From ecc092fa5519e77a47ef560f0137b4cd5f417c5e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Morten=20Johan=20S=C3=B8rvig?= <morten.sorvig@qt.io>
Date: Thu, 2 May 2019 14:01:43 +0200
Subject: Support folderlistmodel for the no-thread config

Scan for files on the main thread instead of using
a dedicated thread. Use a zero-timer to preserve the
async behavior where initiating a scan is fast.

This should work well for use cases like a handful
of files stored as resources.

Task-number: QTBUG-74537
Change-Id: I7bf1b6c7f9dfba69fe4fc2ea1b2dd2f256d66c2c
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
---
 src/imports/folderlistmodel/fileinfothread.cpp | 58 ++++++++++++++++++++------
 1 file changed, 46 insertions(+), 12 deletions(-)

(limited to 'src/imports/folderlistmodel/fileinfothread.cpp')

diff --git a/src/imports/folderlistmodel/fileinfothread.cpp b/src/imports/folderlistmodel/fileinfothread.cpp
index a006f659c9..a93edd3b1b 100644
--- a/src/imports/folderlistmodel/fileinfothread.cpp
+++ b/src/imports/folderlistmodel/fileinfothread.cpp
@@ -39,6 +39,8 @@
 
 #include "fileinfothread_p.h"
 #include <qdiriterator.h>
+#include <qpointer.h>
+#include <qtimer.h>
 
 #include <QDebug>
 
@@ -46,6 +48,7 @@
 FileInfoThread::FileInfoThread(QObject *parent)
     : QThread(parent),
       abort(false),
+      scanPending(false),
 #if QT_CONFIG(filesystemwatcher)
       watcher(nullptr),
 #endif
@@ -109,7 +112,7 @@ void FileInfoThread::setPath(const QString &path)
 #endif
     currentPath = path;
     needUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setRootPath(const QString &path)
@@ -126,7 +129,7 @@ void FileInfoThread::dirChanged(const QString &directoryPath)
     Q_UNUSED(directoryPath);
     QMutexLocker locker(&mutex);
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 #endif
 
@@ -136,7 +139,7 @@ void FileInfoThread::setSortFlags(QDir::SortFlags flags)
     sortFlags = flags;
     sortUpdate = true;
     needUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setNameFilters(const QStringList & filters)
@@ -144,7 +147,7 @@ void FileInfoThread::setNameFilters(const QStringList & filters)
     QMutexLocker locker(&mutex);
     nameFilters = filters;
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setShowFiles(bool show)
@@ -152,7 +155,7 @@ void FileInfoThread::setShowFiles(bool show)
     QMutexLocker locker(&mutex);
     showFiles = show;
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setShowDirs(bool showFolders)
@@ -160,7 +163,7 @@ void FileInfoThread::setShowDirs(bool showFolders)
     QMutexLocker locker(&mutex);
     showDirs = showFolders;
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setShowDirsFirst(bool show)
@@ -168,7 +171,7 @@ void FileInfoThread::setShowDirsFirst(bool show)
     QMutexLocker locker(&mutex);
     showDirsFirst = show;
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setShowDotAndDotDot(bool on)
@@ -177,7 +180,7 @@ void FileInfoThread::setShowDotAndDotDot(bool on)
     showDotAndDotDot = on;
     folderUpdate = true;
     needUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setShowHidden(bool on)
@@ -186,7 +189,7 @@ void FileInfoThread::setShowHidden(bool on)
     showHidden = on;
     folderUpdate = true;
     needUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setShowOnlyReadable(bool on)
@@ -194,7 +197,7 @@ void FileInfoThread::setShowOnlyReadable(bool on)
     QMutexLocker locker(&mutex);
     showOnlyReadable = on;
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 void FileInfoThread::setCaseSensitive(bool on)
@@ -202,7 +205,7 @@ void FileInfoThread::setCaseSensitive(bool on)
     QMutexLocker locker(&mutex);
     caseSensitive = on;
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 
 #if QT_CONFIG(filesystemwatcher)
@@ -211,7 +214,7 @@ void FileInfoThread::updateFile(const QString &path)
     Q_UNUSED(path);
     QMutexLocker locker(&mutex);
     folderUpdate = true;
-    condition.wakeAll();
+    initiateScan();
 }
 #endif
 
@@ -242,6 +245,37 @@ void FileInfoThread::run()
     }
 }
 
+void FileInfoThread::runOnce()
+{
+    if (scanPending)
+        return;
+    scanPending = true;
+    QPointer<FileInfoThread> guardedThis(this);
+
+    auto getFileInfosAsync = [guardedThis](){
+        if (!guardedThis)
+            return;
+        guardedThis->scanPending = false;
+        if (guardedThis->currentPath.isEmpty()) {
+            emit guardedThis->statusChanged(QQuickFolderListModel::Null);
+            return;
+        }
+        emit guardedThis->statusChanged(QQuickFolderListModel::Loading);
+        guardedThis->getFileInfos(guardedThis->currentPath);
+        emit guardedThis->statusChanged(QQuickFolderListModel::Ready);
+    };
+
+    QTimer::singleShot(0, getFileInfosAsync);
+}
+
+void FileInfoThread::initiateScan()
+{
+#if QT_CONFIG(thread)
+    condition.wakeAll();
+#else
+    runOnce();
+#endif
+}
 
 void FileInfoThread::getFileInfos(const QString &path)
 {
-- 
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