TextEditor: speed up searching in huge documents

Avoid creating QTextCursors for checking whether a search result is
inside the find scope. QTextCursor::setPosition seems to layout the
block the cursor is positioned at, which is not for free and not needed
to verify whether a search result is inside the find scope.

Change-Id: Ia1658fbbaa89a61f862e0b97eaa5b059972e2311
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/utils/textutils.cpp

@@ -64,6 +64,16 @@ Position Position::fromCursor(const QTextCursor &c)
     return c.isNull() ? Position{} : Position{c.blockNumber() + 1, c.positionInBlock()};
 }
 
+int Position::toPositionInDocument(const QTextDocument *document) const
+{
+    QTC_ASSERT(document, return -1);
+    const QTextBlock block = document->findBlockByNumber(line - 1);
+    if (block.isValid())
+        return block.position() + qMin(column, block.length() - 1);
+
+    return -1;
+}
+
 int Range::length(const QString &text) const
 {
     if (end.line < begin.line)

src/libs/utils/textutils.h

@@ -33,6 +33,8 @@ public:
     static Position fromFileName(QStringView fileName, int &postfixPos);
     static Position fromPositionInDocument(const QTextDocument *document, int pos);
     static Position fromCursor(const QTextCursor &cursor);
+
+    int toPositionInDocument(const QTextDocument *document) const;
 };
 
 class QTCREATOR_UTILS_EXPORT Range

src/plugins/coreplugin/find/basetextfind.cpp

@@ -425,9 +425,17 @@ bool BaseTextFind::inScope(const QTextCursor &candidate) const
         return false;
     if (d->m_scope.isNull())
         return true;
-    return Utils::anyOf(d->m_scope, [candidate](const QTextCursor &scope){
+    return inScope(candidate.selectionStart(), candidate.selectionEnd());
-        return candidate.selectionStart() >= scope.selectionStart()
+}
-               && candidate.selectionEnd() <= scope.selectionEnd();
+
+bool BaseTextFind::inScope(int candidateStart, int candidateEnd) const
+{
+    if (d->m_scope.isNull())
+        return true;
+    if (candidateStart > candidateEnd)
+        std::swap(candidateStart, candidateEnd);
+    return Utils::anyOf(d->m_scope, [&](const QTextCursor &scope) {
+        return candidateStart >= scope.selectionStart() && candidateEnd <= scope.selectionEnd();
     });
 }
 

src/plugins/coreplugin/find/basetextfind.h

@@ -50,6 +50,7 @@ public:
     using CursorProvider = std::function<Utils::MultiTextCursor ()>;
     void setMultiTextCursorProvider(const CursorProvider &provider);
     bool inScope(const QTextCursor &candidate) const;
+    bool inScope(int candidateStart, int candidateEnd) const;
 
     static QRegularExpression regularExpression(const QString &txt, Utils::FindFlags flags);
 

src/plugins/texteditor/texteditor.cpp

@@ -4031,10 +4031,7 @@ void TextEditorWidgetPrivate::highlightSearchResults(const QTextBlock &block, co
 
         const int start = blockPosition + idx;
         const int end = start + l;
-        QTextCursor result = cursor;
+        if (!m_find->inScope(start, end))
-        result.setPosition(start);
-        result.setPosition(end, QTextCursor::KeepAnchor);
-        if (!q->inFindScope(result))
             continue;
 
         // check if the result is inside the visibale area for long blocks
@@ -6884,9 +6881,16 @@ void TextEditorWidgetPrivate::highlightSearchResultsInScrollBar()
     Utils::onResultReady(m_searchFuture, this, [this](const SearchResultItems &resultList) {
         QList<SearchResult> results;
         for (const SearchResultItem &result : resultList) {
-            SearchResult searchResult;
+            int start = result.mainRange().begin.toPositionInDocument(m_document->document());
-            if (q->inFindScope(selectRange(q->document(), result.mainRange(), &searchResult)))
+            if (start < 0)
-                results << searchResult;
+                continue;
+            int end = result.mainRange().end.toPositionInDocument(m_document->document());
+            if (end < 0)
+                continue;
+            if (start > end)
+                std::swap(start, end);
+            if (m_find->inScope(start, end))
+                results << SearchResult{start, start - end};
         }
         m_searchResults << results;
         addSearchResultsToScrollBar(results);
@@ -6924,12 +6928,20 @@ void TextEditorWidgetPrivate::addSearchResultsToScrollBar(const QVector<SearchRe
     for (const SearchResult &result : results) {
         const QTextBlock &block = q->document()->findBlock(result.start);
         if (block.isValid() && block.isVisible()) {
-            const int firstLine = block.layout()->lineForTextPosition(result.start - block.position()).lineNumber();
+            if (q->lineWrapMode() == QPlainTextEdit::WidgetWidth) {
-            const int lastLine = block.layout()->lineForTextPosition(result.start - block.position() + result.length).lineNumber();
+                const int firstLine = block.layout()->lineForTextPosition(result.start - block.position()).lineNumber();
-            for (int line = firstLine; line <= lastLine; ++line) {
+                const int lastLine = block.layout()->lineForTextPosition(result.start - block.position() + result.length).lineNumber();
+                for (int line = firstLine; line <= lastLine; ++line) {
+                    m_highlightScrollBarController->addHighlight(
+                        {Constants::SCROLL_BAR_SEARCH_RESULT, block.firstLineNumber() + line,
+                         Theme::TextEditor_SearchResult_ScrollBarColor, Highlight::HighPriority});
+                }
+            } else {
                 m_highlightScrollBarController->addHighlight(
-                    {Constants::SCROLL_BAR_SEARCH_RESULT, block.firstLineNumber() + line,
+                    {Constants::SCROLL_BAR_SEARCH_RESULT,
-                            Theme::TextEditor_SearchResult_ScrollBarColor, Highlight::HighPriority});
+                     block.blockNumber(),
+                     Theme::TextEditor_SearchResult_ScrollBarColor,
+                     Highlight::HighPriority});
             }
         }
     }