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      1 /*
      2  * Copyright (C) 2013 Google, Inc. All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY GOOGLE INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL GOOGLE INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef BackgroundHTMLInputStream_h
     27 #define BackgroundHTMLInputStream_h
     28 
     29 #include "platform/text/SegmentedString.h"
     30 #include "wtf/Vector.h"
     31 #include "wtf/text/WTFString.h"
     32 
     33 namespace WebCore {
     34 
     35 typedef size_t HTMLInputCheckpoint;
     36 
     37 class BackgroundHTMLInputStream {
     38     WTF_MAKE_NONCOPYABLE(BackgroundHTMLInputStream);
     39 public:
     40     BackgroundHTMLInputStream();
     41 
     42     void append(const String&);
     43     void close();
     44 
     45     SegmentedString& current() { return m_current; }
     46 
     47     // An HTMLInputCheckpoint is valid until the next call to rewindTo, at which
     48     // point all outstanding checkpoints are invalidated.
     49     HTMLInputCheckpoint createCheckpoint(size_t tokensExtractedSincePreviousCheckpoint);
     50     void rewindTo(HTMLInputCheckpoint, const String& unparsedInput);
     51     void invalidateCheckpointsBefore(HTMLInputCheckpoint);
     52 
     53     size_t totalCheckpointTokenCount() const { return m_totalCheckpointTokenCount; }
     54 
     55 private:
     56     struct Checkpoint {
     57         Checkpoint(const SegmentedString& i, size_t n, size_t t) : input(i), numberOfSegmentsAlreadyAppended(n), tokensExtractedSincePreviousCheckpoint(t) { }
     58 
     59         SegmentedString input;
     60         size_t numberOfSegmentsAlreadyAppended;
     61         size_t tokensExtractedSincePreviousCheckpoint;
     62 
     63 #ifndef NDEBUG
     64         bool isNull() const { return input.isEmpty() && !numberOfSegmentsAlreadyAppended; }
     65 #endif
     66         void clear() { input.clear(); numberOfSegmentsAlreadyAppended = 0; tokensExtractedSincePreviousCheckpoint = 0;}
     67     };
     68 
     69     SegmentedString m_current;
     70     Vector<String> m_segments;
     71     Vector<Checkpoint> m_checkpoints;
     72 
     73     // Note: These indicies may === vector.size(), in which case there are no valid checkpoints/segments at this time.
     74     size_t m_firstValidCheckpointIndex;
     75     size_t m_firstValidSegmentIndex;
     76     size_t m_totalCheckpointTokenCount;
     77 
     78     void updateTotalCheckpointTokenCount();
     79 };
     80 
     81 }
     82 
     83 #endif
     84