Introduce VTTScanner - a parser helper for various VTT parsing needs

Source/core/html/track/vtt/VTTScannerTest.cpp

Index: Source/core/html/track/vtt/VTTScannerTest.cpp
diff --git a/Source/core/html/track/vtt/VTTScannerTest.cpp b/Source/core/html/track/vtt/VTTScannerTest.cpp
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+/*
+ * Copyright (c) 2013, Opera Software ASA. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Opera Software ASA nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "core/html/track/vtt/VTTScanner.h"
+
+#include "wtf/text/WTFString.h"
+
+#include <gtest/gtest.h>
+
+using WebCore::VTTScanner;
+
+namespace {
+
+TEST(VTTScanner, Constructor)
+{
+    String data8("foo");
+    EXPECT_TRUE(data8.is8Bit());
+    VTTScanner scanner8(data8);
+    EXPECT_FALSE(scanner8.isAtEnd());
+
+    String data16(data8);
+    data16.ensure16Bit();
+    EXPECT_FALSE(data16.is8Bit());
+    VTTScanner scanner16(data16);
+    EXPECT_FALSE(scanner16.isAtEnd());
+
+    VTTScanner scannerEmpty(emptyString());
+    EXPECT_TRUE(scannerEmpty.isAtEnd());
+}
+
+void scanSequenceHelper1(const String& input)
+{
+    VTTScanner scanner(input);
+    EXPECT_FALSE(scanner.isAtEnd());
+    EXPECT_TRUE(scanner.match('f'));
+    EXPECT_FALSE(scanner.match('o'));
+
+    EXPECT_TRUE(scanner.scan('f'));
+    EXPECT_FALSE(scanner.match('f'));
+    EXPECT_TRUE(scanner.match('o'));
+
+    EXPECT_FALSE(scanner.scan('e'));
+    EXPECT_TRUE(scanner.scan('o'));
+
+    EXPECT_TRUE(scanner.scan('e'));
+    EXPECT_FALSE(scanner.match('e'));
+
+    EXPECT_TRUE(scanner.isAtEnd());
+}
+
+// Run TESTFUNC with DATA in Latin and then UTF-16. (Requires DATA being Latin.)
+#define TEST_WITH(TESTFUNC, DATA) do {      \
+    String data8(DATA);                     \
+    EXPECT_TRUE(data8.is8Bit());            \
+    TESTFUNC(data8);                        \
+    \
+    String data16(data8);                   \
+    data16.ensure16Bit();                   \
+    EXPECT_FALSE(data16.is8Bit());          \
+    TESTFUNC(data16);                       \
+} while (false)
+
+
+// Exercises match(c) and scan(c).
+TEST(VTTScanner, BasicOperations1)
+{
+    TEST_WITH(scanSequenceHelper1, "foe");
+}
+
+void scanSequenceHelper2(const String& input)
+{
+    VTTScanner scanner(input);
+    EXPECT_FALSE(scanner.isAtEnd());
+    EXPECT_FALSE(scanner.scan("fe"));
+
+    EXPECT_TRUE(scanner.scan("fo"));
+    EXPECT_FALSE(scanner.isAtEnd());
+
+    EXPECT_FALSE(scanner.scan("ee"));
+
+    EXPECT_TRUE(scanner.scan('e'));
+    EXPECT_TRUE(scanner.isAtEnd());
+}
+
+// Exercises scan(<literal>[, length]).
+TEST(VTTScanner, BasicOperations2)
+{
+    TEST_WITH(scanSequenceHelper2, "foe");
+}
+
+bool lowerCaseAlpha(UChar c)
+{
+    return c >= 'a' && c <= 'z';
+}
+
+void scanWithPredicate(const String& input)
+{
+    VTTScanner scanner(input);
+    EXPECT_FALSE(scanner.isAtEnd());
+    // Collect "bad".
+    VTTScanner::Run lcRun = scanner.collectWhile<lowerCaseAlpha>();
+    // collectWhile doesn't move the scan position.
+    EXPECT_TRUE(scanner.match('b'));
+    // Consume "bad".
+    scanner.skipWhile<lowerCaseAlpha>();
+    EXPECT_TRUE(scanner.match('A'));
+    EXPECT_TRUE(scanner.isAt(lcRun.end()));
+
+    // Consume "A".
+    EXPECT_TRUE(scanner.scan('A'));
+
+    // Collect "bing".
+    lcRun = scanner.collectWhile<lowerCaseAlpha>();
+    // collectWhile doesn't move the scan position.
+    EXPECT_FALSE(scanner.isAtEnd());
+    // Consume "bing".
+    scanner.skipWhile<lowerCaseAlpha>();
+    EXPECT_TRUE(scanner.isAt(lcRun.end()));
+    EXPECT_TRUE(scanner.isAtEnd());
+}
+
+// Tests skipWhile() and collectWhile().
+TEST(VTTScanner, PredicateScanning)
+{
+    TEST_WITH(scanWithPredicate, "badAbing");
+}
+
+void tailStringExtract(const String& input)
+{
+    VTTScanner scanner(input);
+    EXPECT_TRUE(scanner.scan("foo"));
+    EXPECT_TRUE(scanner.scan(':'));
+    String barSuffix = scanner.restOfInputAsString();
+    EXPECT_EQ(barSuffix, "bar");
+
+    EXPECT_TRUE(scanner.isAtEnd());
+}
+
+// Tests restOfInputAsString().
+TEST(VTTScanner, ExtractRestAsString)
+{
+    TEST_WITH(tailStringExtract, "foo:bar");
+}
+
+void scanDigits1(const String& input)
+{
+    VTTScanner scanner(input);
+    EXPECT_TRUE(scanner.scan("foo"));
+    int number;
+    EXPECT_EQ(scanner.scanDigits(number), 0u);
+    EXPECT_EQ(number, 0);
+    EXPECT_TRUE(scanner.scan(' '));
+    EXPECT_EQ(scanner.scanDigits(number), 3u);
+    EXPECT_TRUE(scanner.match(' '));
+    EXPECT_EQ(number, 123);
+
+    EXPECT_TRUE(scanner.scan(' '));
+    EXPECT_TRUE(scanner.scan("bar"));
+    EXPECT_TRUE(scanner.scan(' '));
+
+    EXPECT_EQ(scanner.scanDigits(number), 5u);
+    EXPECT_EQ(number, 45678);
+
+    EXPECT_TRUE(scanner.isAtEnd());
+}
+
+void scanDigits2(const String& input)
+{
+    VTTScanner scanner(input);
+    int number;
+    EXPECT_EQ(scanner.scanDigits(number), 0u);
+    EXPECT_EQ(number, 0);
+    EXPECT_TRUE(scanner.scan('-'));
+    EXPECT_EQ(scanner.scanDigits(number), 3u);
+    EXPECT_EQ(number, 654);
+
+    EXPECT_TRUE(scanner.scan(' '));
+
+    EXPECT_EQ(scanner.scanDigits(number), 19u);
+    EXPECT_EQ(number, std::numeric_limits<int>::max());
+
+    EXPECT_TRUE(scanner.isAtEnd());
+}
+
+// Tests scanDigits().
+TEST(VTTScanner, ScanDigits)
+{
+    TEST_WITH(scanDigits1, "foo 123 bar 45678");
+    TEST_WITH(scanDigits2, "-654 1000000000000000000");
+}
+
+#undef TEST_WITH
+
+} // namespace