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Optimize LVCssSelectorRule::check() #528

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merged 1 commit into from
Oct 3, 2023
Merged

Optimize LVCssSelectorRule::check() #528

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17 changes: 9 additions & 8 deletions crengine/src/lvstsheet.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5137,7 +5137,7 @@ bool LVCssSelectorRule::check( const ldomNode * & node, bool allow_cache )
break;
case cssrt_id: // E#id
{
const lString32 val = node->getAttributeValue(attr_id);
const lString32 &val = node->getAttributeValue(attr_id);
if ( val.empty() )
return false;
// With EPUBs and CHMs, using ldomDocumentFragmentWriter,
Expand All @@ -5161,20 +5161,21 @@ bool LVCssSelectorRule::check( const ldomNode * & node, bool allow_cache )
break;
case cssrt_class: // E.class
{
const lString32 val = node->getAttributeValue(attr_class);
const lString32 &val = node->getAttributeValue(attr_class);
if ( val.empty() )
return false;
// val.lowercase(); // className should be case sensitive
// we have appended a space when there was some inner space, meaning
// this class attribute contains multiple class names, which needs
// more complex checks
if ( val[val.length()-1] == ' ' ) {
lString32 value_w_space_after = _value + " ";
if (val.pos(value_w_space_after) == 0)
return true; // at start
lString32 value_w_spaces_before_after = " " + _value + " ";
if (val.pos(value_w_spaces_before_after) != -1)
return true; // in between or at end
int start = 0;
int pos;
while ((pos = val.pos(_value, start)) >= 0) {
if ((pos == 0 || val[pos - 1] == ' ') && val[pos + _value.length()] == ' ')
return true;
start += _value.length();
}
Comment on lines +5174 to +5178
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Moving by the pattern length to continue the search feels like you may miss some stuff, like finding aaa in aa aa aaaa aaa aa aaa. It may work because of the boundary checks for a space, but it feels not obvious :)
Sure it's all sane?

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My assumption is that _value doesn't contain any spaces. With that I can write start += _value.length() + 1 but that looks even more suspicious :p

return false;
}
return val == _value;
Expand Down