Add a SymbolsIterator to aid with Symbols Segmentation

third_party/WebKit/Source/platform/fonts/SymbolsIteratorTest.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/fonts/SymbolsIterator.h"
+
+#include "platform/Logging.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include <string>
+
+namespace blink {
+
+struct TestRun {
+    std::string text;
+    FontFallbackPriority fontFallbackPriority;
+};
+
+struct ExpectedRun {
+    unsigned limit;
+    FontFallbackPriority fontFallbackPriority;
+
+    ExpectedRun(unsigned theLimit, FontFallbackPriority theFontFallbackPriority)
+        : limit(theLimit)
+        , fontFallbackPriority(theFontFallbackPriority)
+    {
+    }
+};
+
+class SymbolsIteratorTest : public testing::Test {
+protected:
+#if !LOG_DISABLED
+    static void SetUpTestCase()
+    {
+        LogFonts = { WTFLogChannelOn };
+    }
+#endif
+
+    void CheckRuns(const Vector<TestRun>& runs)
+    {
+        String text(String::make16BitFrom8BitSource(0, 0));
+        Vector<ExpectedRun> expect;
+        for (auto& run : runs) {
+            text.append(String::fromUTF8(run.text.c_str()));
+            expect.append(ExpectedRun(text.length(), run.fontFallbackPriority));
+        }
+        SymbolsIterator symbolsIterator(text.characters16(), text.length());
+        VerifyRuns(&symbolsIterator, expect);
+    }
+
+    void VerifyRuns(SymbolsIterator* symbolsIterator,
+        const Vector<ExpectedRun>& expect)
+    {
+        unsigned limit;
+        FontFallbackPriority fontFallbackPriority;
+        unsigned long runCount = 0;
+        while (symbolsIterator->consume(&limit, &fontFallbackPriority)) {
+            ASSERT_LT(runCount, expect.size());
+            ASSERT_EQ(expect[runCount].limit, limit);
+            ASSERT_EQ(expect[runCount].fontFallbackPriority, fontFallbackPriority);
+            ++runCount;
+        }
+        WTF_LOG(Fonts, "Expected %zu runs, got %lu ", expect.size(), runCount);
+        ASSERT_EQ(expect.size(), runCount);
+    }
+};
+
+// Some of our compilers cannot initialize a vector from an array yet.
+#define DECLARE_RUNSVECTOR(...)                     \
+    static const TestRun runsArray[] = __VA_ARGS__; \
+    Vector<TestRun> runs; \
+    runs.append(runsArray, sizeof(runsArray) / sizeof(*runsArray));
+
+#define CHECK_RUNS(...)              \
+    DECLARE_RUNSVECTOR(__VA_ARGS__); \
+    CheckRuns(runs);
+
+
+TEST_F(SymbolsIteratorTest, Empty)
+{
+    String empty(String::make16BitFrom8BitSource(0, 0));
+    SymbolsIterator symbolsIterator(empty.characters16(), empty.length());
+    unsigned limit = 0;
+    FontFallbackPriority symbolsFont = FontFallbackPriority::Invalid;
+    ASSERT(!symbolsIterator.consume(&limit, &symbolsFont));
+    ASSERT_EQ(limit, 0u);
+    ASSERT_EQ(symbolsFont, FontFallbackPriority::Invalid);
+}
+
+TEST_F(SymbolsIteratorTest, Space)
+{
+    CHECK_RUNS({ { " ", FontFallbackPriority::Text } });
+}
+
+TEST_F(SymbolsIteratorTest, Latin)
+{
+    CHECK_RUNS({ { "Aa", FontFallbackPriority::Text } });
+}
+
+TEST_F(SymbolsIteratorTest, LatinColorEmojiTextEmoji)
+{
+    CHECK_RUNS({ { "a", FontFallbackPriority::Text },
+        { "⌚", FontFallbackPriority::EmojiEmoji },
+        { "☎", FontFallbackPriority::EmojiText } });
+}
+
+TEST_F(SymbolsIteratorTest, IgnoreVSInMath)
+{
+    CHECK_RUNS({ { "⊆⊇⊈\xEF\xB8\x8E⊙⊚⊚", FontFallbackPriority::Math } });
+}
+
+TEST_F(SymbolsIteratorTest, IgnoreVS15InText)
+{
+    CHECK_RUNS({ { "abcdef\xEF\xB8\x8Eghji", FontFallbackPriority::Text } });
+}
+
+TEST_F(SymbolsIteratorTest, IgnoreVS16InText)
+{
+    CHECK_RUNS({ { "abcdef\xEF\xB8\x8Fghji", FontFallbackPriority::Text } });
+}
+
+TEST_F(SymbolsIteratorTest, NumbersAndHashNormalAndEmoji)
+{
+    CHECK_RUNS({ { "0123456789#", FontFallbackPriority::Text },
+        { "0⃣1⃣2⃣3⃣4⃣5⃣6⃣7⃣8⃣9⃣#⃣", FontFallbackPriority::EmojiEmoji },
+        { "0123456789#", FontFallbackPriority::Text } });
+}
+
+
+TEST_F(SymbolsIteratorTest, SingleFlag)
+{
+    CHECK_RUNS({ { "🇺", FontFallbackPriority::Text } });
+}
+
+// TODO: Perhaps check for invalid country indicator combinations?
+
+TEST_F(SymbolsIteratorTest, FlagsVsNonFlags)
+{
+    CHECK_RUNS({ { "🇺🇸🇸", FontFallbackPriority::EmojiEmoji }, // "US"
+        { "abc", FontFallbackPriority::Text },
+        { "🇺🇸", FontFallbackPriority::EmojiEmoji },
+        { "a🇿", FontFallbackPriority::Text } });
+}
+
+
+TEST_F(SymbolsIteratorTest, EmojiVS15)
+{
+    // A VS15 after the anchor must trigger text display.
+    CHECK_RUNS({ { "⚓\xEF\xB8\x8E", FontFallbackPriority::EmojiText },
+        { "⛵", FontFallbackPriority::EmojiEmoji } });
+}
+
+TEST_F(SymbolsIteratorTest, EmojiZWSSequences)
+{
+    CHECK_RUNS({ { "👩‍👩‍👧‍👦👩‍❤️‍💋‍👨", FontFallbackPriority::EmojiEmoji },
+        { "abcd", FontFallbackPriority::Text },
+        { "👩‍👩‍", FontFallbackPriority::EmojiEmoji },
+        { "efgh", FontFallbackPriority::Text } });
+}
+
+TEST_F(SymbolsIteratorTest, AllEmojiZWSSequences)
+{
+    CHECK_RUNS({ { "💏👩‍❤️‍💋‍👨👨‍❤️‍💋‍👨👩‍❤️‍💋‍👩💑👩‍❤️‍👨👨‍❤️‍👨👩‍❤️"
+        "‍👩👪👨‍👩‍👦👨‍👩‍👧👨‍👩‍👧‍👦👨‍👩‍👦‍👦👨‍👩‍👧‍👧👨‍👨‍👦👨‍👨‍👧👨‍👨‍👧‍👦👨‍👨‍👦‍👦👨‍👨‍👧‍👧"
+        "👩‍👩‍👦👩‍👩‍👧👩‍👩‍👧‍👦👩‍👩‍👦‍👦👩‍👩‍👧‍👧👁‍🗨",
+        FontFallbackPriority::EmojiEmoji } });
+}
+
+TEST_F(SymbolsIteratorTest, EyeSpeechBubble)
+{
+    CHECK_RUNS({ { "👁‍🗨", FontFallbackPriority::EmojiEmoji } });
+}
+
+TEST_F(SymbolsIteratorTest, Modifier)
+{
+    CHECK_RUNS({ { "👶🏿", FontFallbackPriority::EmojiEmoji } });
+}
+
+TEST_F(SymbolsIteratorTest, ExtraZWJPrefix)
+{
+    CHECK_RUNS({ { "\xE2\x80\x8D", FontFallbackPriority::Text },
+        { "\xF0\x9F\x91\xA9\xE2\x80\x8D\xE2"
+        "\x9D\xA4\xEF\xB8\x8F\xE2\x80\x8D"
+        "\xF0\x9F\x92\x8B\xE2\x80\x8D\xF0\x9F\x91\xA8",
+        FontFallbackPriority::EmojiEmoji } });
+}
+
+TEST_F(SymbolsIteratorTest, Arrows)
+{
+    CHECK_RUNS({ { "x", FontFallbackPriority::Text },
+        { "→←", FontFallbackPriority::Math },
+        { "x", FontFallbackPriority::Text },
+        { "←↑↓→", FontFallbackPriority::Math } });
+}
+
+} // namespace blink