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/*
* Copyright (C) 2023 Apple 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. AND ITS 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 APPLE INC. OR ITS 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.
*/
#pragma once
#if ENABLE(AX_THREAD_TEXT_APIS)
#include "FloatRect.h"
#include <wtf/text/MakeString.h>
#include <wtf/text/TextStream.h>
namespace WebCore {
class RenderBlock;
struct AXTextRunLineID {
// Do not dereference, for comparison to other AXTextRunLineIDs only.
void* containingBlock { nullptr };
size_t lineIndex { 0 };
AXTextRunLineID() = default;
AXTextRunLineID(void* containingBlock, size_t lineIndex)
: containingBlock(containingBlock)
, lineIndex(lineIndex)
{ }
bool operator==(const AXTextRunLineID&) const = default;
operator bool() const { return containingBlock; }
String debugDescription() const
{
TextStream stream;
stream << "LineID " << containingBlock << " " << lineIndex;
return stream.release();
}
};
struct AXTextRun {
// The line index of this run within the context of the containing RenderBlock of the main-thread AX object.
size_t lineIndex;
String text;
// This data structure stores the DOM offsets that form the text runs that are concatenated to create |text|.
// DOM offsets are offsets into the raw text node contents, pre-whitespace-collapse, while the |text| we store
// is the rendered-text, post-whitespace-collapse.
//
// These offsets allow us to convert an offset into |text| (a "rendered-text offset") into a DOM offset, and
// vice versa. This is required when we need to create a VisiblePosition from this text run.
//
// For example, consider this text, where "_" is a space: "__Charlie__Delta"
// This would result in two inline textboxes in layout:
// "Charlie "
// "Delta"
// which we combine into |text|: "Charlie Delta"
// This Vector would then have values: [[2, 10], [11, 16]]
Vector<std::array<uint16_t, 2>> textRunDomOffsets;
AXTextRun(size_t lineIndex, String&& text, Vector<std::array<uint16_t, 2>>&& domOffsets)
: lineIndex(lineIndex)
, text(WTFMove(text))
, textRunDomOffsets(WTFMove(domOffsets))
{ }
String debugDescription(void* containingBlock) const
{
AXTextRunLineID lineID = { containingBlock, lineIndex };
return makeString(lineID.debugDescription(), ": |"_s, makeStringByReplacingAll(text, '\n', "{newline}"_s), "|(len "_s, text.length(), ")"_s);
}
const Vector<std::array<uint16_t, 2>>& domOffsets() const { return textRunDomOffsets; }
// Convenience methods for TextUnit movement.
bool startsWithLineBreak() const { return text.startsWith('\n'); }
bool endsWithLineBreak() const { return text.endsWith('\n'); }
};
struct AXTextRuns {
// The containing block for the text runs. This is required because based on the structure
// of the AX tree, text runs for different objects can have the same line index but different
// containing blocks, meaning they are rendered on different lines.
// Do not de-reference. Use for comparison purposes only.
void* containingBlock { nullptr };
Vector<AXTextRun> runs;
bool containsOnlyASCII { true };
// A rough estimate of the size of the characters in these runs. This is per-AXTextRuns because
// AXTextRuns are associated with a single RenderText, which has the same style for all its runs.
// This is still an estimate, as characters can have vastly different sizes. We use this to serve
// APIs like AXBoundsForTextMarkerRangeAttribute quickly off the main-thread, and get more accurate
// sizes on-demand for runs that assistive technologies are actually requesting these APIs from.
static constexpr uint8_t defaultEstimatedCharacterWidth = 12;
uint8_t estimatedCharacterWidth { defaultEstimatedCharacterWidth };
AXTextRuns() = default;
AXTextRuns(RenderBlock* containingBlock, Vector<AXTextRun>&& textRuns, uint8_t estimatedCharacterWidth)
: containingBlock(containingBlock)
, runs(WTFMove(textRuns))
, estimatedCharacterWidth(estimatedCharacterWidth)
{
for (const auto& run : runs) {
if (!run.text.containsOnlyASCII()) {
containsOnlyASCII = false;
break;
}
}
}
String debugDescription() const;
size_t size() const { return runs.size(); }
const AXTextRun& at(size_t index) const
{
return (*this)[index];
}
const AXTextRun& operator[](size_t index) const
{
RELEASE_ASSERT(index < runs.size());
return runs[index];
}
unsigned runLength(size_t index) const
{
RELEASE_ASSERT(index < runs.size());
// Runs should have a non-zero length. This is important because several parts of AXTextMarker rely on this assumption.
RELEASE_ASSERT(runs[index].text.length());
return runs[index].text.length();
}
unsigned lastRunLength() const
{
if (runs.isEmpty())
return 0;
return runs[runs.size() - 1].text.length();
}
unsigned totalLength() const
{
unsigned size = runs.size();
return size ? runLengthSumTo(size - 1) : 0;
}
unsigned runLengthSumTo(size_t index) const;
unsigned domOffset(unsigned) const;
size_t indexForOffset(unsigned textOffset) const;
AXTextRunLineID lineIDForOffset(unsigned textOffset) const;
AXTextRunLineID lineID(size_t index) const
{
RELEASE_ASSERT(index < runs.size());
return { containingBlock, runs[index].lineIndex };
}
String substring(unsigned start, unsigned length = StringImpl::MaxLength) const;
String toString() const { return substring(0); }
// Returns a "local" rect representing the range specified by |start| and |end|.
// "Local" means the rect is relative only to the top-left of this AXTextRuns instance.
// For example, consider these runs where "|" represents |start| and |end|:
// aaaa
// b|bb|b
// The local rect would be:
// {x: width_of_single_b, y: |lineHeight| * 1, width: width_of_two_b, height: |lineHeight * 1|}
FloatRect localRect(unsigned start, unsigned end, float lineHeight) const;
};
} // namespace WebCore
#endif // ENABLE(AX_THREAD_TEXT_APIS)
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