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LibLine: Use grapheme clusters for cursor management

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This makes using the line editor much nicer when multi-code-point
graphemes are present in the input (e.g. flag emojis, or some cjk
glyphs), and avoids messing up the buffer when deleting text, or
cursoring around.
This commit is contained in:
Ali Mohammad Pur 2023-12-15 15:01:58 +03:30 • committed by Andreas Kling
parent 99cc0514a7
commit 36f0499cc8
5 changed files with 58 additions and 48 deletions
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70
Userland/Libraries/LibLine/Editor.cpp
View file

@ -21,6 +21,7 @@
#include <LibCore/Event.h>
#include <LibCore/EventLoop.h>
#include <LibCore/Notifier.h>
#include <LibUnicode/Segmentation.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
@ -1865,66 +1866,53 @@ static MaskedSelectionDecision resolve_masked_selection(Optional<Style::Mask>& m
StringMetrics Editor::actual_rendered_string_metrics(StringView string, RedBlackTree<u32, Optional<Style::Mask>> const& masks, Optional<size_t> maximum_line_width)
{
StringMetrics metrics;
StringMetrics::LineMetrics current_line;
VTState state { Free };
Utf8View view { string };
size_t last_return {};
auto it = view.begin();
Optional<Style::Mask> mask;
size_t i = 0;
auto mask_it = masks.begin();
Vector<u32> utf32_buffer;
utf32_buffer.ensure_capacity(string.length());
for (auto c : Utf8View { string })
utf32_buffer.append(c);
for (; it != view.end(); ++it) {
if (!mask_it.is_end() && mask_it.key() <= i)
mask = *mask_it;
auto c = *it;
auto it_copy = it;
++it_copy;
if (resolve_masked_selection(mask, i, mask_it, view, state, metrics, current_line) == MaskedSelectionDecision::Skip)
continue;
auto next_c = it_copy == view.end() ? 0 : *it_copy;
state = actual_rendered_string_length_step(metrics, view.iterator_offset(it), current_line, c, next_c, state, mask, maximum_line_width, last_return);
if (!mask_it.is_end() && mask_it.key() <= i) {
auto mask_it_peek = mask_it;
++mask_it_peek;
if (!mask_it_peek.is_end() && mask_it_peek.key() > i)
mask_it = mask_it_peek;
}
++i;
}
metrics.line_metrics.append(current_line);
for (auto& line : metrics.line_metrics)
metrics.max_line_length = max(line.total_length(), metrics.max_line_length);
return metrics;
return actual_rendered_string_metrics(Utf32View { utf32_buffer.data(), utf32_buffer.size() }, masks, maximum_line_width);
}
StringMetrics Editor::actual_rendered_string_metrics(Utf32View const& view, RedBlackTree<u32, Optional<Style::Mask>> const& masks)
StringMetrics Editor::actual_rendered_string_metrics(Utf32View const& view, RedBlackTree<u32, Optional<Style::Mask>> const& masks, Optional<size_t> maximum_line_width)
{
StringMetrics metrics;
StringMetrics::LineMetrics current_line;
VTState state { Free };
Optional<Style::Mask> mask;
size_t last_return { 0 };
auto mask_it = masks.begin();
for (size_t i = 0; i < view.length(); ++i) {
Vector<size_t> grapheme_breaks;
Unicode::for_each_grapheme_segmentation_boundary(view, [&](size_t offset) -> IterationDecision {
if (offset >= view.length())
return IterationDecision::Break;
grapheme_breaks.append(offset);
return IterationDecision::Continue;
});
// In case Unicode data isn't available, default to using code points as grapheme boundaries.
if (grapheme_breaks.is_empty()) {
for (size_t i = 0; i < view.length(); ++i)
grapheme_breaks.append(i);
}
for (size_t break_index = 0; break_index < grapheme_breaks.size(); ++break_index) {
auto i = grapheme_breaks[break_index];
auto c = view[i];
if (!mask_it.is_end() && mask_it.key() <= i)
mask = *mask_it;
if (resolve_masked_selection(mask, i, mask_it, view, state, metrics, current_line) == MaskedSelectionDecision::Skip) {
--i;
binary_search(grapheme_breaks, i, &break_index);
continue;
}
auto next_c = i + 1 < view.length() ? view.code_points()[i + 1] : 0;
state = actual_rendered_string_length_step(metrics, i, current_line, c, next_c, state, mask);
auto next_c = break_index + 1 < grapheme_breaks.size() ? view.code_points()[grapheme_breaks[break_index + 1]] : 0;
state = actual_rendered_string_length_step(metrics, i, current_line, c, next_c, state, mask, maximum_line_width, last_return);
if (!mask_it.is_end() && mask_it.key() <= i) {
auto mask_it_peek = mask_it;
++mask_it_peek;
@ -1938,6 +1926,8 @@ StringMetrics Editor::actual_rendered_string_metrics(Utf32View const& view, RedB
for (auto& line : metrics.line_metrics)
metrics.max_line_length = max(line.total_length(), metrics.max_line_length);
metrics.grapheme_breaks = move(grapheme_breaks);
return metrics;
}