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
33namespace blink {
34
35typedef size_t HTMLInputCheckpoint;
36
37class BackgroundHTMLInputStream {
38    WTF_MAKE_NONCOPYABLE(BackgroundHTMLInputStream);
39public:
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
55private:
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#if ENABLE(ASSERT)
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