));
+
+#define MATCH_LINE_BREAKS(LINEBREAKTYPE, ...)        \
+    {                                                \
+        DECLARE_BREAKSVECTOR(__VA_ARGS__);           \
+        MatchLineBreaks(LINEBREAKTYPE, breaks); \
+    }
+
+TEST_F(TextBreakIteratorTest, Basic)
+{
+    SetTestString("a b c");
+    MATCH_LINE_BREAKS(LineBreakType::Normal, { 1, 3, 5 });
+}
+
+TEST_F(TextBreakIteratorTest, Chinese)
+{
+    SetTestString("標準萬國碼");
+    MATCH_LINE_BREAKS(LineBreakType::Normal, { 1, 2, 3, 4, 5 });
+    MATCH_LINE_BREAKS(LineBreakType::BreakAll, { 1, 2, 3, 4, 5 });
+    MATCH_LINE_BREAKS(LineBreakType::KeepAll, { 5 });
+}
+
+TEST_F(TextBreakIteratorTest, KeepEmojiZWJFamilyIsolate)
+{
+    SetTestString("\xF0\x9F\x91\xA8\xE2\x80\x8D\xF0\x9F\x91\xA9\xE2\x80\x8D\xF0\x9F\x91\xA7\xE2\x80\x8D\xF0\x9F\x91\xA6");
+    MATCH_LINE_BREAKS(LineBreakType::Normal, { 11 });
+    MATCH_LINE_BREAKS(LineBreakType::BreakAll, { 11 });
+    MATCH_LINE_BREAKS(LineBreakType::KeepAll, { 11 });
+}
+
+TEST_F(TextBreakIteratorTest, KeepEmojiModifierSequenceIsolate)
+{
+    SetTestString("\xE2\x98\x9D\xF0\x9F\x8F\xBB");
+    MATCH_LINE_BREAKS(LineBreakType::Normal, { 3 });
+    MATCH_LINE_BREAKS(LineBreakType::BreakAll, { 3 });
+    MATCH_LINE_BREAKS(LineBreakType::KeepAll, { 3 });
+}
+
+TEST_F(TextBreakIteratorTest, KeepEmojiZWJSequence)
+{
+    SetTestString("abc \xF0\x9F\x91\xA9\xE2\x80\x8D\xF0\x9F\x91\xA9\xE2\x80\x8D\xF0\x9F\x91\xA7\xE2\x80\x8D\xF0\x9F\x91\xA7 def");
+    MATCH_LINE_BREAKS(LineBreakType::Normal, { 3, 15, 19 });
+    MATCH_LINE_BREAKS(LineBreakType::BreakAll, { 1, 2, 3, 15, 17, 18, 19 });
+    MATCH_LINE_BREAKS(LineBreakType::KeepAll, { 3, 15, 19 });
+}
+
+TEST_F(TextBreakIteratorTest, KeepEmojiModifierSequence)
+{
+    SetTestString("abc \xE2\x98\x9D\xF0\x9F\x8F\xBB def");
+    MATCH_LINE_BREAKS(LineBreakType::Normal, { 3, 7, 11 });
+    MATCH_LINE_BREAKS(LineBreakType::BreakAll, { 1, 2, 3, 7, 9, 10, 11 });
+    MATCH_LINE_BREAKS(LineBreakType::KeepAll, { 3, 7, 11 });
+}
+
+} // namespace blink