CMake: Do not create file system node in main thread

The file system scanning was already in a thread, but creating a tree
from the flat list of file nodes was still done in the main thread.
Creating the tree looks for and creates folder nodes as needed for each
file node, which is not that big of a deal but still takes 1/3 of a
second for the Qt Creator source tree.

Task-number: QTCREATORBUG-25783
Change-Id: I28948ed3ff5233f6fc4b86e93da94d882b81e231
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

1 files changed, 120 insertions, 0 deletions

diff --git a/src/plugins/projectexplorer/projectnodeshelper.h b/src/plugins/projectexplorer/projectnodeshelper.h
new file mode 100644
index 0000000000..6e15957151
--- /dev/null
+++ b/src/plugins/projectexplorer/projectnodeshelper.h
@@ -0,0 +1,120 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "projectnodes.h"
+
+#include <coreplugin/iversioncontrol.h>
+#include <coreplugin/vcsmanager.h>
+
+#include <utils/algorithm.h>
+#include <utils/fileutils.h>
+
+namespace ProjectExplorer {
+
+template<typename Result>
+QList<FileNode *> scanForFiles(QFutureInterface<Result> &future,
+                               const Utils::FilePath &directory,
+                               const std::function<FileNode *(const Utils::FilePath &)> factory);
+
+// IMPLEMENTATION:
+
+namespace Internal {
+template<typename Result>
+QList<FileNode *> scanForFilesRecursively(
+    QFutureInterface<Result> &future,
+    double progressStart,
+    double progressRange,
+    const Utils::FilePath &directory,
+    const std::function<FileNode *(const Utils::FilePath &)> factory,
+    QSet<QString> &visited,
+    const QList<Core::IVersionControl *> &versionControls)
+{
+    QList<FileNode *> result;
+
+    const QDir baseDir = QDir(directory.toString());
+
+    // Do not follow directory loops:
+    const int visitedCount = visited.count();
+    visited.insert(baseDir.canonicalPath());
+    if (visitedCount == visited.count())
+        return result;
+
+    const QFileInfoList entries = baseDir.entryInfoList(QStringList(),
+                                                        QDir::AllEntries | QDir::NoDotAndDotDot);
+    double progress = 0;
+    const double progressIncrement = progressRange / static_cast<double>(entries.count());
+    int lastIntProgress = 0;
+    for (const QFileInfo &entry : entries) {
+        if (future.isCanceled())
+            return result;
+
+        const Utils::FilePath entryName = Utils::FilePath::fromString(entry.absoluteFilePath());
+        if (!Utils::contains(versionControls, [&entryName](const Core::IVersionControl *vc) {
+                return vc->isVcsFileOrDirectory(entryName);
+            })) {
+            if (entry.isDir())
+                result.append(scanForFilesRecursively(future,
+                                                      progress,
+                                                      progressIncrement,
+                                                      entryName,
+                                                      factory,
+                                                      visited,
+                                                      versionControls));
+            else if (FileNode *node = factory(entryName))
+                result.append(node);
+        }
+        progress += progressIncrement;
+        const int intProgress = std::min(static_cast<int>(progressStart + progress),
+                                         future.progressMaximum());
+        if (lastIntProgress < intProgress) {
+            future.setProgressValue(intProgress);
+            lastIntProgress = intProgress;
+        }
+    }
+    future.setProgressValue(
+        std::min(static_cast<int>(progressStart + progressRange), future.progressMaximum()));
+    return result;
+}
+} // namespace Internal
+
+template<typename Result>
+QList<FileNode *> scanForFiles(QFutureInterface<Result> &future,
+                               const Utils::FilePath &directory,
+                               const std::function<FileNode *(const Utils::FilePath &)> factory)
+{
+    QSet<QString> visited;
+    future.setProgressRange(0, 1000000);
+    return Internal::scanForFilesRecursively(future,
+                                             0.0,
+                                             1000000.0,
+                                             directory,
+                                             factory,
+                                             visited,
+                                             Core::VcsManager::versionControls());
+}
+
+} // namespace ProjectExplorer