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LibWeb: Simplify text chunk iteration a little bit

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Instead of TextNode::ChunkIterator having two bool members to remember
things across calls to next(), this patch reorganizes the loop in next()
so that preserved newline/whitespace chunks are emitted right away
instead of in an awkward deferred way.
This commit is contained in:
Andreas Kling 2022-03-26 19:58:10 +01:00
parent dd6a0dd0f7
commit fa99259412
2 changed files with 22 additions and 36 deletions
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56
Userland/Libraries/LibWeb/Layout/TextNode.cpp
View file

@ -99,7 +99,6 @@ TextNode::ChunkIterator::ChunkIterator(StringView text, LayoutMode layout_mode,
, m_utf8_view(text)
, m_iterator(m_utf8_view.begin())
{
m_last_was_space = !text.is_empty() && is_ascii_space(*m_utf8_view.begin());
}
Optional<TextNode::Chunk> TextNode::ChunkIterator::next()
@ -108,48 +107,37 @@ Optional<TextNode::Chunk> TextNode::ChunkIterator::next()
return {};
auto start_of_chunk = m_iterator;
while (m_iterator != m_utf8_view.end()) {
++m_iterator;
if (m_last_was_newline) {
// NOTE: This expression looks out for the case where we have
// multiple newlines in a row. Because every output next()
// that's a newline newline must be prepared for in advance by
// the previous next() call, we need to check whether the next
// character is a newline here as well. Otherwise, the newline
// becomes part of the next expression and causes rendering
// issues.
m_last_was_newline = m_iterator != m_utf8_view.end() && *m_iterator == '\n';
if (auto result = try_commit_chunk(start_of_chunk, m_iterator, true); result.has_value())
return result.release_value();
}
// NOTE: The checks after this need to look at the current iterator
// position, which depends on not being at the end.
if (m_iterator == m_utf8_view.end())
break;
// NOTE: When we're supposed to stop on linebreaks, we're actually
// supposed to output two chunks: "content" and "\n". Since we
// can't output two chunks at once, we store this information as a
// flag to output the newline immediately at the earliest
// opportunity.
if (m_respect_linebreaks && *m_iterator == '\n') {
m_last_was_newline = true;
if (auto result = try_commit_chunk(start_of_chunk, m_iterator, false); result.has_value()) {
// Newline encountered, and we're supposed to preserve them.
// If we have accumulated some code points in the current chunk, commit them now and continue with the newline next time.
if (auto result = try_commit_chunk(start_of_chunk, m_iterator, false); result.has_value())
return result.release_value();
}
// Otherwise, commit the newline!
++m_iterator;
auto result = try_commit_chunk(start_of_chunk, m_iterator, true);
VERIFY(result.has_value());
return result.release_value();
}
if (m_wrap_lines || m_layout_mode == LayoutMode::MinContent) {
bool is_space = is_ascii_space(*m_iterator);
if (is_space != m_last_was_space) {
m_last_was_space = is_space;
if (auto result = try_commit_chunk(start_of_chunk, m_iterator, false); result.has_value()) {
if (is_ascii_space(*m_iterator)) {
// Whitespace encountered, and we're allowed to break on whitespace.
// If we have accumulated some code points in the current chunk, commit them now and continue with the whitespace next time.
if (auto result = try_commit_chunk(start_of_chunk, m_iterator, false); result.has_value())
return result.release_value();
}
// Otherwise, commit the whitespace!
++m_iterator;
if (auto result = try_commit_chunk(start_of_chunk, m_iterator, false); result.has_value())
return result.release_value();
continue;
}
}
++m_iterator;
}
if (start_of_chunk != m_utf8_view.end()) {