1/*
2 * Copyright (C) 2012 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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "config.h"
32#include "SurroundingText.h"
33
34#include "Document.h"
35#include "Range.h"
36#include "TextIterator.h"
37#include "VisiblePosition.h"
38#include "VisibleSelection.h"
39#include "VisibleUnits.h"
40
41namespace WebCore {
42
43SurroundingText::SurroundingText(const VisiblePosition& visiblePosition, unsigned maxLength)
44    : m_positionOffsetInContent(0)
45{
46    if (visiblePosition.isNull())
47        return;
48
49    const unsigned halfMaxLength = maxLength / 2;
50    CharacterIterator forwardIterator(makeRange(visiblePosition, endOfDocument(visiblePosition)).get(), TextIteratorStopsOnFormControls);
51    if (!forwardIterator.atEnd())
52        forwardIterator.advance(maxLength - halfMaxLength);
53
54    Position position = visiblePosition.deepEquivalent().parentAnchoredEquivalent();
55    Document* document = position.document();
56    RefPtr<Range> forwardRange = forwardIterator.range();
57    if (!forwardRange || !Range::create(document, position, forwardRange->startPosition())->text().length()) {
58        ASSERT(forwardRange);
59        return;
60    }
61
62    BackwardsCharacterIterator backwardsIterator(makeRange(startOfDocument(visiblePosition), visiblePosition).get(), TextIteratorStopsOnFormControls);
63    if (!backwardsIterator.atEnd())
64        backwardsIterator.advance(halfMaxLength);
65
66    RefPtr<Range> backwardsRange = backwardsIterator.range();
67    if (!backwardsRange) {
68        ASSERT(backwardsRange);
69        return;
70    }
71
72    m_positionOffsetInContent = Range::create(document, backwardsRange->endPosition(), position)->text().length();
73    m_contentRange = Range::create(document, backwardsRange->endPosition(), forwardRange->startPosition());
74    ASSERT(m_contentRange);
75}
76
77PassRefPtr<Range> SurroundingText::rangeFromContentOffsets(unsigned startOffsetInContent, unsigned endOffsetInContent)
78{
79    if (startOffsetInContent >= endOffsetInContent || endOffsetInContent > content().length())
80        return 0;
81
82    CharacterIterator iterator(m_contentRange.get());
83
84    ASSERT(!iterator.atEnd());
85    iterator.advance(startOffsetInContent);
86
87    ASSERT(iterator.range());
88    Position start = iterator.range()->startPosition();
89
90    ASSERT(!iterator.atEnd());
91    iterator.advance(endOffsetInContent - startOffsetInContent);
92
93    ASSERT(iterator.range());
94    Position end = iterator.range()->startPosition();
95
96    return Range::create(start.document(), start, end);
97}
98
99String SurroundingText::content() const
100{
101    if (m_contentRange)
102        return m_contentRange->text();
103    return String();
104}
105
106unsigned SurroundingText::positionOffsetInContent() const
107{
108    return m_positionOffsetInContent;
109}
110
111} // namespace WebCore
112