From 0633ac93b762405400de39000813e41a237cf7e7 Mon Sep 17 00:00:00 2001
From: Waqar Ahmed <waqar.17a@gmail.com>
Date: Sat, 22 Jan 2022 14:27:01 +0500
Subject: [PATCH] Optimize FileFilter

When Underline Files is enabled and you 'ls' into a big directory,
then hovering / selection becomes really slow.
---
 src/filterHotSpots/FileFilter.cpp        | 44 +++++++++++++++++-------
 src/filterHotSpots/FileFilter.h          |  2 +-
 src/filterHotSpots/FileFilterHotspot.cpp |  8 +++--
 src/filterHotSpots/FileFilterHotspot.h   |  5 ++-
 4 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/src/filterHotSpots/FileFilter.cpp b/src/filterHotSpots/FileFilter.cpp
index f479dc14..6a00c558 100644
--- a/src/filterHotSpots/FileFilter.cpp
+++ b/src/filterHotSpots/FileFilter.cpp
@@ -85,10 +85,10 @@ QSharedPointer<HotSpot> FileFilter::newHotSpot(int startLine, int startColumn, i
         return nullptr;
     }
 
-    QString filename = capturedTexts.first();
+    const QString &filenameRef = capturedTexts.first();
+    QStringView filename = filenameRef;
     if (filename.startsWith(QLatin1Char('\'')) && filename.endsWith(QLatin1Char('\''))) {
-        filename.remove(0, 1);
-        filename.chop(1);
+        filename = filename.mid(1, filename.size() - 2);
     }
 
     // '.' and '..' could be valid hotspots, but '..................' most likely isn't
@@ -98,15 +98,31 @@ QSharedPointer<HotSpot> FileFilter::newHotSpot(int startLine, int startColumn, i
     }
 
     if (filename.startsWith(QLatin1String("[/"))) { // ctest error output
-        filename.remove(0, 1);
+        filename = filename.mid(1);
     }
 
     const bool absolute = filename.startsWith(QLatin1Char('/'));
     if (!absolute) {
-        auto match = std::find_if(_currentDirContents.cbegin(), _currentDirContents.cend(), [&filename](const QString &s) {
-            return filename == s // It's a direct child file or dir
-                || filename.startsWith(s + QLatin1Char{':'}) // filename:lineNumber (output of grep -n)
-                || filename.startsWith(s + QLatin1Char{'/'}); // It's inside a child dir
+        auto match = std::find_if(_currentDirContents.cbegin(), _currentDirContents.cend(), [filename](const QString &s) {
+            // early out if first char doesn't match
+            if (!s.isEmpty() && filename.at(0) != s.at(0)) {
+                return false;
+            }
+
+            const bool startsWith = filename.startsWith(s);
+            if (startsWith) {
+                // are we equal ?
+                if (filename.size() == s.size()) {
+                    return true;
+                }
+                int onePast = s.size();
+                if (onePast < filename.size()) {
+                    if (filename.at(onePast) == QLatin1Char(':') || filename.at(onePast) == QLatin1Char('/')) {
+                        return true;
+                    }
+                }
+            }
+            return false;
         });
 
         if (match == _currentDirContents.cend()) {
@@ -114,8 +130,13 @@ QSharedPointer<HotSpot> FileFilter::newHotSpot(int startLine, int startColumn, i
         }
     }
 
-    return QSharedPointer<HotSpot>(
-        new FileFilterHotSpot(startLine, startColumn, endLine, endColumn, capturedTexts, !absolute ? _dirPath + filename : filename, _session));
+    return QSharedPointer<HotSpot>(new FileFilterHotSpot(startLine,
+                                                         startColumn,
+                                                         endLine,
+                                                         endColumn,
+                                                         capturedTexts,
+                                                         !absolute ? _dirPath + filename.toString() : filename.toString(),
+                                                         _session));
 }
 
 void FileFilter::process()
@@ -125,8 +146,7 @@ void FileFilter::process()
     if (_dirPath != dir.canonicalPath() + QLatin1Char('/')) {
         _dirPath = dir.canonicalPath() + QLatin1Char('/');
 
-        const auto tmpList = dir.entryList(QDir::Dirs | QDir::Files);
-        _currentDirContents = QSet<QString>(std::begin(tmpList), std::end(tmpList));
+        _currentDirContents = dir.entryList(QDir::Dirs | QDir::Files);
     }
 
     RegExpFilter::process();
diff --git a/src/filterHotSpots/FileFilter.h b/src/filterHotSpots/FileFilter.h
index a5493bce..2ee278fe 100644
--- a/src/filterHotSpots/FileFilter.h
+++ b/src/filterHotSpots/FileFilter.h
@@ -41,7 +41,7 @@ private:
 
     QPointer<Session> _session;
     QString _dirPath;
-    QSet<QString> _currentDirContents;
+    QList<QString> _currentDirContents;
     static QRegularExpression _regex;
 };
 
diff --git a/src/filterHotSpots/FileFilterHotspot.cpp b/src/filterHotSpots/FileFilterHotspot.cpp
index 3263ae6f..ae5cada7 100644
--- a/src/filterHotSpots/FileFilterHotspot.cpp
+++ b/src/filterHotSpots/FileFilterHotspot.cpp
@@ -181,13 +181,15 @@ QList<QAction *> FileFilterHotSpot::actions()
 
 QList<QAction *> FileFilterHotSpot::setupMenu(QMenu *menu)
 {
+    if (!_menuActions)
+        _menuActions = new KFileItemActions;
     const QList<QAction *> currentActions = menu->actions();
 
     const KFileItem fileItem(QUrl::fromLocalFile(_filePath));
     const KFileItemList itemList({fileItem});
     const KFileItemListProperties itemProperties(itemList);
-    _menuActions.setParent(this);
-    _menuActions.setItemListProperties(itemProperties);
+    _menuActions->setParent(this);
+    _menuActions->setItemListProperties(itemProperties);
 #if KIO_VERSION < QT_VERSION_CHECK(5, 82, 0)
     _menuActions.addOpenWithActionsTo(menu);
 
@@ -206,7 +208,7 @@ QList<QAction *> FileFilterHotSpot::setupMenu(QMenu *menu)
     menu->insertAction(firstAction, separator);
 #else
     const QList<QAction *> actionList = menu->actions();
-    _menuActions.insertOpenWithActionsTo(!actionList.isEmpty() ? actionList.at(0) : nullptr, menu, QStringList());
+    _menuActions->insertOpenWithActionsTo(!actionList.isEmpty() ? actionList.at(0) : nullptr, menu, QStringList());
 #endif
 
     QList<QAction *> addedActions = menu->actions();
diff --git a/src/filterHotSpots/FileFilterHotspot.h b/src/filterHotSpots/FileFilterHotspot.h
index 9d8ff9f7..15958eec 100644
--- a/src/filterHotSpots/FileFilterHotspot.h
+++ b/src/filterHotSpots/FileFilterHotspot.h
@@ -66,7 +66,10 @@ private:
     void showThumbnail(const KFileItem &item, const QPixmap &preview);
     QString _filePath;
     Session *_session = nullptr;
-    KFileItemActions _menuActions;
+
+    // This is a pointer for performance reasons
+    // constructing KFileItemActions is super expensive
+    KFileItemActions *_menuActions = nullptr;
 
     QPoint _eventPos;
     QPoint _thumbnailPos;