Upstream ios/web/ HTML tokenizer

ios/third_party/blink/src/html_input_stream_preprocessor.h

Index: ios/third_party/blink/src/html_input_stream_preprocessor.h
diff --git a/ios/third_party/blink/src/html_input_stream_preprocessor.h b/ios/third_party/blink/src/html_input_stream_preprocessor.h
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+/*
+ * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ * Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
+ * Copyright (C) 2013 Google, Inc. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
+ */
+
+#ifndef InputStreamPreprocessor_h
+#define InputStreamPreprocessor_h
+
+#include "html_character_provider.h"
+
+namespace WebCore {
+
+// http://www.whatwg.org/specs/web-apps/current-work/#preprocessing-the-input-stream
+template <typename Tokenizer>
+class InputStreamPreprocessor {
+    WTF_MAKE_NONCOPYABLE(InputStreamPreprocessor);
+public:
+    InputStreamPreprocessor(Tokenizer* tokenizer)
+        : m_tokenizer(tokenizer)
+    {
+        reset();
+    }
+
+    ALWAYS_INLINE UChar nextInputCharacter() const { return m_nextInputCharacter; }
+
+    // Returns whether we succeeded in peeking at the next character.
+    // The only way we can fail to peek is if there are no more
+    // characters in |source| (after collapsing \r\n, etc).
+    ALWAYS_INLINE bool peek(CharacterProvider& source)
+    {
+        m_nextInputCharacter = source.currentCharacter();
+
+        // Every branch in this function is expensive, so we have a
+        // fast-reject branch for characters that don't require special
+        // handling. Please run the parser benchmark whenever you touch
+        // this function. It's very hot.
+        static const UChar specialCharacterMask = '\n' | '\r' | '\0';
+        if (m_nextInputCharacter & ~specialCharacterMask) {
+            m_skipNextNewLine = false;
+            return true;
+        }
+        return processNextInputCharacter(source);
+    }
+
+    // Returns whether there are more characters in |source| after advancing.
+    ALWAYS_INLINE bool advance(CharacterProvider& source)
+    {
+        source.next();
+        if (source.isEmpty())
+            return false;
+        return peek(source);
+    }
+
+    void reset(bool skipNextNewLine = false)
+    {
+        m_nextInputCharacter = '\0';
+        m_skipNextNewLine = skipNextNewLine;
+    }
+
+private:
+    bool processNextInputCharacter(CharacterProvider& source)
+    {
+    ProcessAgain:
+        ASSERT(m_nextInputCharacter == source.currentCharacter());
+
+        if (m_nextInputCharacter == '\n' && m_skipNextNewLine) {
+            m_skipNextNewLine = false;
+            source.next();
+            if (source.isEmpty())
+                return false;
+            m_nextInputCharacter = source.currentCharacter();
+        }
+        if (m_nextInputCharacter == '\r') {
+            m_nextInputCharacter = '\n';
+            m_skipNextNewLine = true;
+        } else {
+            m_skipNextNewLine = false;
+            // FIXME: The spec indicates that the surrogate pair range as well as
+            // a number of specific character values are parse errors and should be replaced
+            // by the replacement character. We suspect this is a problem with the spec as doing
+            // that filtering breaks surrogate pair handling and causes us not to match Minefield.
+            if (m_nextInputCharacter == '\0' && !shouldTreatNullAsEndOfFileMarker(source)) {
+                if (m_tokenizer->shouldSkipNullCharacters()) {
+                    source.next();
+                    if (source.isEmpty())
+                        return false;
+                    m_nextInputCharacter = source.currentCharacter();
+                    goto ProcessAgain;
+                }
+                m_nextInputCharacter = 0xFFFD;
+            }
+        }
+        return true;
+    }
+
+    bool shouldTreatNullAsEndOfFileMarker(CharacterProvider& source) const
+    {
+        return source.remainingBytes() == 1;
+    }
+
+    Tokenizer* m_tokenizer;
+
+    // http://www.whatwg.org/specs/web-apps/current-work/#next-input-character
+    UChar m_nextInputCharacter;
+    bool m_skipNextNewLine;
+};
+
+}
+
+#endif // InputStreamPreprocessor_h
+