looqs/gui/previewgeneratorplaintext.cpp
Albert S bb1e653690 gui: PreviewGeneratorPlainText: Truncate dirtily to avoid lags
It was possible the text was getting too big. The GUI
was lagging for previews of some text files. The first
assumption was that we would only have a couple of hits,
which is unreasonable for large .txt files and common
words.

We only ever see a handful of previews, it makes no sense
to get all snippets. So just allow 7 snippets, that's it.

Also, just cut after 1000 chars no matter what.
2022-06-04 17:09:26 +02:00

91 rinda
2.1 KiB
C++

#include <QTextStream>
#include "previewgeneratorplaintext.h"
#include "previewresultplaintext.h"
QSharedPointer<PreviewResult> PreviewGeneratorPlainText::generate(RenderConfig config, QString documentPath,
unsigned int page)
{
PreviewResultPlainText *result = new PreviewResultPlainText(documentPath, page);
QFile file(documentPath);
if(!file.open(QFile::ReadOnly | QFile::Text))
{
return QSharedPointer<PreviewResultPlainText>(result);
}
QTextStream in(&file);
QString resulText = "";
QString content = in.readAll();
QMap<int, QString> snippet;
int coveredRange = 0;
int lastWordPos = 0;
QHash<QString, int> countmap;
const unsigned int maxSnippets = 7;
unsigned int currentSnippets = 0;
for(QString &word : config.wordsToHighlight)
{
int lastPos = 0;
int index = content.indexOf(word, lastPos, Qt::CaseInsensitive);
while(index != -1 && currentSnippets < maxSnippets)
{
countmap[word] = countmap.value(word, 0) + 1;
if(index >= lastWordPos && index <= coveredRange)
{
break;
}
int begin = index - 50;
if(begin < 0)
{
begin = 0;
}
int after = index + 50;
if(after > content.size())
{
after = content.size();
}
snippet[index] = "...<br>" + content.mid(begin, after) + "...<br>";
coveredRange = after;
lastPos = index;
index = content.indexOf(word, lastPos + 1, Qt::CaseInsensitive);
++currentSnippets;
}
lastWordPos = lastPos;
}
auto i = snippet.constBegin();
while(i != snippet.constEnd())
{
resulText.append(i.value());
++i;
}
for(QString &word : config.wordsToHighlight)
{
resulText.replace(word, "<span style=\"background-color: yellow;\">" + word + "</span>", Qt::CaseInsensitive);
}
QFileInfo info{documentPath};
QString header = "<b>" + info.fileName() + "</b> ";
for(QString &word : config.wordsToHighlight)
{
header += word + ": " + QString::number(countmap[word]) + " ";
}
if(currentSnippets == maxSnippets)
{
header += "(truncated)";
}
header += "<hr>";
result->setText(header + resulText.replace("\n", "<br>").mid(0, 1000));
return QSharedPointer<PreviewResultPlainText>(result);
}